Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy in Pediatric Patients: Early and Late Results

Background Symptomatic pediatric patients with obstructive hypertrophic cardiomyopathy (HCM) have a higher death rate (6% annually) compared with adults. Transaortic left ventricular septal myectomy provides excellent outcomes for adults with obstructive HCM. We sought to assess the effect of septal myectomy on late survival and outcome in pediatric patients with obstructive HCM. Methods From 1975 to 2003, 56 pediatric patients underwent septal myectomy for obstructive HCM. Mean age at diagnosis was 6.3 ± 5.4 years. Ages at operation ranged from 2 months to 20 years (mean 11 ± 5.6 years). Concomitant procedures included mitral valve repair (n = 7), closure of atrial septal defect (n = 3), and other (n = 5). Results After myectomy, mean left ventricular outflow tract (LVOT) gradient decreased from 103 ± 34 to 16 ± 12 mm Hg and mean degree of mitral regurgitation decreased from 2.0 ± 1.0 to 1.0 ± 0.3 (both p< 0.0001). There were no early deaths. Four patients underwent elective cardioverter defibrillator implantation and 1 patient received a permanent pacemaker. Follow-up ranged up to 29 years (mean, 8.6 ± 6.2). Cardiac reoperations were required in 8 patients: heart transplantation (n = 2), repeat myectomy (n = 2), mitral valve repair-replacement (n = 2), Konno-Rastan procedure (n = 1), and aortic valve replacement (n = 1). Age 14 years or less at operation was the only predictor of late reoperation (p = 0.017). Two patients died late; one suddenly without residual LVOT obstruction and one from chronic rejection after heart transplantation. Ninety-six percent of surviving patients were in New York Heart Association functional class I or II. Survival estimates at 5 and 10 years were 97% and 93%, respectively. Conclusions Septal myectomy is safe and effective in symptomatic pediatric patients with obstructive HCM. Late survivorship compares very favorably with the natural history of this disease.