Microalbuminuria predicts contrast-induced nephropathy in patients with acute coronary syndrome

Introduction and objectives: Between 10% and 25% of patients hospitalized due to an acute coronary syndrome develop acute kidney injury, a condition associated with higher morbidity and mortality rates. Scores have been developed to predict the occurrence of post-coronary angiography contrast-induced nephropathy (CIN) in patients with acute coronary syndrome. The objective of this study was to assess the association between microalbuminuria and post-coronary angiography CIN in patients with acute coronary syndrome. Methods: Patients admitted with acute coronary syndrome in whom a coronary angiography was performed during their hospitalization and with urinary albumin-to-creatinine ratio (ACR) assessment within the first 24 hours were analyzed. The best ACR cutoff value for coronary angiography-induced CIN was determined using the C-statistic measure. The receiver operating characteristic (ROC) curves were built to compare between the predictive ability of the Mehran score alone and also in combination with the ACR. Results: A total of 148 patients were analyzed. Median age was 64 years (56-73), 35% were women, mean creatinine clearance rate at admission was 86 mL/ min (66-107) and the ACR was 5 mg/g (0-14). The analysis showed that 9.6% of the patients developed post-coronary angiography CIN with ACR levels >= 20 mg/g compared to 1.6% when these levels were < 20 mg/g. The area under the ROC curve of the Mehran score to predict the development of post-coronary angiography CIN was 0.75 (95%CI, 0.68-0.81) and when the ACR was added it went up to 0.82 (95%CI, 0.76-0.87). Conclusions: The ACR levels at admission were associated with the development of post-coronary angiography CIN and bring added value to an already validated predictive score. Therefore, the ACR should be used as a simple and accessible tool to detect and prevent this severe complication in patients with acute coronary syndrome.