Transapical septal myectomy for hypertrophic cardiomyopathy, an experience from Japan.

Background: While there are a variety of surgical options for hypertrophic cardiomyopathy, there are small number of reports of transapical septal myectomy. Furthermore, the characteristics and incidence of anomalous structures in the left ventricle in hypertrophic cardiomyopathy patients which can be identified with imaging studies are not clear.

Methods: We studied hypertrophic cardiomyopathy patients who underwent transapical septal myectomy from July 2013 to December 2019. We evaluated the frequency and characteristics of anomalous structures in the left ventricle which had been identified by preoperative examinations and studied their postoperative results.

Results: A total of 59 patients was included. The median age was 40 years. Sixteen patients (27.4%) were in New York Heart Association Functional Classification III or IV. The median peak intraventricular gradient at rest was 65 mmHg. By preoperative imaging studies, anomalous structures were detected in 56 cases (94.9%), of which 88% were successfully resected with myectomy. There were two perioperative deaths, while one late death caused by acute myocardial infarction occurred. The estimated 5-year survival rate was 95%. The intraventricular gradient had significantly decreased at the time of discharge, and no reoperation for recurrent obstruction was conducted. The left ventricular ejection fraction had significantly decreased after the operation, was however within the normal range. Left atrium volume index and tricuspid regurgitant velocity significantly improved.

Conclusions: Patients receiving transapical septal myectomy restored good hemodynamics from early postoperative period and showed improved subjective symptoms and good mid-term results. With multimodal imaging studies, we could accurately identify anomalous structures in hypertrophic cardiomyopathy patients and reliably treat them by transapical septal myectomy.