Restrictive Mitral Annuloplasty With or Without Papillary Muscle Approximation for Functional Mitral Regurgitation.

Background and aim of the study: The impact of adding papillary muscle approximation (PMA) to restrictive mitral annuloplasty (RMA) on postoperative left ventricular (LV) function is unknown. Changes in LV function parameters and clinical outcome were evaluated following RMA with and without PMA in patients with clinically relevant functional mitral regurgitation (FMR).

Methods: A total of 176 patients with advanced cardiomyopathy underwent RMA either with (n = 59) or without (n = 117) PMA. Propensity score analysis was used to adjust for group differences in several baseline characteristics, such as age, gender and LV ejection fraction (LVEF) (C-statistic = 0.80, goodness-of-fit value = 0.58).

Results: Serial echocardiography in 30 propensity score-matched pairs demonstrated decreases in LV end-systolic dimension (RMA alone: 57 ± 9 mm at baseline versus 54 ±11 mm at one month versus 56 ± 13 mm at latest examination; RMA + PMA: 56 ± 8 mm versus 53 ± 9 mm versus 48 ± 11 mm, respectively) and improvement in LVEF (RMA alone: 28 ± 8% versus 28 ± 11% versus 29 ± 10%; RMA + PMA: 30 ± 8% versus 30 ± 9% versus 36 ± 13%, respectively) in both groups. Greater degrees of changes in value were noted for patients receiving RMA + PMA (group effect p <0.05 for both). The two-year survival of both groups was similar (73 ± 8% versus 77 ± 23%, p = 0.7), but the RMA + PMA group showed a trend towards a greater freedom from composite events, defined as mortality and/or unscheduled heart failure re-admission (48 ± 9% versus 63 ± 9%, p = 0.1).

Conclusions: RMA + PMA induced greater long-term effects on unloading of the left ventricle and improvements in LV systolic function than did RMA alone. PMA may be a useful adjunct repair in combination with RMA, although its clinical benefits remain to be determined.