Ischemic Preconditioning for Prevention of Contrast Medium–Induced NephropathyClinical Perspective: Randomized Pilot RenPro Trial (Renal Protection Trial)

Background— Contrast medium–induced acute kidney injury is associated with substantial morbidity and mortality. The underlying mechanism has been attributed in part to ischemic kidney injury. The aim of this randomized, double-blind, sham-controlled trial was to assess the impact of remote ischemic preconditioning on contrast medium–induced acute kidney injury. Methods and Results— Patients with impaired renal function (serum creatinine >1.4 mg/dL or estimated glomerular filtration rate −1 · 1.73 m −2 ) undergoing elective coronary angiography were randomized in a 1:1 ratio to standard care with (n=50) or without ischemic preconditioning (n=50; intermittent arm ischemia through 4 cycles of 5-minute inflation and 5-minute deflation of a blood pressure cuff). Overall, both study groups were at high risk of developing contrast medium–induced acute kidney injury according to the Mehran risk score. The primary end point was the incidence of contrast medium–induced kidney injury, defined as an increase in serum creatinine ≥25% or ≥0.5 mg/dL above baseline at 48 hours after contrast medium exposure. Contrast medium–induced acute kidney injury occurred in 26 patients (26%), 20 (40%) in the control group and 6 (12%) in the remote ischemic preconditioning group (odds ratio, 0.21; 95% confidence interval, 0.07–0.57; P =0.002). No major adverse events were related to remote ischemic preconditioning. Conclusions— Remote ischemic preconditioning before contrast medium use prevents contrast medium–induced acute kidney injury in high-risk patients. Our findings merit a larger trial to establish the effect of remote ischemic preconditioning on clinical outcomes. Clinical Trial Registration— URL: http://www.germanctr.de. Unique identifier: U1111-1118-8098.