Early post-septal myectomy outcomes for hypertrophic obstructive cardiomyopathy

We aimed to evaluate early outcomes of septal myectomy in patients with hypertrophic cardiomyopathy.

We retrospectively analyzed data collected over a 9-year period from 583 patients who underwent septal myectomy for hypertrophic cardiomyopathy at our institution.

The mean age was 55.7 ± 13.1 years, and 338 (58%) patients were in New York Heart Association class III or IV. There were 11 (1.9%) early deaths, including 3 (0.5%) intraoperative deaths. Early mortality was lowest after isolated septal myectomy (0.8%) and highest after concomitant mitral valve replacement (6.1%). There were 4 (0.7%) and 9 (1.5%) patients with left ventricular wall rupture and ventricular septal defect, respectively, after myectomy. New pacemaker implantation caused by atrioventricular disturbances was required in 29 (5.0%) patients, and was associated with previous alcohol septal ablation (odds ratio 3.34, 95% confidence interval 1.02-11.0, P = 0.047). Left ventricular wall rupture, intraoperative residual (15.5% moderate, 0.3% severe) mitral regurgitation, and pre-discharge residual outflow tract gradient >30 mm Hg (4.6%) occurrences were surgeon-dependent.

The early results are consistent with example targets reported in the 2020 American College of Cardiology/American Heart Association guidelines for septal reduction therapy outcomes. Septal myectomy safety and efficacy are surgeon-dependent. Previous alcohol septal ablation increases the risk of permanent pacemaker implantation due to postoperative complete atrioventricular block. Therefore, continuous education, mentoring, and learning by doing may play an important role in achieving reasonable septal myectomy safety and efficacy.