Gene polymorphism and requirement for vasopressor infusion after cardiac surgery

Background. Genes in the class III region of the MHC, encoding proteins involved in inflammation and vascular regulation, were investigated for association with the occurrence of vasodilation and requirement for vasopressor infusion. Methods. A cohort of 236 elective cardiac surgical patients was studied. Hemodynamic and metabolic variables and dosage of vasopressor medications were recorded for the first 12 hours of intensive care unit admission after cardiac surgery on an electronic patient record. Demographic factors and operative details were recorded from other institutional databases. The DNA was extracted from peripheral blood mononuclear cells and genotyped for the presence of polymorphic alleles in genes coding for inflammation-related proteins. Results. Carriage of the dimethylarginine dimethylaminohydrolase II ( DDAH II) -449 G allele and the lymphotoxin alpha +252 G allele was significantly less frequent in patients who required infusions of vasopressors after cardiac surgery. On multivariate analysis, prior myocardial infarction, prolonged bypass, and the homozygous carriage of the DDAH II C allele were associated with postoperative vasopressor requirement. Conclusions. Vasopressor requirement after surgery may be related to an interaction of genotype, preoperative morbidity, and prolonged surgery.