Does the preoperative mild renal dysfunction effect mortality and morbidity following valve cardiac surgery?

The objective of this study was to investigate the effect of preoperative mild renal dysfunction (RD), not requiring dialysis, on mortality and morbidity after valve cardiac surgery (VCS).

We studied 340 consecutive patients (2008-2012), who underwent VCS with or without coronary artery bypass graft (CABG).

Preoperative RD was calculated with the abbreviated Modification of Diet in Renal Disease formula and was defined as a glomerular filtration rate <60ml/min/1.73m(2). Logistic regression analysis was used to assess the effect of preoperative renal dysfunction (RD) on operative and adverse outcomes.

80 patients (30%) had preoperative mild RD. Patients with preoperative RD were older, had a higher rate of preoperative anemia (43% vs. 25%, p<0.001), and more comorbidities. Patients with preoperative RD had worse outcomes with more reoperation (6.8% vs. 2.3%, p<0.001).

Preoperative RD was significantly and independently associated with more red blood cell transfusions and longer hospital stay (median 9 vs. 8 days, p<0.001). Mortality was similar in both groups (3.4% vs. 2.3%, p=0.43). Preoperative mild RD in patients undergoing cardiac valve surgery is an independent marker of postoperative morbidity.