Preoperative Short‐Term Calorie Restriction for Prevention of Acute Kidney Injury After Cardiac Surgery: A Randomized, Controlled, Open‐Label, Pilot Trial

Abstract

BackgroundAcute kidney injury is a frequent complication after cardiac surgery and is associated with adverse outcomes. Although short‐term calorie restriction (CR) has proven protective in rodent models of acute kidney injury, similar effects have not yet been demonstrated in humans.Methods and Results CR_KCH (Effect of a Preoperative Calorie Restriction on Renal Function After Cardiac Surgery) is a randomized controlled trial in patients scheduled for cardiac surgery. Patients were randomly assigned to receive either a formula diet containing 60% of the daily energy requirement (CR group) or ad libitum food (control group) for 7 days before surgery. In total, 82 patients were enrolled between April 16, 2012, and February 5, 2015. There was no between‐group difference in the primary end point of median serum creatinine increment after 24 hours (control group: 0.0 mg/dL [−0.1 – (+0.2) mg/dL]; CR group: 0.0 mg/dL [−0.2 – (+0.2) mg/dL]; P=0.39). CR prevented a rise in median creatinine at 48 hours (control group: +0.1 mg/dL [0.0 – 0.3 mg/dL]; CR group: −0.1 mg/dL [−0.2 – (+0.1) mg/dL]; P=0.03), with most pronounced effects observed in male patients and patients with a body mass index >25. This benefit persisted until discharge: Median creatinine decreased by 0.1 mg/dL (−0.2 – 0.0 mg/dL) in the CR group, whereas it increased by 0.1 mg/dL (0.0 – 0.3 mg/dL; P=0.0006) in the control group. Incidence of acute kidney injury was reduced by 5.8% (41.7% in the CR group compared with 47.5% in the control group). Safety‐related events did not differ between groups.ConclusionsDespite disappointing results with respect to creatinine rise within the first 24 hours, the benefits observed at later time points and the subgroup analyses suggest the protective potential of short‐term CR in patients at risk for acute kidney injury, warranting further investigation.Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT01534364.

Dietary restriction for prevention of contrast-induced acute kidney injury in patients undergoing percutaneous coronary angiography: a randomized controlled trial

“…Recently, in a randomized controlled clinical trial evaluating the effects of a 7-day preoperative CR (60% of DEE) on renal function in patients undergoing cardiac surgery, a small albeit significant improvement on creatinine kinetics was revealed at 48 h after surgery and before discharge. 21 Similar to the here reported trial, more pronounced beneficial effects were detected in distinct patient subgroups. Despite these promising data, the magnitude of the observed effects is considerably lower than it could have been expected from animal experiments.…”

Modulation of Endocannabinoids by Caloric Restriction Is Conserved in Mice but Is Not Required for Protection from Acute Kidney Injury

“…To answer the question if CR-induced reduction of endocannabinoids and specifically AEA is even conserved in humans, we assembled a set of longitudinally acquired human serum samples before and after CR derived from different investigator initiated clinical trials at our center. The first trial investigated the protective effect of CR in patients undergoing elective cardiac surgery on cardiopulmonary bypass (CR_KCH, NCT01534364, [ 36 ]). After randomization, subjects received a formula diet that supplied 60% of daily energy expenditure (DEE) for the last seven days prior to surgery; control subjects were not restricted in their food intake.…”

The effect of energy restriction on development and progression of chronic kidney disease: review of the current evidence

“…Median weight loss in the control group was 0•1 kg, whereas median weight loss in the ER group was 3•0 kg. There was a trend towards lower incidence of AKI in the ER group (42•0 v. 47•5 %, P 0•06) (23) . These promising studies should be confirmed in larger trials.…”