Abstract 14733: Influence of High Risk Adrenergic Receptor Genotypes on Outcome in Infants With Single Ventricle

Introduction: Variants in adrenergic receptor (ADR) genes are associated with adverse clinical outcomes in patients with heart failure. We evaluated the association of variants in ADR receptor genes with outcomes in infants with single ventricle lesions. Methods: Infants with single ventricle lesions participating in the Pediatric Heart Network Single Ventricle Reconstruction Trial (randomized to Norwood with modified Blalock-Taussig shunt versus right ventricle-pulmonary artery shunt) underwent genotyping for 4 single nucleotide polymorphisms (SNPs) in 3 ADR genes: ADRB1-A/G (rs1801252), ADRB1-C/G (rs1801253), ADRB2-C/G (rs1042714) and ADRA2A-C/T (rs553668). Linear and logistic regression, deviance tests, t-tests and F-tests were used to analyze association of genotype with clinical outcomes including hospital length of stay (LOS) at Norwood, occurrence of serious adverse events (SAE), and transplant-free survival during 14 months follow-up using a dominant model. Results: The study included 347 eligible patients (62% male; 83% white). The mean age at Norwood procedure was 6±3.6 days and median Norwood LOS was 8 days. During 14 months follow-up, 147 patients had SAEs, 94 patients died and 14 were transplanted. ADRB1 AA (rs1801252) genotype was associated with longer Norwood LOS. The difference in LOS between AA vs AG/GG was 7.99 days (confidence intervals, 0.27, 15.71; p=0.043). ADRA2A CC (rs553668) genotype was associated with higher odds of SAEs i.e. 103/216 (47.6%) in CC compared to 36/106 (34%) in CT/TT [Odds ratio 1.77 (confidence intervals, 1.09, 2.87), p=0.018]. Transplant-free survival was not different between genotype groups. Combined analysis of risk genotypes did not confer an additive risk of adverse outcomes. Conclusions: ADR genotypes known to cause adrenergic upregulation were associated with prolonged Norwood hospitalization and/or serious adverse events in infant single ventricles. This may be secondary to adverse effects of adrenergic overexpression on cardiac function and systemic hemodynamics. Analysis is ongoing to replicate these findings for utility as predictive markers for outcomes in infant single ventricles.