Renal Recovery After Postcardiac Surgery Renal Replacement Therapy

The need for renal replacement therapy (RRT) is an uncommon but severe complication after postcardiac surgery acute kidney injury, although there are limited data on the incidence of renal recovery. This study evaluates the rate of renal recovery in cardiac surgery patients who require postoperative RRT and survive to discharge, and describes the clinical factors associated with higher rates of recovery.

All adult patients without preoperative dialysis, heart transplantation, or durable left ventricular assist device who required new onset postoperative RRT after cardiac surgery from 2011-2022 at a high-volume referral center were included. The primary outcome was renal recovery, defined as freedom from dialysis and survival for ≥4 weeks after discontinuation of RRT. Bivariable analyses and multivariable logistic regression were performed.

Total incidence of RRT was 2.1% (322 of 15,609) with a 40.1% in-hospital mortality rate. Over half (59.9%, 193 of 322) of patients requiring RRT survived to discharge. Among these, 65.6% (124 of 189) achieved renal recovery. Compared with the no recovery group, the recovery group was younger, more often male, and had lower rates of diabetes and chronic kidney disease. Higher preoperative creatinine clearance was positively correlated with increased rates of renal recovery. The incidence of renal recovery was highest after aortic operations and lowest after coronary artery bypass surgery.

Of those requiring RRT after cardiac surgery, 60% survived to discharge and 66% of these patients achieved renal recovery. The results of this study can inform discussions with patients and families regarding the expected course of RRT and potential for renal recovery.