WASHINGTON—For patients with impaired renal function, performing CABG off-pump rather than on-pump appears to improve outcomes, a retrospective study showed.

Across the range of renal function, off-pump CABG was associated with a slightly lower rate of in-hospital death or the need for renal replacement therapy compared with on-pump CABG (1.8% versus 2%), according to Lakhmir Chawla, MD, of George Washington University Medical Center, and colleagues.

The benefit of off-pump CABG increased as renal function worsened, the researchers reported online in the Journal of the American Society of Nephrology.

"Prospective trials comparing these procedures in patients with impaired preoperative renal function are warranted," they wrote.

Patients with prolonged exposure to cardiopulmonary bypass have been shown to have a greater risk of postoperative acute kidney injury, and off-pump CABG has been proposed for high-risk patients.

"The link between cardiopulmonary bypass and acute kidney injury is plausible, especially among patients with limited preoperative renal reserve," the researchers wrote, citing detrimental effects from low mean arterial pressures during bypass, the kidney's vulnerability to ischemia, and possible contributions from nonpulsatile renal perfusion, microemboli, and systemic inflammation.

"Despite this mechanistic association, prospective controlled trials of off-pump CABG have included few patients with chronic kidney disease," they wrote.

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