Early Renal-Protective Effects of Remote Ischemic Preconditioning in Elderly Patients with Non-ST-Elevation Myocardial Infarction (NSTEMI).

BACKGROUND With the wide clinical application of angiography, contrast-enhanced nephropathy (CIN) has become the third-leading cause of acute kidney injury (AKI). Remote ischemic preconditioning (RIPC) is a non-fatal ischemia-reperfusion injury that can provide protection against lethal ischemia-reperfusion. This study aimed to assess the effect of RIPC on CIN in elderly patients with non-ST-elevation myocardial infarction (NSTEMI). MATERIAL AND METHODS Patients were randomly divided into 2 groups with 119 patients in each group treated with interventional therapy. Patients in the RIPC group received distal ischemic preconditioning 2 h before contrast exposure, while patients in the control group received a sham RIPC procedure. Incidence of CIN was the primary outcome. Changes in creatinine, NGAL, and KIM-1 after contrast administration were secondary outcomes. RESULTS CIN occurred in a total of 27 (12.3%) patients, including 12 (10.1%) in the RIPC group and 15 (15.1%) in the control group (P=0.329). RIPC treatment significantly reduced the levels of NGAL (P=0.024) and KIM-1 (P=0.007) at 12 h after contrast administration, suggesting RIPC treatment reduces sub-clinical renal damage. Subgroup analysis revealed that significant reduction of KIM-1 and NGAL by RIPC, mainly occurring in patients with a Mehran risk score of 6-10. CONCLUSIONS Although RIPC did not significantly reduce CIN incidence in elderly patients with NSTEMI, the application of more sensitive biomarkers - NGAL and KIM-1 - indicated a reduction of sub-clinical renal damage by RIPC, especially in the early stage of injury. As a simple and well-tolerated method, RIPC may be a potentially feasible option to prevent CIN.