Long-term outcomes of surgery for obstructive hypertrophic cardiomyopathy in a pediatric cohort

Background: Septal reduction therapy via septal myectomy or a modified Konno procedure is the mainstay of therapy for drug-refractory obstructive hypertrophic cardiomyopathy (HCM), although outcomes data on septal myectomy in pediatric patients are limited.We evaluated long-term outcomes following surgery for obstructive HCM in a pediatric cohort. Methods:We retrospectively reviewed patients age 18 years with obstructive HCM who underwent a left and/or right ventricular septal myectomy at our institution between 1992 and 2022.Primary endpoints were transplantation-free survival, freedom from HCM-related death, and cumulative probability of HCM-related reintervention.We further evaluated outcomes in patients with and without Noonan syndrome or other RASopathies.Results: Thirty-seven patients (median age, 7.4 years; interquartile range [IQR], 3.4-12.9years) underwent transaortic septal myectomy.A combined modified Konno procedure was performed in 5 patients (13.9%).Sixteen patients (43.2%) had a RASopathy.A concomitant right ventricular outflow tract resection was performed in 9 patients (24.3%).There was 1 (2.7%) in-hospital death and 4 late deaths at a median follow-up of 10.5 years (IQR, 0.1-29.3).Twenty-year transplant-free survival and freedom from HCM-related death were 80.6% (95% confidence interval [CI], 64.2%-100%) and 87.1% (95% CI, 71.8%-100%), respectively.The 20-year cumulative probability of HCM-related reintervention was 34.2% (95% CI, 12.8%-57.1%).Seven patients required a septal reintervention.There was no difference in any primary endpoints between patients with and without a RASopathy.Conclusions: Surgery for obstructive HCM, including septal myectomy with and without a modified Konno procedure, may be performed with low morbidity and good long-term outcomes in pediatric patients.Recurrent outflow tract obstruction is not uncommon.(JTCVS Open 2023;16:726-38) Hypertrophic cardiomyopathy (HCM) is a genetic disease of the myocardium characterized by pathologic ventricular septal thickening and left ventricular outflow tract (LVOT) obstruction.Histologic hallmarks include myocyte hypertrophy and disarray and interstitial fibrosis. 1Clinically, HCM is a heterogeneous disorder with variability in From the a Section of Pediatric and Congenital Cardiac Surgery and