Transapical beating-heart septal myectomy for hypertrophic cardiomyopathy with latent obstruction

Abstract

Objectives A novel transapical beating-heart septal myectomy (TA-BSM) procedure was performed for patients with latent obstruction through the left intercostal incision and without cardiopulmonary bypass. This study aims to demonstrate the experience of the TA-BSM procedure for patients with latent obstruction and compare outcomes to patients with resting obstruction. Methods We studied 120 symptomatic hypertrophic obstructive cardiomyopathy patients (33 with latent obstruction and 87 with resting obstruction) who underwent TA-BSM. Demographic profiles, echocardiogram-derived ventricular morphology and hemodynamics, and clinical outcomes were analyzed. Results There were no important differences in baseline clinical characteristics between patients with latent obstruction and resting obstruction, including age, symptoms, comorbidities, and medical history. Patients with latent obstruction had lower basal septum thickness, higher midventricular wall thickness, smaller left atrial chamber size, and more frequency of mitral sub-valvular anomalies. There was no difference in early (<30 days) deaths (0/33 vs 1/87, P > 0.999) and mid-term survival between patients with latent obstruction and resting obstruction. At 6 months after surgery, 31 (93.9%) patients with latent obstruction and 80 (92.0%) with resting obstruction achieved optimal procedural success, which was defined as a maximal gradient (after provocation) < 30 mmHg and mitral regurgitation ≤ grade 1+ without mortality. Maximal left ventricular outflow tract gradient, basal septum thickness, midventricular wall thickness, mitral regurgitation grade, and left atrial chamber size were significantly decreased after TA-BSM. In the follow-up, the New York Heart Association class was significantly improved following surgery. Conclusions Transapical beating-heart septal myectomy preserved favorable gold-standard guideline desired outcomes through real time echocardiographic-guided resection. Equipoise of outcomes for this procedure regardless of degree of resting LVOT gradients supports operative management with this approach in symptomatic patients with latent obstruction.