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 (ARF). 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 ARF 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.