The effects of chronic usage of enzyme inhibitors and angiotensin receptor blockers on contrast-induced nephropathy in low-risk patients

Objective: There is conflicting data about the role of renin- angiotensin- aldosterone system (RAAS) blockers in contrast-induced nephropathy (CIN) pathophysiology. In this study, we aimed to investigate the effects of chronic usage of RAAS blocker drugs on development of CIN in low risk patients. Methods: Study was designed as a prospective cohort study. A total of 295 patients were enrolled in the study. Study population was consisted of three subgroups according to prior usage of RAAS blockers: no RAAS blocker group (n=95), angiotensin-converting enzyme inhibitor (ACEI) group (n=106), angiotensin receptor blocker (ARB) group (n=94). CIN was defined as an increase of ≥25% in creatinine over the baseline value or 0.5 mg/dL rise within 48-72 h of angiography. Mehran score was calculated for each patient. Baseline variables and percentage of CIN were compared with ANOVA, Mann-Whitney U, Kruskal-Wallis and Pearson Chi-square tests between groups. In order to determine the independent predictors of CIN, binary logistic regression analyses were performed. Results: CIN occurred in 18 patients (17.0%) in the ACEI group, 17 patients (18.1%) in ARB group and 7 patients (7.4%) in the no RAAS group. CIN occurrence was significantly higher in RAAS than no RAAS group (17.5% vs. 7.4%, p=0.01). Chronic RAAS blocker administration was an independent predictor of CIN (OR=2.69; 95% CI: 1.025-7.067; p=0.04). Mehran score was the only other independent predictor for CIN (OR=1.15; 95% CI: 1.019-1.310; p=0.02). Conclusion: In patients with near normal renal functions who are undergoing elective coronary procedure, chronic usage of ACEI and ARB increases the risk of CIN.