Angiotensin converting enzyme inhibitors and interstage failure in infants with hypoplastic left heart syndrome

Introduction: Angiotensin converting enzyme inhibitors are commonly prescribed medications after the Norwood procedure. There are little data that can be used to determine if angiotensin converting enzyme inhibitors improve interstage outcomes in children with single ventricle defects. The objective of this study was to investigate the relationship between angiotensin converting enzyme inhibitors and interstage failure among infants born with hypoplastic left heart syndrome. Methods: We conducted a retrospective cohort study using data from the National Pediatric Cardiology Quality Improvement Collaborative database (collected between 2008 and 2015). We used logistic regression models to assess the exposure-outcome associations and propensity score matching to account for differences in baseline patient characteristics associated with use of angiotensin converting enzyme inhibitors. Results: A total of 1 487 neonates participated in the study. Thirty-nine percent of patients were prescribed angiotensin converting enzyme inhibitors after the Norwood procedure; 11% experienced interstage failure (death, heart transplantation, and not being a candidate for the second-stage surgery). Before propensity score matching, patients receiving angiotensin converting enzyme inhibitors were significantly more likely to experience interstage failure, compared to patients not on angiotensin converting enzyme inhibitors (OR = 1.44; 95% CI: 1.04, 1.99; P = 0.03). Although there was an increased odds of interstage failure among patients receiving angiotensin converting enzyme inhibitors compared to patients not receiving angiotensin converting enzyme inhibitors in the propensity score-matched cohort, this association was not significantly different (adjusted OR = 1.29; 95% CI: 0.88, 1.95; P = 0.18). Conclusion: Angiotensin converting enzyme inhibitor therapy did not demonstrate a beneficial effect on interstage failure among infants with hypoplastic left heart syndrome, even when patient characteristics associated with the use of angiotensin converting enzyme inhibitors were considered.