Is off-pump revascularization better for patients with non-dialysis-dependent renal insufficiency?

Renal dysfunction is a well-recognized complication following coronary artery bypass grafting (CABG). Coronary revascularization without cardiopulmonary bypass (CPB) has been shown to minimize renal injury in patients with normal preoperative renal function who undergo elective procedures. The purpose of this study was to define the effect of an off-pump revascularization strategy on the incidence of postoperative renal failure and survival of patients with preexisting renal dysfunction.

From January 1, 1999, to December 1, 2002, a total of 371 patients were identified as having a preoperative creatinine concentration greater than or equal to 1.5 mg/dL. This number included 291 patients who did not need hemodialysis or peritoneal dialysis to support renal function. These patients were subdivided into those undergoing traditional CABG with CPB (103 patients) and those undergoing off-pump revascularization (188 patients) whose demographic, operative, and outcome information was retrospectively reviewed and compared.

The off-pump cohort was older than the on-pump cohort (70 +/- 9.6 versus 66 +/- 10.9 years; P =.002), had a lower prevalence of previous myocardial infarction (35% versus 50%; P =.008), and had a modestly higher mean left ventricular ejection fraction (0.47 +/- 0.01 versus 0.43 +/- 0.01; P =.017). Otherwise the groups were well matched. The mean preoperative serum creatinine and creatinine clearance values were not significantly different (1.8 +/- 0.5 versus 1.9 +/- 0.6 mg/dL [ P =.372] and 45.1 +/- 15.5 versus 46.8 +/- 17.2 mL/min [ P =.376] for the off-pump and on-pump cohorts, respectively). There was a significant reduction in postoperative renal failure (17% versus 9% of patients; P =.020) and need for new dialysis (10% versus 3% of patients; P =.022) when CPB was eliminated. Intermediate-term survival analysis revealed a survival benefit for the off-pump group (70% versus 57%) at 42 months, although this value did not reach statistical significance ( P =.143).

The results of this study suggested that patients with preoperative non-dialysis-dependent renal insufficiency have more favorable outcome when revascularization is done off pump. Avoidance of CPB results in (1) a reduction in the incidence of postoperative renal failure; (2) a reduction in the need for new dialysis; and (3) improved in-hospital and midterm survival.