Introduction: Haptoglobin is an acute-phase reactant whose principal clinical everyday utility is in defining conditions of hemolysis. In plasma, haptoglobin binds free hemoglobin released from lysed erythrocytes with high affinity, inhibiting hemoglobin’s oxidative activity. Cardiac surgery, and coronary artery bypass grafting (CABG) in particular, is commonly performed in patients with multiple comorbidities, including atherosclerosis, diabetes, hypertension, and renal failure. Post-cardiac surgery, patients may demonstrate stress-related signs and symptoms, e.g., high glucose levels, hemodynamic instability, renal failure, and atrial fibrillation. Previous studies have shown that the haptoglobin phenotype is an independent risk factor for cardiovascular disease in individuals with diabetes. The current study aimed at investigating the association between haptoglobin type and (i) post-operative atrial fibrillation (ii) acute renal failure, and (iii) length of hospital stay.
Methods: A prospective case-control analysis was performed on 95 patients undergoing elective CABG surgery with cardiopulmonary bypass at Rambam Health Care Campus. Haptoglobin phenotypes were assessed using polyacrylamide gel electrophoresis. The occurrence of post-operative atrial fibrillation was noted, serum creatinine levels were measured pre- and post-operatively, and duration of hospital stay was monitored. Results were controlled for age, bypass and cross-clamp time, and the presence of diabetes.
Results: Fifty-two (55%) patients had the Hp 2-2 phenotype, while 32 (45%) patients were either Haptoglobin 2-1 (34%) or 1-1 (11%). Analysis yielded no significant differences between the haptoglobin groups. Results were comparable in all three genotypes. The only significant difference was in the incidence of diabetes mellitus in the 2-2 group compared to the 2-1 and 1-1 group (58% vs. 31%, 27% respectively, P=0.027).
Conclusions: Current data analysis could not verify that that haptoglobin phenotype is an independent risk factor for the occurrence of, acute renal failure, or increased hospital stay duration. Additional investigation is required to further delineate the association between CABG surgery and diabetes rate in Haptoglobin 2-2 phenotype patients.
