Mid-term results of papillary muscles approximation: a retrospective single-center study

Abstract

Background. Enlargement of the left ventricular chamber and displacement of papillary muscles in the apical and lateral directions increase the tethering forces. Left ventricular and papillary muscle desynchrony and reduced myocardial contractility reduce the closing forces, thus leading to impaired leaflet coaptation and appearance of mitral regurgitation. Therefore, treatment of mitral insufficiency requires an integrated approach, affecting all aspects of the pathogenesis of mitral regurgitation recurrence. Recent publications show that adjunctive subvalvular repair during mitral annuloplasty for secondary mitral regurgitation is effective in preventing recurrent regurgitation. One of these procedures is papillary muscle approximation. However, the safety and the positive impact of this method are still open to question. Aim. This study focused on the assessment of mid-term results of papillary muscles approximation and comparison of the obtained results with those of isolated mitral annuloplasty.Methods. Two hundred and twelve patients with ischemic cardiomyopathy and ischemic mitral regurgitation were enrolled in this retrospective single-center study. The patients were randomised to 2 groups by using propensity score matching (a “neighbor” method) according to the following parameters: end diastolic volume, end systolic volume, stroke volume and ejection fraction. The first group included 112 patients with ischemic cardiomyopathy and mitral regurgitation, who underwent coronary artery bypass grafting, mitral annuloplasty and papillary muscle approximation. The second group included 112 patients with ischemic cardiomyopathy who underwent coronary artery bypass grafting and mitral valve annuloplasty. We evaluated early and mid-term results.Results. Two patients in group 1 and three patients in group 2 died of heart failure progression during 31.3±10.4 month follow-up. According to the Kaplan-Meier analysis, no statistically significant differences were noted between the groups (log-rank test = 0.8). Approximation of papillary muscles in patients with ischemic mitral regurgitation improved mitral valve leaflet coaptation as evidenced by the values of coaptation depth, coaptation line and tenting area (p>0.05). During follow-up, 3 cases (2.7%) of mitral insufficiency recurrence were recorded in group 1 and 16 (14.3%) in group 2. The Kaplan-Meier analysis of cumulative probability showed a significant difference in freedom from recurrence of mitral regurgitation ≥2 between groups in the mid-term postoperative period (log-rank test = 0.041).Conclusion. Adjunctive papillary muscle approximation performed at the time of mitral annuloplasty improves the durability of mitral valve repair. Received 18 April 2018. Revised 12 October 2018. Accepted 18 October 2018. Funding: The study did not have sponsorship. Conflict of interest: Authors declare no conflict of interest.