Minimally Invasive Mitral Valve Surgery: A 6-Year Experience With 714 Patients

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1 Minimally Invasive Mitral Valve Surgery: A 6-Year Experience With 714 Patients Eugene A. Grossi, MD, Aubrey C. Galloway, MD, Angelo LaPietra, MD, Greg H. Ribakove, MD, Patricia Ursomanno, MSN, Julie Delianides, MA, Alfred T. Culliford, MD, Costas Bizekis, MD, Rick A. Esposito, MD, F. Gregory Baumann, PhD, Marc S. Kanchuger, MD, and Stephen B. Colvin, MD Division of Cardiothoracic Surgery, Department of Surgery, and Division of Cardiothoracic Anesthesia, New York University School of Medicine, New York, New York Background. This study analyzes a single institutional experience with minimally invasive mitral valve operations of 6 years, reviewing short-term morbidity and mortality and long-term echocardiographic follow-up data. Methods. Seven hundred fourteen consecutive patients had minimally invasive mitral valve procedures between November 1995 and November 2001; concomitant procedures included 91 multiple valves and 18 coronary artery bypass grafts. Of these 714 patients, 561 patients had isolated mitral valve operations (375 repairs, 186 replacements). Mean age was 58.3 years (range, 14 to 96 years; 30.1% > 70 years), and 15.4% of patients had previous cardiac operations. Arterial cannulation was femoral in 79.0% and central in 21%, with the port access balloon endo-occlusion used in 82.3%. Cardioplegia was transjugular retrograde (54.1%) or antegrade (29.4%). Right anterior minithoracotomy was used in 96.6% and left posterior minithoracotomy in 2.2%. Results. Hospital mortality for primary isolated mitral valve repair was 1.1% and 5.8% for isolated mitral valve replacement. Overall hospital mortality was 4.2% (30 of 714). Mean cross-clamp time was 92 minutes and mean cardiopulmonary bypass time was 127 minutes. Postoperatively, median ventilation time was 11 hours, intensive care unit time was 19 hours, and total hospital stay was 6 days. Complications for all patients included permanent neurologic deficit (2.9%), aortic dissection (0.3%); there was no mediastinal infection (0.0%). Follow-up echocardiography demonstrated 89.1% of the repair patients had only trace or no residual mitral insufficiency. Conclusions. This study demonstrates that the minimally invasive port access approach to mitral valve operations is reproducible with low perioperative morbidity and mortality and with late outcomes that are equivalent to conventional operations. (Ann Thorac Surg 2002;74:660 4) 2002 by The Society of Thoracic Surgeons Alternative approaches to standard sternotomy for mitral valve operations have been advocated in the last decade as facilitating technologies have been developed. These various approaches include minithoracotomies [1], partial sternotomies [2 4], and parasternal incisions [5, 6]. Our institution has based its minimally invasive approach on a right anterior minithoracotomy approach combined with balloon endoaortic occlusion and either peripheral or central arterial cannulation for the vast majority of mitral valve operations [1]. This study examines a single institutional experience with minimally invasive mitral valve operations over a 6-year period with a minithoracotomy approach. The analysis focuses on the technical aspects of the procedures and reviews the short-term morbidity and mortality. Presented at the Thirty-eighth Annual Meeting of The Society of Thoracic Surgeons, Fort Lauderdale, FL, Jan 28 30, Address reprint requests to Dr Grossi, NYU Medical Center, Suite 9-V, 530 First Ave, New York, NY 10016; grossi@cv.med.nyu.edu. Material and Methods Between November 1995 and November 2001, 714 consecutive patients had minimally invasive mitral valve operative procedures. The mean patient age was 58 years (30.1% 70 years; 6.7% 80 years). Preoperative New York Heart Association functional class was 3 or 4 in 328 of these patients (46.0%). Previous cardiac operations had been performed in 110 patients (15.4%). The predominant mitral pathology was degenerative (70.4%). Table 1 lists various patient preoperative comorbidities and basic characteristics. Among the concomitant procedures there were 53 aortic valves (7.4%), 32 tricuspid valves (4.5%), 6 triple valves (0.8%), and 18 coronary artery bypass grafts (2.5%) (Table 2). Of these 714 patients, 561 (78.6%) had isolated mitral valve operations, 375 had repairs (66.8%), and 186 had replacements (33.2%). Operative approaches and techniques are listed in Table 3. Right anterior minithoracotomy [1, 7] was used in 96.9%, and a left posterior minithoracotomy was used in 2.2% of the patients. A major extension of the incision across the sternum oc by The Society of Thoracic Surgeons /02/$22.00 Published by Elsevier Science Inc PII S (02)

2 Ann Thorac Surg GROSSI ET AL 2002;74:660 4 MINIMALLY INVASIVE MITRAL VALVE SURGERY 661 Table 1. List of Basic Patient Characteristics (n 714) Age (y) (mean standard (range,14 96) deviation) Septuagenarian 167 (23.4%) Octo-nonogenarian 48 (6.7%) Male gender (%) 371 (52%) Previous cardiac Operation (%) 110 (15.4%) Cause Degenerative 503 (70.4%) Rheumatic 128 (17.9%) Infective 38 (5.3%) Other 45 (6.3%) New York Heart Association functional class I 65 (9.1%) II 318 (44.5%) III 253 (35.4%) IV 75 (10.5%) Peripheral vascular disease 34 (4.8%) Previous Myocardial infarction 60 (8.4%) Diabetic 50 (7.0%) Preoperative stroke or Transient 55 (7.7%) Ischemic Attack Chronic renal failure 18 (2.5%) curred in 8 patients (1.1%). Mitral and aortic operations were performed through a right third anterior minithoracotomy as described previously [8]. Intraoperative transesophageal echocardiography was used in all patients. Arterial cannulation was femoral in 79.0% using the Port Access Endoclamp (Cardiovations, Somerville NJ) in all except 1 patient. Retrograde arterial perfusion was avoided in patients with peripheral vascular disease or atheromatous aortas identified on transesophageal echocardiography. Ascending aortic cannulation was used in 151 patients (21.1%); 116 of these patients had direct aortic clamping, 24 had endo-balloon occlusion of the aorta, and the remaining patients were fibrillated. Cardioplegia was transjugular retrograde in 54.1%, direct retrograde in 12.0%, and antegrade in 29.4%. Flooding the operative field with CO 2 has been routinely used during the last 5 years. All data were prospectively collected by trained nurse clinicians. Analysis was performed with SPSS version 10 (Chicago, IL) and included -square for univariate and backwards stepwise logistic regression for multivariate analyses. Table 2. List of All Operative Procedures Performed (n 714) Isolated mitral valve procedures (%) 561 (78.6%) Concomitant aortic valve procedures (%) 53 (7.4%) Concomitant tricuspid valve procedures (%) 32 (4.5%) Concomitant triple valve procedures (%) 6 (0.8%) Concomitant coronary artery bypass 18 (2.5%) graft procedures (%) Concomitant other procedures (%) 16 (2.2%) Table 3. List of Operative Techniques Used (n 714) Right anterior minithoracotomy 692 (96.9%) Left posterior minithoracotomy 16 (2.2%) Ministernotomy 6 (0.8%) Femoral arterial cannulation 563 (79.0%) Femoral venous cannula 694 (97.2%) Ascending aorta aortic cannulation 151 (21.1%) Central venous cannula 99 (13.9%) Port access endoclamp Femoral 562 (78.7%) Ascending aorta 24 (3.4%) Direct ascending aorta cross clamp 116 (16.2%) Hypothermic fibrillation 18 (2.5%) Percutaneous transjugular cardioplegia 386 (54.1%) Results Overall hospital mortality was 4.2% (30 of 714); all isolated mitral valve mortality was 2.9% (16 of 561). Primary isolated mitral valve repair had a mortality of 1.1% (4 of 351), and primary mitral valve replacement had a mortality of 5.8% (8 of 137). Univariate risk factor analysis for all patients is presented in Table 4. Advanced age, New York Heart Association functional class 4, previous cardiac operation, emergency operation, and diabetes were associated with increased risk, whereas an isolated mitral procedure was associated with decreased risk. Multivariate analysis revealed that New York Heart Association functional class 4 (odds ratio [OR] 5.40; p 0.001; 95% confidence interval [CI] 2.33 to 12.66), age greater than 69 (OR 2.92; p 0.010; 95% CI 1.29 to 6.62), emergency operation (OR 2.96; p 0.039; 95% CI 1.05 to 8.33), peripheral vascular disease (OR 3.14; p 0.046; 95% CI 1.02 to 9.67), and concomitant procedures (OR 2.20; p 0.060; 95% CI 0.97 to 4.99) were independent predictors of hospital death. In the subset of isolated mitral patients, previous cardiac operation, New York Heart Association functional class 4, advanced age, mitral replacement, and emergency operation were significantly associated with increased risk (Table 5). Multivariate analysis for the isolated mitral patients revealed that New York Heart Association functional class 4 (OR 12.50; p 0.001; 95% CI 4.42 to 35.71) was the only significant independent predictor of hospital death. A morbidity analysis for all patients is shown in Table 6. Major morbidity excluding death occurred in 6.8% of all patients. Additional univariate analysis revealed that the risk of major morbidity was increased in patients greater than 70 years of age (9.8% vs 5.2%; p 0.03) and in patients with previous cardiac operation (10.9% vs 5.2%; p 0.05). Univariant analysis of stroke (new neurologic deficit or positive computerized axial tomography scan, or both) showed that peripheral vascular disease (OR 4.74; p 0.001), history of stroke or transient ischemic attack (OR 2.48; p 0.080), and previous cardiac operation (OR 2.06; p 0.097) were associated risk factors. Retrograde arterial perfusion was not a significant risk factor (OR 0.875; p 0.792). Multivariate analysis revealed that peripheral vascular disease (OR 4.20;

3 662 GROSSI ET AL Ann Thorac Surg MINIMALLY INVASIVE MITRAL VALVE SURGERY 2002;74:660 4 Table 4. Risk Factor Analysis for for All Patients ( 2 Test) Risk Factor With Risk Factor Without Risk Factor p Value Age 70 or older 8.8% (19/215) 2.2% (11/499) Isolated mitral operation 2.9% (16/561) 9.2% (14/153) Previous cardiac operation 12.7% (14/110) 2.6% (16/604) New York Heart Association functional class 4 20% (15/75) 2.3% (15/639) Emergency operation 19.6% (9/46) 3.1% (21/668) Peripheral vascular disease 17.6% (6/34) 3.4% (25/680) Diabetes 12% (6/50) 3.6% (24/664) 0.01 p 0.01; 95% CI 1.43 to 12.20), age (OR 0.98; p 0.16), and previous stroke or transient ischemic attack (OR 2.41; p 0.13; 95% CI 0.78 to 7.45) were associated with the risk of stroke. Permanent neurologic deficit was 2.9%. Postdischarge follow-up echocardiography of mitral repairs demonstrated 89.1% of patients had only trace or no residual mitral insufficiency. Comment For the surgeon who elects to use a minimally invasive approach for mitral valve operations, a broad array of choices of specific techniques is available. Decisions have to be made regarding the type of incision and use of direct aortic or femoral cannulation, balloon endoclamp or direct aortic cross-clamp, video assistance or direct observation, removal of air procedures, and other technical aspects, many of which are interrelated. When minimally invasive mitral valve operation was still in its infancy, such choices could only be based on related surgical experience and intuition. Now, however, experience has evolved with sufficiently large patient groups to permit such decisions to become data driven. Studies such as this one on 714 patients using a specific combination of minimally invasive techniques and examining both complete short-term and partial follow-up results should begin to form a useful basis for future choices. The putative major advantages of minimally invasive mitral valve operations, especially with the port access approach, are reduced postoperative pain, shortened length of hospital stay and reduced interval to return to normal activity, lowered hospital costs, and better cosmesis. Suggested potential disadvantages of the minimally invasive approach include the aortic dissection caused by retrograde cannulation or flow, femoral groin injury, endoclamp migration or production of emboli, difficulty in removal of air, and increased operation cost. Some relatively small, early experiences with minimally invasive mitral valve operations have provided disappointing results, but also acted to reaffirm some of the potential benefits of this approach and highlighted the problems to be overcome [9]. Larger, more recent studies have demonstrated good short- and long-term clinical results with minimally invasive mitral operations that rival or surpass those of the conventional sternotomy approach [10 16]. The 3-year clinical and echocardiographic follow-up of the first one hundred isolated mitral reconstructions in this series was equal to that of the last one hundred operations performed with a sternotomy approach at our institution [10 16]. It is obvious that the lack of total or partial sternotomy and rib osteotomy with the port access approach avoids the complications associated with these incisions. Although some have suggested that a small anterior thoracotomy is associated with equal or greater postoperative pain [17, 18] compared to a sternotomy, there is good evidence that the port access approach reduces postoperative discomfort and enhances recovery [11, 19, 20]. The advent of a new version of the aortic endovascular occluder, which provides for direct cannulation of the ascending aorta and antegrade perfusion, obviates most of the problems related to retrograde perfusion and groin vascular injury. In addition, air removal techniques have been improved with CO 2 use, and increased costs of the Table 5. Risk Factor Analysis for for Isolated Mitral Patients (n 714; 2 Test) Risk Factor With Risk Factor Without Risk Factor p Value Previous Cardiac Surgery 8.9% (7/79) 1.9% (9/482) NYHA Class 4 17% (8/47) 1.6% (8/514) Age 70 or older 5.8% (9/155) 1.7% (7/406) Mitral Repair 1.9% (7/375) 4.8% (9/186) Emergency Operation 10.0% (3/30) 2.4% (13/531) Diabetes 8.6% (3/35) 2.5% (13/526) Peripheral Vascular Dis. 8.3% (2/24) 2.6% (14/537) 0.010

4 Ann Thorac Surg GROSSI ET AL 2002;74:660 4 MINIMALLY INVASIVE MITRAL VALVE SURGERY 663 Table 6. List of Operative Variables and Postoperative Morbidity for All Patients (n 714) Bypass time (min) (mean standard deviation) Cross-clamp time (min) (mean standard deviation) Median ventilation time (h) 11 Median intensive care unit time (h) 19 Median total hospital stay (days) 6 Reoperation for bleeding or effusion 35 (4.9%) Aortic dissection 2 (0.3%) Permanent neurologic deficit 21 (2.9%) Postoperative sepsis 21 (2.9%) Mediastinal infection 0 (0.0%) Leg wound infection 3 (0.4%) Chest wall infection 6 (0.8%) Renal failure 16 (2.2%) Reoperation for valve failure 5 (0.7%) Respiratory failure 51 (7.1%) Any major complication excluding death 47 (6.6%) operation might be outweighed by reduced overall hospital costs. Limitations of the Study This patient series is an uncontrolled but continuous series. The series also encompasses our learning curve with our initial experiences included. In addition, during the first 2 years of this experience, the endo-direct ascending aortic cannulation system was not available for use. Also, the rate of postoperative new onset atrial fibrillation is not available. In conclusion, it is only by continually reexamining and revaluating the ever-expanding experience with minimally invasive mitral valve operations that the relative advantages and widespread applicability have become apparent. Based on the evidence presented here and in other studies, the minimally invasive approach remains our institution s procedure of choice for mitral valve operations. Supported in part by The Foundation for Research in Cardiac Surgery and Cardiovascular Biology. References 1. Grossi EA, La Pietra A, Galloway AC, Colvin SB. Videoscopic mitral valve repair and replacement using the portaccess technique. Adv Card Surg 2001;13: Gundry SR, Shattuck OH, Razzouk AJ, del Rio MJ, Sardari FF, Bailey LL. Facile minimally invasive cardiac surgery via ministernotomy. Ann Thorac Surg 1998;65: Nair RU, Sharpe DA. Limited lower sternotomy for minimally invasive mitral valve replacement. Ann Thorac Surg 1998;65: Gillinov AM, Banbury MK, Cosgrove DM. Hemisternotomy approach for aortic and mitral valve surgery. J Card Surg 2000;15: Cohn LH, Adams DH, Couper GS, et al. Minimally invasive cardiac valve surgery improves patient satisfaction while reducing costs of cardiac valve replacement and repair. Ann Surg 1997;226: Cosgrove DM, 3rd, Sabik JF, Navia JL. Minimally invasive valve operations. Ann Thorac Surg 1998;65: Grossi E, Ribakove G, Galloway A, Colvin S. Minimally invasive mitral valve surgery with endovascular balloon technique. Operative Techniques in Thoracic and Cardiovascular Surgery 2000;5: Colvin S, Grossi E, Ribakove G, Galloway A. Minimally invasive aortic-mitral operation. Operative Techniques in Thoracic and Cardiovascular Surgery 2000;5: Mohr FW, Falk V, Diegeler A, Walther T, van Son JA, Autschbach R. Minimally invasive port-access mitral valve surgery. J Thorac Cardiovasc Surg 1998;115: Grossi EA, La Pietra A, Ribakove GH, et al. Minimally invasive versus sternotomy approaches for mitral reconstruction: comparison of intermediate-term results. J Thorac Cardiovasc Surg 2001;121: Grossi EA, Galloway AC, Ribakove GH, et al. Impact of minimally invasive valvular heart surgery: a case-control study. Ann Thorac Surg 2001;71: Mishra YK, Malhotra R, Mehta Y, Sharma KK, Kasliwal RR, Trehan N. Minimally invasive mitral valve surgery through right anterolateral minithoracotomy. Ann Thorac Surg 1999; 68: Chitwood WR, Jr, Nifong LW. Minimally invasive videoscopic mitral valve surgery: the current role of surgical robotics. J Card Surg 2000;15: Glower DD, Siegel LC, Frischmeyer KJ, et al. Predictors of outcome in a multicenter port-access valve registry. Ann Thorac Surg 2000;70: Schroeyers P, Wellens F, De Geest R, et al. Minimally invasive video-assisted mitral valve surgery: our lessons after a 4-year experience. Ann Thorac Surg 2001;72:S El-Fiky MM, El-Sayegh T, El-Beishry AS, et al. Limited right anterolateral thoracotomy for mitral valve surgery. Eur J Cardiothorac Surg 2000;17: Loulmet DF, Carpentier A, Cho PW, et al. Less invasive techniques for mitral valve surgery. J Thorac Cardiovasc Surg 1998;115: Chaney MA, Morales M, Bakhos M. Severe incisional pain and long thoracic nerve injury after port-access minimally invasive mitral valve surgery. Anesth Analg 2000;91: Glower DD, Landolfo KP, Clements F, et al. Mitral valve operation via port access versus median sternotomy. Eur J Cardiothorac Surg 1998;14:(Suppl 1):S Grossi EA, Zakow PK, Ribakove G, et al. Comparison of post-operative pain, stress response, and qualilty of life in port access vs. standard sternotomy coronary bypass patients. Eur J Cardiothorac Surg 1999;16:1 4. DISCUSSION DR ALAIN CARPENTIER (Paris, France): This is a very nice presentation and I congratulate you on your results. You did not mention any complication due to the cannulation of the femoral vessels, although in our experience we have had some problems at this level. So could you tell us whether you have never seen such complications, and if it is the case, which technique do you use to avoid this problem, which is sometimes something very important or can be important. DR GROSSI (New York, NY): With respect to peripheral cannulation, there were 3 patients in whom we saw a postoperative seroma in the groin incision. I think also you have to realize that

5 664 GROSSI ET AL Ann Thorac Surg MINIMALLY INVASIVE MITRAL VALVE SURGERY 2002;74:660 4 we are very careful to avoid the groin cannulation if there is peripheral vascular. We are using the ascending aortic cannulation site as our cannulation site of preference in the presence of either peripheral vascular disease or atheromatous aortic disease as demonstrated on intraoperative transesophageal echocardiography. DR CARPENTIER: When you cannulate your femoral vessels, do you pay attention to try to maintain the circulation in the leg one way or another? DR GROSSI: No, we have not. DR CARPENTIER: So, in other words, you are occlusive? DR GROSSI: Yes, we used an occlusive technique through a small horizontal incision. Most of the patients who are studied in our institution with advanced age or coronary disease will also have a femoral runoff shot performed at the time as their cardiac catheterization to help us identify those in whom unsuspected peripheral vascular disease is be present. DR BRUCE LYTLE (Cleveland, OH): Dr Grossi, in your conclusions you mentioned that this study showed that there were equivalent late outcomes; but of course there is no data on late outcomes; I mean, there is no length of follow-up, there is no incidence of reoperation, that sort of thing. DR GROSSI: We had immediate follow-up, and within the first 6 months we had follow-up on the isolated reconstructions presented. It will be a year ago this April, we published an intermediate outcome on the first 100 primary isolated mitral valve reconstructions, which showed no difference in terms of the sternotomy approach and the minimally invasive approach. That was published in the Journal of Thoracic and Cardiovascular Surgery. That study basically compared our last 100 sternotomy mitral reconstructions with our first 100 minimally invasive mitral reconstructions. So on the basis of that published data, we feel confident that we are giving the patients the same operation in terms of reconstruction. DR LYTLE: Right, but just to clarify it in my mind, that is a 6 month follow-up of 100 patients, is that correct? DR GROSSI: No, that was a 1- and 3-year follow-up on the cohort of the first 100 patients. DR LYTLE: A second thing is, are you aware of any complications related to the coronary arteries or the aortic valve on the basis of using the Endoclamp, the femoral Endoclamp? DR GROSSI: I am not aware of any valve in our series that was injured. Although we have seen Endoclamps inadvertently protrude through the aortic valve, we have never had any new onset of aortic insufficiency due to balloon migration or to any technique that I am aware of. DR LISHAN AKLOG (Boston, MA): Were any of the twenty three strokes attributable to the port access perfusion techniques? DR GROSSI: I think they are contributable to doing cardiopulmonary bypass and valve surgery on these patients. DR AKLOG: Were there events in the operating room on those patients that would lead you to be concerned with that? DR GROSSI: In terms of malperfusion or balloon misplacement? Not to our knowledge, no, I have not seen that. DR AKLOG: I did notice that it does not seem like you reaped great benefits from the minimally invasive approach in terms of length of stay, intensive care unit time and ventilator time, a median stay of 6 days. Has that changed over time? DR GROSSI: No. I think you have to look at the patients here. We are talking about 7% octo-, and non-agenarians, and another 25% being septuagenarians. Some of these patients came in already on a ventilator preoperatively. This is a very wide experience, and the purpose of this talk was to show the use of this approach in all patients. DR AKLOG: So you believe it did benefit? DR GROSSI: Yes, we did, and with smaller controlled studies, which we have previously published. This current presentation encompasses our overall experience, showing what can be accomplished and what complications occur when we apply this technique to all the patients of whom we take care.