A Comparison Between Two Different Definitions of Contrast-Associated Acute Kidney Injury for Long-Term Mortality in Patients with Chronic Kidney Disease Undergoing Coronary Angiography

Abstract

Background: Contrast-associated acute kidney injury (CA-AKI) is a prevalent complication following coronary angiography (CAG). However, there is ongoing controversy surrounding its precise definition. Although previous studies have demonstrated the successful application of appropriate definitions in managing high-risk CA-AKI patients, there remains limited research on the association between different definitions and prognosis specifically in patients with chronic kidney disease (CKD).

Methods: A total of 4197 CKD patients undergoing coronary angiography (CAG) were included in this study. Two definitions of contrast-associated acute kidney injury (CA-AKI) were used: CA-AKI_A, which was defined as an increase of ≥0.5 mg/dL or >25% in serum creatinine (SCr) from baseline within 72 hours after CAG, and CA-AKI_B, which was defined as an increase of ≥0.3 mg/dL or >50% in SCr from baseline within 48 hours after CAG. Cox regression analysis was employed to assess the association between these two definitions and long-term mortality. Additionally, population attributable risks (PARs) were calculated to evaluate the impact of CA-AKI definitions on long-term prognosis.

Results: During the median follow-up period of 4.70 (2.50-7.78) years, the overall long-term mortality was 23.6%, and the long-term mortality in patients with CA-AKI according to both CA-AKI_A and CA-AKI_B criteria were 33.5% and 33.8%, respectively. We found that CA-AKI_A (HR: 1.45, 95% CI: 1.23-1.70, p<0.001) and CA-AKI_B (HR: 1.44, 95% CI: 1.23-1.69, p<0.001) were associated with long-term mortality. The PARs were the highest for CA-AKI_A (5.87%), followed by CA-AKI_B (5.70%).

Conclusion: Contrast-associated acute kidney injury (CA-AKI) is a frequently observed complication in CKD patients undergoing coronary angiography (CAG), and both definitions of CA-AKI are significantly correlated with a poor long-term prognosis. Consequently, in the clinical management of CKD patients, it is crucial to prioritize CA-AKI, irrespective of the specific CA-AKI definition used.

Keywords: chronic kidney disease; contrast-associated acute kidney injury; definitions; long-term mortality; population attributable risks.