Relationship between High Level of Estimated Glomerular Filtration Rate and Contrast-Induced Acute Kidney Injury in Patients who Underwent an Emergency Percutaneous Coronary Intervention.

Background: Mounts of studies have shown that low estimated glomerular filtration rate (eGFR) is associated with increased risk of adverse outcomes in patients with coronary artery disease. However, high level of eGFR was less reported. In the study, we aimed to explore the relationship between the baseline eGFR, especially the high level, and contrast-induced acute kidney injury (CI-AKI) in a Chinese population who underwent an emergency percutaneous coronary intervention (PCI).

Methods: Patients who underwent an emergency PCI from 2013 to 2015 were enrolled and divided into five groups as eGFR decreasing. Baseline characteristics were collected and analyzed. The rates of CI-AKI and the composite endpoint (including nonfatal myocardial infarction, revascularization, stroke, and all-cause death) at 6- and 12-month follow-up were compared. Logistic analysis for CI-AKI was performed.

Results: A total of 1061 patients were included and the overall CI-AKI rate was 22.7% (241/1061). The separate rates were 77.8% (7/9) in Group 1 (eGFR ≥120 ml·min·1.73 m), 26.0% (118/454) in Group 2 (120 ml·min·1.73 m> eGFR ≥90 ml·min·1.73m), 18.3% (86/469) in Group 3 (90 ml·min·1.73 m> eGFR ≥60 ml·min·1.73 m), 21.8% (26/119) in Group 4 (60 ml·min·1.73 m> eGFR ≥30 ml·min·1.73 m), and 40.0% (4/10) in Group 5 (eGFR <30 ml·min·1.73 m), with statistical significance (χ = 25.19, P < 0.001). The rates of CI-AKI in five groups were 77.8%, 26.0%, 18.3%, 21.8%, and 40.0%, respectively, showing a U-typed curve as eGFR decreasing (the higher the level of eGFR, the higher the CI-AKI occurrence in case of eGFR ≥60 ml·min·1.73 m). The composite endpoint rates in five groups were 0, 0.9%, 2.1%, 6.7%, and 0 at 6-month follow-up, respectively, and 0, 3.3%, 3.4%, 16.0%, and 30.0% at 12-month follow-up, respectively, both with significant differences (χ = 16.26, P = 0.009 at 6-month follow-up, and χ = 49.05, P < 0.001 at 12-month follow-up). The logistic analysis confirmed that eGFR was one of independent risk factors of CI-AKI in emergency PCI patients.

Conclusions: High level of eGFR might be associated with increased risk of CI-AKI in patients with emergency PCI, implying for future studies and risk stratification in clinical practice.