Left ventricular geometry as a risk factor for recurrent subaortic stenosis after primary resection

Background: Discrete subaortic stenosis is a progressive cause of left ventricular outflow tract obstruction in children, and recurrence after surgical resection is not uncommon. We evaluated echocardiographic and morphologic factors associated with reintervention after primary subaortic membrane resection. Methods: We conducted a single-centre retrospective cohort study of paediatric patients (0–14 years) who underwent primary surgical resection of subaortic membrane stenosis between 2002 and 2019. Demographic, clinical, and echocardiographic variables were compared between patients requiring reintervention and those requiring a single operation. Independent predictors were assessed using multivariable logistic regression. Results: Seventy-seven patients were included; 16 required reintervention and 61 did not. On univariate analysis, the reintervention group had higher preoperative left ventricular outflow tract peak and mean gradients and shorter membrane length. In multivariable analysis, shorter membrane length independently predicted reintervention (adjusted odds ratio 0.677 per 1-mm increase, 95% confidence interval 0.487–0.941; p = 0.020), as did higher preoperative left ventricular outflow tract peak gradient (adjusted odds ratio 1.066 per 1-mmHg increase, 95% confidence interval 1.023–1.111; p = 0.002). A smaller aorto-septal angle showed a trend towards increased risk but did not reach statistical significance (adjusted odds ratio 0.933, 95% confidence interval 0.866–1.005; p = 0.067). Aortic regurgitation was significantly worse at follow-up in patients requiring reintervention. Conclusion: Shorter subaortic membrane length and higher preoperative left ventricular outflow tract peak gradient were independent predictors of reintervention after primary resection. These findings may improve risk stratification and support closer echocardiographic surveillance of patients at increased risk of recurrence.