Low operative and late mortality rates, excellent longlasting

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1 Flexible Posterior Mitral Annuloplasty: Five-Year Clinical and Doppler Echocardiographic Results Lionel F. Camilleri, MD, PhD, Bruno Miguel, MD, Patrick Bailly, MD, PhD, Benoit J. Legault, MD, Marie-Claire D Agrosa-Boiteux, MD, Gian Luca Polvani, MD, and Charles M. de Riberolles, MD Department of Cardiovascular Surgery, Gabriel Montpied University Hospital, Clermont-Ferrand, France Background. Stabilization of the posterior annulus seems to be a critical factor to achieve a stable mitral valve repair. To assess the benefit of softer mural annuloplasty, we analyzed results obtained with the flexible linear reducer. Methods. From 1985 to 1993, 120 patients, with pure mitral regurgitation, mainly degenerative, had a mitral reconstruction. Mean age was years and 74% of the patients were in New York Heart Association functional class III or IV. Results. Hospital mortality was 3.3%. Mean follow-up was months. There were 23 late deaths; 10 valve-related including 7 sudden deaths. Two patients (1.7%) required a reoperation. Doppler echocardiographic studies revealed excellent valve function; 5-year freedom from significant regurgitation was 85.8% 5.4%. Mean mitral valve area was cm 2. Although 105 patients were in class I or II, 23 patients were not functionally improved. Previous myocardial infarction and shorter deceleration time of early filling were risk factors for worsening functional disability. Conclusions. This support provides stable repair with excellent clinical and echographic results. Previous myocardial infarction and noncompliant left ventricle negatively influence outcome. (Ann Thorac Surg 1998;66:1692 7) 1998 by The Society of Thoracic Surgeons Low operative and late mortality rates, excellent longlasting clinical and functional results with lowest incidence of valve-related morbidity contribute to the enthusiasm for mitral valve reconstruction and promote its use in all suitable patients regardless of age, functional class, or cause [1, 2]. Valve repair usually includes routine insertion of a prosthetic ring to reduce the annular size and prevent further dilation, to increase leaflet coaptation, and to avoid excessive tension on repaired structures [3]. Increasing experimental [4] and clinical [5 7] studies showed that the anatomic and physiologic characteristics of the mitral annulus are preserved only when a flexible device is implanted. Previously we have reported satisfactory midterm results with mitral valve repair including a posterior annuloplasty with the flexible linear reducer (FLR) [8]. The purpose of the present study was to assess functional results and durability of the repair with the same support and to disclose any predictive factors of adverse outcome. Material and Methods Patient Population From August 1985 to August 1995, 205 patients with pure mitral insufficiency underwent mitral valve repair. We Accepted for publication May 27, Address reprint requests to Dr Camilleri, Chirurgie Cardio-Vasculaire, Hôpital Gabriel Montpied, Place Henri Dunant, BP 69, F Clermont- Ferrand Cedex 1, France. retrospectively studied the first 120 consecutive patients whose repair included a posterior mitral annuloplasty with the FLR. Preoperative characteristics of the patients are listed in Table 1. Mean age was years (range, 27 to 86 years). Mean New York Heart Association (NYHA) functional class was and 74% of the entire group was in class III or IV. Mitral regurgitation was judged moderate (2 ) and severe (3 ) in 24 (20.3%) and 93 (78.8%) patients, respectively. The leading cause of mitral regurgitation was degenerative disease (57.5%), followed by dilated cardiomyopathy and ischemic disease (Table 2). In the ischemic cohort, all patients had a previous myocardial infarct (inferior or lateral, 17; anterior, 1). Ninety-six patients (80%) had an associated procedure among which 41 were tricuspid annuloplasty and 29 myocardial revascularization (Table 2). Preoperative echocardiographic left ventricular measurements are reported in Table 3. Surgical Technique Normothermic (36 C) cardiopulmonary bypass was performed using bicaval cannulation, disposable membrane oxygenator, and hemodilution. Myocardial protection was achieved with topical cooling and antegrade then retrograde cold crystalloid cardioplegia. Exposure of mitral valve was obtained through right atrial and septal incisions, extended across the roof of the left atrium in the majority of patients. When needed valvular and subvalvular reconstruction procedures were performed according to Carpentier s guidelines (Table 2). In all 1998 by The Society of Thoracic Surgeons /98/$19.00 Published by Elsevier Science Inc PII S (98)00890-X

2 Ann Thorac Surg CAMILLERI ET AL 1998;66: DURABILITY OF POSTERIOR FLEXIBLE ANNULOPLASTY 1693 Table 1. Clinical Characteristics Characteristics No. of Patients % Total patients Sex Male Female Rhythm Sinus Atrial fibrillation PM NYHA functional class I II III IV NYHA New York Heart Association; PM Pacemaker. patients, the FLR was implanted, as previously described [8, 9]. The FLR consists of a silicone polymer encasing a braided Dacron core and two copper wires, available in 20-cm segments (Fig 1). It is not extensible and noncompressible longitudinally to assure a predictable reduction but fully flexible across its width to respect mitral physiology. The required length corresponds to the posterior part of the well-suited obturator of a Carpentier rigid ring. It is fixed by mattress stitches only onto the posterior leaflet annulus from trigone to trigone including the anatomic commissures. Annuloplasty alone was performed in 45 patients, whereas valvular or subvalvular repair was undertaken in 75 patients. Residual leak was Table 2. Operative Data Variables No. of Patients % Causes Degenerative Dilated cardiomyopathy Ischemic Rheumatic Endocarditis Functional mechanism Annulus dilation Leaflet prolapse Leaflet restricted motion Valvular or subvalvular repair Leaflet resection Chordal transfer or shortening Chordal division Gore-Tex chordae Papillary muscle reimplantation Concomitant procedure Tricuspid annuloplasty Myocardial revascularization Aortic valve replacement Other Table 3. Preoperative and Postoperative Echocardiographic Data a in 82 Patients Variables Preoperative Postoperative LVDD b LVSD b SF EF a Data are shown as mean standard deviation. b Significant difference from the preoperative value p LVDD left ventricular diastolic diameter; LVSD left ventricular systolic diameter; SF shortening fraction; EF ejection fraction. checked by fluid filling of the arrested left ventricle through the mitral valve. Intraoperative Doppler echocardiography was not used routinely. However, all patients had an echocardiogram before discharge. Anticoagulant Therapy Immediate postoperative heparin treatment was replaced before discharge by antiplatelet therapy or warfarin oral anticoagulation depending on rhythm and severity of left ventricular dysfunction. At last recall, 57% of patients received antiplatelet and 43% received oral anticoagulant therapy, at the discretion of their general practitioner. Echocardiographic Evaluation At the time of last follow-up, 89 patients among the 93 late survivors (96%) had a Doppler echocardiographic examination in our department. These investigations were performed with a wingmed CFM750 Doppler echocardiograph (Diasonics, Horten, Norway) equipped with a 2.5-kHz probe. In apical position, the grade of mitral regurgitation (0 to 3) was qualitatively assessed by the spatial extension of the regurgitant jet in color Doppler mode. In a pulsed Doppler mode, mitral diastolic flow velocity was registered. Early mitral velocity (E), velocity at atrial contraction (A), peak E/A ratio, and deceleration time of early filling were measured. The mitral valve area was estimated by the half-time pressure method. Chamber sizes, in diastole Fig 1. One segment of flexible linear reducer held tightly on the holder to position precisely the suture.

3 1694 CAMILLERI ET AL Ann Thorac Surg DURABILITY OF POSTERIOR FLEXIBLE ANNULOPLASTY 1998;66: and systole were obtained in parasternal position from M echocardiographic mode. Follow-up All patients were either examined in our department or contacted directly by telephone or through their referring physicians during a 6-month closing interval (May to September 1996). Follow-up to death or last assessment (100% complete) ranged from 1 to 104 months (mean, months; total, 6,729 patient-months). Deaths and complications were defined in compliance with published Guidelines for Reporting Morbidity and Mortality After Cardiac Valvular Operations [10]. Statistical Analysis Survival and freedom from event probabilities were estimated with the standard nonparametric Kaplan Meier method. Student s t tests were used to compare normally distributed continuous variables and Pearson 2 analysis was used to compare discrete variables. Statistical analysis was also assessed by using log analysis of variance test. Significance was assumed when the p value was less than Values were expressed as mean standard deviation unless otherwise stated. The patient population was divided in groups depending on NYHA functional class evolution between preoperative and last follow-up data. Results Early Mortality A total of 4 patients (3.3%) died in a mean delay of 31 days (range, 2 to 60 days). Causes of deaths were low cardiac output syndrome (2 patients), perforated gastric ulcer (1), and sudden unexplained death (1 patient). Among these patients, 3 had concomitant procedures and 1 was reoperated on after previous aortic valve replacement associated with myocardial revascularization. There were no early deaths in patients with primary isolated mitral valve repair. Preoperative functional class (p 0.85) and shortening fraction (p 0.90) were not identified as risk factors of operative mortality. Table 4. Causes of Late Deaths Variables No. of Patients % Total Cardiac Valve related Embolism Cerebral hemorrhage Endocarditis Sudden, unexplained Nonvalve related Congestive heart failure Acute myocardial infarction Noncardiac Carcinoma Septicemia aspirin, whereas 3 patients were in sinus rhythm and 2 were in atrial fibrillation. Freedom from thromboembolic complications were 97.8% 2.1% at 5 years and 90.8% 5.3% at 7 years (Fig 3). Forty-nine (42.9%) patients received anticoagulant therapy, although only 32 (28.1%) had chronic atrial fibrillation. Bleeding Event One patient on oral anticoagulation for chronic atrial fibrillation had a cerebral hemorrhage leading to death. At 5 years, 98.0% 1.3% of the patients were free from bleeding complication (Fig 3). Endocarditis Infective valve endocarditis occurred in 1 patient, with a freedom from endocarditis of 99.1% 0.8% at 5 years. Reoperation Two patients (1.7%) required a reoperation, leading to a probability of freedom from reoperation at 5 years of 98.2% 1.3%. The original regurgitation (rheumatic, 1 patient; dilated cardiomyopathy, 1 patient) had been treated by annuloplasty alone without additional mitral Survival There were 23 late deaths, 10 of which were considered valve related, 7 sudden deaths, 1 stroke, 1 cerebral bleeding, and 1 endocarditis. Causes of late deaths are listed in Table 4. Actuarial survival at 5 years, including early mortality was 82.1% 3.8% (Fig 2). Preoperative NYHA functional class III and IV (p 0.16), causes of mitral regurgitation (p 0.48), and shortening fraction (p 0.74) were not significant prognostic indicators for cardiac death. Embolism Thromboembolic events were reported in 5 patients, four strokes (three with residual deficiency, one death) and one transient ischemic attack. At the time of event, 3 patients were receiving warfarin and 2 were receiving Fig 2. Actuarial survival curves from all deaths ( ) and from cardiac death (E).

4 Ann Thorac Surg CAMILLERI ET AL 1998;66: DURABILITY OF POSTERIOR FLEXIBLE ANNULOPLASTY 1695 Fig 3. Actuarial curves of freedom from thromboembolism ( ) and from bleeding event (E). valve repair technique. In 1 patient, the repair was combined with an aortic valve replacement. Causes of recurrent mitral regurgitation was one reducer dehiscence (12 months) and one insufficient annular reduction (24 months). In both instances the valve was replaced by a mechanical prosthesis without mortality. Event-Free Survival From All Valve-Related Events Freedom from death, embolism, bleeding, endocarditis, and reoperation at 5 years was 76.2% 4.4% (Fig 4). Preoperative NYHA class III or IV (p 0.015) were risk factors for morbid events, but causes of mitral regurgitation (p 0.27) and shortening fraction (p 0.84) were not. Functional Status At last follow-up, 105 patients (92.1%) were in NYHA functional class I or II and 9 were (7.9%) in class III or IV (Table 5). There was a functional improvement of at least one class in 91 patients (group I) and 23 had either an identical (18) or worsened (5) functional status (group II). Multivariate analysis showed previous myocardial infarction to be a risk factor of postoperative increase in functional disability (p 0.006, comparison between groups I and II). Echocardiographic Evaluation Doppler echocardiographic examinations, available in 89 patients at a mean interval of 5 years, demonstrated no mitral regurgitation in 50 patients (56.2%), mild insufficiency (1 ) in 28 (31.5%), moderate (2 ) in 10 (11.2%), and severe (3 ) in only 1 patient (1.1%). This latter patient was not reoperated owing to poor ventricular function. At 5 years, freedom from significant mitral regurgitation (2 and 3 ), including 2 reoperated patients, was 85.8% 5.4% (Fig 5). Causes of significant mitral regurgitation were mural leaflet prolapse (2 patients) or retraction (3 patients), septal leaflet prolapse (1 patient) or retraction (2 patients), and ventricular dysfunction (3 patients). Besides the 3 patients who had severe ventricular dysfunction resulting in ventricular and annular dilatation, the recurrent mitral regurgitation could not be directly related to the FLR. No patient had echocardiographic evidence of left ventricular outflow tract obstruction. Comparison of preoperative and last follow-up left ventricular echocardiographic measurements available in 82 patients are reported in Table 3. A significant reduction in diastolic and systolic left ventricular diameters was evidenced, whereas shortening fraction remained unchanged. Mean mitral valve area was cm 2 and mean mitral pressure gradient mm Hg. Mean E and A peak flow velocities were estimated at m/s (range, 0.6 to 2.6 m/s) and m/s (range, 0.5 to 1.8 m/s), E/A ratio was (range, 0.5 to 2.8). Excluding 11 patients who had significant regurgitation, mean deceleration time of early filling was shorter in group II (n 16; ms) than in group I (n 55; m/s). The difference was statistically significant between the two groups (p 0.019). Comment The concept of posterior mitral annuloplasty on a prosthetic support was introduced in 1976 [9, 11]. It is based on anatomic and physiologic evidence. The resistant fibrous constitution of the septal annulus prevents stretching, whereas the weak Henle s tendinous fibers of the mural annulus are prone to dilatation [12]. Furthermore, the annulus is not fixed into a geometric plane, particularly the anterior portion, which is convex, following the shape of the left outflow tract and aortic valve. From a physiologic point of view, the mitral annulus is a dynamic structure, changing from a circular shape in diastole to a flattened D shape in systole reducing the mitral area by approximately 26% [13]. Moreover, clinical studies have shown that rigid fixation of the mitral annulus can affect adversely left diastolic and systolic ventricular functions and effective mitral valve orifice [5, 14]. Thus, we considered that stabilization of the posterior annulus with a prosthetic support, flexible across its width but nonextensible across its length, appeared to be justified. Nevertheless, accuracy in calibration of length Fig 4. Actuarial curve of freedom from all valve-related events (E).

5 1696 CAMILLERI ET AL Ann Thorac Surg DURABILITY OF POSTERIOR FLEXIBLE ANNULOPLASTY 1998;66: Table 5. Preoperative and Last Follow-up New York Heart Association Functional Class in 114 Patients With Available Data Last Follow-up Functional Class (n 114) I [n 2 (2%)] Functional Class Preoperatively (n 114) II [n 41 (36%)] III [n 51 (45%)] IV [n 20 (17%)] I[n 59 (52%)] 1 (50%) 26 (63%) 24 (47%) 8 (40%) II[n 46 (40%)] 1 (50%) 14 (34%) 21 (41%) 10 (50%) III[n 6 (5%)] 0 1 (2%) 3 (6%) 2 (10%) IV[n 3 (3%)] (6%) 0 Group I: functional improvement of at least one class in 91 patients (80%). Group II: worsening functional class, either identical or even deteriorated functional class in 23 patients (20%). of segmental reduction of the posterior annulus according to the septal leaflet size is mandatory. Using a linear noncompressible device such as the FLR, affords a much more precise and predictable reduction than soft material such as pericardium. In this cohort, despite inclusion of relatively high-risk patients with concomitant aortic valve replacement (18%) or coronary artery bypass graft (24%), mainly in NYHA functional class III or IV (74%), a hospital mortality of 3.3% and an overall survival of 82% at 5 years compare favorably to most previous reports [1, 6, 12, 15 18]. As already published, operative mortality is most often related to low cardiac output [19] and late mortality to end-stage cardiac failure [20]. The preoperative characteristics of the patients, such as age, underlying cardiac function, and associated coronary atherosclerosis, have been identified as potent predictors of both early and late mortalities [12, 21 23]. Although most of our early and late cardiac deaths occurred in elderly patients with advanced functional class, these factors did not reach statistical significance in our analysis. The only correlation we found was between NYHA functional class and the occurrence of late morbidity. At present, survival is regarded as an insensitive measure of mitral valve repair performance, and some valve-related events, particularly the incidence of reoperation or the incidence of significant residual mitral regurgitation and deterioration of the functional status can be more pertinent. In this study, using a softer Fig 5. Actuarial curve of freedom from significant residual mitral regurgitation (E). fixation of the mural annulus alone, we were able to obtain at 5 years freedom from reoperation and from significant residual mitral regurgitation of 98.2% and 85.8%, respectively. These especially encouraging results underline the fact that stabilization of the posterior annulus with a support is a critical point to achieve durable repair and could prevent some of the structural dysfunctions observed in the absence of an annuloplasty support [16, 17, 20]. Notwithstanding these impressive results, a perennial concern with mitral valve regurgitation operation is the late occurrence of a progressive incidence of congestive heart failure and cardiac death, both as a result of left ventricular failure [1, 22, 24]. Therefore, in this study we attempted to identify variables that could be associated with unsatisfactory results. Considering worsening of the functional status, between preoperative and last follow-up status, we found that previous myocardial infarction and specific Doppler parameter of left ventricular filling, that is, deceleration time of early filling, correlated strongly with an adverse outcome. Associated coronary artery disease has been identified previously as a powerful predictor of an excess incidence of congestive heart failure and late cardiac death in surgical correction of organic mitral regurgitation. Moreover, this impaired prognosis persists despite concomitant coronary artery bypass grafting [24]. Considering left ventricular function, it has become increasingly apparent that left ventricular diastolic dysfunction rather than systolic functional impairment may contribute to signs and symptoms in patients with cardiac heart failure [25]. The deceleration time of early diastole reflects the rate of equalization of left atrial and left ventricular pressures. A short deceleration time is an index of abnormal filling and diastolic function of the left ventricle and is believed to be caused by markedly increased left ventricular chamber stiffness. It has been previously reported that a short deceleration time in patients with left ventricular systolic dysfunction can predict both congestive heart failure and late cardiac deaths [25]. In conclusion, in mitral insufficiency repair associated with annuloplasty, the initial favorable behavior of the FLR device remains stable with a mean follow-up of 56 months. Remote myocardial infarction and left ventricular diastolic dysfunction are likely limiting the long-term benefit of the surgical procedure.

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