Renal Injury is Associated with Operative Mortality After Cardiac Surgery for Women and Men

Objectives: The purpose of this study was to determine whether acute renal injury develops more frequently in women than in men after cardiac surgery and whether this complication is associated with operative mortality in women.

Methods: Prospectively collected data were evaluated from 9461 patients undergoing coronary artery bypass graft surgery, cardiac valve surgery, or both (3080 women) and not receiving preoperative dialysis. The glomerular filtration rate was estimated by using the Modification of Diet in Renal Disease equations with the last plasma creatinine level before surgical intervention (baseline) and the highest level of the first postoperative week. The primary renal injury outcome was the composite end point of renal injury according to RIFLE criteria (estimated glomerular filtration rate decrease >50% from baseline value) or failure.

Results: Thirty-day operative mortality and renal injury were more common in women than in men (5.9% vs 2.8%, P = .01; 5.1% vs 3.6%, P < .001, respectively). Nonetheless, patient sex was not independently associated with risk for renal injury when the baseline estimated glomerular filtration rate was included in multivariate modeling. Perioperative complications, intensive care unit length of stay, and mortality were more frequent for patients with than without renal injury (women, 20.6% vs 3.2%, P < .0001; men, 18.3% vs 2.2%, P < .001). Renal injury was independently associated with 30-day mortality for women (odds ratio, 3.96; 95% confidence interval, 1.86-8.44; P < .0001) and men (odds ratio, 4.05; 95% confidence interval, 2.19-7.48; P < .0001).

Conclusions: Postoperative renal injury is independently associated with 30-day mortality regardless of patient sex. Higher rates of renal injury in women compared with men might be explained in part by a higher prevalence of low estimated glomerular filtration rate before surgical intervention.