Prevalence and risk factors for acute renal failure in the postoperative of coronary artery bypass grafting

Objective: To determine the prevalence, risk factors, and the clinical outcome of patients undergone coronary artery bypass grafting who progressed with Acute Renal Failure (ARIF). Methods: A retrospective cohort prospective study was performed from data of 186 patients undergone surgery from January 2003 through June 2006. The stored data were analyzed using the software STATA 9.0. Results: The prevalence of ARF was of 30.6% (57/186). In 7.0% (4/57) dialysis therapy was needed. The mean age of patients with and without ARF progression was 62.8 (9.4) years and 61.3 (8.8) years respectively (P=NS). CPB time >115 min (p=0.011) and cross-clamp time >85 min (p=0.044) were related to ARF by the univariate analysis. The need for intra-aortic balloon (P=0.049), mechanical ventilation >24h (P = 0.006), Intensive Care Unit (ICU) stay > three days (P<0.0001), bradycardia (P=0.002), hypotension (P=0.045), arrhythmia (P=0.005) and inotropic infusion (P=0.0001) were higher in the ARF group. Only the ICU stay longer > 3 days showed statistical correlation with ARF by the multivariate analysis (P=0.018). The mortality rate with and without ARF was 8.8% (five cases) and 0.8% (one case) respectively (P=0.016), but it reached 50% (2/4) in dialytic patients. Conclusion: ARIF was a frequent and severe postoperative complication associated with higher mortality and longer ICU stay, which presented as risk factors: longer CPB and cross-clamp times, mechanical ventilation > 24h and hemodynamic instability.