052 Supra-Valvular Pulmonary Stenosis After Arterial Switch Operation: Early Post-Operative Echocardiographic Predictors for Re-Intervention

BACKGROUND: Supra-valvular pulmonary stenosis (SVPS) is the most common complication after Arterial Switch Operation (ASO) for D-Transposition of the Great Arteries (DTGA) in neonates. While the majority improve over time some require re-intervention to relieve symptomatic lesions. We hypothesize that early post-operative echocardiography will predict which patients are at higher risk of re-intervention for significant SVPS following ASO. METHODS: Retrospective review of Manitoba newborns (n 63) who had ASO for D-TGA from 1991-2010. First post-operativeand most recent trans-thoracic echocardiograms (TTE) of all surviving patients (n 59) were reviewed for SVPS. Patients were categorized as needing re-intervention for SVPS (“re-intervention”-group) versus those who did not (“no re-intervention”group). Univariate analysis using Fisher’s Exact Test was used to analyze parameters summarized in table 1. Significant TTE parameters (gradients 40mm Hg plus 2 or more levels of stenosis) were analyzed using the Kaplan-Meier method to calculate probability of freedom from re-intervention. RESULTS: Mean follow-up period was 9.8 (SD -6) years. First post-operative TTE demonstrating 2 or more levels of stenosis, stenosis gradients 40mm Hg, both last mentioned parameters combined, as well as D-TGA plus VSD, were all significantly more prevalent in the “re-intervention”-group (see Table 1 below). For patients that had gradients 40 mm Hg and stenosis at 2 or more levels, the 5 year probability of freedom from re-intervention for SVPS was 40% compared to 100% for those without the two aforementioned parameters (Log Rank p 0.0001). CONCLUSION: SVPS with multiple levels of stenosis causing a gradient 40mmHg at initial TTE post-ASO, allows pediatric cardiologists to identify patients at higher risk of future reintervention for supra-valvular pulmonary stenosis. These findings need to be validated in a larger cohort.