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Benefits Of warm-blood cardioplegic induction to energy-depleted heart
Asia Pacific
J Thorac
Cardiovasc
Surg 1994;3(1)
Cardiothoracic
Aortic Stenosis: A Natural Progression Study
abstracts
cerebral perfusion via a superior vena cava catheter. One patient died during surgery (4.2%). Morbidity included reexploration for bleeding (3), neurologic event (4), tracheostomy (4), myocardial infarct (1). renal insufficiency (2), sternal wound infection (l), pacemaker (1), and reoperation for false aneurysm (2). Kaplan-Meier survival probabilities from the time of operation at 12, 24 and 36 months were 88.0%, 83.5% and 66.7% respectively. These results suggest that surgery on the transverse aortic arch is relatively safe, with low operative mortality and good short-term outcome.
J.R.M. Edwards,M.A.H. Gardner,M.F. O’Brien The Prince Charles Hospital, Brisbane Queensland, Australia Aortic valve replacement has been offered to 25 patients at the Prince Charles Hospital with a history of open heart surgery. Twenty-one patients had previous coronary artery grafts, and four had mitral valve surgery. The interval between operations ranged from 10 months to 13 years. The rate of progression of aortic valve disease is variable. However, patients with an aortic valve gradient of 20 mmHg or more at initial operation all come to aortic valve replacement within 6 years. Gradients were observed to progress at a rate of 9 mmHg per year in bicuspid and 8 mmHg per year in degenerative valves. Progression of disease from even moderate gradients of 35 to 40 mmHg can be manifested by loss of ventricular function rather than increase in gradient. Morbidity and mortality of aortic valve replacement have reduced. Aortic valve repair is not a safer alternative. Reoperative cardiac surgery still entails risks not present at primary procedures. Native valves with a gradient of 20 mmHg or more deteriorate faster than prosthetic valves. From this series, aortic valve replacement should be performed at the same time as coronary artery surgery if the stenotic gradient is 20 mrnHg or more.
Antibiotic Incorporation
Into Prosthetic Heart Valves
B.G. French, K. Wilson, M.L. Wong, M.F. O’Brien The Prince Charles Hospital, Brisbane Queensland, Australia Prosthetic valve endocarditis can be a life threatening condition. Patients particularly at risk are those in whom valve replacement is performed for endocarditis (native and prosthetic valvular). We have studied the incorporation of the antibiotic rifampicin into the dacron sewing ring of the St Jude mechanical valve as well as its retention in vivo after implantation into goat aorta. Several methods of incorporating rifampicin into the sewing ring material were examined. Our data suggests the best results occur when autoclaved, autologous blood is used as a sealant to which the antibiotic is bound by passive soaking. Using this method we consistently demonstrated a linear relationship between rifampicin activity in the sewing ring during the next 5 days. The rifarnpicin activity in the sewing ring at 5 days was highly inhibitory to a pure growth of Staphylococcus aureus on agar. These results suggest that our method of incorporating rifampicin into the sewing ring of the St Jude mechanical valve imparts significant local antibacterial activity for at least 5 days after valve implantation. A current project is assessing the resistance of these valves to Staphylococcal infection.
Transverse Aortic Arch Surgery: Results In 24 Patients S. Finney, P. Tesar, M. Gardner The Prince Charles Hospital, Brisbane Queensland, Australia Surgical repair of the transverse aortic arch, whether for aneurysm, dissection, or trauma, has high morbidity and mortality. Advances in surgical technique, in particular the use of hypothermic circulatory arrest (HCA), have made transverse arch surgery safer. However, it continues to require refinement. To examine the success of surgical procedures performed on the transverse aortic arch, 24 patients operated on between 1986 and 1993 at the Prince Charles Hospital and the St Andrew’s War Memorial Hospital were reviewed. Mean age was 61.4 years for the 16 male and 8 female patients. Preoperative diagnoses were: 9 arch aneurysms (the majority extended from the ascending aorta), 4 saccular aneurysms arising from the transverse arch, ‘7 acute type A dissections with intimal tear in the arch, 2 chronic dissections, and 2 posttraumatic false aneurysms. Reparative procedures were tailored to individual patient pathology: total arch replacement (7 patients), hemiarch replacement (1 1), saccular aneurysm resection and patch (4), and posttraumatic pseudoaneurysm repair (2). Additional procedures included ascending aortic arch replacement (16), aortic valve resuspension or replacement (7), CAB (5), and allograft root replacement (1). Early surgical technique in 10 patients included the use of hypothermia (22”-28”C), antegrade cerebral perfusion via brachiocephalic and left common carotid cannulas, and distal circulatory arrest (mean duration 22.6 min). Recent technique used in 13 patients utilised HCA (18”-20°C; mean 31.3 min). Five of these patients had retrograde
Benefits Of Warm-blood Cardioplegic Induction To Energy-depleted Heart K. Iwaoka, H. Shirotani, N. Kamada Department of Cardiovascular Surgery, Kinki University School of Medicine, Osaka, Japan and Royal North Shore Hospital, Sydney New South Wales, Australia This study was designed to compare the efficacy of different blood cardioplegic induction (CI) temperatures in improving myocardial metabolic recovery in energydepleted hearts. To monitor changes of adenosine triphosphate (ATP) and creatine phosphate (CP), 3lPnuclear magnetic resonance was obtained from isolated rabbit hearts. Inosine content of coronary sinus effluent was analysed by high-performance liquid chromatography, and myocardial water content was measured in 5 hearts of each group at the end of the cardioplegic arrest. The control spectra were collected from each heart during the first 30 min of controlled perfusion with Krebs-Henseleite bicarbonate buffer at 37°C. Fifty percent depletion of myocardial ATP was produced in each group by 30 min of
45
Asia Pacific
J Thorac
Cardiovasc
Surg 1994;3(1)
Cardiothoracic
global ischaemia at 37°C. This was followed by blood cardioplegic induction at 37°C (CI-37:n=lO), 25°C (CI-25:n=lO) and 10°C (CI-lO:n=lO), respectively. Subsequently, cold-blood cardioplegia was done on each group 3 times, every 20 min at 10°C. Five hearts of each group were reperfused for 30 min with Krebs-Henseleite bicarbonate buffer at 37°C. The inosine leakage at cardioplegic induction was least in the CI-25 group (CI-25:0.64 f O.lSymol vs. CI10:1.05 k 0.27pmol and CI-37:1.46 + 0.24pmo1, p < 0.05). After 30 min of reperfusion, the CI-25 group showed good ATP recovery (CI-2584.1 + 16.2% vs. CI10:55.7 + 13.2% and CI-37:54.0 2 16.4%, p < 0.05). However the CI-10 group presented the smallest myocardial water content compared to CI-25 and CI-37 (CI-10:82.4 + 0.5% vs. CI-25:83.6 + 0.7% and CI-37:84.9 f 1.5%, p < 0.05 to CI-37). We conclude that in the group of CI-25, inosine leakage was minimised and myocardial ATP and CP recovered better than in the other 2 groups. In this condition, CI-25 was better than CI-37 and CI-10 in myocardial metabolic protection.
The indication for implantation was documented sustained ventricular tachycardia or aborted sudden cardiac death, not directly associated with acute cardiac ischaemia, and not controlled with anti-arrhythmic medication. Seven patients had cardiomyopathy; 28 had ischaemic heart disease. In 10 patients, ICD implantation was associated with concomitant ventricular aneurysm and/or coronary artery surgery. ,A further 6 patients had previously undergone coronary artery bypass grafting. Ten of the 35 patients have had their defibrillating patches placed at stemotomy, 21 at thoracotomy and four transvenously (2 patients also required a subcutaneous patch). Since 1984 there has been a gradual evolution both in the ICD devices and in the method of their lead placement. Initially all patients had epicardial pace-sense leads and pericardial or epicardial defibrillator patches. Subsequently the pace-sense leads have been placed endocardially. Now there is a move toward a totally transvenous lead implantation system. The device itself has become lighter and smaller, and evolved to having pacing, cardioverting and defibrillating functions. These have been consistently placed between the left rectus muscle and the posterior rectus sheath. Long-term follow-up has been 100% (1 month to 5 years). There have been no perioperative deaths and minimal morbidity, with 1 patient returning to the operating theatre for control of bleeding. There have been 3 late deaths (one from arrhythmia; two from heart failure); 1 patient underwent cardiac transplantation. Two units needed replacement due to power failure. One set of endocardial leads needed replacement following dislodgement. Our experience with the devices has been satisfactory.
Successful Long-term Outcome With Prolonged Ischaemic Tie Allografts G. Matalanis, E. Briganti, P. Bergin, D. Esmore Heart and Lung Replacement Service, Alfred Hospital Melbourne, Victoria, Australia The limited availability of cardiac allografts, together with increasing numbers of patients on the waiting list, restricts the population servicing in heart transplantation. An increase in the available donor pool has been facilitated by the utilisation of allografts with periods of ischaemia greater than 240 minutes. Consideration of the effect of allograft ischaemic time on recipient outome is particularly relevant to the Australian experience, given the size of the country and the location of the transplant units on the Eastern coast, necessitating long retrieval times if donor utilisation and population servicing are to be maximised. Of 150 cardiac transplants performed between February 1989 and March 1993, 44 (29%) were with allografts periods of ischaemia greater than 240 minutes. Basic recipient and donor demographics were similar in the 2 groups. Long-term cardiac allograft function is not compromised by prolonged ischaemic time, according to our data. Current data suggests that transcontinental cardiac allograft retrieval can be performed safely without long-term risk to cardiac transplant recipients and with an associated improvement in population servicing.
Implantuhle Cardioverter-defrihrillator Melbourne Hospital
abstracts
Early Experience With The Jyros Prosthetic Valve C. Munsch, J. McLenachan Leeds General Infirmary, Leeds, U.K. The innovative design of the Jyros valve combines the benefits of a wholely pyrolytic carbon with asymmetric rotating leaflets. This design reduces the potential for stagnation and thrombosis at the hinge mechanism. In vitro testing at IBEES Sheffield has demonstrated excellent haemodynamic and wear characteristics. The valve has been available clinically in the U.K. for 2 years and has been implanted by 6 surgeons in 5 centres. There have been 156 patients implanted, with a follow-up of 46,729 patient months. There have been 4 non-valve related hospital deaths and 2 incidences of endocarditis. There has been 1 non-valve related late death. There have been no reported thromboembolic episodes and no haemolysis. Ten mitral implants in our centre have been recently reviewed with doppler echocardiography. Calculated mean valve area for the 28 mm prosthesis was 3.30 cm2 (range, 1.75 to 4.92), comparing favourably with existing bileaflet valves. Rotation of the leaflets has been detected by radiological screening. Although we have relatively little follow-up data, early results for this new valve are encouraging.
Usage At Royal
T. McKenzie, J. Tatoulis Department of Cardio-Thoracic Surgery, Royal Melbourne Hospital, Melbourne, Victoria, Australia Between 1984 and May 1993, 37 implantable cardioverter-defibrillators (ICD) have been implanted in 35 patients. The patient population consisted of 29 males and 6 females with an average age of 58.5 years at implantation.
46
J Thorac
Cardiovasc
Surg 1994;3(1)
Cardiothoracic
Aortic Stenosis: A Natural Progression Study
abstracts
cerebral perfusion via a superior vena cava catheter. One patient died during surgery (4.2%). Morbidity included reexploration for bleeding (3), neurologic event (4), tracheostomy (4), myocardial infarct (1). renal insufficiency (2), sternal wound infection (l), pacemaker (1), and reoperation for false aneurysm (2). Kaplan-Meier survival probabilities from the time of operation at 12, 24 and 36 months were 88.0%, 83.5% and 66.7% respectively. These results suggest that surgery on the transverse aortic arch is relatively safe, with low operative mortality and good short-term outcome.
J.R.M. Edwards,M.A.H. Gardner,M.F. O’Brien The Prince Charles Hospital, Brisbane Queensland, Australia Aortic valve replacement has been offered to 25 patients at the Prince Charles Hospital with a history of open heart surgery. Twenty-one patients had previous coronary artery grafts, and four had mitral valve surgery. The interval between operations ranged from 10 months to 13 years. The rate of progression of aortic valve disease is variable. However, patients with an aortic valve gradient of 20 mmHg or more at initial operation all come to aortic valve replacement within 6 years. Gradients were observed to progress at a rate of 9 mmHg per year in bicuspid and 8 mmHg per year in degenerative valves. Progression of disease from even moderate gradients of 35 to 40 mmHg can be manifested by loss of ventricular function rather than increase in gradient. Morbidity and mortality of aortic valve replacement have reduced. Aortic valve repair is not a safer alternative. Reoperative cardiac surgery still entails risks not present at primary procedures. Native valves with a gradient of 20 mmHg or more deteriorate faster than prosthetic valves. From this series, aortic valve replacement should be performed at the same time as coronary artery surgery if the stenotic gradient is 20 mrnHg or more.
Antibiotic Incorporation
Into Prosthetic Heart Valves
B.G. French, K. Wilson, M.L. Wong, M.F. O’Brien The Prince Charles Hospital, Brisbane Queensland, Australia Prosthetic valve endocarditis can be a life threatening condition. Patients particularly at risk are those in whom valve replacement is performed for endocarditis (native and prosthetic valvular). We have studied the incorporation of the antibiotic rifampicin into the dacron sewing ring of the St Jude mechanical valve as well as its retention in vivo after implantation into goat aorta. Several methods of incorporating rifampicin into the sewing ring material were examined. Our data suggests the best results occur when autoclaved, autologous blood is used as a sealant to which the antibiotic is bound by passive soaking. Using this method we consistently demonstrated a linear relationship between rifampicin activity in the sewing ring during the next 5 days. The rifarnpicin activity in the sewing ring at 5 days was highly inhibitory to a pure growth of Staphylococcus aureus on agar. These results suggest that our method of incorporating rifampicin into the sewing ring of the St Jude mechanical valve imparts significant local antibacterial activity for at least 5 days after valve implantation. A current project is assessing the resistance of these valves to Staphylococcal infection.
Transverse Aortic Arch Surgery: Results In 24 Patients S. Finney, P. Tesar, M. Gardner The Prince Charles Hospital, Brisbane Queensland, Australia Surgical repair of the transverse aortic arch, whether for aneurysm, dissection, or trauma, has high morbidity and mortality. Advances in surgical technique, in particular the use of hypothermic circulatory arrest (HCA), have made transverse arch surgery safer. However, it continues to require refinement. To examine the success of surgical procedures performed on the transverse aortic arch, 24 patients operated on between 1986 and 1993 at the Prince Charles Hospital and the St Andrew’s War Memorial Hospital were reviewed. Mean age was 61.4 years for the 16 male and 8 female patients. Preoperative diagnoses were: 9 arch aneurysms (the majority extended from the ascending aorta), 4 saccular aneurysms arising from the transverse arch, ‘7 acute type A dissections with intimal tear in the arch, 2 chronic dissections, and 2 posttraumatic false aneurysms. Reparative procedures were tailored to individual patient pathology: total arch replacement (7 patients), hemiarch replacement (1 1), saccular aneurysm resection and patch (4), and posttraumatic pseudoaneurysm repair (2). Additional procedures included ascending aortic arch replacement (16), aortic valve resuspension or replacement (7), CAB (5), and allograft root replacement (1). Early surgical technique in 10 patients included the use of hypothermia (22”-28”C), antegrade cerebral perfusion via brachiocephalic and left common carotid cannulas, and distal circulatory arrest (mean duration 22.6 min). Recent technique used in 13 patients utilised HCA (18”-20°C; mean 31.3 min). Five of these patients had retrograde
Benefits Of Warm-blood Cardioplegic Induction To Energy-depleted Heart K. Iwaoka, H. Shirotani, N. Kamada Department of Cardiovascular Surgery, Kinki University School of Medicine, Osaka, Japan and Royal North Shore Hospital, Sydney New South Wales, Australia This study was designed to compare the efficacy of different blood cardioplegic induction (CI) temperatures in improving myocardial metabolic recovery in energydepleted hearts. To monitor changes of adenosine triphosphate (ATP) and creatine phosphate (CP), 3lPnuclear magnetic resonance was obtained from isolated rabbit hearts. Inosine content of coronary sinus effluent was analysed by high-performance liquid chromatography, and myocardial water content was measured in 5 hearts of each group at the end of the cardioplegic arrest. The control spectra were collected from each heart during the first 30 min of controlled perfusion with Krebs-Henseleite bicarbonate buffer at 37°C. Fifty percent depletion of myocardial ATP was produced in each group by 30 min of
45
Asia Pacific
J Thorac
Cardiovasc
Surg 1994;3(1)
Cardiothoracic
global ischaemia at 37°C. This was followed by blood cardioplegic induction at 37°C (CI-37:n=lO), 25°C (CI-25:n=lO) and 10°C (CI-lO:n=lO), respectively. Subsequently, cold-blood cardioplegia was done on each group 3 times, every 20 min at 10°C. Five hearts of each group were reperfused for 30 min with Krebs-Henseleite bicarbonate buffer at 37°C. The inosine leakage at cardioplegic induction was least in the CI-25 group (CI-25:0.64 f O.lSymol vs. CI10:1.05 k 0.27pmol and CI-37:1.46 + 0.24pmo1, p < 0.05). After 30 min of reperfusion, the CI-25 group showed good ATP recovery (CI-2584.1 + 16.2% vs. CI10:55.7 + 13.2% and CI-37:54.0 2 16.4%, p < 0.05). However the CI-10 group presented the smallest myocardial water content compared to CI-25 and CI-37 (CI-10:82.4 + 0.5% vs. CI-25:83.6 + 0.7% and CI-37:84.9 f 1.5%, p < 0.05 to CI-37). We conclude that in the group of CI-25, inosine leakage was minimised and myocardial ATP and CP recovered better than in the other 2 groups. In this condition, CI-25 was better than CI-37 and CI-10 in myocardial metabolic protection.
The indication for implantation was documented sustained ventricular tachycardia or aborted sudden cardiac death, not directly associated with acute cardiac ischaemia, and not controlled with anti-arrhythmic medication. Seven patients had cardiomyopathy; 28 had ischaemic heart disease. In 10 patients, ICD implantation was associated with concomitant ventricular aneurysm and/or coronary artery surgery. ,A further 6 patients had previously undergone coronary artery bypass grafting. Ten of the 35 patients have had their defibrillating patches placed at stemotomy, 21 at thoracotomy and four transvenously (2 patients also required a subcutaneous patch). Since 1984 there has been a gradual evolution both in the ICD devices and in the method of their lead placement. Initially all patients had epicardial pace-sense leads and pericardial or epicardial defibrillator patches. Subsequently the pace-sense leads have been placed endocardially. Now there is a move toward a totally transvenous lead implantation system. The device itself has become lighter and smaller, and evolved to having pacing, cardioverting and defibrillating functions. These have been consistently placed between the left rectus muscle and the posterior rectus sheath. Long-term follow-up has been 100% (1 month to 5 years). There have been no perioperative deaths and minimal morbidity, with 1 patient returning to the operating theatre for control of bleeding. There have been 3 late deaths (one from arrhythmia; two from heart failure); 1 patient underwent cardiac transplantation. Two units needed replacement due to power failure. One set of endocardial leads needed replacement following dislodgement. Our experience with the devices has been satisfactory.
Successful Long-term Outcome With Prolonged Ischaemic Tie Allografts G. Matalanis, E. Briganti, P. Bergin, D. Esmore Heart and Lung Replacement Service, Alfred Hospital Melbourne, Victoria, Australia The limited availability of cardiac allografts, together with increasing numbers of patients on the waiting list, restricts the population servicing in heart transplantation. An increase in the available donor pool has been facilitated by the utilisation of allografts with periods of ischaemia greater than 240 minutes. Consideration of the effect of allograft ischaemic time on recipient outome is particularly relevant to the Australian experience, given the size of the country and the location of the transplant units on the Eastern coast, necessitating long retrieval times if donor utilisation and population servicing are to be maximised. Of 150 cardiac transplants performed between February 1989 and March 1993, 44 (29%) were with allografts periods of ischaemia greater than 240 minutes. Basic recipient and donor demographics were similar in the 2 groups. Long-term cardiac allograft function is not compromised by prolonged ischaemic time, according to our data. Current data suggests that transcontinental cardiac allograft retrieval can be performed safely without long-term risk to cardiac transplant recipients and with an associated improvement in population servicing.
Implantuhle Cardioverter-defrihrillator Melbourne Hospital
abstracts
Early Experience With The Jyros Prosthetic Valve C. Munsch, J. McLenachan Leeds General Infirmary, Leeds, U.K. The innovative design of the Jyros valve combines the benefits of a wholely pyrolytic carbon with asymmetric rotating leaflets. This design reduces the potential for stagnation and thrombosis at the hinge mechanism. In vitro testing at IBEES Sheffield has demonstrated excellent haemodynamic and wear characteristics. The valve has been available clinically in the U.K. for 2 years and has been implanted by 6 surgeons in 5 centres. There have been 156 patients implanted, with a follow-up of 46,729 patient months. There have been 4 non-valve related hospital deaths and 2 incidences of endocarditis. There has been 1 non-valve related late death. There have been no reported thromboembolic episodes and no haemolysis. Ten mitral implants in our centre have been recently reviewed with doppler echocardiography. Calculated mean valve area for the 28 mm prosthesis was 3.30 cm2 (range, 1.75 to 4.92), comparing favourably with existing bileaflet valves. Rotation of the leaflets has been detected by radiological screening. Although we have relatively little follow-up data, early results for this new valve are encouraging.
Usage At Royal
T. McKenzie, J. Tatoulis Department of Cardio-Thoracic Surgery, Royal Melbourne Hospital, Melbourne, Victoria, Australia Between 1984 and May 1993, 37 implantable cardioverter-defibrillators (ICD) have been implanted in 35 patients. The patient population consisted of 29 males and 6 females with an average age of 58.5 years at implantation.
46