Improved Long-Term Outcome after Standardized Subvalvular Mitral Valve Repair for Type IIIB Functional Mitral Regurgitation

Objectives: The major drawback of isolated annuloplasty in the treatment of functional mitral regurgitation (FMR) with restricted leaflet motion during systole (type IIIb) is the reoccurrence of MR, leading to an impaired long-term outcome. Additional realignment of both papillary muscles specifically addresses leaflet tethering to durably restore MV geometry. We aimed to prospectively compare the long-term outcome of annuloplasty with simultaneous realignment of both papillary muscles versus isolated annuloplasty.

Methods: A total of 105 consecutive type IIIb FMR patients with preoperative LVEF < 45%, LVEDD > 55 mm and a tenting height > 10 mm, reached 2-year postoperative FU after MV repair and were included in the current analysis. 51 underwent annuloplasty + realignment of both papillary muscles (Study group). 54 patients underwent isolated annuloplasty (Control group). Primary composite study-endpoint comprised death or the reoccurrence of MR ≥ 2 at 2 years postoperatively. Secondary endpoints were adverse events, echocardiographic and functional patient outcome.

Result: Baseline variables indicating the severity left ventricular dysfunction and mitral valve tethering parameters (tenting height, tenting area, and leaflet angles) were comparable. The duration of the surgery (290 ± 8 vs. 300 ± 87; p = 0.56), cardiopulmonary bypass (173 ± 50 vs. 178 ± 36; p = 0.52) and aortic cross clamp time (100 ± 31 vs. 100 ± 27; p = 0.97) were similar. Although a right-anterolateral minimally invasive approach was more frequent in the Study group, there was no difference regarding periprocedural complications. Discharge TTE revealed significantly reduced mitral leaflet tethering parameters in the Study group in comparison to the Control group. After 2 years there was a significant reduction of NYHA functional class within the Study group (preoperative NYHA>II 74% versus postoperative NYHA>II 16%; p < 0.001). Furthermore, 2 years after surgery the composite endpoint (occurrence of death or MR ≥ 2) was significantly reduced in the Study group 19.6% [10/51] in comparison to the Control group 44.4% [24/54] (p = 0.002). 2-year mortality was 7.8% [4/51] in the Study group, versus 18.5% [10/54] in the Control group (p = 0.086).

Conclusion: Standardized subvalvular realignment of both papillary muscles in addition to mitral annuloplasty specifically addresses leaflet tethering, thereby enhancing long-term durability after mitral valve repair. Furthermore, freedom from composite study-endpoint (death or recurrent MR) was significantly improved 2 years after surgery.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
19 February 2021