Aorto-septal Angle as a Predictor of Left Ventricular Outflow Tract Obstruction in Pediatric Patients With Subaortic Stenosis and Subaortic Membrane Development: A Study at Prince Sultan Cardiac Center, Buraydah, Saudi Arabia 2023.

Background: The interventricular septum (IVS)/anterior aortic angle is typically measured at 120° in healthy individuals but is more acute in patients with left ventricular outflow tract (LVOT) narrowing, aortic valve anomalies, and discrete subaortic membrane (SAM).

Objectives: This study aimed to assess this angle in pediatric patients with abnormal aortic valves and/or LVOT obstruction and evaluate its association with SAM development.

Methodology: A prospective cohort observational study was conducted in the pediatric cardiology department at PSCC-Qassim from September 2022 to June 2023. Echocardiographic assessments were performed on pediatric patients (neonates to 14 years) with bicuspid aortic valve (BAV), with or without SAM. Patients with ventricular septal defect (VSD), atrioventricular septal defect (AVSD), or single ventricle pathology were excluded. The Aortoseptal angle was measured in the long-axis parasternal view.

Result: Among 319 cases, 153 served as controls with normal cardiac anatomy. The remaining 194 cases included 104 (53 %) with isolated BAV, 51 (26 %) with isolated SAM, and 11 (6 %) with BAV and SAM. The male-to-female ratio was 2.2:1. SAM was observed in 64 (33 %) cases, and significant aortic stenosis in 13 (6.7 %). Cardiac surgery was performed in SAM resection (4.1 %). The Aortoseptal angle ranged from 110° to 135° across groups, with no statistically significant differences between patients with SAM and controls. However, ROC analysis indicated that an angle <116° predicted SAM presence with 97 % sensitivity and 87 % specificity.

Conclusion: While a more acute Aortoseptal angle was common in SAM patients, no statistically significant differences were found. An angle <115° may warrant close monitoring for SAM development.