Totally thoracoscopic transmitral versus transaortic septal myectomy for hypertrophic cardiomyopathy: A propensity score-matched comparative study.

Abstract

To assess the perioperative safety and short-term efficacy of totally thoracoscopic transmitral septal myectomy as an alternative to the conventional transaortic approach in patients with hypertrophic cardiomyopathy. In this single-center retrospective study, between January 2022 and September 2024, 74 patients underwent totally thoracoscopic transmitral myectomy and 390 underwent transaortic myectomy. Two separate 1:1 propensity score-matched analyses were performed on the basis of key clinical and anatomical variables: one evaluating perioperative outcomes (n = 69 per group) and the other assessing follow-up echocardiographic outcomes (n = 45 per group). Transmitral myectomy led to significant reductions in interventricular septal thickness (IVST: 14.0 [12.0, 17.0] mm), left ventricular outflow tract gradient (13.0 [8.0, 17.6] mm Hg), midventricular pressure gradient (8.0 [8.0, 14.4] mm Hg), and mitral regurgitation, with complete resolution of systolic anterior motion at discharge. These outcomes were comparable with those in the transaortic group. No in-hospital mortality occurred, and complication rates did not differ significantly. New-onset conduction disturbances-primarily left bundle branch block-were more frequent in the transmitral group but were not associated with increased rhythm-related interventions. Intensive care unit and hospital stays were significantly shorter in the transmitral group. At follow-up, left ventricular outflow tract gradient continued to decline in the transmitral group (10.0 [7.0, 14.0] mm Hg), whereas midventricular pressure gradient increased significantly in the transaortic group. Totally thoracoscopic transmitral myectomy is a safe and effective minimally invasive alternative to the transaortic approach, offering comparable hemodynamic outcomes and enabling direct correction of mitral and subvalvular abnormalities.