Comparison of transient changes in renal function between off-pump and on-pump coronary artery bypass grafting

Acute renal failure following coronary artery bypass grafting (CABG) surgery is associated with high morbidity and mortality. Approximately half of all patients who develop acute kidney injury (AKI) subsequently develop acute renal failure (ARF). The purpose of the study was to compare early transient changes in renal function within the first post-operative week following CABG in patients that were either off-pump or on-pump.

Eight hundred and forty-nine consecutive patients with isolated CABG in a single institution between January 1990 and August 2006 were retrospectively analyzed, including 518 off-pump and 331 on-pump patients. A multivariate Logistic regression model was constructed to identify risk factors for the development of AKI.

Sixty-one off-pump patients and 63 on-pump patients developed AKI. Risk factors for the development of post-operative AKI included an ejection fraction > or =50% or < or =30%, a pulse pressure > or =60 mmHg, peripheral vascular disease, diabetes, emergent procedure, triple-vessel disease, body mass index, peri-operative and post-operative. intra-aortic balloon pumping, NYHA class III and IV, and cardiopulmonary bypass. An ejection fraction > or =50% and peri-operative and post-operative intra-aortic balloon pumping were protective (OR <1). Peak serum creatinine for post-operative AKI was noted 12 hours and 24 hours in the off-pump and on-pump patients, respectively. Serum creatinine kinetics revealed rapid recovery in the 24th to 48th hour (off-pump) and the 48th to 72nd hour (on-pump).

Renal protection strategies are indicated from general anesthesia induction until 48 and 72 hours post-operatively in off-pump and on-pump patients, respectively.