Efficacy and safety of a transaortic approach to midventricular and apical septal myectomy

The study objective was to evaluate the safety and efficacy of a transaortic approach to midventricular and apical septal myectomy in patients with hypertrophic cardiomyopathy with left ventricular outflow tract or midventricular obstruction.

From January 2018 to August 2023, 940 patients underwent transaortic septal myectomy at the Cleveland Clinic, of whom 682 (73%) had midventricular or apical resection. Patients who underwent isolated basal myectomies were excluded. Templated operative reports designated septal regions resected as basal (opposition to mitral valve up to the leaflet tips), midventricular (leaflet tips to just beyond the papillary muscle heads), and apical (apical third of the ventricle). Myocardial resection specimen weights, intraventricular gradients, and clinical outcomes were assessed.

Of the 682 patients, 582 (85%) had basal plus midventricular resection and 78 (11%) had basal, midventricular, and apical resection. Mean preoperative intraventricular gradient was 102 ± 41 mm Hg. Median resection weight was 10 g (15th, 85th percentiles: 7, 15), and mean postoperative intraventricular gradient was 16 ± 10 mm Hg, with 625 (96%) patients achieving gradients 36 mm Hg or less. There were no iatrogenic mitral or aortic valve injuries. Permanent pacemaker placement was required in 38 patients (5.6%), of whom 8 (1.2%) had normal preoperative conduction. Operative mortality occurred in 1 patient (0.1%) after an intraoperative ventricular septal defect.

Most patients undergoing septal myectomy for relief of obstruction required resection beyond the basal septum. With specialized instrumentation, detailed imaging and knowledge of variable septal anatomy, resecting midventricular and apical septal muscle can be safely and effectively achieved through a transaortic approach.