Midterm outcomes of thoracoscopic trans-mitral myectomy for hypertrophic obstructive cardiomyopathy: A single-center,...

Hypertrophic obstructive cardiomyopathy (HOCM) is traditionally treated with septal myectomy via sternotomy. Thoracoscopic trans-mitral myectomy (TTM) is a minimally invasive alternative, but midterm outcomes remain unclear. We aimed to evaluate the midterm efficacy and safety of TTM versus open trans-aortic myectomy (OTM) in obstructive HOCM patients.

A retrospective cohort study was conducted at a single institution, including patients who underwent either TTM or OTM from January 2020 to December 2023. Primary endpoints included changes in echocardiographic parameters (left ventricular outflow tract [LVOT] gradient, septal thickness, left ventricular volume, and mitral regurgitation severity) and functional improvement (NYHA class). Secondary outcomes included complications, re-intervention, and survival at 12 months.

A total of 102 patients were included, with 57 undergoing TTM and 45 undergoing OTM. Both techniques led to significant reductions in LVOT gradient and septal thickness (both p < 0.001), with no significant intergroup differences. TTM showed superior improvement in mitral regurgitation severity, with moderate-to-severe mitral regurgitation decreasing from 42 % to 9 % versus 38 % to 20 % in OTM (p < 0.05). Functional status improved, with 88 % of TTM and 87 % of OTM patients achieving NYHA class I at 12 months. No significant differences were observed with respect to re-interventions or 12-month survival.

TTM is a safe and effective alternative to OTM for HOCM, offering similar relief of LVOT obstruction and functional improvement, with superior reduction in mitral regurgitation severity. Larger, multicenter studies are needed to confirm these findings and define TTM's role in HOCM management.