Standardized papillary muscle relocation for type IIIb secondary mitral regurgitation improves 2-year outcome

Abstract

Objectives: The major drawback of isolated annuloplasty for treatment of secondary mitral regurgitation (SMR) with restricted leaflet motion during systole (type IIIb) is the recurrence of SMR, leading to adverse clinical outcome. Additional papillary muscle relocation (PMR) specifically addresses leaflet tethering to restore mitral valve geometry. We aimed to compare the 2-year outcome of annuloplasty with additional PMR vs isolated annuloplasty.

Methods: A total of 105 consecutive type IIIb SMR patients with preoperative left ventricular (LV) ejection faction <45%, left ventricular end-diastolic diameter >55 mm and a tenting height >10 mm reached 2-year postoperative follow-up after mitral valve repair and were included in the current analysis. A total of 51 patients underwent annuloplasty and additional PMR (study group). A total of 54 patients underwent isolated annuloplasty (control group). Primary composite study end point comprised death or recurrence of mitral regurgitation ≥2 at 2 years postoperatively.

Results: Echocardiographic baseline variables indicating the severity of LV dysfunction and mitral leaflet tethering were similar. Procedural and periprocedural outcome was comparable in both groups. The primary composite end point was significantly improved in the study group (19.6% [10/51]) in comparison to the control group (44.4% [24/54]; P = 0.009). Two-year all-cause mortality was 7.8% [4/51] in the study group vs 18.5% [10/54] in the control group (P = 0.098). After 2 years, a significant improvement in New York Heart Association functional class as compared to the baseline values was observed in the study group.

Conclusions: Additional PMR to treat SMR type IIIb resulted in an improved 2-year outcome in comparison to isolated annuloplasty. PMR specifically addressing mitral leaflet tethering represents a valid therapeutic option for heart failure patients with SMR type IIIb.

Keywords: Chronic heart failure; Functional mitral regurgitation; Mitral leaflet tethering; Papillary muscle relocation; Secondary mitral regurgitation; Subvalvular mitral valve repair.