Abstract 15701: Prevalence and Surgical Result of Intraventricular Anomalies in Hypertrophic Obstructive Cardiomyopathy: Single Operator’s Experience With 423 Patients

IntroductionExtended septal myectomy is the recommended therapy for refractory hypertrophic obstructive cardiomyopathy. Multiple anomalies involving septal muscle bundles and mitral apparatus were thought to participate obstruction. We hereby report our experience of addressing anomalies besides hypertrophic septum.MethodsFour hundreds and twenty-three patients underwent myectomy by one surgeon in Fuwai Hospital from May 2010 to May 2016 were included in the present study. Intraventricular anatomic anomalies observed in operation were classified and perioperative data were collected.ResultsMean age at operation was 44.8±14.4 years, and 251 (59.3%) patients were male. Resting gradient of left ventricular outflow tract (LVOT) was 76 mmHg (interquartile range, 62-98 mmHg). Records of classified anatomic anomalies of 374 patients were available. Anomalous muscle bundles from basal or middle septum to ventricular apex were observed in 295 (78.9%) patients. Anomalous attachment or muscle bundles between anterior papillary muscle and septum leading to dislocation of anterior papillary muscle were found in 251 (67.1%) patients. Accessory muscles originated from papillary muscles or septal and inserted to mitral leaflets were observed in 25 (6.7%) patients. All these anomalies within LVOT were corrected. To relocate leaflets coaption point away from LVOT, secondary chordae cutting were performed in 29 (6.9%) patients. Septal myectomy was extended to apical ventricle. Concomitant operations were performed in 203 (48.0%) patients, to address coronary problems, valvular insufficiency, atrial fibrillation or other cardiac disease. Perioperative death occurred in 3 (0.71%) patients, and postoperative gradient of survival patients was 11 mmHg (interquartile range, 8-15 mmHg). Only one patients had slight residual mitral systolic anterior motion.ConclusionAnatomical anomalies within LVOT were common in hypertrophic obstructive cardiomyopathy. Surgical correction of these anomalies and adequate septal myectomy should be performed to abolish systolic anterior motion of anterior mitral valve and middle ventricle obstruction.