Concomitant Mitral Valve Surgery During Surgical Treatment of Hypertrophic Obstructive Cardiomyopathy

Due to variable involvement of mitral valve (MV) anomalies in hypertrophic obstructive cardiomyopathy (HOCM), MV repair may be added to septal myectomy. This study reports on our experience with HOCM surgery, including the effect of MV surgery. The HOCM population was divided per treatment in group 1 = septal myectomy/ablation only, and group 2 = septal myectomy + MV surgery. Clinical endpoints as survival and reoperation rate, and echocardiographic results were compared. The study comprised 47 patients (group 1 = 18 - group 2 = 29). Group 2 showed more MV anomalies (group 1:29% - group 2:79%, p = 0.023) as increased leaflet length and annular calcification (group 1:0% - group 2:17.2%, p = 0.062) and SAM-related MR (MR ≥ 2: group 1=17.7% - group 2=75.8%, p < 0.001). MV surgery consisted of anterior leaflet patch augmentation (n = 20), secondary chordae resection (n = 15), Alfieri-repair (n = 2) and MV replacement (n = 6). Within median follow-up of 7.2y (IQR: 1.2-13.4), 5 to 10 year survival was 87.2% ± 8.6% and 79.3% ± 10.9% for group 1, and 85.6% ± 6.7% and 66.7% ± 13.2% for group 2 (p = 0.333). Procedure-related reoperation was required in 6 patients. LVOTO relief was effective showing a comparable postoperative gradient reduction (group 1: 53.6 ± 32.2 > 19.5 ± 9.3 mm Hg - group 2: 69.0 ± 42.3 > 19.1 ± 8.5 mm Hg), which was maintained during FU (group 1: 11.2 ± 3.8 mm Hg - group 2: 12.2 ± 6.3 mm Hg). Although septal myectomy remains the cornerstone in the treatment of HOCM, a significant MV contribution to the LVOTO is observed in many patients, often amenable to MV repair. LVOTO relief by septal myectomy with or without MV surgery is effective and durable, however at a potential risk of reoperation for recurrent MV dysfunction after MV repair.