Surgical Repair of Secondary Subaortic Stenosis in Congenital Heart Disease Without Initial Subaortic Obstruction.

BACKGROUND Secondary subaortic stenosis (SSS) is a rare heart disease of the left ventricular outflow tract (LVOT). It usually occurs after cardiovascular correction with or without initial left ventricular outflow tract obstruction (LVOTO). Because most patients with SSS are asymptomatic, many do not realize the need for reoperation until the obstruction worsens. Few studies suggest the characteristics and reasons of SSS without initial SAS. We conducted a retrospective study to describe the characteristics and surgical outcomes of these patients. METHODS In this study, we examined a single-center retrospective cohort of SSS patients without initial SAS undergoing resection from 2010 to 2019. Patients are defined as secondary subaortic obstruction requiring surgery after cardiovascular correction. Demographics, perioperative findings, and clinical data were analyzed. RESULTS Twenty-three patients had undergone secondary cardiac surgery for SSS without initial SAS during 10 years in our center. The median age at operation was 7.3 (4.0-13.5) years. In this study, the most commonly associated cardiac lesions were ventricular septal defect (VSD), atrioventricular septal defect (AVSD), patent ductus arteriosus (PDA), and coarctation arch hypoplasia (COA). The surgical techniques included membranous resection of five patients, fibromuscular resection of 17 patients, and reconstruction of the intraventricular baffle of one patient. The results of surgery in these patients are satisfied. The average LVOT gradient at the last follow up was 14.9 (7.8-26.2) mmHg. There was no operative mortality. Two patients had postoperative complications. The median follow-up period was 2.9 (1.1-4.3) years with one late death. Two patients (8.7%) had recurrence of stenosis. CONCLUSIONS Secondary subaortic stenosis is an uncommon heart disease. The reason is related to several causes, including missed diagnosis, unnoticed abnormalities of LVOT, and further changes of geometric morphology by intracardiac surgery. The results of surgery in these patients are satisfied. However, the recurrence of stenosis is still frequent.