Abstract 902: A Beta-2 Adrenergic Receptor Polymorphism Is Associated With Increased Left Ventricular Remodeling Following First ST-Elevation Myocardial Infarction
Background: Prior studies demonstrate an association between specific β-adrenergic receptor polymorphisms and clinical outcomes in patients with chronic heart failure and following an acute coronary syndrome. The mechanism may relate to an effect on left ventricular (LV) remodeling. We hypothesized that β-adrenergic receptor polymorphisms predict LV remodeling after acute ST elevation myocardial infarction (STEMI).
Methods: We assessed the presence of β-1 and β-2 adrenergic receptor polymorphisms in 122 patients after their first STEMI enrolled in a single-center randomized, double-blind placebo controlled trial of L-arginine vs. placebo, 91% of whom received successful early reperfusion therapy. All patients were treated with a beta-1 receptor antagonist and underwent baseline (mean 5.9 days following STEMI) and 6-month LV volume evaluation using gated blood pool imaging. Univariate and multivariate linear and logistic regressions were used to assess the relationships between the polymorphisms, β1 Arg389Gly, β1 Ser49Gly, β2 Gly16Arg and β2 Gly27Glu and the six-month changes in LV volumes. The top quintiles of LV end-systolic (ESV) and end-diastolic (EDV) 6-month volume increases and LV ejection fraction decrease were compared to the lower quintiles in the logistic regression analyses.
Results: The polymorphisms β1 Arg389Gly, β1 Ser49Gly, β2 Gly16Arg were not associated LV remodeling. However, the 25% of patients homozygous for the β2 Glu27 variant were 5.2 times more likely to have an increase in 6-month ESV than those who had the Gln27 variant (OR 5.2, 95%CI 1.4 –19.0). Multiple linear regression analyses demonstrated that absolute ESV at six months was 19 ml greater (p = 0.02) and EDV was 21 ml greater (p = 0.01) in post STEMI patients with the β2 Glu27 polymorphism compared to the wild type or heterozygous patients.
Conclusions: Increased LV volumes post-STEMI are associated with an increased risk of heart failure and death. The common β2 receptor polymorphism, Glu27Glu, is associated with increased odds of adverse LV remodeling in patients treated with a beta-one receptor antagonist. Whether treatment with a non-specific β-adrenergic receptor blocker guided by this genetic polymorphism ameliorates the effect requires further study.