Abstract 12260: Reoperation Was an Effective Therapy in Patients with Obstructive Hypertrophic Cardiomyopathy After Septal Reduction Therapy

Abstract

Introduction: This study aims to analyze the clinical characteristics of patients with obstructive hypertrophic cardiomyopathy (OHCM) undergoing repeated septal reduction therapy (SRT), and preliminarily describe the genotype in the recruited patients. Methods: Patients with OHCM who received repeated SRT were recruited from 2014 to 2019 in Fuwai Hospital. Patients were divided into septal myectomy (SM) group or alcohol septal ablation (ASA) group according to the primary procedure of SRT. Sixteen of these patients underwent genetic testing. Pathogenic mutations were those mutations identified as pathogenic, likely pathogenic, or variants of uncertain significance according to the ACMG criteria. Results: A total of 31 patients (21 males) was included. The average age was 48.7±12.2 years. There were 7 patients in the SM group and 24 patients in the ASA group. Preoperative electrocardiogram showed that 7 patients in the ASA group presented with complete right bundle branch block (CRBBB). After the operation, 4 patients were implanted with permanent pacemakers due to complete atrioventricular block, of which 3 patients were in the ASA group with CRBBB. Pathogenic mutations were identified in 50.0% (8/16) of the study patients. Pathogenic mutations were mostly located in the MYH7 gene (5/9,55.6%), MYBPC3 gene (3/9,33.3%), and TNNT2 gene (1/9,11.1%). There was no difference between patients carrying pathogenic mutations or not, in terms of interventricular septal thickness and left ventricular outflow tract gradient. During the perioperative period, except for one death caused by electrical storm, the remaining patients had no serious complications. The results of follow-up echocardiography showed that except for 2 patients who had left ventricular outflow tract obstruction again, the thickness of interventricular septum and left ventricular outflow tract gradient was significantly lower compared with preoperative echocardiography. Conclusions: In conclusion, the surgery of SM is an effective treatment in OHCM patients with a history of previous SRT procedures. Patients with the first procedure of ASA are at high risk of developing atrioventricular block after a repeated SM.