The Preinterventional Cystatin-Creatinine-Ratio: A Prognostic Marker for Contrast Medium-Induced Acute Kidney Injury and Long-Term All-Cause Mortality

Abstract

Background/Aims: Contrast medium-induced acute kidney injury (CI-AKI) is an important iatrogenic complication following the injection of iodinated contrast media. The level of serum creatinine (SCr) is the currently accepted ‘gold standard' to diagnose CI-AKI. Cystatin C (CyC) has been detected as a more sensitive marker for renal dysfunction. Both have their limitations. Methods: The role of the preinterventional CyC-SCr ratio for evaluating the risk for CI-AKI and long-term all-cause mortality was retrospectively analyzed in the prospective single-center ‘Dialysis-versus-Diuresis trial'. CI-AKI was defined and staged according to the Acute Kidney Injury Network classification. Results: Three hundred and seventy-three patients were included (average age 67.4 ± 10.2 years, 16.4% women, 29.2% with diabetes mellitus, mean baseline glomerular filtration rate 56.3 ± 20.2 ml/min/1.73 m² [as estimated by Chronic Kidney Disease Epidemiology Collaboration Serum Creatinine Cystatin C equation], 5.1% ejection fraction <35%). A total of 79 patients (21.2%) developed CI-AKI after elective heart catheterization, and 65 patients (17.4%) died during follow-up. Multivariate analyses by logistic regression confirmed that the preinterventional CyC-SCr ratio is independently associated with CI-AKI (OR 9.423, 95% CI 1.494-59.436, p = 0.017). Also, the Cox regression model found a high significant association between preinterventional CyC-SCr ratio and long-term all-cause mortality (mean follow-up 649 days, hazards ratio 4.096, 95% CI 1.625-10.329, p = 0.003). Conclusion: The preinterventional CyC-SCr ratio is independently associated with CI-AKI and highly significant associated with long-term mortality after heart catheterization.