Recurrence Risk in Subaortic Stenosis: A Comparative Study of Primary and Secondary Lesions

Subaortic stenosis is surgically correctable, yet recurrence remains common. This study compares presentation, surgical strategy, and long-term outcomes in children with primary and secondary subaortic stenosis. We reviewed all patients undergoing discreate subaortic membrane resection (January 2007-August 2024). Demographics, echocardiographic findings, surgical details, including resection site and concomitant myomectomy, and outcomes were compared. Membrane involvement of adjacent valves was recorded. Freedom from reoperation was assessed using Kaplan-Meier and Cox proportional hazards regression. We reviewed 153 patients who underwent subaortic membrane resection at a single institution. Seventy-nine had primary subaortic stenosis and 74 had secondary disease after prior cardiac surgery. The median follow-up was 4.43 years for primary and 3.92 years for secondary subaortic stenosis. Two deaths occurred, both in the secondary group. Genetic syndromes were more common in secondary group (p < 0.001), and abnormal aortic valve morphology was more frequent (p < 0.001). Concomitant myectomy was performed more often in secondary cases (p = 0.003). Reintervention occurred in 28.4% of secondary vs. 20.3% of primary group (p = 0.325). On Cox regression, secondary subaortic stenosis was not independently associated with reoperation, whereas younger age at surgery and prematurity were associated with increased reoperation risk. Surgical resection yields good long-term outcomes for both primary and secondary subaortic stenosis. Secondary lesions more often require concomitant myectomy and may carry a higher recurrence risk, warranting vigilant follow-up and counselling recurrence risk.