Association of β₁ and β₂-adrenoceptor polymorphisms with the demand for inotropic catecholamine support following CABG surgery

Hemodynamic instability is a common complication in the first hours following cardiac surgery and inotropic catecholamine support is an acceptable treatment strategy for its management. β₁ and β₂-adrenoceptors (β₁ and β₂ AR) are mediated the positive inotropic and chronotropic responses of the heart to catecholamines. Previous evidence has suggested an association between β₁ and β₂AR polymorphisms and cardiac response and change in receptor signaling. This study aimed to evaluate the relationship between β₁ and β₂AR polymorphisms with the demand for catecholamine inotropic support among coronary artery bypass grafting (CABG) patients. One hundred ninety-eight consecutive patients who underwent CABG with cardiopulmonary bypass were included in this study. We assessed hemodynamic parameters, dose, and duration of inotropic support according to β₁ and β₂AR genotypes in the post-operative period. DNA genotyping was assessed through polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and PCR genotyping results were confirmed by direct DNA sequencing. Our results indicated that patients carrying one or two alleles of the Arg389-β₁AR variant required significantly shorter inotropic support time compared with patients homozygous for the Gly389-β₁AR (p=0.003). Finally, neither β₁AR polymorphisms nor Arg16Gly-β₂AR polymorphisms are associated with catecholamine-induced hemodynamic effects. These findings suggest that genetic variability in the β₁ and β₂AR polymorphisms may not be a major determinant of cardiac responses to catecholamine treatment in the Iranian population. However, larger-scale studies with different ethnicities are needed for confirmation.