ABSTRACT: Importance:Determining the association of contrast volume during percutaneous coronary intervention (PCI) with the risk of acute kidney injury (AKI) is important for optimizing PCI safety. Objective:To quantify how the risk of AKI is associated with contrast volume, accounting for the possibility of nonlinearity and heterogeneity among different baseline risks. Design, Setting, and Participants:This prognostic study used data from the American College of Cardiology National Cardiovascular Data Registry CathPCI Registry for 1694 US hospitals. Derivation analysis included 2?076?694 individuals who underwent PCI from July 1, 2011, to June 30, 2015. Validation analysis included 961?863 individuals who underwent PCI from July 1, 2015, to March 31, 2017. Data analysis took place from July 2018 to May 2019. Exposure:Contrast volume during PCI. Main Outcomes and Measures:Acute kidney injury was defined using 3 thresholds for preprocedure to postprocedure creatinine level increase (ie, ?0.3 mg/dL, ?0.5 mg/dL, and ?1.0 mg/dL). A model quantifying the association of contrast volume with AKI was developed, and the existence of nonlinearity and heterogeneity were examined by likelihood ratio tests. The model was derived in the training set (a random 50% of the derivation cohort), and performance was evaluated in the test set (the remaining 50% of the derivation cohort) and an independent validation set by area under the receiver operating characteristic curve (AUC) and calibration slope of observed vs predicted risks. Results:The 2?076?694 patients in the derivation set had a mean (SD) age of 65.1 (12.1) years, and 662?525 (31.9%) were women; 133?306 (6.4%) had creatinine level increases of at least 0.3 mg/dL, 66?626 (3.2%) had creatinine level increases of at least 0.5 mg/dL, and 28?378 (1.4%) had creatinine level increases of at least 1.0 mg/dL. In the validation set of 961?843 patients (mean [SD] age, 65.7 [12.1] years; 305?577 [31.8%] women), these rates were 62?913 (6.5%), 34?229 (3.6%), and 15?555 (1.6%), respectively. The association of contrast volume and AKI risk was nonlinear (?226?=?1436.2; P?
