Continuous renal replacement therapy after cardiac surgery - Review of 85 cases

Background/Aims: To evaluate the outcome of patients who require continuous renal replacement therapy (CRRT) following cardiac surgery. Methods: All patients who received CRRT after cardiac surgery over more than 4 years at the Surgical Intensive Care Unit of the Montreal Heart Institute were reviewed. Among 5,564 consecutive patients, 85 underwent CRRT postoperatively. Results: The mean delay between surgery and CRRT initiation was 5 days, and the duration of CRRT was 9 days, without a difference between survivors and non-survivors. Delivered clearances with CRRT were estimated at 25 - 28 ml/min (approximate to40 liters/day), 29 - 32 ml/min (approximate to46 liters/ day) and 17 ml/min (approximate to25 liters/day) for continuous venovenous hemofiltration, continuous veno-venous hemodiafiltration and continuous veno-venous hemodialysis, respectively. In-hospital mortality was 43.5%. No difference in mortality was observed between patients with normal renal function at baseline and those with preoperative renal dysfunction. Mortality was 33.3% after a coronary artery bypass graft (CABG), 57.1% after CABG and valve surgery, 60% after valve surgery, and 72.7% for redo-CABG or redo-valve surgery. 79% of survivors and 86% of non-survivors had received a cardiopulmonary bypass ( p = NS). The Simplified Acute Physiology Score II upon intensive care unit (ICU) admission and the requirement of an intra-aortic balloon pump were higher in non-survivors ( p < 0.05). The mean length of ICU and hospital stay was 27.4 and 34.2 days for survivors and 17.9 and 22.3 days for non-survivors, respectively ( p < 0.05). Conclusions: Renal impairment is relatively common after cardiac surgery. The mortality of patients who required CRRT after cardiac surgery was 43.5% and was particularly influenced by the type of surgery. Copyright (C) 2004 S. Karger AG, Basel.