Several new considerations in mitral valve repair

Abstract

Background and aim of the study: A retrospective evaluation was made of a small personal series of patients undergoing mitral valve repair in order to address four contemporary questions: (i) What is the best method of achieving a stable repair in mitral valve prolapse?; (ii) How should patients with pure annular dilatation without prolapse or antecedent ischemia be categorized?; (iii) Are valve procedures in ischemic mitral regurgitation (MR) still associated with less satisfactory early and late outcomes?; and (iv) Is prophylactic amiodarone therapy safe and effective in reducing postoperative arrhythmias?

Methods: Between 1993 and 2002, a total of 118 patients with non-rheumatic MR undergoing isolated mitral valve repair with or without coronary bypass was analyzed retrospectively: of these patients, 66 had prolapse (Group I), 21 had pure annular dilatation (Group II), and 31 had ischemic MR (Group III). All three groups routinely underwent Carpentier ring annuloplasty. Twenty-three patients in Group I were managed with leaflet resection and reconstruction (LRR), but in 1996 the technique for Group I was changed to uniform artificial chordal replacement (ACR) and no leaflet resection (n = 43). Also in 1996, prophylactic amiodarone therapy was first used routinely, and postoperative arrhythmia data were compared to those from prior patients. Baseline and outcome variables were assessed for each group and compared between the three groups. Survival data were evaluated using the Cox proportional hazards model.

Results: Significant differences in baseline characteristics were observed: Group II was predominantly female; Group III more often experienced acute presentation; and Groups II and III had more comorbid disorders and left ventricular dysfunction (all p < 0.01). ACR was highly successful for repair of prolapse, and no ACR patient exhibited significant residual MR or outflow tract obstruction. Operative mortality and morbidity were low in all groups, and ischemic etiology failed to be an independent predictor of early or late adverse outcome (p > 0.10). Cox model analysis to nine years of follow up (median 4 years) identified only advanced age and number of comorbidities as influencing late mortality (both p < 0.03). Over the follow up period, 8.7% of LRR patients required reoperation for valve failure due to late chordal rupture, whereas none of the ACR patients failed. Finally, prophylactic amiodarone significantly reduced postoperative arrhythmias (p = 0.03) with no observed complications, and also eliminated death due to arrhythmia.

Conclusion: Ischemic etiology may be diminishing as an independent risk factor in Group III, at least partially because of uniform valve repair. Group II comprised a distinct entity of females with higher comorbidity, and prophylactic amiodarone therapy seemed useful as a routine measure. Finally, ACR appeared to produce a stable repair in virtually all Group I patients, suggesting that prolapse might be appropriately managed with ring annuloplasty and uniform ACR. However, future studies are suggested for further consideration of these hypotheses.