Background: A simple, contemporary risk score for the prediction of contrast-associated acute kidney injury (CA-AKI) after percutaneous coronary intervention (PCI) was recently updated, although its external validation is lacking.

Objectives: The aim of this study was to validate the updated CA-AKI risk score in a large cohort of acute coronary syndrome patients from the MATRIX (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of angioX) trial.

Methods: The risk score identifies 4 risk categories for CA-AKI. The primary endpoint was to appraise the receiver-operating characteristics of an 8-component and a 12-component CA-AKI model. Independent predictors of Kidney Disease Improving Global Outcomes-based acute kidney injury and the impact of CA-AKI on 1-year mortality and bleeding were also investigated.

Results: The MATRIX trial included 8,201 patients with complete creatinine values and no end-stage renal disease. CA-AKI occurred in 5.5% of the patients, with a stepwise increase of the 4 risk categories. The receiver-operating characteristic area under the curve was 0.67 (95% CI: 0.64-0.70) with model 1 and 0.71 (95% CI: 0.68-0.74) with model 2. CA-AKI risk was systematically overestimated with both models (Hosmer-Lemeshow goodness-offit test: P<0.05). The 1-year risks of all-cause mortality and bleeding were higher in CA-AKI patients (HR: 7.03 [95% CI: 5.47-9.05] and HR: 3.20 [95% CI: 2.56-3.99]; respectively). There was a gradual risk increase for mortality and bleeding as a function of the CA-AKI risk category for both models. Conclusions: The updated CA-AKI risk score identifies patients at incremental risks of acute kidney injury, bleeding, and mortality. (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of angioX [MATRIX]; NCT01433627).