Transapical Beating-Heart Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy: Lessons Learned After the Learning Curve Period.

Background: The transapical beating-heart septal myectomy (TA-BSM) procedure was developed to enhance efficiency and reduce surgical trauma compared with conventional septal myectomy in treating obstructive hypertrophic cardiomyopathy. The current study aimed to delineate a refined TA-BSM surgical technique and summarize the midterm outcomes of the cohort immediately after the learning curve period.

Methods: Employing a beating-heart myectomy device and guided by real-time transesophageal echocardiography, TA-BSM was conducted through a left mini-thoracotomy. Multiple tailored resections were performed on the beating heart to optimize hemodynamics and morphology. The primary outcome was procedural success, defined by resting/provoked left ventricular outflow tract gradient <30/50 mm Hg and mitral regurgitation ≤grade 2+ (of 4+) at 3- to 6-month follow-up.

Results: Between January 2023 and January 2024, 418 patients with heterogeneous anatomic presentations of obstructive hypertrophic cardiomyopathy underwent TA-BSM. The maximal left ventricular outflow tract gradient decreased from a median of 85 (interquartile range, 65-114) mm Hg preoperatively to 19 (interquartile range, 12-28) mm Hg at 3- to 6-month follow-up. Mitral regurgitation improved with 98.8% of patients achieving ≤grade 2+ upon follow-up, versus 47.7% preoperatively. Overall, procedural success was achieved in 91.1% of the patients. Major adverse events included left ventricular apical tear (n=3, 0.7%), iatrogenic mitral valve injury (n=3, 0.7%), permanent pacemaker implantation (n=10, 2.4%), and transient ischemic stroke (n=2, 0.5%). All affected patients recovered uneventfully. The 30-day mortality was 0.2% (n=1). The estimated 1-year survival was 98.7% (95% CI, 97.6%-99.9%) over a median follow-up of 310 (interquartile range, 207-408) days.

Conclusions: With real-time echocardiographic guidance, the individualized TA-BSM approach can effectively and safely achieve adequate and precise resections of septal myocardium. The technique's midterm results further confirmed its therapeutic advantages, potentially broadening the applicability of surgical septal reduction in obstructive hypertrophic cardiomyopathy treatment. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05332691.