Papillary Muscle Approximation Versus Restrictive Annuloplasty Alone for Severe Ischemic Mitral Regurgitation

Abstract

Background: Guidelines recommend surgery for patients with severe ischemic mitral regurgitation (MR). Nonrandomized studies suggest that subvalvular repair is associated with longer survival, but randomized studies are lacking.

Objectives: This study sought to investigate the benefit of papillary muscle surgery on long-term clinical outcomes of patients with ischemic MR.

Methods: Ninety-six patients with severe ischemic MR were randomized to either undersizing restrictive mitral annuloplasty (RA) or papillary muscle approximation with undersizing restrictive mitral annuloplasty (PMA) associated with complete surgical myocardial revascularization. The primary endpoint was change in left ventricular end-diastolic diameter (LVEDD) after 5 years, measured as the absolute difference from baseline, which was evaluated by paired Student t tests. Secondary endpoints included changes in echocardiographic parameters, overall mortality, the composite cardiac endpoint (major adverse cardiac and cerebrovascular events [MACCE]), and quality of life (QOL) during the 5-year follow-up.

Results: At 5 years, mean LVEDD was 56.5 ± 5.7 mm with PMA versus 60.6 ± 4.6 mm with RA (mean change from baseline -5.8 ± 4.1 mm and -0.2 ± 2.3 mm, respectively; p < 0.001). Ejection fraction was 44.1 ± 6% in the PMA group versus 39.9 ± 3.9% in the RA group (mean change from baseline 8.8 ± 5.9% and 2.5 ± 4.3%, respectively; p < 0.001). There was no statistically significant difference in mortality at 5 years, but freedom from MACCE favored PMA in the last year of follow-up. PMA significantly reduced tenting height, tenting area, and interpapillary distance soon after surgery and for the long-term, and significantly lowered moderate-to-severe MR recurrence. No differences were found in QOL measures.

Conclusions: Compared with RA only, PMA exerted a long-term beneficial effect on left ventricular remodeling and more effectively restored the mitral valve geometric configuration in ischemic MR, which improved long-term cardiac outcomes, but did not produce differences in overall mortality and QOL.

Keywords: mitral valve annuloplasty; mitral valve insufficiency; myocardial infarction; myocardial revascularization; undersizing annuloplasty; ventricular remodeling.