Abstract 4131412: Effects of Angiotensin Converting Enzyme Inhibition And Afterload Reduction in Single Ventricle Patients Prior To Fontan: Not What You Might Think

Introduction: Pts with single ventricle (SV) after bidirectional Glenn (BDG) are placed on angiotensin converting enzyme inhibitors (ACEI) to reduce afterload, improve ventricular performance and allow for decreased systemic to pulmonary collateral flow (APC). No large scale data exists to support ACEI use in BDG pts to accomplish this. We hypothesized that ACEI may not perform as predicted. Goals: To determine if ACEI use in BDG pts decreases APC and improves ventricular function. Methods: Single center retrospective study of all BDG pts who underwent cardiac magnetic resonance (CMR) from 2010 to present. Demographics, medication, ventricular function and flow data were collected. Pts included were >1 year old and on ACEI for >3 months prior to CMR. Wilcoxon and Fisher Exact tests were used. Significance P<0.05 Results: Of the 320 BDG pts (median 2.8 years old) studied, 137 (43%) were treated with ACEI. See table for all data. There was no difference in age, sex, medications (except for ACEI) or body surface area (BSA) between both groups. APC as a % of aortic flow and APC/BSA were not different between those treated with ACEI compared to those who were not, whether right (RV) or left ventricle (LV) dominant. There was no correlation of APC with time on ACEI or ACEI dosage. Ejection fraction (EF) was lower and end-diastolic volume (EDV) was higher in BDG on ACEI for the entire group and RVs. Although LV EDV was higher with those on ACEI, LV EF was the same for those on ACEI and those who weren’t (graph). APC as a % of aortic flow and APC/BSA positively correlated with EDV (rho 0.25-0.34, P<.001). There was no difference in atrioventricular valve regurgitation between those on ACEI and those who were not (median 5 vs 6% respectively). As a surrogate for cerebral blood flow (CBF), superior vena caval (SVC) flow was lower for those on ACEI compared to those who were not. Conclusion: BDG pts treated with ACEI did not demonstrate decreased APC or improved ventricular performance. There is a suggestion that ventricular performance may be worse on ACEI. CBF is decreased in BDG on ACEI using SVC flow as a surrogate. This suggests that ACEI use in SV pts at the BDG stage is not indicated and should be discouraged.