Haptoglobin Polymorphism as a Determinant of Adverse Outcome After Cardiac Surgery in Diabetic Patients

Diabetes mellitus is a major risk factor for postoperative morbidity and mortality after cardiac surgery, mainly because of accelerated atherosclerosis and target-organ injury that predispose these patients to increased incidence of postoperative morbidity (such as but not limited to, postoperative adverse cardiac events, renal injury or stroke) and mortality.

Over the past several years haptoglobin has been identified as a risk factor that predicts the development of cardiovascular complications in diabetics. There are 3 major haplotypes of haptoglobin: 1-1; 1-2 and 2-2. Several studies have demonstrated that diabetic individuals with the 2-2 genotype have up to 5 fold increased risk to develop cardiovascular complications as compared to diabetic patients with a non-2-2 haptoglobin genotype. There is no data in the literature that evaluated whether the haptoglobin 2-2 genotype is a risk factor for increased postoperative morbidity and/or mortality after cardiac surgery in patients with DM.

Therefore, the aims of the study are to evaluate whether diabetic patients with the 2-2 genotype are at increased risk for postoperative morbidity and/or mortality after cardiac surgery.

Preliminary studies in diabetic patients demonstrated that those with haptoglobin 2-2 genotype are at increased risk for cardiovascular complications of diabetes. Moreover, these patients were found to have increased in-hospital mortality after acute MI compared to diabetic individuals that do not have the 2-2 genotype, and they also suffer from increased incidence of post catheterization stent thrombosis compared to diabetics that do not have the 2-2 genotype