Risk Index for Perioperative Renal Dysfunction/Failure. Critical Dependence on Pulse Pressure Hypertension.

The aim of this study was to explore whether acute renal event after coronary bypass graft surgery is associated with high mortality and substantial additive cost.

This prospective and descriptive study of 4801 patients having coronary bypass graft surgery with cardiopulmonary bypass from November 1996 to June 2000 at 70 centres in 16 countries established associations between predictor variables and postoperative renal composite (renal dysfunction and/or renal failure) from a cohort of 2381 patients and developed a risk index assessed in a validation cohort of 2420 patients. Postoperative renal composite occurred in 231 patients (4.8%). Independent and significant risk factors were age >75 years (odds ratio [OR], 2.04; 95% confidence interval [CI], 1.23 to 3.37; P=0.006), preoperative congestive heart failure (OR, 2.38; CI, 1.55 to 3.64; P<0.001), prior myocardial infarction (OR, 1.75; CI, 1.08 to 2.83; P=0.023), preexisting renal disease (OR, 3.71; CI, 2.41 to 5.70; P<0.001), intraoperative multiple inotrope use (OR, 2.75; CI, 1.75 to 4.31; P<0.001), intraoperative intra-aortic balloon pump insertion (OR, 4.41; CI, 2.21 to 8.80; P<0.001), cardiopulmonary bypass >2 hours (OR, 1.78; CI, 1.15 to 2.74; P=0.01), and preoperative pulse pressure such that for every additional 20-mm Hg increment in pulse pressure >40 mm Hg, there was an OR of 1.49 (CI, 1.17 to 1.89; P=0.001). Patients with pulse pressure hypertension >80 mm Hg were 3 times more likely to die a renal-related death compared with those without (3.7% versus 1.1%). Researchers concluded that beside established risk factors, pulse pressure is independently and significantly associated with increased renal composite.(Source: Circulation : Duke University Medical Centre : February 2007.)