Volume-to-creatinine clearance ratio in patients undergoing coronary angiography with or without percutaneous coronary intervention: Implications of varying definitions of contrast-induced nephropathy

Objectives Whether predicting the risk of early serum creatinine rise using the ratio of the volume of contrast media administered to the estimated creatinine clearance (V/CrCl) is applicable to the broader definition of contrast‐induced nephropathy (CIN) (≥0.5 mg/dL absolute and/or 25% relative increase from baseline serum creatinine) is unknown. Background A V/CrCl ≥4 has been proven to predict the risk of ≥0.5 mg/dL postprocedural absolute rise in serum creatinine. Methods A total of 722 patients undergoing coronary angiography ± percutaneous coronary intervention (PCI) between March 2011 and October 2011 with paired serum creatinine determinations at preprocedure and within 72‐hr postprocedure were analyzed. The V/CrCl ratio was calculated by dividing the volume of contrast received by the patient's creatinine clearance. CIN using different definitions was termed as CINnarrow (rise in serum creatinine ≥0.5 mg/dL) and CINbroad (rise in serum creatinine ≥0.5 mg/dL and/or ≥25% increase in baseline serum creatinine). Results The mean age was 66 ± 11 years and the mean baseline serum creatinine was 1.1 ± 0.8 mg/dL. Patients with V/CrCl ≥4 were significantly older and more frequently underwent ad hoc PCI compared with those with V/CrCl