Long-term outcome of simultaneous septal myectomy and anterior mitral leaflet retention plasty in hypertrophic obstructive cardiomyopathy: the Berlin experience.

BACKGROUND: Various surgical strategies designed to relieve left ventricular outflow tract obstruction (LVOTO) and correct mitral regurgitation (MR) in hypertrophic obstructive cardiomyopathy (HOCM) have evolved, yet reports on the long-term outcomes of each technique are scarce. We provide an update on over 20 years' experience at our institution in the standardized surgical treatment of HOCM.

METHODS: Between April 1986 and April 2014, 320 cases of endomyocardial resection and 305 septal myectomies were performed at our institution. Out of this sample, 57 patients (mean age 38±2.5 years, median 16.2, range 3 months-79.8 years) underwent surgery for HOCM involving septal myectomy and anterior leaflet retention plasty (ALRP), intended to obviate the systolic anterior motion (SAM) phenomenon. The preoperative mean LVOT pressure gradient was 98.98±26.2 (median 90, range 60-160) mmHg with moderate-severe MR. Standard transaortic septal myectomy was performed by resecting long blocks of septal myocardium, continued apically beyond the point of the mitral-septal contact. Through a left atriotomy, the segment of anterior mitral leaflet (AML) closest to the trigones was sutured to the corresponding posterior annulus on both sides. Cardiopulmonary bypass was resumed for repeat septal myectomy if the LVOT pressure gradient was greater than 20 mmHg.

RESULTS: Following surgical correction, the mean LVOT pressure gradient was significantly decreased to 12.3±2.7 (median 14, 18-25) mmHg (P<0.001). Septal thickness was reduced from a preoperative mean of 28.2±3.4 (median 30, 25-34) to 10.5±1.1 (12, 15-23) mm (P<0.001). During a mean follow-up of 17.5±1.3 years (median 12, range 1-23.2 years), MR was trivial in 87% and SAM was non-existent in all, outcomes that were maintained at the latest follow-up. Two patients underwent mitral valve (MV) replacement 1 and 5 years after ALRP for recurrent MR. Two patients eventually underwent heart transplantation for end-stage heart failure, 2 and 11 years later, respectively. Twenty-year freedom from repeat MV intervention and cumulative survival rate was 92.9% and 91.2%, respectively.

CONCLUSIONS: Long-term follow up of HOCM patients who underwent simultaneous septal myectomy and ALRP showed sustained absence of SAM, attenuation of MI, absence of residual LVOT obstruction and sustained improvement in hemodynamic and functional status.