Mitral Valve Repair at King Chulalongkorn Memorial Hospital; A Preliminary Report.

Transcription

1 Mitral Valve Repair at King Chulalongkorn Memorial Hospital; A Preliminary Report. Jiranut Cholteesupachai, MD.*, Smonporn Boonyaratavej Songmuang, MD.*, Seri Singhatanadgige, MD. ** King Chulalongkorn Memorial Hospital Bangkok Thailand *From Department of Medicine, King Chulalongkorn Memorial Hospital Bangkok Thailand **From Department of Surgery, King Chulalongkorn Memorial Hospital Bangkok Thailand Abstract Background: Mitral valve repair has many advantages over mitral valve prosthetic replacement. Advantages include better functional preservation of the mitral valve apparatus and of the ventricular performance with only few valve-related complications. The investigators studied intermediate results of mitral valve repair in King Chulalongkorn Memorial Hospital (KCMH) Design: Nested case follow-up study Material and Method: From January 2000 to December 2004, there were103 consecutive patients with mitral regurgitation who had mitral valve repair at KCMH by the same surgeon. Baseline characteristics and operative data were recorded. Out outcomes included death, reoperation for recurrent mitral regurgitation and hospitalization from heart failure. Information was collected from hospital records, repeated echocardiogram; mailed questionnaires and telephone contacts. Results: Median follow up time was 34 months. Mean age was 47±22 years (3 to 80 years), 60% were male. Primary MR was the cause of regurgitation in 74%. The other causes were ischemic heart disease 17.5%, dilated cardiomyopathy 3.9%. Follow-up data revealed that valve-related reoperation was performed in 7.5%, hospitalization in 5.4% and Significant MR in 11%. All-cause mortality was 10.8% and cardiac related mortality 2.2%. Mitral valve (MV) repair failure wa seen in 11.8%. A preoperative history of diabetes and NYHA functional class IV were significant independent risk factors for all-cause mortality. Conclusion: Our experience revealed similar satisfactory data for intermediate results of mitral valve repair as those reported from other countries. Longer term follow-up is now in progress. Thai heart J 2007; 20 : E-Journal : Introduction The prognosis of patients with mitral valve disease has improved as the result of developments in mitral valve surger (1-2). Formerly, operative procedures in mitral valve surgery consisted mainly of valve replacement. Today valve repair is the main procedure for mitral valve regurgitation. During the past 10 years, procedures for mitral valve surgery have changed tremendously (3-16). The advantages of mitral valve repair over replacement are well established (17-21). They include better functional Correspondence to: Smonporn Boonyaratavej Songmuang address: echochula-fellows@ yahoo.com preservation of the mitral valve apparatus and ventricular function with only few valve-related complications. There was a decrease in thromboembolic complications and a decreased risk of endocarditis and this translates to a survival advantage. King Chulalongkorn Memorial Hospital (KCMH) has had experience with mitral valve repair prior the year 2000 and preliminary experience provided promising results (22). Methods Patients From January 2000 to December 2004 mitral valve repair at KCMH was performed in 103 patients (62 males, 41 females). All were operated

2 172 Jiranut Cholteesupachai, MD, Smonporn Boonyaratavej Songmuang, MD, Seri Singhatanadgige, MD. on by one surgeon. A retrospective chart review was conducted. The patients were aged from 3 to 80 years (mean age, 47.21±21.99 years). Preoperative New York Heart Association functional class (FC) was 3 or 4 in 69 of these patients (67%). The preoperative patient characteristics and perioperative outcome data are shown in Table 1. Table 1. Preoperative patient s characteristics N % Patients (n) 103 Male / Female 62/ /39.8 Age (yr) 3-80 Mean age (mean ± SD) ± NYHA class I-II class III class IV Underlying disease Diabetes Hypertension Renal impairment (Cr > 2 mg/dl) Previous stroke History of heart failure History of angina pectoris Cardiac rhythm Atrial fibrillation Sinus rhythm Preoperative LVEF ³ 60% % < 30% Methods Mitral valve regurgitation (MR) was assessed using tranthoracic echocardiography. MR was graded according to the percentage regurgitant jet area to the left atrium. Preoperative MR indicated a moderate degree in 29% and a severe degree in 71% Demographics as well as intraoperative, perioperative and intermediate outcome data included overall survival, cardiac death rate including mitral valve related deaths, rate of reoperation, endecarditis, rate of recurrent significant MR and risk factors for recurrence that had traditionally been classified as procedure-related or valve-related, thromboembolic events, bleeding events, and heart-related hospitalized events. The study was approved by the Institutional Review Board and Ethical Committee. Operative technique Our institutional policy was to perform mitral valve (MV) Repair whenever possible. Mitral valve replacement (MVR) was performed if an adequate repair was not considered feasible. The approach to the heart was through a midline sternotomy and the mitral valve repair was performed using cardiopulmonary bypass and mild systemic hypothermia(30-32). Myocardial protection was obtained with combined antegrade and retrograde cold blood cardioplegia through the aortic root and the coronary sinus without topical hypothermia. (4:1) Approach to the mitral valve was standard incision or a superior transeptal approach. Table 2-3 summarizes causes of mitral regurgitation and the anatomic findings of the mitral valve. Isolated MV repair was done in 60 cases (58.3%). There were 43 patients (41.7%) who had concomitant procedures performed with repair of the mitral valve. Other associated operations were shown in Table 4. The most common surgical procedures were those used to correct the prolapsing leaflet by quadrangular resection of the posterior leaflet (PML), subvulvular correction and suture annuloplasty. We also started to do anterior mitral leaflet (AML) repair by using various techniques. The details were shown in Table 5 In most of the patients (96.1%), the Cosgrove-Edwards Annuloplasty System were used to reduce the size of the annulus, reshape it, and reinforce the repaired valve. Table 2. Causes of mitral regurgitation Causes N % Mitral valve prolapse Rheumatic heart disease Ischemic heart disease Infective endocarditis Dilated cardiomyopathy Congenital mitral valve cleft Unknown 1 1.0

3 Mitral Valve Repair at King Chulalongkorn Memorial Hospital; A Preliminary Report. 173 Table 3. Anatomic details of mitral valve pathology Pathology N % Annular dilatation Prolapsed leaflet Posterior / Anterior 26/28 48/52 Restricted leaflet Ischemic MR Congenital mitral valve cleft Table 4. Concomittant operations Concomittant N % Coronary artery bypass surgery Tricuspid valve repair Aortic valve repair Maze procedure Others (eg; suture patent foramen ovale, repair abdominal aortic aneurysm, patch closure atrial septal defect) Table 5. Operative technique of MV repair Operative technique N % P2 quadrangular resection Chordal transfer Artificial chordae Closure of commissure P3 resection Subvulvular correction Annuloplasty Only annuloplasty Closure of mitral cleft Anticoagulation Anticoagulant treatment was not given to the patients who had a sinus rhythm. Warfarin sodium was always used for patients with atrial fibrillation to maintain the international normalized ratio between 2.0 and 3.0. Follow-up Most the patients underwent a postoperative transternal echocardiographic study before discharge from the hospital. Hospital records, mailed questionnaires or telephone follow-up were then used to assess the patients current status and medical regimen. Patients have been followed for at least 12 months after mitral valve repair. The mean period of follow-up is 33.7±19 months and 10 patients were lost to follow up. Statistical analysis Data were represented as frequency distributions and percentages. Descriptive statistics are reported as a mean ± standard deviation (SD) for continuous variables and as frequencies and percentages for categoric variables unless otherwise noted. Continuous variables were compared using paired t tests, whereas categorical variables were compared by means of x2 test. For all analyses, a p value of less than 0.05 was considered statistical ly significant. Kaplan-Meier analysis was used to estimate the intermediate or mid-term survival or outcome events along with a log-rank p value when comparing groups eg as well as overall survival, mitral valve repair failures, and heart failure-related hospitalized rate Cox regression was used to evaluate the impact of variables on the mid-term outcome. Only preoperative variables with p<0.25 (23) at univariate analysis were considered for inclusion in the multivariable Cox regression model. A p< 0.05 was considered statistically significant. The adjusted risk ratios for the independent predictors and their 95% confidence intervals are presented in the tables. All data were analyzed utilizing the Statistical package for the Social Sciences; SPSS 13 (SPSS Inc, Chicago,IL). Results Two patients died in the hospital, giving an operative mortality rate of 1.9 %. One had CABG and AV repair concomitant with MV repair. He died on the 35 th post-operative day. The death was due to pneumonia and respiratory failure and one had low pre-op left ventricular ejection fraction (LVEF) 23%, acute renal failure and had high dose inotropic drug.he died on the 5 th post-operative day. The death was due to heart failure.

4 174 Jiranut Cholteesupachai, MD, Smonporn Boonyaratavej Songmuang, MD, Seri Singhatanadgige, MD. There were 8 late deaths (8.6%). Common causes of death were nonvalvular, noncardiac causes. Data are shown in table 6. Ninety-one percent of the surviving patients were in FC I and 7.8% were in FC.II. There were 7 patients who needed reoperation; 4 for valve replacement and 3 for repeat valve repair. A common cause was intravascular hemolysis after valve repair. An echocardiogram of the repaired MV was performed before discharge and during follow up (at least after 1 year of post MV repairs). All patients improved as far as the regurgitant status was concerned on the early postoperative echocardiogram and nearly 90% of patients were in non-significant regurgitation and 70% of patients had no or trivial regurgitation when echocardiogram were done in the follow up period. About ten percent have at least moderate mitral regurgitation that refers to significant MR that shown in Figure 1. Other postoperative complications are show in table 6. The diameters of the left atrium, left ventricular end diastolic (LVED) and left ventricular end systolic (LVES) pressure are shown in Figure 2. The comparison of the left ventricular ejection fractions is shown in Figure 3. Table 6 Post-operative complications Complications N (%) Death 10 (10.8) - Early 2 (2.2) - Late 8 (8.6) MV repair failure 11 (11.8) Reoperation 7 (7.5) - MV replacement 4 (4.3) - Redo MV repair 3 (3.2) Hospitalization 29 ( 31.2) - Heart failure 5 (5.4) - Other cardiac causes 5 (5.4) - Non cardiac causes 19 (20.4) Bleeding 8 (8.6) Thromboembolism 8 (8.6) Endocarditis 0 (0) Figure 1. Comparison of preoperative, postoperative, during follow up at least 1 yr MR

5 Mitral Valve Repair at King Chulalongkorn Memorial Hospital; A Preliminary Report. 175 Figure 2. Parameters from pre/post operative echocardiogram Figure 3. Pre/post-operative left ventricular ejection fraction Figure 4. Kaplan-Meier estimates of the cumulative survival from all cause mortality Cumulative survival No.of Patients At Risk Survival Mortality was 94% at 1 year, 92% at 3 years. Preoperative history of New York Heart Association category IV and diabetes were significant independent risk factors for events and death (Figure 4, 5 and Table 8). Event-free rate of MV repair failure (MV related reoperation and/or rehospitalization from heart failure) was 93% at 1 year, 92% at 3 years as shown in Figure 6. When we combined all causes of mortality and MV repair failure events to all composite end points, it s shown that event-free rate from all composite end points was 88% at 1 year, 86% at 3 years as in Figure 7. There was no significant risk factor to predict these events. Discussion Our present study confirmed that mitral valve repair for regurgitation is associated with a favorable intermediate outcome. However the reoperation rate was higher than reported in the literature. This was mostly due to intravascular hemolysis that occurred within 30 days after valve repair. However, a number of variables have been found to be associated with less satisfactory outcomes. These were a preoperative history of heart failure or diabetes which was significant independent predictors. This study demonstrated higher proportion of anterior leaflet repair in mitral valve prolapse than other reports where posterior leaflet repairs were more common. The Maze procedure was done in only one patient that in our early experience. Later, the Maze procedure was performed in most patients with preoperative atrial fibrillation. Serial echocardiographic parameters showed a decrease in the size of left ventricular end diastolic diameter

6 176 Jiranut Cholteesupachai, MD, Smonporn Boonyaratavej Songmuang, MD, Seri Singhatanadgige, MD. Figure 5. Kaplan-Meier estimates of the cumulative survival from all caues mortality Table 8. Analysis of risk factors for all causes mortality by Cox proportional-hazards model Univariate predictor variable Hazard ratio from proportional hazards regression P value from proportional hazards regression P value from multivariable analysis* Male 1.30 ( ) Age > 60 yrs at operation 6.83 ( ) Diabetes 5.90 ( ) Hypertension 3.05 ( ) 0.08 Ischemic heart disease 3.12 ( ) 0.10 Atrial fibrillation 2.31 ( ) New York Heart 5.61 ( ) Association IV Cause (Ischemic) 4.28 ( ) Primary MR 0.28 ( ) Anterior leaflet 1.23 ( ) Co-operate with CABG 5.60 ( ) Preoperative LVEDD 1.02 ( ) Preoperative LVESD 1.06 ( ) Preoperative LA 1.0 ( ) 0.89 Only variables with a P value of less than 0.25 at univariable analysis were considered (LVEDD), left ventricular end systolic diameter (LVESD) and left atrium (LA) and a decreased left ventricular ejection fraction (LVEF) during the early postoperative echocardiogram. There was also improvement compared to preoperative echocardiographic baseline LVEF in later follow up. Lack of serial echocardiographic evaluation of all patients prevents any definitive conclusion whether any died before a possible mitral valve reoperation. In fact, it is possible that a few patients deteriorated before adequate cardiologic evaluation was not performed in a timely manner. The recent study by Flameng and colleagues (24) reminds us that continuous echocardiographic follow up may disclose much poorer results than depicted by late cardiac deaths or that some could have been prevented by repeat mitral valve surgery. In Flmeng s sries, the 5-year survival rate was 94.7% and survival freedom from mitral valve reoperation was 96.1%. These Figures are similar to the ones reported by other authors. However, a serial 6- month interval echocardiographic follow up showed that 5-year survival freedom from mitral valve regurgitation grade >1 was 58.6%, whereas it was 82.8% for regurgitation >2. Thus, the difference between freedom from severe recurrent regurgitation (>2) at 5 years is about 16%. These observations suggest that, despite good clinical results, a number of patients experience significant mitral valve regurgitation after mitral valve surgery, but do not undergo repeat mitral valve surgery. In order to better identify the risk factors associated with late failure of mitral valve repair, it would be appropriate to evaluate actural estimates of echocardiographically verified recurrent severe mitral valve regurgitation.

7 Mitral Valve Repair at King Chulalongkorn Memorial Hospital; A Preliminary Report. 177 Figure 6. Kaplan-Meier estimates of the cumulative survival from MV repair failure The limitations of this study include that it was relatively small and statistical values of certain variables might have been influenced by chance alone. This represents the clinical experience of a single surgeon and the results can not be generalized. Only intermediate results were available for this analysis, and longer follow up is needed to obtain enough data for definitive inferences on the effects of mitral valve repair. In conclusion, our experience confirmed the favorable clinical intermediate results after mitral valve repair. Long-term follow-up is now ongoing. References Figure 7. Kaplan-Meier estimates of the cumulative survival from all composite end points 1. Delahaye JP, Gare JP, Viguier E, Delahaye F, De Gevigney G, Milon H. Natural history of severe mitral regurgitation. Eur Heart J 1991;12: B Ling LH, Enriquez- Sarano M, Seward J, et al. Clinical outcome of mitral regurgitation due to fail leaflets. N Engl J Med 1996; 335: Heikkinen J, Biancari F, Uusimaa P, et al. Longterm outcome after mitral valve repair. Scand Cardiovasc J 2005; 39: Jebara VA, Mihaileanu S, Acar C, et al. Left ventricularoutflow tract obstruction after mitral valve repair.results of the sliding leaflet technique. Circulation 1993; 88: Cosgrove DM III, Arcidi JM, Rodiguez L, Stewart WJ, Powell K, Thomas JD. Initial experience with the Cosgrove-Edwards annuloplasty system. Ann Thorac Surg 1995; 60: David TE, Komeda M, Pollick C, Burns RJ. Mitral valve annuloplasty. Ann Thorac Surg 1989; 47: Cohn LH, Kowalker W, Bhatia S, et al. Comparative morbidity of mitral valve repair versus replacement for mitral regurgitation with and without coronary artery disease:an update in Ann Thorac Surg 1995; 60: Perrier P, DeLoache A, Chauvaud S, et al. Comparative evaluation of mitral valve repair and replacement with Starr, Bjork, and porcine valve prostheses. Circulation 1984; 70:

8 178 Jiranut Cholteesupachai, MD, Smonporn Boonyaratavej Songmuang, MD, Seri Singhatanadgige, MD. 9. Alfieri O, De Bonis M, Lapenna E, et al. Edge to-edge repair for anterior mitral leaflet prolapse. Seminar Thorac Cardiovasc Surg 2004;16: Carpentier A. Cardiac valve surgery:the French correction. J Thorac Cardiovasc Surg 1983; 86: Zussa C, Polesel E, Da Col U, Galloni M, Valfre C. Seven-year experience with chordal replacement with expanded polytetrafluoroethylene in floppy mitral valve. J Thorac Cardiovasc Surg 1994; 108: David TE, Armstrong S, Sun Z. Replacement of chordae tendineae with Gore-Tex sutures: a ten-year experience. J Heart Valve Dis 1996; 5: Lessana A, Romano M, Lutfalla G, et al. Treatment of ruptured or elongated anterior mitral valve chordae by partial transposition of the posterior leaflet: experience with 29 patients. Ann Thorac Surg 1988; 45: Sousa UM, Grare P, Jebara V, et al. Transposition of chordae in mitral valve repair. Mid-term results. Circulation 1993; 88: II Dreyfus GD, Bahrami T, Alayle N, Mihealainu S, Dubois C, De Lentdecker P. Repair of anterior leaflet prolapse by papillary muscle repositioning: a new surgical option. Ann Thorac Surg 2001; 71: Totaro P, Tulumello E, Fellini P, et al. Mitral valve repair for isolated prolapse of the anterior leaflet: an 11-year follow-up. Eur J Cardiothorac Surg 1999; 15: Galloway AC, Colvin SB, Baumann FG, Eet al. Long-term results of mitral valve reconstruction with Carpentier techniques in 148 patients with mitral insufficiency. Circulation 1988; 78: I Yun KL, Miller DC. Mitral valve repair versus replacement. Cardiology Clinics 1991; 9: Enriquez-Sarano M, Schaff HV, Orszulak TA, Tajik AJ, Bailey KR, Frye RL. Valve repair improves the outcome of surgery for mitral regurgitation. A multivariate analysis. Circulation 1995; 91: Ren JF, Aksut S, Lighty GW, Jr., et al. Mitral valve repair is superior to valve replacement for the early preservation of cardiac function: relation of ventricular geometry to function. Am Heart J 1996;131: Thourani VH, Weintraub WS, Guyton RA, el al. Outcomes and long-term survival for patients undergoing mitral valve repair versus replacement: effect of age and concomitant coronary artery bypass grafting. Circulation. 2003; 108: Singhatanadgige S, Boonyaratavej S. Immediate Results of Mitral Valve Repair at King Chulalongkorn Memorial Hospital. J Med Assoc Thai 2003; 86: S Kleinbaum DG. The Cox Proportional Hazards Model and Its Characteristics.In: Survival Analysis, A Self-Learning Text..Springer; 1996: Flameng W, Herijgers P, Bogaerts K. Recurrence of mitral valve regurgitation after mitral valve repair in degenerative valve disease. Circulation 2003;107:

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