Background-Impaired renal function after coronary artery bypass graft (CABG) surgery is a key risk factor for in-hospital mortality. However, perioperative increases in serum creatinine and the association with mortality has not been well-studied. We assessed the hypothesis that perioperative increases in creatinine are associated with increased 90-day mortality. Methods and Results-We studied 1391 patients in northern New England undergoing CABG in 2001 and evaluated preoperative and

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... ive creatinine. Patients with preoperative dialysis were excluded. Data were linked to the National Death Index to assess 90-day survival. Kaplan-Meier and log-rank techniques were used. Patients were stratified by percent increase in creatinine from baseline: Ͻ25%, 25% to 49%, 50% to 99%, Ն100%. We assessed 90-day survival and calculated adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) for creatinine groups, adjusting for age and sex. Patients with the largest creatinine increases (50% to 99% or Ն100%) had significantly higher 90-day mortality compared with patients with a smaller increase (Ͻ50%; PϽ0.001). Adjusted HR and 95% CI confirmed patients in the higher 2 groups had an increased risk of mortality compared with the Ͻ25% (referent); however, the 25% to 49% group was not different from the referent: 1.80 (95% CI: 0.73 to 4.44), 6.57 (95% CI, 3.03 to 14.27), and 22.10 (95% CI, 11.25 to 43.39). Conclusions-Patients with large creatinine increases (Ն50%) after CABG surgery have a higher 90-day mortality compared with patients with small increases. Efforts to identify patients with impaired renal function and to preserve renal function before cardiac surgery may yield benefits for patients in the future. (Circulation. 2006; 114[suppl I]:I-409-I-413.)