Among at-risk patients undergoing elective coronary angiography (CAG) or PCI, delayed remote ischemic preconditioning (RIPC) reduces the incidence of contrast-associated acute kidney injury (CA-AKI) compared with sham preconditioning, according to a randomized trial published March 11 in the European Heart Journal.

Ping Jia, PhD, et al., conducted a prospective trial at six teaching hospitals in China between April 2019 and July 2021 to determine whether delayed RIPC performed 24 hours before CAG or PCI would reduce the occurrence of CA-AKI and postoperative complications in patients at risk of AKI. RIPC included four cycles of five-minute inflations and deflations on one upper arm 24 hours before contrast exposure.

The researchers defined the primary endpoint of occurrence of AKI as an increase in serum creatinine of ≥0.3 mg/dL from baseline within 48 hours after CAG or PCI.

A total of 501 patients (median age, 74 years; 28% women) were randomized to undergo either RIPC or sham ischemic pre-conditioning; 93.2% completed outcome assessments at 90 days.

Results showed that the incidence of CA-AKI was lower with delayed vs. sham RIPC (3.2% vs. 7.6%; odds ratio, 0.40; p=0.03). Looking at secondary endpoints, 90-day all-cause mortality was lower in the RIPC group (0%) vs. the control group (2.4%), and no significant between-group differences were seen in renal replacement therapy, myocardial infarction, stroke or rehospitalization. The authors note the trial was not powered to show impacts on the secondary outcomes.

The trial results indicate that "delayed RIPC may be a promising strategy for the prevention of AKI in patients undergoing diagnostic or interventional procedures that require contrast medium administration," the authors write.

However, the authors note that "the low incidence of CA-AKI influenced the validity of the original power calculation. Therefore, more adequately powered trials involving high-risk patients are needed to assess the effects of delayed RIPC on CA-AKI."

According to Guy S. Reeder, MD, FACC, "Ischemic preconditioning refers to an incompletely understood mechanism by which temporary vascular occlusion reduces subsequent ischemic risk to the ipsilateral supplied distal tissue. Remote ischemic preconditioning is said to occur when a resistance to ischemia is produced in one vascular bed by temporary occlusion of a different vascular bed. Delayed remote ischemic preconditioning applies to the technique performed 24 hours prior to the anticipated ischemic event. In the paper by Jia et al., the authors demonstrated the efficacy of delayed remote ischemic preconditioning in mitigating the risk of CA-AKI. In a sham controlled, blinded, randomized trial including patients at increased risk of CA-AKI, they demonstrated that repeated brachial artery compression by blood pressure cuff applied 24 hours prior to contrast administration reduced the incidence of CA-AKI by over 50%. If confirmed by additional studies, this drug free and inexpensive intervention may have significant clinical benefit."