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Beating Heart Minimally Invasive Mitral Valve Surgery in Patients With Patent Coronary Bypass Grafts
Canadian Journal of Cardiology
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(2016) 1e6
Clinical Research
Beating Heart Minimally Invasive Mitral Valve Surgery in Patients With Patent Coronary Bypass Grafts Aly Ghoneim, MD,* Ismail Bouhout, MD, MSc,* Amine Mazine, MD, MSc, William Fortin, MD, Ismail El-Hamamsy, MD, PhD, Hugue Jeanmart, MD, Michel Pellerin, MD, and Denis Bouchard, MD, PhD Department of Cardiovascular Surgery, Montreal Heart Institute and Universite de Montre al, Montreal, Quebec, Canada
ABSTRACT
RESUM E
Background: Redo mitral valve surgery in patients with patent coronary bypass grafts carries a risk of graft injury and postoperative bleeding. We compare early results of reoperative minimally invasive on-pump beating heart mitral valve surgery (OPBMS) via mini thoracotomy vs the results of standard sternotomy mitral valve surgery (SSMS) in the presence of patent coronary bypass grafts. Methods: Between 2009 and 2015, 12 patients underwent OPBMS through a right mini thoracotomy and 6 patients underwent SSMS. All patients had at least 1 patent bypass graft. Results: Median age and EuroSCORE II were not statistically different between the 2 groups. There was no early death in the OPBMS group vs 1 death (17%) in the SSMS group. There was a statistically significant lower median perioperative blood loss in
pe tition de la chirurgie de la valve mitrale chez les Introduction : La re abilite des greffons après pontage coropatients montrant une perme sions des greffons et d’he morragie postnarien comporte un risque de le ratoire. Nous comparons les premiers re sultats de la re pe tition de la ope chirurgie minimalement invasive de la valve mitrale sous circulation sultats extracorporelle (CEC) à cœur battant par mini-thoracotomie vs les re sence de la chirurgie de la valve mitrale par sternotomie standard en pre abilite des greffons après pontage coronarien. d’une perme thodes : Entre 2009 et 2015, 12 patients ont subi la chirurgie de la valve Me mitrale sous CEC à cœur battant par mini-thoracotomie droite et 6 patients ont subi la chirurgie de la valve mitrale par sternotomie standard. Tous les au moins 1 greffon perme able après le pontage. patients ont montre sultats : L’âge me dian et l’EuroSCORE II n’e taient pas statistiqueRe rents entre les 2 groupes. Aucun de cès pre coce n’a e te ment diffe
As the population ages, the rate of repeated cardiac surgery is increasing, carrying a high risk of intraoperative and postoperative complications.1 Over time, some patients with previous coronary artery bypass grafting (CABG) surgery develop significant symptomatic mitral valve insufficiency. Correction of mitral regurgitation (MR) in these patients increases survival, reduces symptoms, and improves quality of life.2,3 However, repeated surgery for these patients remains a surgical challenge especially in the presence of patent bypass grafts.1,4 The standard median sternotomy approach comes with a risk of injuring the functioning grafts and/or cardiac structures.5,6
A right thoracotomy approach might provide a safer solution.6 Furthermore, in previous studies, this approach has been shown to reduce the surgery time and amount of blood loss.6,7 It also helps to avoid unnecessary tissue dissection and minimize the risk of injury to a patent left internal mammary artery (LIMA), venous grafts, and/or adherent ventricles. We assessed the hypotheses that redo on-pump beating mitral valve surgery (OPBMS) via a small mini thoracotomy for patients with patent bypass grafts can be safely performed. We reviewed our experience with redo mitral valve surgery in this setting and compared it with another control group of redo isolated mitral valve surgery through a conventional standard sternotomy.
Received for publication June 17, 2015. Accepted September 23, 2015.
Methods Between July 2009 and February 2015, we identified 18 consecutive patients who underwent mitral valve redo surgery in the context of previous isolated CABG. Patients with concomitant valvular surgeries were excluded. All patients had at least 1 patent graft. Redo OPBMS via a small mini thoracotomy was performed in 12 patients (67%), and 6 (33%)
*These authors contributed equally to this work and share first authorship. Corresponding author: Dr Denis Bouchard, Montreal Heart Institute, University of Montreal School of Medicine, 5000 Belanger St, Montreal, Quebec H1T 1C8, Canada. Tel.: þ1-514-376-3330 3715; fax: þ1-514593-2157. E-mail: [email protected] See page 5 for disclosure information.
http://dx.doi.org/10.1016/j.cjca.2015.09.016 0828-282X/Ó 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.
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Canadian Journal of Cardiology Volume - 2016
the OPBMS group compared with the SSMS group (200 vs 650 mL; P ¼ 0.005). Four patients (33%) in the OPBMS group required blood transfusion compared with 4 in the SSMS group (67%; P ¼ 0.32). There was 1 perioperative stroke (17%) and 1 acute myocardial infarction (17%) in the SSMS group. Four patients developed acute renal failure in the OPBMS group compared with 3 in the SSMS group (50%; P ¼ 0.62). The predischarge transthoracic echocardiogram showed 1 mitral regurgitation in all patients. Conclusions: Redo mitral surgery in patients with patent bypass grafts can safely be performed via minimally invasive mini thoracotomy on a beating heart. The main benefits of this approach are to avoid the sternotomy and decrease the amount of postoperative blood loss.
dans le groupe de chirurgie de la valve mitrale sous CEC à observe cès (17 %) a e te observe dans le groupe de cœur battant vs 1 de chirurgie de la valve mitrale par sternotomie standard. Une perte de diane significativement plus faible sur le plan statistique en sang me riope ratoire a e te observe e dans le groupe de chirurgie de la phase pe valve mitrale sous CEC à cœur battant comparativement au groupe de chirurgie de la valve mitrale par sternotomie standard (200 ml vs 650 ml; P ¼ 0,005). Quatre patients (33 %) du groupe de chirurgie de la valve mitrale sous CEC à cœur battant comparativement à 4 patients du groupe de chirurgie de la valve mitrale par sternotomie standard cessite une transfusion sanguine. Il y a eu 1 (67 %; P ¼ 0,32) ont ne re bral en phase pe riope ratoire (17 %) et 1 accident vasculaire ce infarctus du myocarde aigu (17 %) dans le groupe de chirurgie de la veloppe valve mitrale par sternotomie standard. Quatre patients ont de nale aiguë dans le groupe de chirurgie de la valve une insuffisance re mitrale sous CEC à cœur battant comparativement à 3 patients dans le groupe de chirurgie de la valve mitrale par sternotomie standard chocardiogramme transthoracique avant la sortie (50 %; P ¼ 0,62). L’e 1 re gurgitation mitrale chez tous les patients. de l’hôpital a montre pe tition de la chirurgie mitrale chez les patients Conclusions : La re abilite des greffons après pontage peut être montrant une perme alise e de manière sûre et minimalement invasive par minire thoracotomie à cœur battant. Les principaux avantages de cette vitement de la sternotomie et la diminution de la approche sont l’e de la perte de sang en phase postope ratoire. quantite
had a standard median sternotomy redo mitral valve surgery (SSMS). We retrospectively analyzed these 2 groups. Data were collected from medical records and our Valve Clinic database. Perioperative outcomes were defined according to the Society of Thoracic Surgeons guidelines for reporting mortality and morbidity.8 The local ethics committee approved the study and a waiver of consent was obtained. Surgical mortality was defined as death occurring within 30 days of surgery or during the index hospitalization.
to prevent LV ejection and optimize the surgical field. The mitral leaflets were inspected with direct vision and with thoracoscopic assistance, then standard mitral valve surgery (repair or replacement) was conducted.
Surgical approach of minimally invasive OPBMS The techniques for minimally invasive mitral approach and onpump beating mitral surgery have been described elsewhere.7,9-14 The same surgeon performed all surgeries in the OPBMS group. All patients were placed in a left lateral position and slightly rotated to elevate the left heart. External defibrillator pads were placed and a right-sided transvenous ventricular pacemaker lead was installed. A small (4-5 cm) muscle-sparing right mini thoracotomy was done and the right chest cavity was entered through the fourth intercostal space. After heparinization, the right femoral vein and artery were cannulated. The pericardium was incised carefully and the left atrium was exposed, 2 retraction stitches were placed above the pericardiophrenic bundle. Cardiopulmonary bypass was then initiated, a CO2 line was installed, and temperature was allowed to drift down to 34 C, while the mean systemic perfusion pressure was kept at approximately 80 mm Hg. There was no aortic clamping or cardioplegia administration. If present, the course of the right-sided patent bypass graft was identified and a standard left atriotomy in the Sondergaard groove was performed.15 Continuous venting of the left ventricle (LV) was obtained throughout the procedure. We used intermittent rapid ventricular pacing in 5 patients (42%)
Statistical analysis Statistical analyses were performed using Statistical Package for Social Sciences version 20 (SPSS; Chicago, IL). Continuous variables are presented as median (range) and categorical variables are presented as frequency (%). Variables were analyzed using nonparametric tests. Continuous variables were compared using the Mann-Whitney test and ordinal variables using Fisher exact test. Statistical significance was set at a ¼ 0.05. Results Patient baseline characteristics The median age of patients in the OPBMS group was 67 years (ranging from 59 to 79 years) and 68 years (ranging from 55 to 79 years) in the SSMS group (P ¼ 0.77). At the time of surgery, 11 patients (61%) had severe MR, 6 (33%) had moderate to severe MR, and 1 (2%) had moderate MR. A total of 16 patients (88%) had type IIIb MR and 2 patients (12%) had mixed type MR. All patients had patent LIMA grafts (100%). In the OPBMS group, 2 (17 %) had no patent venous grafts, 3 (25%) had a single patent venous graft, 6 (50%) had 2 patent venous grafts, and 1 patient (8%) had 3 patent venous grafts. In the SSMS group, 1 (17%) had both internal mammary artery grafts patent with 1 patent venous graft, 4 (66%) had 2 patent venous grafts, and 1 (17%) had 3 patent venous grafts. The preoperative left ventricular ejection fraction (LVEF) in the OPBMS group was 50% in 3
Ghoneim et al. Redo Beating Minimally Invasive Mitral Surgery
patients (25%), between 31% and 50% in 6 patients (50%) and < 30% in 3 patients (25%), and in the SSMS group was between 31% and 50% in 2 patients (33%) and < 30% in 4 patients (67%). In both groups, 6 (33%) patients had mild aortic insufficiency and 12 (67%) had a normal competent aortic valve. Median logistic EuroSCORE II was 8.8% (range, 3.2%-30%) in the OPBMS group compared with 10.7% (range, 1.6%-19.5%) in the SSMS group (P > 0.99). In the OPBMS group, 2 patients (17%) had chronic renal failure (not receiving permanent dialysis) vs 3 patients (50%) in the other group (P ¼ 0.34). Demographic data are presented in Table 1. Surgical findings Mitral valve repair was performed in 9 patients (50%) and replacement was performed in the other 9 (50%). In the OPBMS group, 1 patient (8%) had a perioperative unsuccessful mitral valve repair and underwent a mitral valve replacement in the same surgical sitting. In the SSMS group, 1 patient (17%) had a patent LIMA on a left anterior descending (LAD) graft injury during the sternotomy. This was successfully repaired with a saphenous venous patch and there was no perioperative myocardial infarction. All mitral valve repairs were done with a restrictive annuloplasty using a downsized ring: 3 patients (17%) with an Etlogix ring (Edwards Lifesciences, Irvine, CA), 4 (22%) with Carbomedics Annuloflo ring (Sorin Group, Saluggia, Italy) and 2 (11%) with Physio II ring (Edwards Lifesciences). One patient (6%) had artificial chordae added at P2 for a mixed type MR. Seven patients (39%) had their valve replaced with a perimount Carpentier-Edwards valve (Edwards Lifesciences) and 2 (11%) with the St Jude Epic biological mitral valve (St Jude Medical, Saint Paul, MN). Six patients (33%) had concomitant surgical procedures: 3 (17%) had a Maze procedure, 2 (11%) had an atrial septal defect (ASD) closure, and 1 (6%) had the Maze procedure and an atrial septal defect closure. There was no conversion to sternotomy in the OPBMS group. The median bypass time was 102 minutes (range, 55-156 minutes) in the OPBMS group and 116 minutes (range, 69-131 minutes) in the SSMS group (P ¼ 0.70). There was a statistically significant lower perioperative blood loss in the OPBMS group compared with the SSMS group (200 mL; range, 100-1500 mL) vs 650 mL (range, 350-900 mL; P ¼ 0.005). Surgical data are presented in Table 2.
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Table 1. Demographic data
Variable
Beating heart; n ¼ 12
Standard sternotomy; n¼6
P
Age (years) 67 [59, 79] 68.5 [55, 79] 0.77 Male sex 11 (92) 5 (83) 0.71 Hypertension 12 (100) 6 (100) Diabetes 1 (8) 3 (50) 0.09 COPD 3 (25) 2 (33) 0.56 Chronic renal failure 2 (17) 3 (50) 0.34 NYHA I 1 (8) 0 (0) > 0.99 II 1 (8) 0 (0) > 0.99 III 8 (67) 6 (100) 0.61 IV 2 (17) 0 (0) > 0.99 EuroSCORE II, % 8.8 [3.2, 30] 10.7 [1.6, 19.5] > 0.99 LVEF 50% 3 (25) 0 (0) > 0.99 31%-50% 6 (50) 2 (33) 0.2 <30% 3 (25) 4 (67) 0.14 Number of previous surgery 1 11 (92) 6 (100) 0.57 2 1 (8) 0 (0) > 0.99 MR grade 2 1 (8) 0 (0) > 0.99 3 5 (42) 1 (17) 0.60 4 6 (50) 5 (83) 0.32 Number of patent grafts (apart from LIMA on LAD coronary artery) 0 2 (17) 0 (0) 0.53 1 3 (25) 1 (17) > 0.99 2 6 (50) 4 (67) 0.64 3 1 (8) 1 (17) > 0.99 Categorical variables are presented as frequency (%); continuous variables as median [minimum, maximum]. COPD, chronic obstructive pulmonary disease; LAD, left anterior descending; LIMA, left internal mammary artery; LVEF, left ventricular ejection fraction; MR, mitral regurgitation; NYHA, New York Heart Association.
SSMS group (P ¼ 0.11). Five patients (28%) required permanent pacemaker implantation and there was no difference between the 2 groups (P ¼ 0.61). Of these, 2 had sinus sick syndrome, 2 had second-degree atrioventricular Mobitz 2 block, and 1 had third-degree atrioventricular block. In the OPBMS group, 4 patients (33%) developed acute renal failure, but only 1 (8%) required temporary hemofiltration. Among these 4 patients, 2 (50%) were known for chronic
Table 2. Surgical data
Perioperative outcomes There were no perioperative deaths, myocardial infarctions, or neurological events in the OPBMS group. Ten days after the surgery, 1 patient (17%) died in the SSMS group secondary to a myocardial infarction, a cardiogenic shock, and a cerebral embolic stroke. No patient required repeated surgery for failed repair in both groups and the predischarge transthoracic echocardiogram showed a mild or less MR in all patients. In the OPBMS group, 1 patient (8%) required reintervention for early bleeding vs 1 patient (17%) in the SSMS group. Four patients (33 %) in the OPBMS group required blood transfusion compared with 4 in the SSMS group (67 %; P ¼ 0.32). The median postoperative peak serum CK-MB level in the OPBMS group was 45 mg/L (range, 12-78 mg/L) and 83 mg/L (range, 20-265 mg/L) in the
Variable CPB time, minutes Procedure Repair MVR Additional maze Additional ASD closure Median perioperative blood loss, mL Conversion to sternotomy Rapid venticular pacing
Beating heart; n ¼ 12
Standard sternotomy; n¼6
102 [55, 156]
116 [69, 131]
7 (58) 5 (42) 3 (25) 3 (25) 200 [100, 1500]
2 (33) 4 (67) 1 (17) 0 (0) 650 [350, 900]
P 0.70 0.62 0.62 > 0.99 0.52 0.005
0 (0) 5 (42)
Categorical variables are presented as frequency (%); continuous variables as median [minimum, maximum]. ASD, atrial septal defect; CPB, cardiopulmonary bypass; MVR, mitral valve replacement.
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renal failure. All of these patients recovered their baseline renal function. In the SSMS group, 3 patients (50%) developed acute renal failure, but only 1 patient (17%) required temporary hemofiltration. These 3 patients (100%) were known for chronic renal failure and only 2 recovered their baseline renal function. There was no statistically significant difference in postoperative renal failure and hemofiltration between the 2 groups. The median intensive care unit and hospital stay were respectively 3 days (range, 1-10 days) and 8 days (range, 5-17 days) in the OPBMS group compared with 5 days (range, 3-8 days) and 8 days (range, 6-10 days) in the SSMS group (respectively, P ¼ 0.25 and P ¼ 0.58). Postoperative outcomes are presented in Table 3. Clinical follow-up The median follow-up was 1.6 years (range, 0.2-4.1 years) and was 94% complete at 2 years. In the OPBMS group, 6 patients (50%) were classified as New York Heart Association (NYHA) functional class I, 4 (33%) NYHA functional class II, and 1 (8%) NYHA functional class III. One patient (8%) died 2 months after surgery; the cause of death was unknown. In the SSMS group, 2 patients (33%) were classified as NYHA functional class I, 2 (33%) NYHA functional class II, and 2 (33%) NYHA functional class III. In this group, 1 patient (17%) died 2 months after surgery secondary to a complicated infective endocarditis on the mitral valve prosthesis. One patient (17%) underwent heart transplantation 3 years after the surgery. Echocardiography was available for 12 patients (68%) at a median follow-up of 1.8 years (range, 0.1-4 years). One patient with mitral valve replacement in the OPBMS group had a perivalvular leak that was addressed by a percutaneous approach 4 months after surgery. At the time of mitral valve replacement, this patient had a severely calcified mitral annulus that required extensive decalcification. Intraoperative transesophageal echocardiography and discharge echocardiogram showed no perivalvular leak. Among all patients who underwent mitral valve repair in this study, no mitral valve regurgitation was reported in the OPBMS group at follow-up compared with 1 patient with grade II MR in the SSMS group 1 year after surgery. The median LVEF was 28% at follow-up compared with 45% before surgery. Discussion Mitral valve surgery in the context of previous sternotomy presents several challenges, particularly in the presence of patent coronary artery bypass grafts. With the standard sternotomy, extensive dissection of the heart and great vessels harbours a high risk of injury to cardiac structures. As a result, the interest for the use of minimally invasive mitral valve surgery (MIMVS) in this setting is increasing nowadays. In the present study, we reported 1 injury of a functioning LIMA graft on the LAD coronary artery during sternotomy. This was successfully repaired with a saphenous venous patch. Although there was no perioperative myocardial infarction in this specific case, a patent LIMA graft injury is a major lifethreatening complication of redo sternotomy in this context.16 In our study, the blood loss during surgery was lower in the OPBMS group compared with the SSMS group.
Canadian Journal of Cardiology Volume - 2016 Table 3. Postoperative data
Variable CK-MB peak, mg/L Peak lactate Median duration of inotropic/ vasoconstrictor support, hours Acute renal failure Need for hemofiltration Postoperative PPM Stroke Number of patients who required blood transfusion Reintervention for bleeding In-hospital mortality Myocardial Infarction Wound Infection Median hospital stay, days Median ICU stay, days
Beating heart; n ¼ 12
Standard sternotomy; n¼6
45 [12, 78] 83 [20, 265] 2.5 [17, 9.2] 3.7 [2, 7] 48 [12, 96] 48 [12, 192] 4 1 4 0 4
(33) (8) (33) (0) (33)
1 (8) 0 (0) 0 (0) 0 (0) 8 [5, 17] 3 [1, 10]
3 1 1 1 4
P 0.11 0.58 0.90
(50) (17) (17) (0) (67)
0.62 > 0.99 0.61 0.32 0.32
1 (17) 1 (17) 1 (17) 0 (0) 8 [6, 10] 5 [3, 8]
> 0.99 0.32 0.32 > 0.99 0.58 0.25
Categorical variables are presented as frequency (%); continuous variables as median [minimum, maximum]. PPM, permanent pacemaker; ICU, intensive care unit.
There was a trend toward a lower rate of blood transfusion in the OPBMS group (33% vs 67%). In their study, Murzi et al. similarly reported a lower rate of postoperative blood loss.17 Despite our high-risk patient cohort in both groups (median EuroSCORE of 8.8% in the OPBMS group and 10.7% in the SSMS group), there was no perioperative mortality reported in the OPBMS group and 1 case of mortality in the SSMS group. Several studies have shown low early mortality with redo MIMVS (varying from 2% to 4%).17-19 MIMVS was previously shown to reduce the rate of postoperative acute renal failure.20,21 However, we found a high rate of postoperative acute renal injury (40%) in the OPBMS group. This was comparable with the SSMS group (50%; P ¼ 0.62). This could be explained by the preoperative chronic renal failure prevalence in the whole cohort (28%), which is an independent predictor of acute renal injury.21,22 In the whole cohort, there was a decline in the LVEF at or in follow-up (45% vs 28%). This could be explained by the mitral regurgitation correction and the subsequent LV volumetric adjustment in the context of dilated ventricles.23 In light of our small patient number, any conclusion drawn on lower early mortality and morbidity with the beating onpump minimally invasive mitral valve redo surgery remains speculative. However, our results show that this approach is safe compared with a standard redo sternotomy. Furthermore, these 12 patients of the minimally invasive OPBMS group represent our first experience with this approach and further improvements are expected considering the learning curve. In the presence of functioning CABG, clamping the aorta (either with a transthoracic clamp or an endovascular balloon) in redo MIMVS harbours the risk of occluding the grafts proximally. This can increase the risk of perioperative myocardial malperfusion, a complication that is particularly worrisome in the presence of significant ventricular dysfunction. By avoiding aortic clamping, on-pump beating heart surgery offers an interesting solution for these patients. In addition, avoidance of aortic clamping spares the patient from using large doses of cardioplegia to arrest the heart and achieve optimal myocardial protection in the presence of a patent
Ghoneim et al. Redo Beating Minimally Invasive Mitral Surgery
LIMA graft on the LAD coronary artery.24,25 In this study, the postoperative need for inotropes, peak CK-MB, and lactate levels were similar in both groups. However, there was a tendency toward lower median postoperative peak CK-MB in the OPBMS group (45 mg/L vs 83 mg/L). One patient experienced postoperative myocardial infarction in the SSMS group compared with none in the OPBMS group. To our knowledge, the present study represents one of the largest series13,26 to use the MIMVS on-pump beating approach. Furthermore, avoiding aortic manipulation reduces the risk of atheromatous plaque dislodgement.27 Concerns still persist regarding the risk of stroke secondary to air embolism in onpump beating heart surgery.7,26 However, we think that maintaining a good and constant systemic perfusion pressure during the cardiopulmonary bypass and continuous suctioning within the LV through the mitral valve are adequate to protect against air emboli generated during LV contraction. As an additional precaution, careful transesophageal echocardiography-monitored deairing of the heart cavities is performed at the end of each procedure before removing the LV vent. Retrograde perfusion through femoral cannulation is associated with an increased risk of adverse neurologic events, especially in patients with severe atherosclerotic disease, because of potential dislodgement of intravascular plaque.28 In our study, no patient had extensive atherosclerotic aortic disease. However, we believe such patients would benefit from a minimally invasive approach with central aortic cannulation through an extended thoracotomy or an additional mini sternotomy. In the present series, there were no patients in the OPBMS group who suffered from postoperative neurological events compared with 1 ischemic stroke in the SSMS group. Our sample size was small, however, it should still be a consideration in future studies. The beating heart approach, unlike the fibrillating one, provides a full myocardial perfusion during diastole, perhaps offering more protection to the heart throughout the operation. Maintaining a continuous coronary perfusion reduces the release of free radicals that are responsible for myocardial ischemia and reperfusion injury.29 In the OPBMS group, postoperative CK-MB and lactate levels were low. No myocardial infarction was reported. Romano et al. published a study on 134 patients who underwent redo mitral valve surgery on fibrillating heart compared with 316 patients on beating heart through sternotomy.30 The latter group had shorter bypass time and postoperative ventilation duration, with a lower blood transfusion rate and perioperative mortality. In addition, the use of normothermic bypass could prevent postoperative coagulopathy and has been associated with reduced transfusions rates compared with hypothermic perfusion.31 Rapid LV pacing is commonly used with transcatheter aortic valve replacement.32 We used this technique in 5 cases among the beating heart group when excessive LV blood backflow obscured the surgical field, rendering the surgery more difficult. The temporary rapid LV pacing allowed us to lower the LV ejection, decrease the retrograde blood in the surgical field, and enhance the mitral valve exposure. The present study is limited by the relatively small sample size, which limits a proper comparison between the 2 groups. This is also a retrospective single-centre study with a relatively
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short follow-up. Further studies will be needed to confirm our findings and compare this procedure with other alternative techniques. In conclusion, redo mitral valve surgery in the presence of patent coronary bypass grafts represents a surgical challenge. Minimally invasive on-pump beating mitral valve surgery in these patients is a valid and safe option compared with the standard median sternotomy approach. In addition, it provides optimal myocardial perfusion and a low incidence of perioperative complications. More studies are needed to confirm our findings and ensure adequate long-term results. Disclosures Denis Bouchard discloses that he has received proctorship and lecturer fees from Sorin and Edwards Canada. The other authors have no conflicts of interest. References 1. Roselli EE, Pettersson GB, Blackstone EH, et al. Adverse events during reoperative cardiac surgery: frequency, characterization, and rescue. J Thorac Cardiovasc Surg 2008;135:316-23. 323.e311-6. 2. David TE, Armstrong S, McCrindle BW, Manlhiot C. Late outcomes of mitral valve repair for mitral regurgitation due to degenerative disease. Circulation 2013;127:1485-92. 3. Vassileva CM, Mishkel G, McNeely C, et al. Long-term survival of patients undergoing mitral valve repair and replacement: a longitudinal analysis of Medicare fee-for-service beneficiaries. Circulation 2013;127: 1870-6. 4. Adams DH, Filsoufi F, Byrne JG, Karavas AN, Aklog L. Mitral valve repair in redo cardiac surgery. J Card Surg 2002;17:40-5. 5. Park CB, Suri RM, Burkhart HM, et al. Identifying patients at particular risk of injury during repeat sternotomy: analysis of 2555 cardiac reoperations. J Thorac Cardiovasc Surg 2010;140:1028-35. 6. Byrne JG, Karavas AN, Adams DH, et al. The preferred approach for mitral valve surgery after CABG: right thoracotomy, hypothermia and avoidance of LIMA-LAD graft. J Heart Valve Dis 2001;10:584-90. 7. Byrne JG, Aranki SF, Adams DH, Rizzo RJ, Couper GS, Cohn LH. Mitral valve surgery after previous CABG with functioning IMA grafts. Ann Thorac Surg 1999;68:2243-7. 8. Akins CW, Miller DC, Turina MI, et al. Guidelines for reporting mortality and morbidity after cardiac valve interventions. Ann Thorac Surg 2008;85:1490-5. 9. Atoui R, Bittira B, Morin JE, Cecere R. On-pump beating heart mitral valve repair in patients with patent bypass grafts and severe ischemic cardiomyopathy. Interact Cardiovasc Thorac Surg 2009;9:138-40. 10. Ueda T, Hatanaka N. Mitral annuloplasty and coronary artery bypass grafting (CABG) with on-pump beating via left thoracotomy for ischemic mitral valve regurgitation with patent internal thoracic artery (ITA) grafts after CABG; report of a case [in Japanese]. Kyobu Geka 2014;67:146-8. 11. Tsuda Y, Hama G, Niitsu H, Shiratori K, Takemura T. On pump beating heart mitral and tricuspid valve annuloplasty via right mini thoracotomy approach in a patient who had undergone cardiac surgery 3 times [in Japanese]. Kyobu Geka 2013;66:803-5. 12. Seeburger J, Borger MA, Falk V, et al. Minimally invasive mitral valve surgery after previous sternotomy: experience in 181 patients. Ann Thorac Surg 2009;87:709-14.
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13. Botta L, Cannata A, Bruschi G, et al. Minimally invasive approach for redo mitral valve surgery. J Thorac Dis 2013;5(suppl 6):S686-93. 14. Holman WL, Goldberg SP, Early LJ, et al. Right thoracotomy for mitral reoperation: analysis of technique and outcome. Ann Thorac Surg 2000;70:1970-3. 15. Byrne JG, Hsin MK, Adams DH, et al. Minimally invasive direct access heart valve surgery. J Card Surg 2000;15:21-34. 16. Nashef SA, Roques F, Sharples LD, et al. EuroSCORE II. Eur J Cardiothorac Surg 2012;41:734-44 [discussion: 744-35]. 17. Murzi M, Miceli A, Di Stefano G, et al. Minimally invasive right thoracotomy approach for mitral valve surgery in patients with previous sternotomy: a single institution experience with 173 patients. J Thorac Cardiovasc Surg 2014;148:2763-8. 18. Arcidi JM Jr, Rodriguez E, Elbeery JR, et al. Fifteen-year experience with minimally invasive approach for reoperations involving the mitral valve. J Thorac Cardiovasc Surg 2012;143:1062-8. 19. Umakanthan R, Petracek MR, Leacche M, et al. Minimally invasive right lateral thoracotomy without aortic cross-clamping: an attractive alternative to repeat sternotomy for reoperative mitral valve surgery. J Heart Valve Dis 2010;19:236-43. 20. McCreath BJ, Swaminathan M, Booth JV, et al. Mitral valve surgery and acute renal injury: port access versus median sternotomy. Ann Thorac Surg 2003;75:812-9.
Canadian Journal of Cardiology Volume - 2016 23. Suri RM, Schaff HV, Dearani JA, et al. Determinants of early decline in ejection fraction after surgical correction of mitral regurgitation. J Thorac Cardiovasc Surg 2008;136:442-7. 24. Borger MA, Rao V, Weisel RD, et al. Reoperative coronary bypass surgery: effect of patent grafts and retrograde cardioplegia. J Thorac Cardiovasc Surg 2001;121:83-90. 25. Byrne JG, Karavas AN, Filsoufi F, et al. Aortic valve surgery after previous coronary artery bypass grafting with functioning internal mammary artery grafts. Ann Thorac Surg 2002;73:779-84. 26. Thompson MJ, Behranwala A, Campanella C, Walker WS, Cameron EW. Immediate and long-term results of mitral prosthetic replacement using a right thoracotomy beating heart technique. Eur J Cardiothorac Surg 2003;24:47-51 [discussion: 51]. 27. Mazine A, Pellerin M, Lebon JS, et al. Minimally invasive mitral valve surgery: influence of aortic clamping technique on early outcomes. Ann Thorac Surg 2013;96:2116-22. 28. Svensson LG, Gillinov AM, Blackstone EH, et al. Does right thoracotomy increase the risk of mitral valve reoperation? J Thorac Cardiovasc Surg 2007;134:677-82. 29. Baker GL, Corry RJ, Autor AP. Oxygen free radical induced damage in kidneys subjected to warm ischemia and reperfusion. Protective effect of superoxide dismutase. Ann Surg 1985;202:628-41. 30. Romano MA, Haft JW, Pagani FD, Bolling SF. Beating heart surgery via right thoracotomy for reoperative mitral valve surgery: a safe and effective operative alternative. J Thorac Cardiovasc Surg 2012;144:334-9.
21. Valdez GD, Mihos CG, Santana O, et al. Incidence of postoperative acute kidney injury in patients with chronic kidney disease undergoing minimally invasive valve surgery. J Thorac Cardiovasc Surg 2013;146: 1488-93.
31. Birdi I, Regragui I, Izzat MB, Bryan AJ, Angelini GD. Influence of normothermic systemic perfusion during coronary artery bypass operations: a randomized prospective study. J Thorac Cardiovasc Surg 1997;114:475-81.
22. Thakar CV, Arrigain S, Worley S, Yared JP, Paganini EP. A clinical score to predict acute renal failure after cardiac surgery. J Am Soc Nephrol 2005;16:162-8.
32. Covello RD, Ruggeri L, Landoni G, et al. Transcatheter implantation of an aortic valve: anesthesiological management. Minerva Anestesiol 2010;76:100-8.
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(2016) 1e6
Clinical Research
Beating Heart Minimally Invasive Mitral Valve Surgery in Patients With Patent Coronary Bypass Grafts Aly Ghoneim, MD,* Ismail Bouhout, MD, MSc,* Amine Mazine, MD, MSc, William Fortin, MD, Ismail El-Hamamsy, MD, PhD, Hugue Jeanmart, MD, Michel Pellerin, MD, and Denis Bouchard, MD, PhD Department of Cardiovascular Surgery, Montreal Heart Institute and Universite de Montre al, Montreal, Quebec, Canada
ABSTRACT
RESUM E
Background: Redo mitral valve surgery in patients with patent coronary bypass grafts carries a risk of graft injury and postoperative bleeding. We compare early results of reoperative minimally invasive on-pump beating heart mitral valve surgery (OPBMS) via mini thoracotomy vs the results of standard sternotomy mitral valve surgery (SSMS) in the presence of patent coronary bypass grafts. Methods: Between 2009 and 2015, 12 patients underwent OPBMS through a right mini thoracotomy and 6 patients underwent SSMS. All patients had at least 1 patent bypass graft. Results: Median age and EuroSCORE II were not statistically different between the 2 groups. There was no early death in the OPBMS group vs 1 death (17%) in the SSMS group. There was a statistically significant lower median perioperative blood loss in
pe tition de la chirurgie de la valve mitrale chez les Introduction : La re abilite des greffons après pontage coropatients montrant une perme sions des greffons et d’he morragie postnarien comporte un risque de le ratoire. Nous comparons les premiers re sultats de la re pe tition de la ope chirurgie minimalement invasive de la valve mitrale sous circulation sultats extracorporelle (CEC) à cœur battant par mini-thoracotomie vs les re sence de la chirurgie de la valve mitrale par sternotomie standard en pre abilite des greffons après pontage coronarien. d’une perme thodes : Entre 2009 et 2015, 12 patients ont subi la chirurgie de la valve Me mitrale sous CEC à cœur battant par mini-thoracotomie droite et 6 patients ont subi la chirurgie de la valve mitrale par sternotomie standard. Tous les au moins 1 greffon perme able après le pontage. patients ont montre sultats : L’âge me dian et l’EuroSCORE II n’e taient pas statistiqueRe rents entre les 2 groupes. Aucun de cès pre coce n’a e te ment diffe
As the population ages, the rate of repeated cardiac surgery is increasing, carrying a high risk of intraoperative and postoperative complications.1 Over time, some patients with previous coronary artery bypass grafting (CABG) surgery develop significant symptomatic mitral valve insufficiency. Correction of mitral regurgitation (MR) in these patients increases survival, reduces symptoms, and improves quality of life.2,3 However, repeated surgery for these patients remains a surgical challenge especially in the presence of patent bypass grafts.1,4 The standard median sternotomy approach comes with a risk of injuring the functioning grafts and/or cardiac structures.5,6
A right thoracotomy approach might provide a safer solution.6 Furthermore, in previous studies, this approach has been shown to reduce the surgery time and amount of blood loss.6,7 It also helps to avoid unnecessary tissue dissection and minimize the risk of injury to a patent left internal mammary artery (LIMA), venous grafts, and/or adherent ventricles. We assessed the hypotheses that redo on-pump beating mitral valve surgery (OPBMS) via a small mini thoracotomy for patients with patent bypass grafts can be safely performed. We reviewed our experience with redo mitral valve surgery in this setting and compared it with another control group of redo isolated mitral valve surgery through a conventional standard sternotomy.
Received for publication June 17, 2015. Accepted September 23, 2015.
Methods Between July 2009 and February 2015, we identified 18 consecutive patients who underwent mitral valve redo surgery in the context of previous isolated CABG. Patients with concomitant valvular surgeries were excluded. All patients had at least 1 patent graft. Redo OPBMS via a small mini thoracotomy was performed in 12 patients (67%), and 6 (33%)
*These authors contributed equally to this work and share first authorship. Corresponding author: Dr Denis Bouchard, Montreal Heart Institute, University of Montreal School of Medicine, 5000 Belanger St, Montreal, Quebec H1T 1C8, Canada. Tel.: þ1-514-376-3330 3715; fax: þ1-514593-2157. E-mail: [email protected] See page 5 for disclosure information.
http://dx.doi.org/10.1016/j.cjca.2015.09.016 0828-282X/Ó 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.
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Canadian Journal of Cardiology Volume - 2016
the OPBMS group compared with the SSMS group (200 vs 650 mL; P ¼ 0.005). Four patients (33%) in the OPBMS group required blood transfusion compared with 4 in the SSMS group (67%; P ¼ 0.32). There was 1 perioperative stroke (17%) and 1 acute myocardial infarction (17%) in the SSMS group. Four patients developed acute renal failure in the OPBMS group compared with 3 in the SSMS group (50%; P ¼ 0.62). The predischarge transthoracic echocardiogram showed 1 mitral regurgitation in all patients. Conclusions: Redo mitral surgery in patients with patent bypass grafts can safely be performed via minimally invasive mini thoracotomy on a beating heart. The main benefits of this approach are to avoid the sternotomy and decrease the amount of postoperative blood loss.
dans le groupe de chirurgie de la valve mitrale sous CEC à observe cès (17 %) a e te observe dans le groupe de cœur battant vs 1 de chirurgie de la valve mitrale par sternotomie standard. Une perte de diane significativement plus faible sur le plan statistique en sang me riope ratoire a e te observe e dans le groupe de chirurgie de la phase pe valve mitrale sous CEC à cœur battant comparativement au groupe de chirurgie de la valve mitrale par sternotomie standard (200 ml vs 650 ml; P ¼ 0,005). Quatre patients (33 %) du groupe de chirurgie de la valve mitrale sous CEC à cœur battant comparativement à 4 patients du groupe de chirurgie de la valve mitrale par sternotomie standard cessite une transfusion sanguine. Il y a eu 1 (67 %; P ¼ 0,32) ont ne re bral en phase pe riope ratoire (17 %) et 1 accident vasculaire ce infarctus du myocarde aigu (17 %) dans le groupe de chirurgie de la veloppe valve mitrale par sternotomie standard. Quatre patients ont de nale aiguë dans le groupe de chirurgie de la valve une insuffisance re mitrale sous CEC à cœur battant comparativement à 3 patients dans le groupe de chirurgie de la valve mitrale par sternotomie standard chocardiogramme transthoracique avant la sortie (50 %; P ¼ 0,62). L’e 1 re gurgitation mitrale chez tous les patients. de l’hôpital a montre pe tition de la chirurgie mitrale chez les patients Conclusions : La re abilite des greffons après pontage peut être montrant une perme alise e de manière sûre et minimalement invasive par minire thoracotomie à cœur battant. Les principaux avantages de cette vitement de la sternotomie et la diminution de la approche sont l’e de la perte de sang en phase postope ratoire. quantite
had a standard median sternotomy redo mitral valve surgery (SSMS). We retrospectively analyzed these 2 groups. Data were collected from medical records and our Valve Clinic database. Perioperative outcomes were defined according to the Society of Thoracic Surgeons guidelines for reporting mortality and morbidity.8 The local ethics committee approved the study and a waiver of consent was obtained. Surgical mortality was defined as death occurring within 30 days of surgery or during the index hospitalization.
to prevent LV ejection and optimize the surgical field. The mitral leaflets were inspected with direct vision and with thoracoscopic assistance, then standard mitral valve surgery (repair or replacement) was conducted.
Surgical approach of minimally invasive OPBMS The techniques for minimally invasive mitral approach and onpump beating mitral surgery have been described elsewhere.7,9-14 The same surgeon performed all surgeries in the OPBMS group. All patients were placed in a left lateral position and slightly rotated to elevate the left heart. External defibrillator pads were placed and a right-sided transvenous ventricular pacemaker lead was installed. A small (4-5 cm) muscle-sparing right mini thoracotomy was done and the right chest cavity was entered through the fourth intercostal space. After heparinization, the right femoral vein and artery were cannulated. The pericardium was incised carefully and the left atrium was exposed, 2 retraction stitches were placed above the pericardiophrenic bundle. Cardiopulmonary bypass was then initiated, a CO2 line was installed, and temperature was allowed to drift down to 34 C, while the mean systemic perfusion pressure was kept at approximately 80 mm Hg. There was no aortic clamping or cardioplegia administration. If present, the course of the right-sided patent bypass graft was identified and a standard left atriotomy in the Sondergaard groove was performed.15 Continuous venting of the left ventricle (LV) was obtained throughout the procedure. We used intermittent rapid ventricular pacing in 5 patients (42%)
Statistical analysis Statistical analyses were performed using Statistical Package for Social Sciences version 20 (SPSS; Chicago, IL). Continuous variables are presented as median (range) and categorical variables are presented as frequency (%). Variables were analyzed using nonparametric tests. Continuous variables were compared using the Mann-Whitney test and ordinal variables using Fisher exact test. Statistical significance was set at a ¼ 0.05. Results Patient baseline characteristics The median age of patients in the OPBMS group was 67 years (ranging from 59 to 79 years) and 68 years (ranging from 55 to 79 years) in the SSMS group (P ¼ 0.77). At the time of surgery, 11 patients (61%) had severe MR, 6 (33%) had moderate to severe MR, and 1 (2%) had moderate MR. A total of 16 patients (88%) had type IIIb MR and 2 patients (12%) had mixed type MR. All patients had patent LIMA grafts (100%). In the OPBMS group, 2 (17 %) had no patent venous grafts, 3 (25%) had a single patent venous graft, 6 (50%) had 2 patent venous grafts, and 1 patient (8%) had 3 patent venous grafts. In the SSMS group, 1 (17%) had both internal mammary artery grafts patent with 1 patent venous graft, 4 (66%) had 2 patent venous grafts, and 1 (17%) had 3 patent venous grafts. The preoperative left ventricular ejection fraction (LVEF) in the OPBMS group was 50% in 3
Ghoneim et al. Redo Beating Minimally Invasive Mitral Surgery
patients (25%), between 31% and 50% in 6 patients (50%) and < 30% in 3 patients (25%), and in the SSMS group was between 31% and 50% in 2 patients (33%) and < 30% in 4 patients (67%). In both groups, 6 (33%) patients had mild aortic insufficiency and 12 (67%) had a normal competent aortic valve. Median logistic EuroSCORE II was 8.8% (range, 3.2%-30%) in the OPBMS group compared with 10.7% (range, 1.6%-19.5%) in the SSMS group (P > 0.99). In the OPBMS group, 2 patients (17%) had chronic renal failure (not receiving permanent dialysis) vs 3 patients (50%) in the other group (P ¼ 0.34). Demographic data are presented in Table 1. Surgical findings Mitral valve repair was performed in 9 patients (50%) and replacement was performed in the other 9 (50%). In the OPBMS group, 1 patient (8%) had a perioperative unsuccessful mitral valve repair and underwent a mitral valve replacement in the same surgical sitting. In the SSMS group, 1 patient (17%) had a patent LIMA on a left anterior descending (LAD) graft injury during the sternotomy. This was successfully repaired with a saphenous venous patch and there was no perioperative myocardial infarction. All mitral valve repairs were done with a restrictive annuloplasty using a downsized ring: 3 patients (17%) with an Etlogix ring (Edwards Lifesciences, Irvine, CA), 4 (22%) with Carbomedics Annuloflo ring (Sorin Group, Saluggia, Italy) and 2 (11%) with Physio II ring (Edwards Lifesciences). One patient (6%) had artificial chordae added at P2 for a mixed type MR. Seven patients (39%) had their valve replaced with a perimount Carpentier-Edwards valve (Edwards Lifesciences) and 2 (11%) with the St Jude Epic biological mitral valve (St Jude Medical, Saint Paul, MN). Six patients (33%) had concomitant surgical procedures: 3 (17%) had a Maze procedure, 2 (11%) had an atrial septal defect (ASD) closure, and 1 (6%) had the Maze procedure and an atrial septal defect closure. There was no conversion to sternotomy in the OPBMS group. The median bypass time was 102 minutes (range, 55-156 minutes) in the OPBMS group and 116 minutes (range, 69-131 minutes) in the SSMS group (P ¼ 0.70). There was a statistically significant lower perioperative blood loss in the OPBMS group compared with the SSMS group (200 mL; range, 100-1500 mL) vs 650 mL (range, 350-900 mL; P ¼ 0.005). Surgical data are presented in Table 2.
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Table 1. Demographic data
Variable
Beating heart; n ¼ 12
Standard sternotomy; n¼6
P
Age (years) 67 [59, 79] 68.5 [55, 79] 0.77 Male sex 11 (92) 5 (83) 0.71 Hypertension 12 (100) 6 (100) Diabetes 1 (8) 3 (50) 0.09 COPD 3 (25) 2 (33) 0.56 Chronic renal failure 2 (17) 3 (50) 0.34 NYHA I 1 (8) 0 (0) > 0.99 II 1 (8) 0 (0) > 0.99 III 8 (67) 6 (100) 0.61 IV 2 (17) 0 (0) > 0.99 EuroSCORE II, % 8.8 [3.2, 30] 10.7 [1.6, 19.5] > 0.99 LVEF 50% 3 (25) 0 (0) > 0.99 31%-50% 6 (50) 2 (33) 0.2 <30% 3 (25) 4 (67) 0.14 Number of previous surgery 1 11 (92) 6 (100) 0.57 2 1 (8) 0 (0) > 0.99 MR grade 2 1 (8) 0 (0) > 0.99 3 5 (42) 1 (17) 0.60 4 6 (50) 5 (83) 0.32 Number of patent grafts (apart from LIMA on LAD coronary artery) 0 2 (17) 0 (0) 0.53 1 3 (25) 1 (17) > 0.99 2 6 (50) 4 (67) 0.64 3 1 (8) 1 (17) > 0.99 Categorical variables are presented as frequency (%); continuous variables as median [minimum, maximum]. COPD, chronic obstructive pulmonary disease; LAD, left anterior descending; LIMA, left internal mammary artery; LVEF, left ventricular ejection fraction; MR, mitral regurgitation; NYHA, New York Heart Association.
SSMS group (P ¼ 0.11). Five patients (28%) required permanent pacemaker implantation and there was no difference between the 2 groups (P ¼ 0.61). Of these, 2 had sinus sick syndrome, 2 had second-degree atrioventricular Mobitz 2 block, and 1 had third-degree atrioventricular block. In the OPBMS group, 4 patients (33%) developed acute renal failure, but only 1 (8%) required temporary hemofiltration. Among these 4 patients, 2 (50%) were known for chronic
Table 2. Surgical data
Perioperative outcomes There were no perioperative deaths, myocardial infarctions, or neurological events in the OPBMS group. Ten days after the surgery, 1 patient (17%) died in the SSMS group secondary to a myocardial infarction, a cardiogenic shock, and a cerebral embolic stroke. No patient required repeated surgery for failed repair in both groups and the predischarge transthoracic echocardiogram showed a mild or less MR in all patients. In the OPBMS group, 1 patient (8%) required reintervention for early bleeding vs 1 patient (17%) in the SSMS group. Four patients (33 %) in the OPBMS group required blood transfusion compared with 4 in the SSMS group (67 %; P ¼ 0.32). The median postoperative peak serum CK-MB level in the OPBMS group was 45 mg/L (range, 12-78 mg/L) and 83 mg/L (range, 20-265 mg/L) in the
Variable CPB time, minutes Procedure Repair MVR Additional maze Additional ASD closure Median perioperative blood loss, mL Conversion to sternotomy Rapid venticular pacing
Beating heart; n ¼ 12
Standard sternotomy; n¼6
102 [55, 156]
116 [69, 131]
7 (58) 5 (42) 3 (25) 3 (25) 200 [100, 1500]
2 (33) 4 (67) 1 (17) 0 (0) 650 [350, 900]
P 0.70 0.62 0.62 > 0.99 0.52 0.005
0 (0) 5 (42)
Categorical variables are presented as frequency (%); continuous variables as median [minimum, maximum]. ASD, atrial septal defect; CPB, cardiopulmonary bypass; MVR, mitral valve replacement.
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renal failure. All of these patients recovered their baseline renal function. In the SSMS group, 3 patients (50%) developed acute renal failure, but only 1 patient (17%) required temporary hemofiltration. These 3 patients (100%) were known for chronic renal failure and only 2 recovered their baseline renal function. There was no statistically significant difference in postoperative renal failure and hemofiltration between the 2 groups. The median intensive care unit and hospital stay were respectively 3 days (range, 1-10 days) and 8 days (range, 5-17 days) in the OPBMS group compared with 5 days (range, 3-8 days) and 8 days (range, 6-10 days) in the SSMS group (respectively, P ¼ 0.25 and P ¼ 0.58). Postoperative outcomes are presented in Table 3. Clinical follow-up The median follow-up was 1.6 years (range, 0.2-4.1 years) and was 94% complete at 2 years. In the OPBMS group, 6 patients (50%) were classified as New York Heart Association (NYHA) functional class I, 4 (33%) NYHA functional class II, and 1 (8%) NYHA functional class III. One patient (8%) died 2 months after surgery; the cause of death was unknown. In the SSMS group, 2 patients (33%) were classified as NYHA functional class I, 2 (33%) NYHA functional class II, and 2 (33%) NYHA functional class III. In this group, 1 patient (17%) died 2 months after surgery secondary to a complicated infective endocarditis on the mitral valve prosthesis. One patient (17%) underwent heart transplantation 3 years after the surgery. Echocardiography was available for 12 patients (68%) at a median follow-up of 1.8 years (range, 0.1-4 years). One patient with mitral valve replacement in the OPBMS group had a perivalvular leak that was addressed by a percutaneous approach 4 months after surgery. At the time of mitral valve replacement, this patient had a severely calcified mitral annulus that required extensive decalcification. Intraoperative transesophageal echocardiography and discharge echocardiogram showed no perivalvular leak. Among all patients who underwent mitral valve repair in this study, no mitral valve regurgitation was reported in the OPBMS group at follow-up compared with 1 patient with grade II MR in the SSMS group 1 year after surgery. The median LVEF was 28% at follow-up compared with 45% before surgery. Discussion Mitral valve surgery in the context of previous sternotomy presents several challenges, particularly in the presence of patent coronary artery bypass grafts. With the standard sternotomy, extensive dissection of the heart and great vessels harbours a high risk of injury to cardiac structures. As a result, the interest for the use of minimally invasive mitral valve surgery (MIMVS) in this setting is increasing nowadays. In the present study, we reported 1 injury of a functioning LIMA graft on the LAD coronary artery during sternotomy. This was successfully repaired with a saphenous venous patch. Although there was no perioperative myocardial infarction in this specific case, a patent LIMA graft injury is a major lifethreatening complication of redo sternotomy in this context.16 In our study, the blood loss during surgery was lower in the OPBMS group compared with the SSMS group.
Canadian Journal of Cardiology Volume - 2016 Table 3. Postoperative data
Variable CK-MB peak, mg/L Peak lactate Median duration of inotropic/ vasoconstrictor support, hours Acute renal failure Need for hemofiltration Postoperative PPM Stroke Number of patients who required blood transfusion Reintervention for bleeding In-hospital mortality Myocardial Infarction Wound Infection Median hospital stay, days Median ICU stay, days
Beating heart; n ¼ 12
Standard sternotomy; n¼6
45 [12, 78] 83 [20, 265] 2.5 [17, 9.2] 3.7 [2, 7] 48 [12, 96] 48 [12, 192] 4 1 4 0 4
(33) (8) (33) (0) (33)
1 (8) 0 (0) 0 (0) 0 (0) 8 [5, 17] 3 [1, 10]
3 1 1 1 4
P 0.11 0.58 0.90
(50) (17) (17) (0) (67)
0.62 > 0.99 0.61 0.32 0.32
1 (17) 1 (17) 1 (17) 0 (0) 8 [6, 10] 5 [3, 8]
> 0.99 0.32 0.32 > 0.99 0.58 0.25
Categorical variables are presented as frequency (%); continuous variables as median [minimum, maximum]. PPM, permanent pacemaker; ICU, intensive care unit.
There was a trend toward a lower rate of blood transfusion in the OPBMS group (33% vs 67%). In their study, Murzi et al. similarly reported a lower rate of postoperative blood loss.17 Despite our high-risk patient cohort in both groups (median EuroSCORE of 8.8% in the OPBMS group and 10.7% in the SSMS group), there was no perioperative mortality reported in the OPBMS group and 1 case of mortality in the SSMS group. Several studies have shown low early mortality with redo MIMVS (varying from 2% to 4%).17-19 MIMVS was previously shown to reduce the rate of postoperative acute renal failure.20,21 However, we found a high rate of postoperative acute renal injury (40%) in the OPBMS group. This was comparable with the SSMS group (50%; P ¼ 0.62). This could be explained by the preoperative chronic renal failure prevalence in the whole cohort (28%), which is an independent predictor of acute renal injury.21,22 In the whole cohort, there was a decline in the LVEF at or in follow-up (45% vs 28%). This could be explained by the mitral regurgitation correction and the subsequent LV volumetric adjustment in the context of dilated ventricles.23 In light of our small patient number, any conclusion drawn on lower early mortality and morbidity with the beating onpump minimally invasive mitral valve redo surgery remains speculative. However, our results show that this approach is safe compared with a standard redo sternotomy. Furthermore, these 12 patients of the minimally invasive OPBMS group represent our first experience with this approach and further improvements are expected considering the learning curve. In the presence of functioning CABG, clamping the aorta (either with a transthoracic clamp or an endovascular balloon) in redo MIMVS harbours the risk of occluding the grafts proximally. This can increase the risk of perioperative myocardial malperfusion, a complication that is particularly worrisome in the presence of significant ventricular dysfunction. By avoiding aortic clamping, on-pump beating heart surgery offers an interesting solution for these patients. In addition, avoidance of aortic clamping spares the patient from using large doses of cardioplegia to arrest the heart and achieve optimal myocardial protection in the presence of a patent
Ghoneim et al. Redo Beating Minimally Invasive Mitral Surgery
LIMA graft on the LAD coronary artery.24,25 In this study, the postoperative need for inotropes, peak CK-MB, and lactate levels were similar in both groups. However, there was a tendency toward lower median postoperative peak CK-MB in the OPBMS group (45 mg/L vs 83 mg/L). One patient experienced postoperative myocardial infarction in the SSMS group compared with none in the OPBMS group. To our knowledge, the present study represents one of the largest series13,26 to use the MIMVS on-pump beating approach. Furthermore, avoiding aortic manipulation reduces the risk of atheromatous plaque dislodgement.27 Concerns still persist regarding the risk of stroke secondary to air embolism in onpump beating heart surgery.7,26 However, we think that maintaining a good and constant systemic perfusion pressure during the cardiopulmonary bypass and continuous suctioning within the LV through the mitral valve are adequate to protect against air emboli generated during LV contraction. As an additional precaution, careful transesophageal echocardiography-monitored deairing of the heart cavities is performed at the end of each procedure before removing the LV vent. Retrograde perfusion through femoral cannulation is associated with an increased risk of adverse neurologic events, especially in patients with severe atherosclerotic disease, because of potential dislodgement of intravascular plaque.28 In our study, no patient had extensive atherosclerotic aortic disease. However, we believe such patients would benefit from a minimally invasive approach with central aortic cannulation through an extended thoracotomy or an additional mini sternotomy. In the present series, there were no patients in the OPBMS group who suffered from postoperative neurological events compared with 1 ischemic stroke in the SSMS group. Our sample size was small, however, it should still be a consideration in future studies. The beating heart approach, unlike the fibrillating one, provides a full myocardial perfusion during diastole, perhaps offering more protection to the heart throughout the operation. Maintaining a continuous coronary perfusion reduces the release of free radicals that are responsible for myocardial ischemia and reperfusion injury.29 In the OPBMS group, postoperative CK-MB and lactate levels were low. No myocardial infarction was reported. Romano et al. published a study on 134 patients who underwent redo mitral valve surgery on fibrillating heart compared with 316 patients on beating heart through sternotomy.30 The latter group had shorter bypass time and postoperative ventilation duration, with a lower blood transfusion rate and perioperative mortality. In addition, the use of normothermic bypass could prevent postoperative coagulopathy and has been associated with reduced transfusions rates compared with hypothermic perfusion.31 Rapid LV pacing is commonly used with transcatheter aortic valve replacement.32 We used this technique in 5 cases among the beating heart group when excessive LV blood backflow obscured the surgical field, rendering the surgery more difficult. The temporary rapid LV pacing allowed us to lower the LV ejection, decrease the retrograde blood in the surgical field, and enhance the mitral valve exposure. The present study is limited by the relatively small sample size, which limits a proper comparison between the 2 groups. This is also a retrospective single-centre study with a relatively
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short follow-up. Further studies will be needed to confirm our findings and compare this procedure with other alternative techniques. In conclusion, redo mitral valve surgery in the presence of patent coronary bypass grafts represents a surgical challenge. Minimally invasive on-pump beating mitral valve surgery in these patients is a valid and safe option compared with the standard median sternotomy approach. In addition, it provides optimal myocardial perfusion and a low incidence of perioperative complications. More studies are needed to confirm our findings and ensure adequate long-term results. Disclosures Denis Bouchard discloses that he has received proctorship and lecturer fees from Sorin and Edwards Canada. The other authors have no conflicts of interest. References 1. Roselli EE, Pettersson GB, Blackstone EH, et al. Adverse events during reoperative cardiac surgery: frequency, characterization, and rescue. J Thorac Cardiovasc Surg 2008;135:316-23. 323.e311-6. 2. David TE, Armstrong S, McCrindle BW, Manlhiot C. Late outcomes of mitral valve repair for mitral regurgitation due to degenerative disease. Circulation 2013;127:1485-92. 3. Vassileva CM, Mishkel G, McNeely C, et al. Long-term survival of patients undergoing mitral valve repair and replacement: a longitudinal analysis of Medicare fee-for-service beneficiaries. Circulation 2013;127: 1870-6. 4. Adams DH, Filsoufi F, Byrne JG, Karavas AN, Aklog L. Mitral valve repair in redo cardiac surgery. J Card Surg 2002;17:40-5. 5. Park CB, Suri RM, Burkhart HM, et al. Identifying patients at particular risk of injury during repeat sternotomy: analysis of 2555 cardiac reoperations. J Thorac Cardiovasc Surg 2010;140:1028-35. 6. Byrne JG, Karavas AN, Adams DH, et al. The preferred approach for mitral valve surgery after CABG: right thoracotomy, hypothermia and avoidance of LIMA-LAD graft. J Heart Valve Dis 2001;10:584-90. 7. Byrne JG, Aranki SF, Adams DH, Rizzo RJ, Couper GS, Cohn LH. Mitral valve surgery after previous CABG with functioning IMA grafts. Ann Thorac Surg 1999;68:2243-7. 8. Akins CW, Miller DC, Turina MI, et al. Guidelines for reporting mortality and morbidity after cardiac valve interventions. Ann Thorac Surg 2008;85:1490-5. 9. Atoui R, Bittira B, Morin JE, Cecere R. On-pump beating heart mitral valve repair in patients with patent bypass grafts and severe ischemic cardiomyopathy. Interact Cardiovasc Thorac Surg 2009;9:138-40. 10. Ueda T, Hatanaka N. Mitral annuloplasty and coronary artery bypass grafting (CABG) with on-pump beating via left thoracotomy for ischemic mitral valve regurgitation with patent internal thoracic artery (ITA) grafts after CABG; report of a case [in Japanese]. Kyobu Geka 2014;67:146-8. 11. Tsuda Y, Hama G, Niitsu H, Shiratori K, Takemura T. On pump beating heart mitral and tricuspid valve annuloplasty via right mini thoracotomy approach in a patient who had undergone cardiac surgery 3 times [in Japanese]. Kyobu Geka 2013;66:803-5. 12. Seeburger J, Borger MA, Falk V, et al. Minimally invasive mitral valve surgery after previous sternotomy: experience in 181 patients. Ann Thorac Surg 2009;87:709-14.
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13. Botta L, Cannata A, Bruschi G, et al. Minimally invasive approach for redo mitral valve surgery. J Thorac Dis 2013;5(suppl 6):S686-93. 14. Holman WL, Goldberg SP, Early LJ, et al. Right thoracotomy for mitral reoperation: analysis of technique and outcome. Ann Thorac Surg 2000;70:1970-3. 15. Byrne JG, Hsin MK, Adams DH, et al. Minimally invasive direct access heart valve surgery. J Card Surg 2000;15:21-34. 16. Nashef SA, Roques F, Sharples LD, et al. EuroSCORE II. Eur J Cardiothorac Surg 2012;41:734-44 [discussion: 744-35]. 17. Murzi M, Miceli A, Di Stefano G, et al. Minimally invasive right thoracotomy approach for mitral valve surgery in patients with previous sternotomy: a single institution experience with 173 patients. J Thorac Cardiovasc Surg 2014;148:2763-8. 18. Arcidi JM Jr, Rodriguez E, Elbeery JR, et al. Fifteen-year experience with minimally invasive approach for reoperations involving the mitral valve. J Thorac Cardiovasc Surg 2012;143:1062-8. 19. Umakanthan R, Petracek MR, Leacche M, et al. Minimally invasive right lateral thoracotomy without aortic cross-clamping: an attractive alternative to repeat sternotomy for reoperative mitral valve surgery. J Heart Valve Dis 2010;19:236-43. 20. McCreath BJ, Swaminathan M, Booth JV, et al. Mitral valve surgery and acute renal injury: port access versus median sternotomy. Ann Thorac Surg 2003;75:812-9.
Canadian Journal of Cardiology Volume - 2016 23. Suri RM, Schaff HV, Dearani JA, et al. Determinants of early decline in ejection fraction after surgical correction of mitral regurgitation. J Thorac Cardiovasc Surg 2008;136:442-7. 24. Borger MA, Rao V, Weisel RD, et al. Reoperative coronary bypass surgery: effect of patent grafts and retrograde cardioplegia. J Thorac Cardiovasc Surg 2001;121:83-90. 25. Byrne JG, Karavas AN, Filsoufi F, et al. Aortic valve surgery after previous coronary artery bypass grafting with functioning internal mammary artery grafts. Ann Thorac Surg 2002;73:779-84. 26. Thompson MJ, Behranwala A, Campanella C, Walker WS, Cameron EW. Immediate and long-term results of mitral prosthetic replacement using a right thoracotomy beating heart technique. Eur J Cardiothorac Surg 2003;24:47-51 [discussion: 51]. 27. Mazine A, Pellerin M, Lebon JS, et al. Minimally invasive mitral valve surgery: influence of aortic clamping technique on early outcomes. Ann Thorac Surg 2013;96:2116-22. 28. Svensson LG, Gillinov AM, Blackstone EH, et al. Does right thoracotomy increase the risk of mitral valve reoperation? J Thorac Cardiovasc Surg 2007;134:677-82. 29. Baker GL, Corry RJ, Autor AP. Oxygen free radical induced damage in kidneys subjected to warm ischemia and reperfusion. Protective effect of superoxide dismutase. Ann Surg 1985;202:628-41. 30. Romano MA, Haft JW, Pagani FD, Bolling SF. Beating heart surgery via right thoracotomy for reoperative mitral valve surgery: a safe and effective operative alternative. J Thorac Cardiovasc Surg 2012;144:334-9.
21. Valdez GD, Mihos CG, Santana O, et al. Incidence of postoperative acute kidney injury in patients with chronic kidney disease undergoing minimally invasive valve surgery. J Thorac Cardiovasc Surg 2013;146: 1488-93.
31. Birdi I, Regragui I, Izzat MB, Bryan AJ, Angelini GD. Influence of normothermic systemic perfusion during coronary artery bypass operations: a randomized prospective study. J Thorac Cardiovasc Surg 1997;114:475-81.
22. Thakar CV, Arrigain S, Worley S, Yared JP, Paganini EP. A clinical score to predict acute renal failure after cardiac surgery. J Am Soc Nephrol 2005;16:162-8.
32. Covello RD, Ruggeri L, Landoni G, et al. Transcatheter implantation of an aortic valve: anesthesiological management. Minerva Anestesiol 2010;76:100-8.