The other second messenger gas: Carbon monoxide signalling for myocardial protection?

Heart, Lung and Circulation 2001; 10 (Suppl.): A35–A53

ABSTRACTS of the

16TH ANNUAL INTER ASC–ASCTS MEETING Overseas Guests Dr Joseph Coselli

Dr W.R.E. Jamieson

Dr Mark Eastwood

Baylor College of Medicine Houston, Texas, USA

Vancouver General Hospital Vancouver, British Columbia, Canada

University of Westminster London, UK

THURSDAY 25–SUNDAY 28 OCTOBER 2001 SUNSHINE COAST, QUEENSLAND

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16th Annual Inter ASC–ASCTS Meeting

Oral Presentations A RETROSPECTIVE COMPARATIVE STUDY OF DEEP HYPOTHERMIC CIRCULATORY ARREST, RETROGRADE, AND ANTEGRADE CEREBRAL PERFUSION IN AORTIC ARCH SURGERY George Matalanis, Mitsumasa Hata and Brian F. Buxton The Department of Cardiac Surgery, Austin & Repatriation Medical Centre, University of Melbourne, Melbourne, Australia Objective: Although there have been major advances in cerebral protection during aortic arch surgery, there remains a significant incidence of transient and permanent neurological dysfunction. Several ancillary measures such as antegrade (ACP) and retrograde (RCP) cerebral perfusion in addition to deep hypothermic arrest (DHA) have been advocated. Despite the theoretical advantages of these adjuncts, there is still controversy about the best method of cerebral protection. We reviewed our experience with neurological outcome after aortic arch repair with particular reference to the method of protection used. Methods: Sixty-two patients with aortic arch aneurysm or dissection were operated on between January 1996 and December 2000. Five patients (8.1%) had Marfan’s syndrome, 11 (18%) had previous cardiac operations, and 13 (21%) had coronary bypass grafts. The extent of arch replacement was proximal in 40 (65%), distal in 18 (29%), and total in 13 (21%). The method of cerebral protection was DHA alone in 14 patients, DHA with RCP in 24, and DHA with ACP in 25. The frequency of pre-, intra-, postoperative variables in the 3 categories of cerebral protection was tested using the Chi-square and ANOVA (Scheffe’s method). Specifically, the independent predictors of mortality and stroke and transient neurological dysfunction (TND) were identified using the Cox proportional hazards regression analysis. Results: Overall hospital mortality was 5 (8%). Stroke occurred in 4 patients (6%), and TND in 5 (8%). There were no significant difference among the three methods of cerebral protection in mortality or neurological dysfunction. Total brain exclusion time was significantly longer in ACP group compared to either DHA or the RCP group (DHA:25.2 ± 12.0min, ACP:61.8 ± 44.1min, RCP:36.4 ± 20.5min, P = 0.023). The extent of arch replacement was also significantly greater in the ACP group (DHA:8 (57%), ACP:19 (76%), RCP:6 (26%), (P = 0.0002). Multivariate analysis showed that re-operation and total brain exclusion time >90 minuets were significant predictors of stroke (P = 0.0073, 0.0232). The total actuarial survival rate was 88.7% at 5 years (DHA:85.7%, ACP:80%, RCP:92.9%). Conclusions: Aortic arch replacement can be achieved with acceptable mortality and neurological dysfunction. Despite more complicated arch repairs, requiring significantly longer cerebral exclusion time, were performed in the group receiving ACP, there was no significant increase in stroke or death rates. Increasing confidence in the ability of ACP to provide nutritive cerebral blood flow during brain exclusion, has led us to perform the most appropriate arch repair without compromising the extent of replacement for fear of exceeding the ‘safe’ period of circulatory arrest. INTRAOPERATIVE EPIAORTIC IMAGING FOR PREDICTION OF THE EXTENT OF BRAIN INJURY DURING CORONARY ARTERY BYPASS Kiyoshi Doi, Don Kang, Allen James, James Edwards, Alan Boyd and Duncan Thomson Department of Cardiothoracic Surgery, John Hunter Hospital, Newcastle, New South Wales, Australia

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Introduction: Embolization of atheroma resulting from manipulations of the ascending aorta is believed to be the principal cause of brain infarction during CABG.1 This study investigated whether the epiaortic echocardiography assessment of the atherosclerotic aorta would be useful to predict the extent of perioperative brain injury. Methods: We studied 22 patients undergoing CABG (18 on-pump, 4 off-pump). Intraopertive epiaortic echocardiography was performed on these patients, and maximal intimal wall thickness of the ascending aorta was measured as an indicator of the severity of atherosclerosis. The number of microembli in middle cerebral artery was also counted by use of transcranial Doppler ultrasonography (TCD) during operation. Serum levels of S100b protein, a potential marker of brain injury, were measured before surgery and post operatively after 0 h, 12 h and 24 h. Standard neuropsychological assessment was performed at presurgery (baseline) and at 3 months post surgery. Results: All patients had no remarkable neurological complications except for one case who presented major stroke 2 days after operation because of Af. In the on-pump CABG group, the increase in intimal wall thickness was found to correlate with the emboli counts (r = 0.585, P = 0.012). This group also demonstrated a significant correlation between intimal wall thickness and S100b level at 24 h postoperatively (r = 0.767, P < 0.01). The emboli counts in the on-pump group was remarkably greater than those in the offpump group (P = 0.023). Follow-up test revealed that 3 patients in the on-pump group had cognitive dysfunction, but patients in the off-pump group showed no significant neurological deficit. Discussion: Many previous reports have demonstrated that the use of epiaortic echocardiogram could detect large debris or plaque on ascending aorta that would potentially cause perioperative stroke.2 Besides noticeable neurologic event, it is well known that 30–40% patients present minor nerologic abnormality (cognitive dysfunction), which is believed to be due to microemboli.1 Our study suggested that intimal wall thickness of ascending aorta, measured with epiaortic imaging, seemed to have positive correlation with the extent of perioperative brain injury. This also poses a hypothesis that some degree of neurologic event is an inevitable consequence of on-pump CABG, even if it is not measurable. In this respect, off-pump CABG might be preferable. References 1. J Murkin. Etiology and incidence of brain dysfunction after cardiac surgery. J. Cardiothorac. Vasc. Anesth. 1999; 13: 12–17. 2. S Sylivris et al. The intraoperative assessment of ascending aortic atheroma: epiaortic imaging is superior to both transesophageal echocardiography and direct palpation. J. Cardiothorac. Vasc. Anesth. 1997; 5: 704–707. SURGICAL EXPERIENCE WITH AORTO-PULMONARY WINDOW Andrew D. Cochrane, A. Bullock, S. Menahem and C. P. Brizard Royal Children’s Hospital, Parkville, Victoria, Australia Introduction: Aortopulmonary window (APW) is an uncommon congenital defect associated with a very large left to right shunt, leading commonly to early heart failure and significant pulmonary hypertension. It is reported to occur in association with other important defects in up to 50% of cases. The aim was to review the incidence of isolated APW (associated with no other defect or only an ASD or PDA) vs. complex APW (associated with other major defects), the types of associated lesion and the outcome of surgical repair in our department. Methods: A retrospective review was performed from 1980 to mid2001. The clinical presentation, associated lesions, method of repair and outcome were recorded, and current clinical and

16th Annual Inter ASC–ASCTS Meeting

Heart, Lung and Circulation 2001; 10

echocardiographic follow-up was performed through the referring cardiologist or hospital. Results: There were 32 infants or children seen over a 21-year period. In 18 patients with an isolated APW (12 females, 6 males), median age 3 months at presentation (range 1 week–14 months), there was no early or late mortality and excellent long-term outcome. Surgery usually involved complete division of the window leaving a cuff of pulmonary artery wall attached to the aorta, direct repair of the aorta and pericardial patch repair of the pulmonary artery. In 14 patients with complex APW (7 females and 7 males), median age 17 days at presentation, the associated defects were interrupted aortic arch (Type A) with or without VSD (6 patients), VSD alone (4 patients), Fallot’s/DORV (2 patients), and scimitar syndrome (2 patients). The majority presented as neonates with shock and acidosis or respiratory distress. There were 3 early deaths and one late death, with 10 years actuarial survival of 71%. Conclusion: Aortopulmonary window presents early in life, either in the neonatal period (complex types) or in the first months of life (isolated type). Surgery for isolated APW has an excellent early and late outcome, with normal functional status in this group of patients, but the complex types have a poorer outcome and remain a major surgical challenge. CARDIAC SURGERY OUTCOME IN OCTOGENARIANS P. W. Grant, D. Law, T. Ngo, H. D. Wolfenden and D. C. Newman Department of Cardiothoracic Surgery, The Prince of Wales Hospital, Randwick Sydney, New South Wales, Australia Introduction: Due to increased life expectancy and improved surgical management surgery on patients 80 years and over is becoming more common. We reviewed the preoperative findings, operative details and outcome in 195 patients 80 years and over (80+) who underwent cardiac surgery. Method: Prospective 4 years review (July 1996 to June 2000) of 195 consecutive patients aged 80+. Clinical and operative details were analysed during the surgical admission. Long-term follow-up was done by mail and phone to assess the patient’s cardiac capacity and quality of life (AQOL). Patients 80+ were compared with two younger groups of patients, those aged in their 70s and those less than 70 years of age. Results: Patients aged 80+ had a significantly higher proportion of females, incidence of valve surgery and preoperative pulmonary hypertension than those in the younger age groups. Operative mortality (Op mort) was significantly higher in 80+ patients for both isolated CAB and overall cardiac surgery. Patients 80+ had a significant increase in postoperative length of stay, blood transfusions and inotrope requirements but there was no increase in myocardial infarction or strokes. Operative mortality: Age groups Cardiac surgery Isolated CAB 80+ 70–79 <70

6.1% (195) 2.6% (1173) 1.6% (2089)

6.1% (98) 2.0% (836) 0.8% (1626)

Out of 195 patients aged 80+ long-term follow-up (mean 32 months, range 1–6 years) was obtained on all but 3 patients. The Kaplan-Meier mean survival time was 50 months (median 58 months) with the cumulative mortality 17.7% (34 patients). For the surviving patients 91% remained in NYHA class I or II while 89% were still living in their own home. 120 patients completed a quality of life survey (AQOL) with two thirds of patients scoring above the average life quality score. Operative mortality occurred in 12 patients with the cause of death being cardiac 8, infection 3 and neurological 1. Another

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22 patients died during the follow-up period: cardiac 9, cancer 5, neurological 3, infection 2, respiratory 1, renal failure 1, and vascular 1. There were no risk factors predictive of operative mortality in this 80+ age group. Conclusion: While cardiac surgery for octogenarians carries a higher operative mortality than for those in the younger age categories the results are still satisfactory. Long-term survival and quality of life was maintained for the majority of patients. Appropriate patient selection is important in attaining these results.

BRONCHOSCOPIC LUNG VOLUME REDUCTION: A PILOT STUDY G. I. Snell, J. A. Smith, A. J. Silvers, K. R. Thomson, F. L. Rosenfeldt, L. Holsworth and T. J. Williams The Alfred, Melbourne, Victoria, Australia Introduction: Lung volume reduction surgery (LVRS) can provide symptomatic improvement in patients (pts) with advanced emphysema. The open or video-assisted approach may have significant morbidity and mortality in high risk pts. Selective bronchoscopic placement of bronchial blockers into upper lobe segmental bronchi may achieve lung volume reduction via promoting absorption atelectasis in the upper zones and subsequent expansion of the lower zones. Aim: To perform a pilot study to evaluate the safety and effectiveness of a novel method of bronchoscopic LVR. Methods: A preliminary study in 4 normal sheep was under taken to resolve issues of airway management and to improve operator technique. The Phase 1 clinical procedure was performed via an endotracheal tube under general anaesthesia in the operating room. A one-way silicone valve mounted within a Nitinol®‚ bronchial stent (4–7 mm diameter; Emphasys Medical, Inc., Redwood City, CA, USA) was placed over a guidewire under bronchoscopic vision into the majority of upper lobe segmental bronchi. Placement was aided by fluoroscopic control. Results: Five pts with upper zone predominant emphysema, otherwise suitable for conventional operative LVRS (2 M, 3 F; mean age = 62 years, range = 57–69 years), under went bronchoscopic LVRS. Preoperative mean FEV1 = 0.72 L (0.38–1.02 L) and mean 6 minute walk = 354 m (315–402 m). One pt was on supplemental home oxygen therapy. Duration of the procedure to place the prostheses ranged from 90 to 135 min. The total number of prostheses placed ranged from 6 to 11. All pts were extubated at the end of the procedure and, after a brief period of observation in the recovery room, were transferred to the general respiratory ward. Hospital stay ranged from 4 to 8 days. There was no mortality. Radiological lung volume reduction was seen in one pt (#5). Major morbidity was: haemoptysis (n = 1), pneumothorax (n = 1, not requiring intercostal catheter), lower lobe pneumonia (n = 1). One pt was readmitted on postop. day 10 with an infective exacerbation of COPD. Early symptomatic improvement was reported by two pts (#4 & #5). Improved lung function was seen in pt #4 after 15 days and follow-up testing is pending in pt #5. No change in lung function was seen in pts #1, #2 and #3 at 30 day testing. Discussion: Bronchoscopic LVRS is a novel therapy for advanced emphysema and this experience represents the initial clinical evaluation of the valved bronchial occlusion device. Our pilot study showed that the device can be safely placed. The absence of radiological LVR may represent significant collateral ventilation to the upper zones in the emphysematous state. Intrapulmonary shunting was not observed. Further experience and longer duration follow-up is pending.

16th Annual Inter ASC–ASCTS Meeting

BRIDGE TO RECOVERY OF THE ‘DAMAGED’ HEART H. Fukuda, D. S. Esmore, K. N. Waters, J. A. Mack and J. A. Smith Heart and Lung Transplant Service, The Alfred, Melbourne, Victoria, Australia Bridge to recovery is an evolving application for artificial heart technology. Over an 11-year period our Unit has performed 363 heart transplants: over the same period 47 patients have been implanted as a bridge to transplantation with a 55% success rate. Over the same period 12 patients have been supported as a bridge to recovery, 9 for post transplant primary graft failure, 2 with post partum cardiomyopathy and one with acute myocarditis. In the post transplant group 4 patients were supported with Thoratec LVAD alone, 3 (75%) being successfully weaned following periods of support of 6, 8 and 6 days. Four post transplant patients were implanted with a Thoratec LVAD and a Biomedicus RVAD, 1 patient (25%) being successfully weaned on day 12 and discharged. These postpartum cardiomyopathy patients were supported for periods of 155 and 85 days both being successfully weaned. A male with acute viral myocarditis was supported with a Thoratec LVAD for a period of 20 days, again being successfully weaned, remaining a long-term survivor. One post transplant graft failure, a potential Thoratec bridge to recovery, had ECMO inserted urgently in the ICU. He was supported for a period of 7 days, being successfully weaned and remains a long-term survivor. Of the 12 bridge to recovery 8 (67%) have therefore been

Bridge to Recovery of the Damaged Heart

Figure 1:

B to Rec.(n=12) Heart Tx(n=366)

100 80 60 40 20

12

11

12

10

8

9

7

2

5

3

6

5

4

3

0

2

Introduction: Retrosternal pericardial adhesion formation constitutes a major hazard during re-do coronary artery surgery, with a potential to damage the heart, great vessels and patent grafts at re-sternotomy. Numerous techniques aimed at prevention, or decreasing adhesion formation at the primary operation have been tried. The aetiology and patho-physiology of adhesion formation is not fully understood. Mesothelial cells possess fibrinolytic activity which may have a role in preventing adhesion formation. We proposed that lateral dissection of the parietal pleura from over the internal mammary artery (IMA) proceeding harvest, with use of it as an on-lay flap covering the mammary bed at the end of coronary artery grafting, may decrease pericardial adhesions. Methods: Sixteen sheep underwent study within appropriate Animal Ethics Committee guidelines. Each animal served as its own control. Following median sternotomy both IMA were harvested. A dissected pleural flap on the study side was used to cover the internal mammary bed, the control side being left uncovered. Half the sheep were humanely killed after a mean of 101 days, the remainder after a mean of 175.8 days. Post-operative adhesions were scored by an independent observer blinded to the initial operation. Results: There was a significant decrease in adhesion formation on the study side covered by the mobilised pleural flap compared to the control side (P-value 0.008). No animals had any increased pulmonary morbidity or sternotomy wound problems from raising the lateral pleural flap. Discussion: This simple easily performed technique appears to be an effective method of preventing adhesion formation following coronary artery bypass grafting utilising the IMA. It is associated with no additional risks or morbidity and would appear to facilitate re-do sternotomy. Application of this promising method to a human controlled trial appears warranted.

successfully weaned from a Thoratec-based combination of devices. The Cutler-Ederer actuarial survival curve is depicted in Fig. 1. The Thoratec VAD with its unique deployment flexibility remains a pivotal device in facilitating ‘recovery’ of the reversibly damaged heart.

1

LIMITING PERICARDIAL ADHESIONS FOLLOWING CORONARY ARTERY BYPASS SURGERY – AN ANIMAL STUDY Kamales Saha, Winston McEwan, Glenn McKay and Harsh Singh Christchurch, New Zealand

Heart, Lung and Circulation 2001; 10

0

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1 Bridge to Recovery Opening Survivors Years Post Implant/Transplant

THE CONVERGE TOP-END – EARLY EXPERIENCE WITH A PROXIMAL ANASTOMOTIC DEVICE Jai Raman, Melissa Byrne, John Power and Katrina Christy Department of Cardiac Surgery, A&RMC; Baker Institute of Medical Research, Melbourne, Australia Abstract: Proximal anastomoses between conduits of different types and the aorta have traditionally required some form of clamp and a sutured anastomosis. We present our early experience with an anastomotic device that helps perform an aorta to graft anastomosis without a clamp. Methods: Twelve sheep were studied. The left common carotid artery (LCA) was harvested from all the sheep and used as the conduit. In group 1 (8 sheep), the proximal anastomosis between the aorta and the LCA was performed using the Converge Proximal Anastomosis system. In group 2 (4 sheep), the proximal anastomosis was performed using a side biting clamp on the aorta and 6/0 prolene sutures. Distal anastomosis was then performed between the LCA and the main circumflex coronary artery or a major circumflex marginal branch, with the heart beaging. Graft flow was recorded and the coronary artery proximal to the anastomosis ligated. Graft angiography was performed after 8 weeks and the animals sacrificed. Results: One sheep in each group died intraoperatively due to lethal arrhythmias when the circumflex coronary artery was occluded. The proximal anastomoses in group 1 were performed at mean time of 36 s (range 11–56 s) without a clamp and were hemostatic. In group 2, mean duration of proximal anastomoses in group 2 was 510 s (range 360–660 s) (P < 0.001). Graft flows were similar in both groups. Late angiography and terminal histology show patency of all grafts. Conclusions: Proximal anastomoses can be safely performed with the Converge anastomotic system in a short period of time without clamps. This has potential clinical applications.

RADIOFREQUENCY ABLATION OF BOTH ATRIA FOR ATRIAL FIBRILLATION – MID-TERM RESULTS Susumu Ishikawa, MD, Jai S. Raman, FRACS and Brian F. Buxton, MB BS, FRCS The Department of Cardiac Surgery, Austin & Repatriation Medical Centre, University of Melbourne, Melbourne, Australia Introduction: Despite success in treating atrial fibrillation (AF) with the Maze procedure, this procedure has not been widely adopted

Heart, Lung and Circulation 2001; 10

because of long procedure time and increased morbidity. Radiofrequency ablation (RFA) was introduced to Australia in March 2000 and has been used in a multicentre registration setting. Methods: Eighty-six patients had RFA in Australia and New Zealand between March 2000 and August 2001. Eight patients have been followed up for longer than 12 months after RFA and another 19 patients have undergone six months’ follow-up study. The mean age of these 27 patients was 61-year-old-ranging from 41 to 83. They included 15 males and 12 females. The average duration of preoperative rhythm disturbance was 49 months per patient. Preoperatively, chronic atrial fibrillation was detected in 59% of patients, paroxysmal atrial fibrillation in 37% and atrial flutter in 4%. The surgical procedures in conjunctive with RFA were mitral valve surgery in 55%, CABG in 15%, double valve procedure in 7%, CABG plus valve surgery in 4% and aortic valve replacement in 4%. RFA was performed to create lesions at 80–85 for 2 min with Cobra probe (EPT-Boston Scientific Corp.). Left-sided lesions were endocardial as adjacent to mitral procedure, or epicardial with arotic valve or CABG procedures. The right atrial epicardial lesions were common to all groups of patients. Results: There were no serious postoperative complications concerning RFA. All the eight patients after 12-month follow-up were in sinus rhythm. The AF-free rate at three and six months after surgery was 88%, 94%, respectively. Conclusion: Interim results of RFA for AF suggest that it is safe, with the expectation of good cure from AF. It may be easily adopted by the wide cardiac surgical community.

HAND ASSISTED THORACOSCOPIC SURGERY (HATS) FOR PULMONARY SECONDARIES DOESN’T COMPROMIZE DIAPHRAGMATIC FUNCTION C. P. Clarke, A. Ali, R. Mosshinsky and S. Seevanayagam Austin & Repatriation Medical Centre, Heidelberg, Victoria, Australia The lungs are often the only sites of metastases from primary lesions elsewhere but their management has been complicated by the inability to exclude other occult metastases and find and deal with all the pulmonary lesions present. Positron Emission Tomography (PET) has allowed exclusion of patients with uncontrolled primary lesions or other occult metastases and HATS has allowed detection of all pulmonary lesions and their management in a minimally invasive manner. This involves detaching the diaphragm from the costal margin raising concerns about possible deleterious effects on diaphragmatic function. We have carried out Pulmonary Function Tests and Screening of diaphragmatic movement before and after surgery and have shown that this is a safe procedure if done somewhat more laterally than originally described which was advocated as a trans-xiphoid procedure.1 Reference 1. TC Mineo, E Pompeo, V Ambrogi, C Pistolese. Transxiphoid video-assisted approach for bilateral pulmonary metasectomy. Ann. Thorac. Surg. 1999; 67: 1808–1810.

THE ONGOING ROLE OF SURGERY FOR CONGENITAL AORTIC VALVE STENOSIS A. J. B Clarke, P. G. Pohlner and H. J. Jalali The Prince Charles Hospital, Brisbane, Australia Introduction: The quest for optimal management of congenital aortic stenosis especially in the neonatal period remains controversial. The relative merits of surgical valvotomy vs balloon

16th Annual Inter ASC–ASCTS Meeting

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valvuloplasty are still debated. The aim of this study was to evaluate the results of aortic valvuloplasty including repair when necessary, for congenital aortic stenosis over a 21-year period, comparing our results with those of balloon valvuloplasty in the published literature. Methods: The hospital records of patients undergoing surgical treatment for congenital aortic stenosis including echocardiography findings pre and post operative were evaluated. When performed catheter data was included in this analysis. The cohort included 106 patients between the ages of 2 day and 14 years, operated on from January 1979 til December 2000. Patients with aortic valve size or left ventricular hypoplasia sufficient to preclude a biventricular repair or other major cardiac defects were excluded. Results: The average age of the cohort was 4.9 years. Twenty-six (25%) of the subjects were less than one month of age. Valvotomy with varying degree of valvuloplasty was performed in all patients at first operation. Early mortality occurred in 4 patients (3.8%) with 3 of the 4 being less than 1 month (11% mortality for this group). There were no early mortalities in patients older than 7 months. Major morbidity occurred in 16% of patients. Short-term post procedural aortic regurgitation was grade 1–2 out of 4 or better in 98% of patients. Thirty-one subjects (29%) required reoperation with a mean interval to reoperation of 5.4 years. At first reoperation the native valve was preserved in half of these patients (52%). Eleven patients required a second reoperation and 4 a third. There was no mortality in the reoperative groups. Conclusions: This series illustrates a low mortality from surgical intervention for congenital aortic stenosis (3.8%), with the greatest risk in the 1st month of life (11%). Short and long-term morbidity is extremely uncommon. Retention of the native aortic valve is feasible and desirable, with reoperation required in only 29%. Thus 79% of the cohort retained their native valve even though they may have required repeat operative procedures. Surgical aortic valvotomy maximises the orifice area and leaflet mobility whilst retaining a competent valve, explaining the high freedom from reoperation and low incidence of post procedure AR. We believe it remains the optimal treatment of congenital aortic stenosis.

HUMAN VALVES FOR AORTIC VALVE REPLACEMENT IN PATIENTS AGED LESS THAN 20 YEARS Hiroki Yamaguchi, Alan Kerr, Kirsten Finucane and Peter Raudkivi Cardiothoracic Surgical Unit, Green Lane Hospital, Auckland, New Zealand Introduction: The use of human valves (aortic allografts or pulmonary autografts) in children has many advantages, including low risk of thromboembolic events, freedom from requirement for anticoagulation and excellent hemodynamic results especially in small annuli. The pulmonary autograft has emerged as the alternative approach because of the limited longevity of aortic allografts in children. The implantion technique of aortic allografts (subcoronary implantation or aortic root replacement) may affect their long-term results. The purpose of this study is to evaluate our results of aortic valve replacement utilizing human valves in patients aged under 20. Methods: Retrospective review of 125 consecutive aortic valve replacements utilizing cryopreserved aortic allografts or pulmonary autografts in patients aged under 20 from 1986 to December 2000. Patients were divided into three groups depending on the surgical techniques: (1) Subcoronary group (freehand aortic allograft implantation in a subcoronary position) (2) Root group (aortic root replacement with aortic allograft) and (3) Ross group (pulmonary autograft implantation as an aortic root replacement).

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Results: Group

Subcoronary

Root

Ross

Procedures (cases)

70

36

19

Age (years)

3–20 (15.9 ± 3.7)

2–20 (12.6 ± 4.8*)

1–19 (12.1 ± 4.4*)

25 (36%)

17 (47%)

2 (11%)

125 ± 35/100 ± 29

156 ± 42/130 ± 34*

184 ± 22/157 ± 17*†

47%

39%

11%*†

18%

24%

6%

3/9

1/2

1/0

74%/48%

87%/65%

94%/94%

re-operation

(non Marfan)

(at 6 years)

or death‡ at

30% at 5 yrs

Associated procedure (cases) Bypass time/ Clamp time (min) % in preop. NYHA III/IV % of preop LV impairment Early death/ Late death Freedom from

5 yrs/10yrs Patients’ actuarial

(Marfan) 87%/81%

88%/88%

survival‡ at 5 yrs/10 yrs *P

< 0.05 vs Subcoronary;

< 0.05 vs Root;

‡Kaplan–Meier

IMPROVED BIOCHEMICAL, PHYSIOLOGICAL AND CLINICAL OUTCOMES IN CABG SURGERY WITH PREOPERATIVE COENZYME Q10 THERAPY W. Lyon, S. Marasco, S. Pepe, M. Wowk, F. Sheeran, R. Ou, J. A. Smith, A. Pick, M. Rabinov, B. B. Davis, D. Esmore and F. L. Rosenfeldt Cardiac Surgical Research Unit, Alfred Hospital & Baker Medical Research Institute, Melbourne, Australia

95%/95% (at 6 years)

†P

all samples relative to preop. In contrast, CABG CD18 expression remained unchanged relative to preop during bypass and was reduced relative to preop in postop samples, but not to the same extent as OPCAB postop samples (3 h postop; CABG 62 ± 5% OPCAB 45 ± 4%) (P < 0.001). Discussion: PMN integrin expression, and not PMN degranulation distinguish the post CABG and post OPCAB inflammatory state. After OPCAB PMN express less CD11b and CD18 than occurs after CABG, and thus may reduce end-organ injury.

analysis excl. 3 Konno

operations.

Discussion: There is no clear difference in the results of subcoronary and root replacement technique using aortic allografts in this age group. Root replacement with aortic allografts may be contraindicated in Marfan’s syndrome. The Ross operation provided excellent intermediate results, whilst cryopreserved subcoronary aortic allografts were less satisfactory. CORONARY ARTERY SURGERY WITHOUT BYPASS REDUCES NEUTROPHIL ACTIVATION RELATIVE TO SURGERY WITH BYPASS M. P. Vallely,1,2,3 P. G. Bannon,2,3 C. F. Hughes,2,3 M. S. Bayfield,2,3 M. Wong4 and L. Kritharides1,5 1Clinical Research Group, Heart Research Institute, 2The Baird Centre for Heart and Lung Research, 3Cardiothoracic Surgical Units, Royal Prince Alfred and Strathfield Private Hospitals, 4Department of Immunology, Children’s Hospital Westmead and 5Department of Cardiology, Concord Hospital, Sydney, Australia Introduction: Coronary artery surgery without cardiopulmonary bypass (OPCAB) may reduce bypass-related (CABG) inflammation. However, detailed comparison of neutrophil (PMN) activation after CABG and OPCAB has not been undertaken. The relative importance of PMN integrins CD11b and CD18, essential for endothelial transmigration, and PMN degranulation (detected by release of lactoferrin), in CABG- and OPCAB-related inflammation are unknown. Methods: Patients undergoing first time CABG (n = 10) or OPCAB (n = 10) had 6 blood samples taken before surgery (preop), before and during ischaemia, during reperfusion, 3 h and 24 h postoperatively (postop). PMN were isolated and analyzed by flow cytometry for expression of cell-surface CD11b, CD18 and lactoferrin. Total PMN counts were also determined. Data are expressed as mean ± SEM of 10 subjects, and robust cluster multiple linear regression used for comparisons between groups. Results: OPCAB and CABG demonstrated an identical 3.5-fold increase in circulating PMN postop and similar steady expression of lactoferrin. However, OPCAB reduced CD11b expression in all samples relative to preop, at 3 h postop being only 52 ± 6% of preop value. In contrast, during CABG ischaemia and reperfusion CD11b expression was 130 ± 22% and 137 ± 23%, respectively, of preop, and in other samples CD11b expression remained unchanged relative to preop (P < 0.001). OPCAB reduced CD18 expression in

Introduction: Coenzyme Q10 (CoQ10) is an integral component of cellular membranes, essential for antioxidant function and mitochondrial energy production. Aims: To test whether CoQ10 therapy given prior to CABG surgery: (1) Increases CoQ10 content in atrial trabeculae and mitochondria; (2) Improves mitochondrial respiration; (3) Protects the myocardium against posthypoxic contractile dysfunction; (4) Attenuates intraoperative myocardial injury; (5) Improves quality of life. Methods: 124 patients (mean age 66) were randomised in a double blinded manner to receive either CoQ10 (300 mg/day) or placebo orally for at least 7 days prior to elective surgery. Trabeculae were excised and mitochondria were isolated from discarded right atrial appendages. Biochemical physiological and clinical parameters were measured postoperatively. Quality of life was determined at 2 years. Results: Compared to placebo, CoQ10 therapy increased CoQ10 content of atrial trabeculae (17.2 ± 1 vs 43.4 ± 3 µg/g w.w., P = 0.0001) and isolated mitochondria (4.0 ± 0.7 vs 9.5 ± 0.9 µg CoQ10/mg protein, P = 0.0002). Mitochondrial respiration was more efficient after CoQ10 pretreatment (ADP:O, placebo vs CoQ10: 2.9 ± 0.4 vs 4.2 ± 0.2, P = 0.011). After 30 min hypoxia CoQ10 treated trabeculae exhibited a greater recovery of developed force compared to placebo (46.2 ± 28% vs 64.0 ± 18%, P = 0.001). Compared to placebo, CoQ10 patients had a lower release of TnI (64.5 ± 4.1 vs 39.4 ± 8.5 µg/L, P = 0.0001), and had a shorter total length of hospital stay (8.7 ± 2.1 vs 6.8 ± 0.7 days, P = 0.044) with an improved physical quality of life score (42.0 ± 2.1 vs 47.5 ± 1.6, P = 0.046). Conclusions: Preoperative oral CoQ10 therapy: (1) Increases CoQ10 content in atrial trabeculae and mitochondria. (2) Improves efficiency of mitochondrial energy production. (3) Improves posthypoxic myocardial contractile function. (4) Reduces myocardial damage. (5) Reduces total postoperative hospital stay. (6) Improves long-term quality of life.

SEMI-SKELETONIZED INTERNAL MAMMARY ARTERY GRAFTS AND STERNAL WOUND COMPLICATIONS Yongzhi Deng and Hugh S. Paterson Westmead Hospital, Sydney, Australia Objective: This study aims to evaluate the risk factors for sternal wound complications in patients undergoing myocardial revascularization using bilateral semiskeletonized internal mammary arteries. Methods: Prospectively collected data on 625 patients undergoing coronary artery surgery from September 1994 to February 2001

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Heart, Lung and Circulation 2001; 10

were analyzed. The mean age was 56 years; 523 (84%) were males; 61 (10%) were older than 65 years of age; 142 (23%) were diabetic. Twenty-nine variables were subjected to multivariate analysis with the end point being sternal wound complications. Results: Thirty-two (5.1%) patients developed sternal wound complications. Sternal infection occurred in 18 (2.9%) patients, of which 12 (1.9%) patients had sternal infection with mediastinitis and 6 (1.0%) patients had sternal infection alone. Independent risk factors for sternal wound complications were chronic obstructive airway disease (odds ratio, OR: 6.8), preoperative acute myocardial infarction (within 1 week) (OR: 20.1), the need for an intra-aortic balloon (OR: 5.1), reexploration for low cardiac output (OR: 29.8), and reexploration for bleeding (OR: 12.0). The peri-operative mortality rate was 1.4% (9/625). The mortality of patients with sternal wound complications was higher than that of patients without those complications (6.3% vs. 1.2%, P < 0. 05). Conclusion: The use of bilateral semiskeletonized internal mammary artery conduits carries a sternal wound complication rate comparable to that of other harvesting techniques. Preoperative chronic obstructive pulmonary disease and postoperative low cardiac output increase the risk of sternal wound complications. We recommend a selective approach to the use of bilateral semiskeletonized internal mammary arteries in patients with preoperative risk factors. OFF PUMP CORONARY ARTERY BYPASS VERSUS CONVENTIONAL CORONARY ARTERY BYPASS: CLINICAL AND ANGIOGRAPHIC RESULTS IN 154 CONSECUTIVE OPCAB CASES AT MEAN FOLLOW UP OF 18 MONTHS S. C. M. Moten, R. A. Baker and J. L. Knight Flinders Medical Centre, Bedford Park, SA, Australia Introduction: Early results of OPCAB appear promising, but little is known about efficacy beyond the initial hospital stay. Concerns about early graft patency, return of angina, readmission to hospital for IHD and increased revascularization rates in OPCAB compared to CCAB have been raised.1,2 Methods: We reviewed our experience of 154 consecutive OPCAB patients between January 1999 and July 2000 and compared them to case matched controls undergoing isolated conventional CABG on bypass (CCAB). Results: Average follow up 18 months (range 8.0–31.2 months). Rate of MI, stroke, and operative motality are similar. Median total intubation time (14.2 ± 25.2 h OPCAB vs 27.2 ± 84.2 h CCAB, P < 0.01) and length of stay (7.5 ± 4.2 day vs 8.2 ± 6.1 day, P < 0.05) were reduced in the OPCAB group. Overall mortality in the follow up period did not vary. Recurrence of angina was similar between the groups (19.4% vs 22.4%) however, the OPCAB group relied more on the use of antianginal medication to control their angina. The rate of readmission to hospital for IHD (10.7% OPCAB vs 6.3% CCAB), and revascularization procedures (PCI or redo surgery) (4.2% vs 3.9%) was not different despite more frequent performance of angiograms in the OPCAB group (12/140 (8.5%) vs 8/126 (6.3%)). Angiographic results are presented. Quality of life, general health and return to preoperative levels of activity were comparable in both groups. Conclusion: OPCAB is a safe and effective procedure with similar early and mid term results to CCAB. Recurrence of angina, readmission for IHD and reintervention rate does not appear to differ between the two groups. Patient satisfaction with the procedure is similar to CCAB. Long-term follow up is required to confirm these findings.

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References 1. KV Arom et al. Safety and Efficacy of Off-Pump Coronary Artery Bypass Grafting. Ann. Thor. Surg. 2000; 69: 704–710. 2. JD Puskas et al. Clinical Outcomes and Angiographic Patency in 125 Consecutive Off-Pump Coronary Bypass Patients. Heart Surgery Forum 1999; 2: 216–221. ENDOTHELIAL VCAM-1 EXPRESSION IS INCREASED AFTER OPCAB AND DECREASED AFTER CABG WITH BYPASS M. P. Vallely,1,2,3 P. G. Bannon,2,3 C. F. Hughes,2,3 M. S. Bayfield2,3 and L. Kritharides1,4 1Clinical Research Group, Heart Research Institute, 2The Baird Centre for Heart and Lung Research, 3Cardiothoracic Surgical Units, Royal Prince Alfred and Strathfield Private Hospitals and 4Department of Cardiology, Concord Hospital, Sydney, Australia Introduction: Endothelial cell activation is thought to be central to the inflammatory response after coronary artery surgery with cardiopulmonary bypass. The effects of coronary artery surgery without bypass (OPCAB) on endothelial cell activation are not known. Cell adhesion molecules (CAMs) (E-selectin, ICAM-1 and VCAM-1) are useful markers of endothelial cell activation. We have previously demonstrated that plasma taken after CABG, containing increased soluble ICAM-1 and VCAM-1 decreases human umbilical vein endothelial cell (HUVEC) expression of ICAM-1 and VCAM-1 in vitro. We compared plasma CAMs and HUVEC expression of the same CAMs when exposed to plasma taken before, during and after OPCAB or CABG. Methods: Patients undergoing first time CABG (n = 10) or OPCAB (n = 10) had 6 blood samples taken before surgery (preop), before and during ischaemia, during reperfusion, 3 h and 24 h postoperatively (postop). Plasma samples were assayed for E-selectin, ICAM-1 and VCAM-1. The same plasma samples were exposed to passage 2 HUVEC and cell-surface expression of E-selectin, ICAM-1 and VCAM-1 measured. Data are expressed as mean ± SEM of 10 subjects, and a robust cluster multiple linear regression was used for comparisons between groups. Results: Plasma E-selectin, which is endothelial specific, was unchanged in either group. Plasma ICAM-1 and VCAM-1, which are not endothelial specific (being released by monocytes, macrophages, dendritic cells, fibroblasts) were elevated 24 h postoperatively in both groups (P < 0.01), but there were no differences between the groups. Plasma taken 24 h post-OPCAB increased basal and IL-1b induced expression of endothelial VCAM-1 by 133 ± 16% and 140 ± 27%, respectively. In contrast, plasma taken 3 and 24 h post-CABG decreased endothelial VCAM-1 expression by 76 ± 10% and 85 ± 13%, respectively (P < 0.001) Perioperative plasma had no effect endothelial expression of E-selectin or ICAM-1 in either groups. Discussion: Soluble ICAM-1 and VCAM-1 are equally elevated after OPCAB and CABG. Post-OPCAB plasma increased HUVEC expression of VCAM-1, whilst post-CABG plasma decreased HUVEC VCAM-1 expression. Directing therapy against endothelial adhesion molecules may not ameliorate the post-CABG inflammatory response. CARIPORIDE (HOE-642) IMPROVES CARDIAC ALLOGRAFT PRESERVATION IN A PORCINE MODEL OF ORTHOTOPIC HEART TRANSPLANTATION J. Ryan, M. Wilson, M. Hicks, J. Cropper, S. Garlick, C. Soto, S. Kesteven, M. Feneley and P. Macdonald Heart & Lung Transplant Unit, St Vincent’s Hospital, Sydney, Australia Introduction: Anaerobic metabolism during hypothermicischaemic preservation of the donor heart results in activation of

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the Na+/H+ Exchanger. This leads to cell death from intracellular calcium overload by secondary activation of the Na+/Ca2+ Exchanger. Aim: To determine if inhibition of the myocardial Na+/H+ Exchanger, by Cariporide, improves cardiac allograft preservation. Methods: Twelve orthotopic heart transplants were performed on inbred Westran pigs (36–68 kg). Brain death was induced in the donor animals by inflation of a subdural balloon. In the control group (n = 6), the heart was stored for 4 h using conventional hypothermic ischaemic preservation techniques – arrest with an aspartate enriched crystalloid cardioplegic solution followed by submersion in ice. In the treatment group (n = 6), the heart was preserved in the same way but the donor and recipient also received intravenous Cariporide, 2 mg/kg, 15 min prior to harvesting and reperfusion, respectively. Myocardial injury was assessed by serial measurement of serum Troponin I. Cardiac function was assessed by ability to wean from bypass, freedom from ventricular arrhythmias and left ventricular pressure-volume loop indices. Results: Mean serum troponin I levels (µg/L) were significantly lower in the Cariporide treated group at 1, 2 and 3 h post reperfusion (29.6 ± 10.3, 51.2 ± 22.9, 68.0 ± 46.3 vs 50.0 ± 17.0, 122.3 ± 49.7, 209.7 ± 116.1; P = 0.02). More Cariporide treated hearts could be weaned from bypass at the first attempt (6 vs 3; P = 0.18). Fewer Cariporide treated hearts developed ventricular arrhythmias requiring defibrillation (1 vs 4; P = 0.24). On multiple linear regression, the stroke work-, dPdT Max- & end diastolic pressureend diastolic volume and end systolic pressure-volume relationships were all significantly better in the Cariporide treated hearts (all P < 0.0001). Conclusion: Cariporide reduced the myocardial injury associated with conventional hypothermic ischaemic preservation, resulting in improved cardiac allograft performance post-transplantation. THE Na+/H+ EXCHANGE INHIBITOR CARIPORIDE PROTECTS AGAINST CALCIUM OVERLOAD IN THE RAT HEART AND AGAINST POST-ISCHEMIC CONTRACTILE DYSFUNCTION IN HUMAN MYOCARDIUM F. L. Rosenfeldt, M. J. Zhang, Y. Fukuhiro, R. Ou, W. Lyon, M. Wowk, S. Pepe and D. Esmore Cardiac Surgical Research Unit, Alfred Hospital & Baker Medical Research Institute, Melbourne, Australia Background: Prevention of calcium overload has improved myocardial preservation during cardiac surgery. Calcium control in cardioplegia (CP) has traditionally been achieved by low calcium solutions or by addition of citrate. Na+/H+ exchange inhibitors have also been shown in animal experiments to prevent postischaemic Ca2+ overload and associated contractile dysfunction. Aims: A. To compare calcium control with citrate and the Na+/H+ exchange inhibitor, Cariporide in isolated rat hearts. B. To test whether Cariporide is protective in an in vitro model of ischemiareperfusion injury in human atrial trabeculae. Methods: (1) Isolated working rat heart preparations were perfused with oxygenated Krebs-Henseleit buffer and subjected to 60 min of 37°C arrest and reperfusion using K ± Mg2+ CP with different Ca2+ concentrations and with the addition of citrate or Cariporide. (B) Trabeculae were dissected from right atrial appendages discarded during surgery. Trabeculae were connected to tissue bath force transducers, electrically paced at 1 Hz in Ringer’s solution (95%O2/5%CO2, 37°C) and were subjected to 60min simulated ischemia (humidified N2, no perfusate). After 30min reperfusion, postischemic recovery of developed force (DF) was expressed as percentage of preischaemic values. Results: A. Lowering calcium in the cardioplegic solution

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(0.25 mmol/L) improved recovery of aortic flow (58.3 ± 2.5%) compared to standard (1.0 mm/L) Ca++ CP (47.6 ± 1.7%, P < 0.05). When citrate was used to reduce Ca++ concentration, it also chelated Mg++ and was detrimental to postischaemic aortic flow (41.6 ± 3%, P < 0.05 vs standard CP). Cariporide addition to standard CP significantly improved recovery (62.4 ± 1.7%, P < 0.05). B. In isolated trabeculae increasing the concentration of cariporide up to 1 µmol/L was associated with improved recovery of force: Cariporide dose µM (n= )

0 (10)

0.001 (8)

0.01 (12)

0.1 (11)

1 (12)

% Rec DF ± SEM P-value (vs 0)

38.2 4.8 *

41.6 5.2 0.68

47.7 6.8 0.29

48.5 6.6 0.25

62.3 8.8 0.03

Conclusions: (1) Lowered Ca2+ concentration in CP is beneficial in Mg2 ± containing cardioplegia. (2) The use of citrate to chelate Ca2+ in Mg2 ± containing cardioplegia is detrimental in the crystalloidperfused isolated working rat heart and possibly in humans. (3) Cariporide in CP is as efficacious in preservation of the ischaemic myocardium as is the direct reduction in Ca2+. (4) Cariporide can improve recovery of human myocardium after simulated ischaemia which lends justification to the current multicentre clinical trial of Cariporide in cardiac surgery patients. MECHANICAL PROPERTIES OF SHEEP AORTA J. Iliopoulos, C. Manganas, G. Moloney, R. M. Gillies, D. C. Newman and W. R. Walsh University of New South Wales, Department of Cardiothoracic Surgery, Prince of Wales Hospital, Sydney, Australia Introduction: The development of biologic aortic grafts requires knowledge of the elastic properties of the aorta. Preconditioning of the aorta is required prior to uniaxial mechanical testing to establish a repeatable reference state. Uniaxial tensile testing of aortic tissue generates a force displacement curve which allows comparison of the elastic properties of different regions of the aorta. The aims of this study are: 1. To determine the effect of the amplitude and frequency of preconditioning on the number of cycles required to achieve a repeatable steady state in the sheep aorta. 2. To determine the effect of the position (proximal vs distal aorta) and orientation (transverse vs longitudinal) of the aortic strip on the force displacement curve. Methods: 10 Fresh sheep descending thoracic aortas were obtained and bathed in PBS immediately after sacrifice. Each aorta was cut into rectangular strips (10 mm × 35 mm). 8 strips were obtained per aorta. Transverse and longitudinal strips were obtained from the proximal and distal segments of the descending thoracic aorta. Uniaxial tensile tests were performed using a micromechanical testing machine-Mach-1 (Biosyntech Inc. v2000). Preconditioning was performed using dynamic sinusoidal displacements of amplitude 2000 and 4000 micrometers and frequency 0.1Hz and 0.3Hz. Each sample underwent 30 cycles during preconditioning. Preconditioning was followed by uniaxial mechanical testing to failure at a velocity of 4 mm/s, to generate a force displacement curve. Results: Specimens required approximately 25–30 cycles to achieve a steady state. The number of cycles required to reach steady state was not influenced by the frequency and amplitude of preconditioning, or by the position or orientation of the strip. The amplitude and frequency of preconditioning did not affect the stiffness of aortic strips. The amplitude of preconditioning did not affect the rupture load of aortic strips. Strips preconditioned at 0.3Hz ruptured at a smaller load than strips preconditioned at 0.1Hz. The stiffness of transverse and longitudinal strips from the same region of the aorta was similar. The failure load was greater

Heart, Lung and Circulation 2001; 10

for transverse strips than longitudinal strips in the same region of the aorta. The stiffness of distal aortic strips was greater than proximal aortic strips. Conclusions: The amplitude and frequency of preconditioning does not affect the number of cycles required to reach a repeatable steady state in the sheep aorta prior to uniaxial mechanical testing. The stiffness of the aorta is similar in the transverse and longitudinal orientation, and increases distally from the heart. TREATMENT OF TYPE B DISSECTIONS AND DESCENDING AORTIC ANEURYSMS WITH ENDOVASCULAR STENT GRAFTS: PRELIMINARY RESULTS S. Redzepagic,1 I. Nixon,1 P. Mossop2 and T. Wilson1 Department of 1Cardiothoracic Surgery and 2Department of Interventional Radiology, St Vincent’s Hospital, Melbourne, Australia Introduction: Open surgical interventions for type B dissections and aneurysms of descending thoracic aorta are associated with high mortality and morbidity. The purpose of this study is to evaluate the safety, feasibility and clinical outcome of endovascular stent-graft placement in the treatment for diseases of the descending thoracic aorta. Methods: Between July 1999 and May 2001, endovascular stentgraft repair was used in 9 patients to treat disease of descending thoracic aorta. Patients were divided into 2 groups according to the type of lesion. Group A (n = 4) included patients with atherosclerotic aneurysms and chronic post-traumatic pseudoaneurysm. Patients with chronic type B dissections (n = 5) were included in group B. All patients underwent CT scan and angiography as preoperative assessment. The deployed stent-grafts systems were Cook Zenith TAA grafts inserted via femoral artery access. Clinical status of each patient was monitored and postoperative CT and ECHO studies were done within 1 month and at 3 and 12 months intervals after the procedure. Results: Successful deployment of the endovascular stent-grafts was achieved in all patients. Repeat stenting was done in 1 patient with type B dissection because of leakage distally from the stentgraft several months after the initial procedure. There were no early or late mortality in both groups. No procedure related complications were observed except for postimplantation syndrome including fever, leukocytosis, elevation of C-reactive protein and transient back pain. At the follow-up period 4–26 months no stentgraft related complications have been observed and all patients remain well. Conclusion: Stent-graft repair of the descending thoracic aortic aneurysm and type B dissections is a safe and effective method and may be an alternative to surgical graft replacement in selected patients. An exact definition of inclusion criteria and longer followup in larger series of patients is desirable to confirm these initial positive results. References 1. M Grabenwoger et al. Thoracic aortic aneurysms: treatment with endovascular self-expandable stent grafts. Ann. Thorac. Surg. 2000; 69: 441–5. 2. AS Bortone et al. Endovascular stent-graft treatment for diseases of the descending thoracic aorta. Eur. J. Cardiothorac. Surg. 2001; 20: 514–9. 3. JY Won et al. Elective endovascular treatment descending thoracic aortic aneurysms chronic dissections with stent-grafts. J. Vasc. Interv. Radiol. 2001; 12: 575–82.

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CIRCULATORY ARREST FOR REPAIR OF DISTAL ARCH ANEURYSM N. Kang, I. A. Nicholson and R. B. Chard Westmead Hospital, NSW, Australia Introduction: Distal arch aneurysm may be seen more frequently as children operated for coarctation or interrupted arch survive into adulthood. Correction of this lesion poses difficulty related to crossclamping the aortic arch such as stroke, bleeding, dissection, spinal cord ischaemia and recurrent laryngeal nerve injury. We have developed a method of ‘clampless’ repair using deep hypothermic circulatory arrest, and have applied this technique to other distal arch aneurysms. Methods: 15 years single institution retrospective study using computerized database and chart review. Results: Seventeen patients underwent left thoracotomy and repair of distal arch aneurysm using circulatory arrest. Pathology included postcoarctation aneurysm (11), chronic dissection (1), connective tissue disorder (1) and other (4). Three cases presented emergently as aorto-bronchial fistulas. Age range was 18–73 years (median 27 years). Cardiopulmonary bypass was employed via femoro-femoral or central cannulation with cooling to 18–22°C. Median circulatory arrest time was 37 min (range 7–55 min). Repair involved prosthetic aortic replacement using PTFE or Dacron interposition grafts. Four patients had additional tube graft replacement of the left subclavian artery. There was no operative mortality, stroke, paraplegia or recurrent nerve palsy. Two patients developed chylothorax requiring reoperation. There was one case of Horner’s syndrome following subclavian artery replacement. Discussion: Circulatory arrest allows for accurate repair of this difficult pathology and avoids the risk of clamp-related injuries. Residual hypoplastic arch can also be addressed. Our current practice is to combine left thoracotomy with groin cannulation using vacuum-assisted drainage. Follow-up out to 15 years demonstrates this technique of repair to be durable, with no late deaths or reoperations for recurrent aneurysm. QUANTITATIVE AND TEMPORAL DIFFERENCES IN PLATELET ACTIVATION AND THROMBIN GENERATION BETWEEN CABG WITH BYPASS AND OPCAB M. P. Vallely1,2,3, P. G. Bannon2,3, C. F. Hughes2,3, M. S. Bayfield2,3 and L. Kritharides1,4 1Clinical Research Group, Heart Research Institute, 2The Baird Centre for Heart and Lung Research, 3Cardiothoracic Surgical Units, Royal Prince Alfred and Strathfield Private Hospitals and 4Department of Cardiology, Concord Hospital, Sydney, Australia Introduction: Coronary artery surgery without cardiopulmonary bypass (OPCAB) may reduce bypass (CPB)-related (CABG) coagulopathy. However OPCAB surgery has been associated with increased incidence of thromboembolic events, including graft thrombosis, deep venous thrombosis and pulmonary emboli. We present a detailed comparison of the clotting cascade after OPCAB and CABG. Methods: Patients undergoing first time CABG (n = 10) or OPCAB (n = 10) had 6 blood samples taken before surgery (preop), before and during ischaemia, during reperfusion, 3 h and 24 h postoperatively (postop). Plasma samples were assayed for P-selectin (P-sel) (platelet activation), von Willebrand Factor Antigen (vWFAg) (endothelial activation), Prothrombin Fragments I + II (PFI + II) (thrombin generation) and activated Factor VII (FVIIa) (tissue factor activation). Data are expressed as mean ± SEM of 10 subjects, and a robust cluster multiple linear regression was used for comparisons between groups.

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Results: See table below for details. P-sel was significantly elevated after the commencement of CPB, and remained elevated for the study period (P = 0.02), but was unchanged after OPCAB. FVIIa and vWFAg were significantly elevated in both groups 3 and 24 h postop (P < 0.001), but there was no difference between the groups. PFI + II were elevated earlier and more significantly in the CABG group (P = 0.004). However, whilst the CABG levels were decreasing at 24 h, there was a late and significant rise in PFI + II in the OPCAB group (P = 0.003). Pre-Op

Heparin

Ischaemia

Reper-

3 h postop 24 h postop

Conclusions: The models allow trainees to practice complex cardiac surgical procedures in a realistic environment where there is no risk of patient morbidity and mortality. Both models may be used for teaching workshops and for the formal examination of surgical technique and skill. STRUCTURED REGISTRAR TRAINING IN GRAFT TO CORONARY ARTERY ANASTOMOSES B.G. French, J. Iliopoulos and P. G. Bannon Liverpool Hospital, Sydney, Australia

fusion

P-sel

CABG

62 ± 6

60 ± 5

72 ± 5

82 ± 4

89 ± 7

85 ± 5

(pg/mL)

OPCAB

58 ± 3

60 ± 2

61 ± 3

59 ± 3

56 ± 4

55 ± 7

FVIIa

CABG

74 ± 10

59 ± 16

60 ± 9

73 ± 6

118 ± 14

110 ± 9

74 ± 9

86 ± 11

(mU/mL) OPCAB

71 ± 12

47 ± 7

86 ± 12

110 ± 9

VWFAg

CABG

1.2 ± 0.1

1.0 ± 0.1 2.2 ± 0.7

1.4 ± 0.2

2.4 ± 0.1

2.2 ± 0.2

(U/mL)

OPCAB

1.3 ± 0.2

1.4 ± 0.2 1.6 ± 0.2

1.6 ± 0.3

2.3 ± 0.2

2.3 ± 0.2

PFI + II

CABG

(nmol/L) OPCAB

1.1 ± 0.2

1.1 ± 0.1 2.3 ± 0.5

3.1 ± 0.5

5.2 ± 1.5

1.8 ± 0.3

1.2 ± 0.1

1.1 ± 0.1 1.2 ± 0.1

1.2 ± 0.1

2.3 ± 0.3

2.4 ± 0.2

Discussion: OPCAB and CABG cause similar activation of the early factors in the coagulation cascade (FVIIa, vWFAg). However, the generation of the final products of coagulation (thrombin-PFI + II) and the activation of platelets are greater, and occur earlier after CABG. CARDIOTHORACIC TRAINING MODELS J. Iliopoulos, C. Manganas, S. Webber, W. R. Walsh, R. M. Gillies, D. C. Newman, and H. D. Wolfenden University of New South Wales, Department of Cardiothoracic Surgery, Prince of Wales Hospital, Sydney, Australia Introduction: Coronary artery surgery and heart valve surgery represent technically challenging procedures where a high degree of skill and precision are required to avoid significant morbidity and mortality to the patient, and to obtain the maximum benefit from the procedure. We have developed a simple bench simulator of coronary artery and heart valve surgery, as well as a live porcine model of off bypass coronary artery surgery, for the purpose of teaching cardiothoracic procedures to trainees. Methods: The benchtop simulator consists of a Perspex box with a slit in the superior surface that simulates a median sternotomy wound. Hearts are placed in the box in the anatomical position, and coronary artery surgery and heart valve surgery are performed through the superior slit. The live porcine model allows simulation of off bypass coronary artery surgery. Adult pigs are anaesthetised and intubated, and a median sternotomy is performed. Following harvest of the left and right internal mammary arteries the heart is stabilised using the Octopus stabiliser (Medtronic). The mammary arteries are anastomosed to the coronary veins in the region of the left anterior descending artery, the marginal circumflex arteries, and the posterior descending artery. Trainee skill and progress is assessed subjectively by surgical mentors with both models. The quality of the anastomosis in the live porcine model is assessed using an ultrasonic flowmeter. Results: The bench simulator model is a good simulator of on bypass coronary artery surgery and heart valve surgery via a median sternotomy. The live porcine model is a good simulator of off bypass coronary artery surgery. Anastomosis of the mammary arteries to the coronary veins allows multiple anastomoses to be performed without hemodynamic compromise during the procedure. Trainee skill improves with practise using both models.

Introduction: The acquisition of competence in the performance of surgically challenging procedures such as a graft to coronary anastomosis is an integral component in the training of cardiothoracic surgeons. We believe these skills should be soundly learned early in the training period and in an environment where suboptimal results do not have adverse consequences to patients. We have therefore devised and present a bench model to accomplish this task Method: Three Junior Registrars were taught a technique of anastomosing a graft to the Left Anterior Descending (LAD) Coronary Artery. They initially underwent a 2-week period of supervised familiarisation with the technique and also of operating using magnification loupes and micro surgical instruments which they had not used before. Pig hearts and pig carotid artery were used. An initial assessment of a graft to LAD anastomosis was then performed. Hand-eye coordination, graft preparation, LAD preparation, tissue handling, suture technique, adherence to the taught anastomotic stages, end result and time for completion of the graft were all objectively assessed. The registrars were then encouraged, and provision was made for them to perform as many anastomoses using the pig tissue as they could over the next 2 weeks and another objective assessment was made. Those registrars who were successful in the 2nd assessment were then supervised in the performance of graft to LAD anastomoses in the operating theatre. Results and discussion: The outcome of this structured teaching approach is presented and the implications and possible applications for training cardiothoracic surgeons are discussed.

EVIDENCE FOR AORTIC VALVE ALLOGRAFT STRUCTURAL DETERIORATION SECONDARY TO IMMUNE RESPONSE Rebecca Dignan,1 Mark O’Brien,2 Patrick Hogan,3 Alycia Thornton,3 Kirsten Fowler,3 Daniel Byrne,1 Fiona Stephens,4 Susan Harrocks2 1Department of CT Surgery and Clinical Research Center, Vanderbilt University, Nashville, TN, 2Department of Cardiac Surgery, The Prince Charles and St Andrews Hospitals, 3Department of Immunology, Princess Alexandra Hospital and 4School of Mathematical Sciences, Queensland University of Technology, Brisbane, Australia Introduction: Evidence suggests that donor-recipient class 2 human leukocyte antigen (HLA) mismatch is associated with aortic valve allograft (AVA) structural deterioration. An AVA recipient cohort was studied to determine whether high levels of antibodies to class 1 and class 2 HLA were also associated with AVA structural deterioration. Methods: Both donor and recipient HLA types were obtained for 162 recipients of cryopreserved AVA’s. Structural deterioration of the AVA’s was defined as at least moderate aortic stenosis or regurgitation by echocardiography. Class 1 and 2 antigens were typed by molecular genotyping. Recipient sera were assayed for anti-HLA antibodies using 3 separate assays: complementdependent cytotoxicity (CDC) on T and B lymphocyte panels, flow cytometry using HLA-coated beads and ELISA using HLA coated microwells. The specificity of anticlass 1 and 2 HLA antibodies was

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determined on T and B cell panels by CDC. Associations between results of the 3 assays and specific HLA antibodies and structural deterioration were analysed using Kaplan–Meier curves of freedom from structural deterioration and Cox proportional-hazards multivariable analysis. Results: Patients highly positive for HLA class 2 antibodies using the ELISA test had a significant association (P = 0.007) with structural deterioration. Patients with specific antibodies to class 2 antigen had significantly less freedom from structural deterioration (P = 0.035) than those without specific antibodies. Discussion: The association between AVA dysfunction and class 2 HLA antibodies adds evidence that antidonor immune response damages the AVA. Recipients with high class 2 antibodies may be targeted for immunotherapy. RADIAL ARTERY 2000 Mitsumasa Hata, MD, Narelle Manson, CCRN, Alexander Rosalion, FRACS, George Matalanis, FRACS, Jai Raman, FRACS, Siven Seevanayagam, FRACS and Brian F. Buxton, FRACS The Department of Cardiac Surgery, Austin & Repatriation Medical Centre,University of Melbourne, Melbourne Australia Objective: A number of reports have been published concerning the advantages of using arterial conduits in coronary artery bypass grafting (CABG) instead of vein grafts. The use of radial artery (RA) has become a topic of renewed interest. However, long-term follow up results for the patients with RA have not been described in detail. The aim of this study is to review our experience with using more than 2000 RAs over the last 7 years, and to assess the various configurations used with RA conduit and medium-term outcome. Methods: Between June 1994 and June 2001, total 2024 RAs have been used in 1613 patients. They were consisted of 1281 male and 332 female with average age of 64.4 ranging from 32 to 85 years. Isolated CABG was performed in 1485 patients, and this group included 46 patients undergoing ventricular repair and 44 of offpump CABG. Concomitant valve surgery was performed in 114, and concomitant aortic surgery in 14 patients, respectively. Bilateral RAs were used in 411 patients (25.5%). Y-graft between the internal thoracic artery and RA was used 157 patients (9.7%). RA sequential bypass was employed in 299 patients (18.5%). Varied modifications such as multiple bridge graft, RA interposition, and internal thoracic artery extension with RA were used in 30 patients (1.9%). The mean duration of follow-up was 40.1 months and ranged from 1 to 88 months. We evaluated postoperative complication rate, coronary event free rate, actuarial survival rate, and graft patency. Results: In the patients with concomitant valve and aortic surgery, the use of Y-graft was significantly higher than aorto-coronary grafting. In the isolated CABG series, average numbers of graft was 3.1 ± 0.8. Perioperative myocardial infarction was indicated in 13 patients (0.8%), stroke in 24 (1.6%), and recurrent myocardial ischemia in 5 patients (0.3%), respectively. Overall hospital mortality was 35 patients (2.4%). At the time of follow-up, late mortality was 37 patients (2.5%). Postoperative angiography has only been employed in 46 patients so far. All RAs were patent, except for one RA with 70% stenosis. The actuarial survival rate was 95.1% and coronary event free rate 99.6%, respectively. Conclusions: Our 7-year experience of CABG with RA suggested that the use of RA was safe and had excellent results in postoperative graft patency and low incidence of complications. The medium-term outcome was also excellent. Furthermore, RA can be used in various configurations with safety in CABG.

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OPERATIVE STRATEGY WHEN REGRAFTING THE TOTALLY OBSTRUCTED LAD SUPPLIED BY A PATENT SAPHENOUS VEIN GRAFT B. Weiss, FRACS, D. C. Newman, FRACS, P. W. Grant, FRACS and H. D. Wolfenden, FRACS Department of Cardiothoracic Surgery, Prince of Wales Hospital, Sydney, Australia Introduction: Regrafting strategy of the graft-dependent left anterior descending coronary artery (LAD) which is supplied by a patent (but diseased) saphenous vein graft (SVG) remains controversial. Reports of left internal mammary artery (LIMA) hypoperfusion syndrome when regrafting the LAD with a LIMA and dividing the SVG may make the surgeon reluctant to adopt this strategy. Leaving the SVG intact however, has resulted in reports of the LIMA becoming occluded with time. We reviewed our grafting strategies and results in this group of patients. Methods: A retrospective review was performed of prospectively collected data on patients undergoing redo coronary artery bypass grafting, where the LAD was totally obstructed and supplied by a patent saphenous vein graft, during the 5-year period July 1, 1996 to June 30, 2001. Of 3575 coronary artery bypass grafting (CAGs) operations performed during this time, 256 were redo CAGs, of which 89 cases met the criteria. Patients were divided into 2 groups based on those with a subcritical (< 50%) old SVG stenosis (Group A, 29 patients) or = 50% (Group B, 60 patients). Grafting strategies consisted of either using a LIMA or SVG to graft the LAD, then either ligating the old SVG or leaving it patent. Endpoints included death, myocardial infarction, and evidence of LIMA hypoperfusion syndrome. Mean age was 69.4 years, and 76 were males. 80 patients underwent CAG only (8 off-pump), and 9 had additional valve surgery. Overall, 80 patients (90%) received a LIMA; 21 of these underwent ligation or division of the old SVG (10 in Group A, and 11 in group B). Results: There were no cases of LIMA hypoperfusion syndrome. Operative mortality (30 day) was 3.4% (3 patients, all in Group B, where a LIMA was placed on the LAD and the SVG left intact). Perioperative Q-wave myocardial infarction rate was 1.1% (1 patient, lateral infarction, SVG < 50% and not ligated). Followup angiography was performed in 14 symptomatic patients. In 4 patients receiving a LIMA, where the SVG was < 50% and not ligated (22% of this subgroup), the LIMA was occluded. In 7 patients where the SVG was = 50% or the SVG was ligated, the LIMA was patent. One patient had both SVG and LIMA patent (where there was a 50% LAD stenosis between the SVG and LIMA), and two patients who had received new SVGs to the LAD had 70% distal anastomotic and 90% proximal anastomotic stenoses, respectively. Conclusions: LIMA hypoperfusion syndrome was not seen in patients undergoing ligation of the old SVG. Our limited angiographic follow-up suggests that when regrafting with a LIMA onto the totally obstructed LAD, the SVG may be divided or partially ligated/occluded if < 50% stenosed, but may be left intact if more than 50% stenosed. DOES CONVERSION TO CARDIOPULMONARY BYPASS IN OFF PUMP CORONARY ARTERY BYPASS SURGERY LEAD TO ADVERSE OUTCOME? C. K. Choong, H. Jalali, R. Tam and M. Gardner The Prince Charles Hospital and St Andrew’s Hospital, Brisbane, Australia Introduction: Off pump coronary artery bypass surgery (OPCAB) is now an established procedure. There is little in literature regarding the patients requiring conversion to cardiopulmonary bypass (CPB). This report reviews the incidence, reasons for conversion and outcome of this subgroup.

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Methods: Between October 1997 and June 2001, prospective data were collected for all patients undergoing OPCAB. Conversion was defined as the necessity to institute CPB once an OPCAB anastomosis had commenced. These patients were identified and their data analyzed. Results: 15 (3.7%) out of 401 patients underwent OPCAB conversions. Demographics include 11 males, mean age was 63 years old (range 36–79), preoperative ejection fraction was normal in 12 patients (EF > 55%) and severely impaired in 2 (EF < 35%). Eight patients had triple vessel coronary artery disease, 6 had double and 1 had single vessel disease. Two patients underwent redo coronary surgery and another patient had concomitant unilateral carotid endarterectomy. The average number of bypass grafts was 3 per patient (6 patients had 2 grafts, 6 had 3 grafts and 3 had 5 grafts). Reasons for conversion were hemodynamic instability in 12 patients (80%) and technical reasons in 3 patients (20%). The identified potential reasons for hemodynamic instability were nonuse of shunt in 5 patients, incomplete revascularization in 1 and poorly tolerated cardiac displacement in 3 patients who also had left main stenosis. Intraoperative inotropic support was required in 9 patients and postoperative inotropic support in ICU was required in 3 patients. Blood transfusion was administered to 6 patients with a mean of 2 units each. Postoperative day 1 troponin I in 5 patients was mean 0.6 (range 0.06–2.5) and troponin T in 6 other patients was mean 8.9 (range 1.9–34.8). There were no new changes in the postoperative serial ECGs in comparison to the preoperative ECGs to suggest intra or postoperative myocardial infarction. There was no hospital mortality. Morbidities include 1 patient who required IPPV for 5 days, one patient developed postoperative renal impairment, another patient with preoperative chronic renal failure (creatinine 0.37) required postoperative dialysis and 4 patients developed postoperative atrial fibrillation. Average postoperative length of stay (LOS) was 7.8 days of which 11 patients had LOS 7 days or less. Conclusions: The incidence of OPCAB conversion is small with hemodynamic instability accounting for the majority of conversions. It has not been associated with any mortality or a high incidence of postoperative major morbidities, nor any significant myocardial injury. Blood transfusion requirements may be larger and the length of hospital stay may be longer. EVOLVING ASPECTS OF LUNG VOLUME REDUCTION SURGERY P. E. Munro, J. A. Smith and G. I. Snell Australian and New Zealand Lung Volume Reduction Surgery Database, The Alfred, Melbourne, Victoria, Australia Introduction: Lung Volume Reduction Surgery (LVRS) has been shown to improve lung function, exercise performance and quality of life in highly selected individuals with severe emphysema. Major questions regarding the safety and efficacy of LVRS still remain unanswered. The Australian and New Zealand LVRS database continues to audit local clinical practice. Aims: To provide an update regarding current activity levels, patient selection and technical aspects of Lung Volume Reduction Surgery in Australia. To discuss the Australian and New Zealand data in view of the findings of the U.S. National Emphysema Treatment Trial (NETT) Research Group.1 Methods: Data was collected from 542 patients from 14 centres in Australia and New Zealand. 13 patients who had LVRS following lung transplantation were excluded. Pre-operative demographics, physiological measures, surgical and postoperative variables were analysed. Results: Age at surgery (mean ± SD) was 63 ± 7 years, 58% of patients were male.

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Pre-operatively, mean FEV1 was 29 ± 9% predicted, mean TLC was 138 ± 20% predicted, mean RV was 250 ± 64% predicted and mean 6 Minute Walk (6MW) 327 ± 111 m. There has been a reduction in the overall number of cases and centres performing LVRS since 1999 (see Fig. 1). There has been significant increase in the proportion of unilateral LVRS performed in the period 1998–2000 compared with 1995–97, p = 0.045. 140

128

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Figure 1. No of LVRS cases per year Discussion: LVRS continues to be performed in Australia predominantly in large tertiary hospitals. As recently shown in the NETT study, no single characteristic adequately predicts which patients are at high risk of death and who are unlikely to benefit from surgery. Human trials of bronchoscopic LVR have begun in Australia and may offer an alternative to traditional LVRS. It remains difficult to capture long-term lung function and even survival outcomes in this population. References 1. National Emphysema Treatment Trial Research Group: Patients at high risk of death after Lung-Volume-Reduction Surgery. Available at: http://nejm.org/earlyrelease (14 August 2001). WHAT IS THE BEST AVR PROSTHESIS FOR THE YOUNG–MIDDLE AGE (17–50) PATIENT? A 705 PATIENT AUSTRALIA–USA BICENTER 15 YEARS ANALYSIS M. F. O’Brien, R. C. Elkins, S. Harrocks, M. M. Lane, E. G. Stafford, M. A. H. Gardner, P. G. Pohlner, H. Jalali and B. Garlick The Prince Charles and St Andrew’s Hospital, Brisbane Australia and University of Oklahoma, Oklahoma, USA Objective: The preferred AVR device in the young-middle age patient is unclear. Patients requiring AVR at two medical centers from January 1986 to December 1998 are analyzed to answer the impact of valve choice on patient survival and valve related morbidity. Methods: AVR in 705 patients (age 17–50 years) with a mechanical valve (MECH, n = 347), Aortic Allograft (ALLO 193) or a pulmonary autograft (PA 165) were reviewed. Follow-up of 98% of surviving patients within one year of closing the study was obtained. The Median follow-up time was 5.1 years (max 13.7, total patient year 3852). Median age for MECH was 43 year, Allo 37 and PA 32 (< 0.001). Survival, valve replacement, valve-related morbidity (valve related deaths, thrombo-embolism or haemorrhage) and echocardiographic evaluation of valve function were compared for the three valves types. Results: Operative mortality was 2.1% (15/705) for the entire series (actuarially: 89% ± 3% at 13 years). At 11 years SURVIVAL was 89% ± 2% for Mech, 96% ± 2% for Allo and 96% ± 2% for PA. Freedom from AV RE-REPLACEMENT was 86% ± 4% at 13 years

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for the 690 early survivors (95% ± for Mech, 92% ± 3% for PA, 72% ± 9% for Allo (P = 0.20). Freedom from all valve-related MORBIDITY was 68% for Mech, 63% ± 9% for Allo and 76% for PA (P = 0.05). Moderate to severe AI on echo assessment of AV FUNCTION revealed 2% of Mech, 9.7% of Allo and 7.7% of PA. Moderate to severe AS occurred in 1.5% of Mech, 1.7% Allo and none of PA patients. Additional facts: Allo patients <30 years have been shown to have inferior durability compared to those >30 years at implantation. PA patients have been shown to have better longterm valve performance with the technical advances of valve annulus fixation and reduction annuloplasty, where indicated. Conclusions: (1) Autograft and Allografts require more frequent reoperation, but their long-term survival compared to mechanical valve patients was less affected. (2) All valve-related morbidity was lower at 11 years for PA patients. (3) For Surgical Units without Allo facilities/PA experience, the mechanical valve should give the best results and for them is the valve of choice in this age group. For Units with such facilities/experience, the best results for the young patient (<30 years) is the PA and for the middle age patient (>30 years) is the Allo. Both valves with these age delineations are superior to the Mechanical Valve.

THE ROSS PROCEDURE: MID-TERM RESULTS BUT PROCEED WITH CARE? Elizabeth M. Rumball, Peter J. Raudkivi and Alan R. Kerr Department of Cardiothoracic Surgery, Greenlane Hospital, Auckland, New Zealand Introduction: The Ross procedure has gained popularity for aortic valve replacement in children and young adults. Benefits include avoidance of anticoagulation, growth potential, and haemodynamic performance. However, there are concerns about the longevity of the pulmonary autograft in the systemic circulation, the durability of the right ventricular outflow tract reconstruction, influence of the initial valve lesion, and cardiac disease. Methods: Between May 1994 and August 2001 50 patients underwent the Ross Procedure at Greenlane Hospital. A retrospective review of patient records was undertaken. Preoperative, postoperative, clinical, and echocardiographic data were collected in an attempt to identify risk factors for failure of the autograft or the RVOT reconstruction. Results: The majority of patients were male. Mean age at operation was 25 years (6 months to 48 year). Aortic stenosis was the operative indication in 9 patients and aortic insufficiency in 41. Rheumatic valve disease was a feature in 14 patients (active in 1). 13 patients had previously undergone aortic valve intervention (balloon valvotomy 2, surgical valvotomy 2 and homograft AVR 8 and complex repair arch/resection subaortic stenosis1). Autograft insertion technique was scalloped 1, inclusion 14, and root replacement 35. Annuloplasty to reduce geometric mismatch was utilized in 17 patients (16/17 AI). Two patients died perioperatively (4%). Complications included nonfatal MI (1), SVT/AF (2), tamponade and reoperation for bleeding (2), and pneumonia (1). Two patients underwent explantation of the autograft during the initial operative admission for moderate aortic regurgitation. These patients were early in the experience. No patient was discharged with more than mild regurgitation (nil 10, trivial 29, mild 7). Late autograft failure has occurred in 4/40 (10%) patients reviewed more than 12 months from operation. Redo aortic valve replacement has been required in 1. 3 patients (all with AI) have developed moderate aortic regurgitation on echocardiography between 14 and 74 months postoperatively. 2 of the 3 have a background of rheumatic valve disease. Late abnormalities of the right ventricular outflow tract

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homograft reconstruction were present in 6 of the 40 patients (moderate PR 3, severe PR 2 and significant distal anastomotic stenosis 1). None of these patients have required reoperation. Recommended follow-up is 12 monthly clinical review and echocardiography. Only 29 of 40 (73%) patients eligible for 12 month follow-up have had any echocardiography and in 12 (30%) is follow-up complete. Discussion: The Ross procedure is a useful adjunct in the management of aortic valve disease. Operative mortality is low and late death rare. However, this small series raises several concerns. Autograft degeneration may be more common than initially expected. Preoperative aortic insufficiency appears to be associated with an increased incidence of autograft failure and this may be particularly prevalent in the rheumatic population. Given these concerns, close follow-up is imperative and to date has likely been inadequate.

TEN YEAR FOLLOW UP OF HOMOGRAFT AORTIC VALVES AT THE ALFRED HOSPITAL S. F. Marasco, B. B. Davis and D. Esmore CJ Officer Brown Cardiothoracic Unit, Alfred Hospital, Melbourne, Australia We last reported on our homograft aortic valve replacement program in 1995. Now at 10 years follow up, we report our results in 85 homograft aortic valve replacements since the inception of our homograft program in 1988. All patients who had received an aortic valve replacement using a homograft since the inception of the program in 1988 were identified by means of the cardiothoracic unit database. Data is prospectively entered into the database and is maintained by our database manager. The charts of all patients were reviewed. Those patients who had been lost to follow up at the hospital were then tracked with the assistance of their general practitioners to obtain up to date information about their clinical status. Eighty-five patients were identified via the database and follow up was 100% complete. 68% were male and the average age was 51 years. The indications for aortic valve replacement were mostly calcific aortic stenosis and rheumatic aortic stenosis. Details regarding thromboembolic and haemorrhagic complications, freedom from reoperation and survival were analysed. SURGICAL OUTCOME OF AORTIC ROOT REPLACEMENT: A 5-YEAR EXPERIENCE WITH 70 CONSECUTIVE PATIENTS George Matalanis, Mitsumasa Hata and Brian F. Buxton The Department of Cardiac Surgery, Austin & Repatriation Medical Centre, University of Melbourne, Melbourne, Australia Objective: The mortality of aortic root replacement has been variously reported as 5–20%. These finding are often derived from series spanning 10–15 years. Recent advances in surgical techniques and anesthesia are likely to have lowered the mortality of root replacement over the last few years. On the other hand, the complexity of patients undergoing this procedure, in terms of age, comorbidities and concomitant procedures, is ever increasing and may negate the impact of the former. The aim of this study was to review our experience with aortic root replacement over the last 5 years, and to analyze the impact of complicating factors on outcome. Methods: Seventy patients were operated on between January 1996 and December 2000. Twelve patients (17.1%) had Marfan’s syndome. Eleven patients (15.7%) had previous cardiac operations. Extended arch replacement was performed in 14 patients (20.0%). Coronary bypass was performed 19 patients (27.1%). We compared patients undergoing isolated aortic root replacement with those

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having concomitant coronary bypass (Grouping 1), an initial operation with a reoperation (Grouping 2), and isolated aortic root replacement with extended arch replacement (Grouping 3) in terms of the early surgical outcome with Chi-square, Mann–Whitney U, and Student t-tests. The independent predictors of hospital mortality were also examined using the Cox proportional hazards regression analysis. Results: Overall hospital mortality was 3 patients (4.3%). All mortality occurred in the reoperation group. In grouping 1 and 3, there were no significant differences in hospital mortality (1 (2.0%) vs 2 (10.5%), P = 0.36; and 3 (5.4%) vs none (0%), P = 0.93, respectively). In grouping 2, however, the mortality was significantly higher in reoperation group (3 (27.3%) vs none (0%), P = 0.001). Multivariate analysis showed that re-do operation was the only significant predictor of hospital death (P = 0.012). The mean duration of follow-up was 40.4 months and ranged from 1 to 66 months. The total actuarial survival rate was 91.4% at 5 years (isolated root: 100%, concomitant CABG: 80%, extended arch: 92.9%, reoperation: 75%). Conclusions: Our recent 5-year experience with aortic root replacement suggests that this procedure can be performed with low risk (4.3%). Indeed for first time operation, even when concomitant procedures such as arch replacement or coronary bypass grafting are required, these were no perioperative deaths. The medium term outlook was also excellent. This supports our early and aggressive approach towards surgical repair of aortic root dilatation. REPAIR OF THE ANTERIOR LEAFLET IN DEGENERATIVE MITRAL VALVE DISEASE B. Weiss, FRACS, J. Iliopoulos, MB BS, BSc, P. W. Grant, FRACS, D. C. Newman, FRACS and H. D. Wolfenden, FRACS Department of Cardiothoracic Surgery, Prince of Wales Hospital, Sydney, Australia Introduction: Techniques for repair of the prolapsing anterior mitral leaflet (AML) in degenerative mitral valve disease are more varied, controversial, and technically more demanding than those of the posterior leaflet. We reviewed our techniques and results over the last 5 years, including clinical and echocardiographic followup. Methods: A retrospective review of prospectively collected data between 1/7/96 and 30/6/01, yielded 42 patients (29 males) who had undergone AML repair for degenerative disease (mean age 65); this represented 23.5% of all mitral valve repairs for degenerative disease during the period. The degenerative process affected the AML only in 64%, and both leaflets in 36%. Various repair techniques were used, and a modified Duran posterior annuloplasty performed routinely where possible (38 patients, 90.5%). Thirty-five patients were in NYHA class 3 or 4 preoperatively, the remaining seven in NYHA 2. Preoperative mitral regurgitation (MR) was graded moderate–severe or severe in 35 patients (83.3%), and moderate in the remainder. Followup was performed by a questionnaire mailed out to the cardiologists, and direct telephone interview with the patients and their local doctors. Qualitative and quantitative variables were compared using the chi-squared test and analysis of variance, respectively. Results: Operative mortality was zero. There were no perioperative myocardial infarctions or permanent cerebrovascular accidents (CVA). Postoperative transoesophageal echo results graded MR as nil-mild in 41 patients (97.6%). Two patients underwent subsequent mitral valve replacement during the followup period, one at 24 months with re-ruptured chordae of the anterior mitral leaflet and annular dilatation (no annuloplasty at initial operation), and one at 50 months due to progressive MR following inability to perform annuloplasty at initial surgery due to a heavily calcified

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mitral annulus. Statistical analysis yielded no predictors of repair failure. Seven patients died during the followup period (4 of malignancy, 2 sudden deaths, and 1 after subsequent redo MVR). Echocardiographic followup was available in 34 patients (81%), with mean time being 19 months (range 1–58 months); MR was graded nil to mild in 30 patients, moderate in 1, and moderate–severe in 3 patients (2 of which underwent subsequent redo mitral surgery). Clinical followup was 100% complete, at a mean interval of 25.6 months (range 2–58 months), with 90.5% (38) of patients in NYHA classes 1 or 2. Three patients were in NYHA 3 (one with asbestosis, one with lung cancer, and one who subsequently underwent redo mitral surgery), and one in NYHA 4 (also underwent subsequent redo mitral surgery). Conclusions: Repair of the AML in degenerative mitral disease is safe, successful and durable in the intermediate term. Whilst statistical analysis yielded no predictors of repair failure, we note that two of the four patients without annuloplasty at initial operation required reoperation. MITRAL VALVE REPLACEMENT AFTER INITIAL SUCCESSFUL REPAIR FOR DEGENERATIVE MITRAL VALVE DISEASE G. J. Hart, M. A. H. Gardner, G. Stafford and P. Tesar The Prince Charles Hospital and St Andrews War Memorial Hospital, Brisbane, Australia Introduction: The aim of this paper was to review those patients whose mitral reparative surgery was initially successful but subsequently required mitral valve replacement in order to identify long-term successful repair and whether the type of leaflet pathology or reparative technique had an influence on repair failure and therefore determine possible solutions. Methods: The database of a single surgeons experience in mitral valve surgery from 1990 to June 2001 was interrogated to find those patients whose initial repair procedure had failed and resulted in subsequent replacement. Results: A total of 399 patients under went mitral valve surgery for degenerative mitral valve disease. 336 with primary repair and 63 with primary replacement (including 9 on-table conversions). Of the 336 successful repairs there were 3 deaths (in-hospital or less than 30 days). This gave 333 available for follow up. Of these there were 11 postoperative repair failures that resulted in replacement (3.3%). Pre-repair valve dysfunction was posterior mitral leaflet (PML) prolapse in 6 cases and 5 with either anterior mitral leaflet (AML) prolapse or Bileaflet prolapse. Annuloplasty was performed in 9 cases (5 Cosgrove-Edward rings and 4 treated pericardium). Post pump TOE showed trivial to 1+ mitral regurgitation (MR) in 8, 1 with 1–2 regurgitation, 1 with 2+ MR and one with more than 2+ MR and systolic anterior movement (SAM) which subsequently went onto have a second pump run and successful revision of repair with a trace of MR. Time to re-operation varied from 2 days to 4 years with 9 occurring between 2 days and 9 months and 2 at 31/2 years and 4 years. The mechanism of repair failure was erosion of AML in 3 cases, tearing of PML repair in 3 cases (1 without a ring), retraction of PML and failure to coapt in 3 cases. 1 case had avulsion of an artificial chordae and 1 case of progressive MR after 1+ MR on post pump TOE. Haemolysis was present in 5 cases prior to replacement. There was 1 sudden death 2 weeks after valve replacement and 1 severe global cerebral hypoxic injury associated with urgent valve replacement surgery. Conclusions: The results of this study suggest: 1. That the incidence of subsequent replacement following valve repair is acceptably low. 2. That with quadrantic resection it is important that there is a

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secure repair of the leaflet and repair of the annulus (by ring or treated pericardium) performed without tension. 3. To ensure that sufficient leaflet is left after reduction or slide techniques on the PML. 4. Prolene with the knots on the left atrial side may be traumatic to the AML. This finding has resulted in a change of practice. The limitation of this study is that the end point taken to determine a failed repair is that of re-operation. There may still be other patients in need of valve replacement or who may have had valve replacement elsewhere and therefore be unreported.

Poster Presentations BIOGLUE® A RECENT ADDITION TO THE GROUP OF SURGICAL ADHESIVES – AN APPRAISAL OF THE INDICATIONS FOR ITS USE IN CARDIAC AND THORACIC SURGERY J. Passage, R. Tam, M. Windsor, S. Harrocks and M. O’Brien Department of Cardio-Thoracic Surgery, The Prince Charles Hospital, Brisbane, Australia Introduction: The recent emergence of Bioglue® has widened the field of available surgical adhesives for the Cardio-thoracic surgeon. So far there are only experimental studies or small series of specific conditions, such as aortic dissections, which look into the use of Bioglue®. The present study is the first larger scale study evaluating the use of this new adhesive in a wider spectrum of cardiac and thoracic procedures. Methods: Bioglue® was utilised in 152 Patients (mean age 55, male 117, female 35) from 09.09.1998 to 12.03.2001. Pre-, intra- and postoperative data were examined to establish the use, indications and outcomes in patients undergoing cardiac and thoracic procedures. Results: Bioglue® was used in 114 cardiac and in 38 thoracic procedures. Of the CARDIAC patients the commonest diagnosis were Aortic Dissection 30 (Type A 24, Type B 6); Aortic aneurysm 39 (ascending 29, ascending and arch 5, descending 5); Ischaemic heart disease 30; Valve disease 43 (Aortic 40, Mitral 8, Tricuspid 2, Pulmonary 1). Seven patients had Marfan’s disease. Twenty patients were coagulopathic and 20 patients were on Aspirin at the time of operation. The procedures carried out were: Aortic root replacement 36, Aortic wall replacement 39 (23 ascending, 6 ascending and arch, 10 descending). Ascending aorta repair 2, isolated CABG 8, Valve procedures 11, ventricular aneurysm repair 6 and congenital 12. The indications for Bioglue® use were Haemostasis in 79, Tissue adherence in 21 and Tissue strengthening in 30. The total mortality was 10% (11). Two patients dying in the operating room. Sixteen patients had to return to theatre for bleeding and/or tamponade. The mean blood loss at 12 h was 543 mL and at 24 h 611 mL. Ten Patients developed a CVA postoperatively (9%), Thirteen patients had wound infections. No patient has been re-operated on at TPCH to date. Among the THORACIC patients the predominant primary diagnosis was malignancy (18 pulmonary, 2 pleural). Other underlying conditions were recurrent pneumothorax (7), COAD (4) and miscellaneous (7). In 29 cases Bioglue® was used during the primary procedure while in the remaining 9 cases persistent air- or lymph leak lead to a further procedure requiring the use of glue. Patients underwent the following procedures: Lobectomy 11, pleurodesis 7, segment-/wedge-resection 7, LVRS 4, and miscellaneous 9. The indications for Bioglue® use were parenchymal air leak in 34, Broncho-pleural fistula in 2 and lymph

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leak in 2 cases. There was one death. Only 2 patients had to have further intervention for ongoing air leak, 1 patient returned to theatre for a persisting lymph leak. Three patients developed empyema postoperatively, 2 pneumonia and 3 patients pleural effusions. The mean duration of pleural drainage with ICCs was 4 days. Discussion: All involved surgeons felt that Bioglue® facilitated the operation. Further studies will have to be undertaken to compare our results with similar patient cohorts to validate our early promising results and to establish the long-term outcome of patients treated with Bioglue®. FUNCTIONAL TRICUSPID REGURGITATION SECONDARY TO AORTIC ANNULAR ABSCESS: AN UNUSUAL PRESENTATION Nand Kejriwal, Ravi Ullal, Geoff Long and Spencer Heald Waikato Hospital, Hamilton, New Zealand Introduction: Annular abscesses are serious complications of infective valvular endocarditis. There is a higher incidence of annular abscess formation in aortic compared to mitral or tricuspid infections. We present a case of aortic annular abscess, where the patient presented with features of gross tricuspid regurgitation (TR) without direct involvement of the tricuspid valve (TV). TR disappeared following surgical repair of the annular abscess. Case report: A 52-year-old male was referred for aortic valve replacement for aortic stenosis. Six months later, whilst awaiting surgery, he was admitted with increasing shortness of breath. Examination revealed clubbing, bilateral ankle oedema and marked enlargement of liver. A clinical diagnosis of gross TR was made. Transthoracic echocardiography (TTE) revealed vegetations on the aortic valve with a perivalvular abscess extending onto the interventricular septum. There was severe aortic regurgitation and severe TR. Blood cultures were negative. Cardiac catheter revealed raised right-sided pressures. He was referred for emergency surgery on the basis of failed medical treatment for culture negative endocarditis. Intraoperative Transoesophageal echocardiography (TOE) confirmed the presence of the abscess cavity, which was extending onto the tricuspid annulus. Colour Doppler showed a severe TR jet. Aortotomy revealed the anterior leaflet had detached from the annulus with a large abscess cavity underneath. The floor of the cavity was formed by the right atrium and the upper part of the interventricular septum. After debridement, the abscess cavity was closed with a bovine pericardial patch. The aortic valve was replaced with a pericardial bioprosthesis. As the tricuspid annulus was not significantly dilated and the leaflets appeared structurally normal, TV was not inspected. After weaning the patient off CPB, TOE revealed the TR jet had completely disappeared. The patient made an uneventful recovery in the postoperative period. Repeat TTE four months later showed only a trivial jet of TR with no evidence of pulmonary hypertension. Discussion: The intracardiac consequences of infective endocarditis range from trivial, characterized by infected vegetation with no attendant tissue damage, to catastrophic, when infection is locally destructive or extends beyond the valve leaflet. TOE has been reported to be highly sensitive in detecting vegetations on the valves. In this case, TOE proved invaluable not only in confirming the diagnosis and delineating the exact anatomy, but also in assessing the need for surgical intervention on the TV. The disappearance of TR on coming off CPB confirmed that TR was functional rather than organic in origin. The most plausible explanation seems to be that, as the abscess cavity was impinging on the tricuspid annulus, flow into the cavity was distorting the tricuspid valve resulting in regurgitation. Once the cavity was closed with the patch, the tricuspid regurgitation disappeared.

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Tricuspid valve endocarditis is rare and usually occurs in intravenous drug users or in patients with congenital right heart defects. Aortic annular abscess distorting the tricuspid annulus and thereby causing tricuspid regurgitation without actual involvement of the tricuspid valve has not been previously reported. It is worth considering in cases of aortic valve endocarditis where there is ‘unexplained’ right heart involvement. AIDS AND HEART DISEASE: IS CARDIAC SURGERY JUSTIFIED? M. Agaskar, N. Ghorpade and M. Mohajeri Department of Cardiothoracic Surgery, Barwon Health, The Geelong Hospital, Victoria, Australia Compromised immune system in HIV/AIDS patients and their limited life expectancy has been a major concern about considering cardiac surgery for them. However, with growing number of HIV/AIDS patient population, longer survival with the use of Highly Active Antiretroviral Therapy (HAART) and risk of development of premature coronary artery disease related to protease inhibitors; it is time to adopt more liberal surgical approach in the management of cardiac diseases in HIV/AIDS patients. We report a case of a known AIDS patient who successfully underwent coronary artery bypass grafting last year at the Geelong Hospital. This patient’s postoperative course was free from any complications, in particular, no infections and no exacerbation of AIDS. Ten months after the surgery, he continues to do well, he is free from angina and his HIV infection is well under control on antiretroviral therapy. We will discuss the justification of offering cardiac surgery to HIV/AIDS patients, patient selection criteria and safety measures to be taken during the operation. References 1. A Aris, JL Pomar, E Saura. Cardiopulmonary bypass in HIVpositive patients. Ann. Thorac. Surg. 1993; 55: 104–8. 2. V Mahan, J Balaguer, T Pezzella, T Vender Salm, B Mady. Successful Coronary Artery Surgery in a Patient With AIDS. Ann. Thorac. Surg. 2000; 70: 1698–9. 3. D Flum, D Tyras, M Wallack. Coronary Artery Bypass Grafting in Patients with Human Immunodeficiency Virus. J. Card. Surg. 1997; 12: 98–101. 4. M Sousa, V Jebara, J Fabiani, S Castel, C Acar, P Grare, J Dib, A Deloche, A Carpentier. J. Card. Surg. 1992; 7: 240–4. 5. K Henry, H Melroe, J Huebsch, J Hermundson, C Levine, L Swensen, J Daley. Severe premature coronary artery disease with protease inhibitors. Lancet 1998; 351: 1328. 6. D Condit, R Frater. Human Immunodeficiency Virus and the Cardiac Surgeon: A Survey of Attitudes. Ann. Thorac. Surg. 1999; 67: 1203–4. 7. R Pollock, F Ames, P Rubio et al. Protracted severe immune dysregulation induced by cardiopulmonary bypass: a predisposing etiologic factor in blood transfusion related AIDS? J. Clin. Lab. Immunol. 1987; 22: 1–5. 8. The CASCADE (Concerted Action on SeroConversion to AIDS and Death in Europe) Collaboration. Survival after introduction of HAART in people with known duration of HIV-1 infection. Lancet 2000; 355: 1158–9. 9. The CASCADE (Concerted Action on SeroConversion to AIDS and Death in Europe) Collaboration. Time from HIV-1 seroconversion to AIDS and death before widespread use of highly active antiretroviral therapy: a collaborative re-analysis. Lancet 2000; 355: 1131–7.

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MANAGEMENT OF COMPLEX SUPERIOR VENA CAVAL OBSTRUCTION Sanjay Sharma,1 David Cameron2 and Mark Edwards1 1Department of Cardiothoracic Surgery and 2Department of Radiology, Royal Perth Hospital, Perth, Western Australia Introduction: Whilst malignancy remains the most common cause of Superior vena caval obstruction, iatrogenic causes have increased in frequency. The management of Superior Vena Caval obstruction is variable incorporating thrombolysis, chemotherapy, radiotherapy, intravascular stenting and surgery. Best long-term results in the published literature lie with surgery with up to 90% 20 years patency rates described. Methods and results: Two cases of severe indiopathic superior vena caval obstruction are presented. Both patients had obliteration of all major thoracic and neck venous structures making management extremely difficult. Case one presented with intractable chylothorax and ultimately succumbed despite thrombolysis, stenting, pleuro-peritoneal shunting and intravascular stenting. This patient had rarely described venous collaterals through the liver. Case two has been managed with intravascular stenting, with the initial stent diameter too small, predisposing to recurrent thrombosis despite anticoagulation. This patient has required intermittent percutaneous thrombectomy. Discussion: Superior venal caval obstruction associated with loss of thoracic and neck vessels is a management dilemma for the Cardiothoracic surgeon. Our unit’s experience with stenting has not been favourable. This raises the question should early surgical intervention with bypass grafting be performed in preference to stenting? LEFT ATRIAL MYXOMA AND COEXISTENT CORONARY ARTERY DISEASE: SURGICAL MANAGEMENT Nand Kejriwal and Ravi Ullal Waikato Hospital, Hamilton, New Zealand Introduction: Myxomas are the most common primary cardiac tumor. 86% of these occur in the left atrium. The tumor can embolise in the coronary artery resulting in acute myocardial infarction. However it may rarely be associated with atherosclerotic coronary artery disease (CAD). We present our experience with one such patient who underwent removal of left atrial (LA) myxoma with simultaneous coronary artery bypass grafting with good result. Case report: A 68-year-old lady presented with a 12-month history of progressively worsening shortness of breath (NYHA class IV). She also experienced episodes of angina (CCS class III). Transthoracic echocardiography (TTE) showed a dilated left ventricle with impaired function and a mass in the left atrium. A transoesophageal echocardiography confirmed the presence of LA myxoma. This was nonpedunculated, and measured 4.5 cm × 2.5 cm. There was mild mitral regurgitation. A coronary angiogram revealed triple vessel disease. At surgery, myocardial protection was achieved by the infusion of cold blood cardioplegia through the aortic root. We tried to negotiate the retrograde catheter through the coronary sinus, but it proved difficult. After a right atriotomy, the myxoma was excised through an incision in the interatrial septum. The mitral valve looked normal. The defect in the septum was closed with a patch of bovine pericardium. The left internal mammary artery was anastomosed to the mid LAD. The individual saphenous vein grafts were anastomosed to the distal RCA, the second OM and the first diagonal artery, respectively. The patient made an uneventful recovery. Nine months later, she was in NYHA functional class I with no evidence of recurrence. Discussion: Patients with a left atrial myxoma present with nonspecific symptoms such as chest pain and syncope, which can

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also be present in the patients with CAD. The mean age of the patients with myxoma is 56 years, when CAD is also common. Tumor vascularity may be visible on coronary angiography, which could give a clue to the diagnosis of a cardiac myxoma associated with CAD. In cases of myxoma, a coronary angiography is recommended when a positive history of angina is obtained or when the patient is over 35 years of age. In this patient, a TTE was done to assess the left ventricular function and the presence of a myxoma was a surprise finding. A coronary angiogram was performed in the view of the age of the patient and the presence of angina and this revealed a triple vessel disease. Some authors have advocated coronary artery bypass grafting prior to resection of the myxoma to ensure adequate myocardial protection. We prefer removal of the myxoma first to avoid the risk of embolisation. As insertion of the retrograde coronary sinus catheter was difficult, we abandoned further attempts to minimize the manipulation of the heart. LA Myxoma coexisting with CAD is not common. A high index of suspicion is needed to avoid missing the combined diagnosis. With careful planning, a good surgical outcome can be expected. PSEUDOXANTHOMA ELASTICUM: IS THE LIMA A SUITABLE CONDUIT FOR CORONARY ARTERY BYPASS GRAFTING J. Iliopoulos, C. Manganas, N. Jepson and D. C. Newman University of New South Wales, Department of Cardiothoracic Surgery, Prince of Wales Hospital, Sydney, Australia Introduction: Pseudoxanthoma elasticum (PXE) is a rare inherited disorder of connective tissue that is associated with numerous systemic manifestations including premature severe coronary artery disease. The use of left internal mammary artery (LIMA) grafts in these patients remains controversial and requires clarification. Coronary artery revascularisation has been previously performed in seven PXE patients with coronary artery disease. There are no previous reports of PXE patients undergoing coronary artery bypass grafting in Australia. We report two cases of patients with PXE who have undergone coronary artery revascularisation. Case 1: A 29-year-old male with a known history of PXE presented with a four-month history of exertional chest pain and palpitations. Coronary angiography demonstrated the presence of severe triple vessel disease, and in August 1997, double coronary artery bypass grafting was performed using segments of reversed long saphenous vein. The postoperative course was unremarkable and the patient was discharged home Day 5 postoperatively. The patient has remained asymptomatic 4 years postoperatively. Coronary angiography performed at 36 months postoperatively showed patent grafts, which were disease free, with good run-off. There were no significant changes in the native circulation. Angiography of the in-situ LIMA showed a patent vessel that was macroscopically free of disease. Case 2: A 56-year-old-male with a known history of PXE presented with unstable angina. Coronary angiography demonstrated the presence of severe triple vessel disease and in June 2001, coronary artery bypass grafting was performed. Preoperative angiography of the LIMA showed a patent vessel that was free of disease, and the LIMA was anastomosed sequentially to the left anterior descending artery and to the first diagonal branch. Reversed saphenous vein was anastomosed sequentially to the postero-lateral right coronary artery, marginal circumflex artery, and to the intermediate coronary artery. The postoperative course was unremarkable and the patient was discharged home Day 5 postoperatively. The patient has remained asymptomatic 2 months postoperatively. Biopsy of the saphenous vein graft, mammary artery, and aortic wall showed no evidence of elastic degeneration. Conclusions: Coronary artery revascularization remains a feasible

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and beneficial treatment for coronary artery disease in patients with PXE. Careful angiographic evaluation of the LIMA and coronary arteries is required in patients with PXE with suspected coronary artery disease. A nonstenosed LIMA at angiography may be safely used as a conduit for coronary artery revascularisation. SURGICAL MANAGEMENT OF PLEURAL COMPLICATIONS FOLLOWING CORONARY ARTERY BYPASS SURGERY R. Moshinsky, F. Daniels, S. Knight and C. P. Clarke Austin & Repatriation Medical Centre, Melbourne, Australia Introduction: Pleural effusions occur in up to 90% of patients following coronary artery bypass surgery. The majority are small and self-limiting and do not cause significant problems. In a small percentage of patients however, pleural complications following coronary artery bypass surgery will cause significant morbidity. Persistent pleural collections may lead to trapped-lung syndrome requiring surgical management. Method: This study consisted of a retrospective analysis of patients referred to the thoracic surgery unit for operative management of pleural complications following cardiac surgery during the period January 1992 to December 2000. 10 patients were retrieved from the thoracic surgery database for this period. Results: All 10 patients required decortication for trapped-lung syndrome. In 5 patients it was possible to perform the decortication with VATS techniques. The other 5 patients required thoracotomy. The persistent pleural effusions caused significant morbidity in all patients prior to definitive surgical management. One patient underwent six admissions to hospital for drainage of pleural effusions prior to definitive surgery. No patient required further pleural drainage thereafter. Discussion: A small number of pleural collections post coronary artery bypass surgery will result in significant patient morbidity. Patients with persistent or recurrent pleural collections may benefit from early surgical management to prevent the development of trapped lung syndrome. In our experience, surgical management of pleural complications following coronary bypass surgery could be achieved with VATS techniques in 50% of the cases. DOES LEFT VENTRICULAR RECONSTRUCTION INFLUENCE OUTCOME IN PATIENTS WITH ISCHEMIC LEFT VENTRICULAR DYSFUNCTION? – CASE CONTROL STUDY Mitsumasa Hata, Jai Raman, Siven Seevanayagam and Brian F. Buxton The Department of Cardiac Surgery, Austin & Repatriation Medical Centre, University of Melbourne, Melbourne, Australia Objective: Recent studies have suggested that increased left ventricular size is a risk factor for perioperative mortality in patients with low ejection fraction (EF) undergoing coronary bypass surgery (CABG). We previously presented a new method of geometric left ventricular reconstruction (GER) as representing a more physiologically effective repair. The aim of this study is to assess whether GER confers benefits compared to patients undergoing CABG alone. Methods: Between July 1996 and July 2001, 116 patients with low EF of less than 35% have undergone CABG in Austin Hospital. We divided them into two groups. Group I consisted of 52 patients undergoing isolated CABG. Group II consisted 64 patients undergoing CABG and GER. We compared the two groups in terms of EF, NYHA class, incidence of recurrent heart failure, and mortality. Results: Average number of grafts was 3.1 ± 0.7 in group I and 3.0 ± 0.8 in group II, respectively. Complete arterial CABG was performed in 13 patients (25.5%) of group I and 27 (42.2%) of group

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II (NS). Preoperative EF was 27.7 ± 6.1% in group I and 27.4 ± 5.7% in group II, respectively (NS), with significant improvement in both groups. NYHA class were also significantly improved postoperatively (from 3.3 to 1.8 in group I, and 3.6–1.7 in group II). There were 15 patients (28.8%) hospitalized for heart failure in group I, postoperatively, compared to 7 patients (10.9%) in group II (P = 0.026). Cardiac event free rate was also significantly higher in group II (88.9% in group II vs 70.6% in group I, P = 0.05). The actuarial survival rate was 88.2% in group I and 95.3% in group II, respectively. Conclusions: Left ventricular reconstruction along with CABG for ischemic ventricular dysfunction may provide symptomatic and survival benefits, compared to CABG alone. AVOIDING THE PUMP IN TRICUSPID VALVE ENDOCARDITIS – VEGETECTOMY UNDER IN-FLOW OCCLUSION Mitsumasa Hata, Jai Raman and Rinaldo Bellomo Department of Cardiac Surgery and Intensive Care, Austin & Repatriation Medical Centre, University of Melbourne, Heidelberg, Australia Background: Surgical treatment of tricuspid valve endocarditis (TVE) ranges from vegetectomy to valve replacement, with the use of cardiopulmonary bypass, with risks of systemic and lung

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complications. We present our experience with tricuspid valve vegetectomy under in-flow occlusion. Methods: Between July, 1998 and July, 2001, seven patients with a mean age of 27 years underwent tricuspid valve vegetectomy under vena caval in-flow occlusion (VCIO). All of these patients also had drainage of bilateral pleural effusions and decortication of empyemas in 3 patients, at the same sitting, through the sternotomy incision. Six of the seven had methicillin sensitive staphylococcus aureus and one had streptococcus viridans positive blood cultures. All patients had significant bilateral lung infiltrates, and significant renal impairment at the time of surgery, while three had been on high dose intravenous antibiotics for over 72 h. Five patients had postoperative high volume veno-venous hemofiltration. Results: There were no deaths. Mean VCIO time was 2 min. All patients had resolution of sepsis within 48 h and improvement in respiratory status. Five patients had trivial and two had moderate tricuspid regurgitation. There was significant adsorption of C3A and C5A by hemofiltration. Six patients were discharged home within 14 days with no long-term sequelae. One patient required long-term dialysis for renal failure. One patient required a late thoracotomy for drainage of a loculated empyema. Conclusions: Tricuspid valve vegetectomy can be performed safely under VCIO. The sternotomy approach allows access and intervention to both pleural cavities. HVVF promotes removal of inflammatory mediators thus improving recovery.

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Author Index 16th Annual Inter ASC–ASCTS Meeting *Presenting Author Agaskar, M. A50* Ali, A. A39 Baker, R. A. A41 Bannon, P. G. A40, 41, 43, 44 Bayfield, M. S. A40, 41, 43 Bellomo, R. A52 Boyd, A. A36 Brizard, C. P. A36 Bullock, A. A36 Buxton, B. F. A36, 38, A45, A47, A51 Byrne, D. A44 Byrne, M. A38 Cameron, D. A50 Chard, R. B. A43 Choong, C. K. A45* Christy, K. A38 Clarke, A. J. B. A39* Clarke, C. P. A39*, A51 Cochrane, A. D. A36* Cropper, J. A41 Daniels, F. A51 Davis, B. B. A40, 47 Deng, Y. A40* Dignan, R. A44* Doi, K. A36* Edwards, J. A36 Edwards, M. A50 Elkins, R. C. A46 Esmore, D. S. A38 Esmore, D. A40, 42, 47 Feneley, M. A41 Finucane, F. A39 Fowler, K. A44 French, B. G. A44* Fukuda, H. A38* Fukuhiro, Y. A42 Gardner, M. A. H. A46, 48 Gardner, M. A45 Garlick, B. A46 Garlick, S. A41 Ghorpade, N. A50 Gillies, R. M. A42, 44 Grant, P. W. A37*, 45, 48 Harrocks, S. A44, 46, 49 Hart, G. J. A48* Hata, M. A36*, 45*, 47*, 51*, 52*

Heald, S. A49 Hicks, M. A41 Hogan, P. A44 Holsworth, L. A37 Hughes, C. F. A40, 41, 43 Iliopoulos, J. A42*, 44*, 48, 51* Ishikawa, S. A38* Jalali, H. J. A39 Jalali, H. A45, 46 James, A. A36 Jepson, N. A51 Kang, D. A36 Kang, N. A43* Kejriwal, N. A49*, 50* Kerr, A. R. A47 Kerr, A. A39 Kesteven, S. A41 Knight, J. L. A41 Knight, S. A51 Kritharides, L. A40, 41, 43 Lane, M. M. A46 Law, D. A37 Long, G. A49 Lyon, W. A40*, 42 Macdonald, P. A41 Mack, J. A. A38 Manganas, C. A42, 44, 51 Manson, N. A45 Marasco, S. F. A47* Marasco, S. A40 Matalanis, G. A36, 45, 47 McEwan, W. A38 McKay, G. A38* Menahem, S. A36 Mohajeri, M. A50 Moloney, C. A42 Moshinsky, R. A51* Mosshinsky, R. A39 Mossop, P. A43 Moten, S. C. M. A41* Munro, P. E. A46 Newman, D. C. A37, 42, 44, 45, 51 Ngo, T. A37 Nicholson, I. A. A43 Nixon, I. A43 O’Brien, M. F. A46* O’Brien, M. A44, 49 Ou, R. A40, 42

Passage, J. A49* Paterson, H. S. A40 Pepe, S. A40, 42 Pick, A. A40 Poer, J. A38 Pohlner, P. G. A39, 46 Rabinov, M. A40 Raman, J. S. A38*, 45, 51, 52 Raudkivi, P. J. A47 Raudkivi, P. A39 Redzepagic, S. A43 Rosalion, A. A45 Rosenfeldt, F. L. A37, 40, 42* Rumball, E. M. A47* Ryan, J. A41* Saha, K. A38 Seevanayagam, S. A39, 45, 51 Sharma, S. A50* Sheeran, F. A40 Silvers, A. J. A37 Singh, H. A38 Smith, J. A. A37*, 38, 40, 46* Snell, G. I. A37, 46 Soto, C. A41 Stafford, E. G. A46 Stafford, G. A48 Stephens, F. A44 Tam, R. A45, 49 Tesar, P. A48 Thomson, D. A36 Thomson, K. R. A37 Thornton, A. A44 Ullal, R. A49, 50 Vallely, M. P. A40*, 41*, 43* Walsh, W. R. A42, 44 Waters, K. N. A38 Webber, S. A44 Weiss, B. A45*, 48* Williams, T. J. A37 Wilson, M. A41 Wilson, T. A43 Windsor, M. A49 Wolfenden, H. D. A37, 44, 45 Wong, M. A40 Wowk, M. A40, 42 Yamaguchi, H. A39* Zhang, M. J. A42

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