Aim To compare the incidence, and risk factors, in-hospital and at the 18-month prognosis of contrast-induced nephropathy (CIN) according to the definition utilized: as an increase in serum creatinine (Scr) ≥0.5 mg/dL (CIN 1) or as an increase in Scr ≥25% above baseline values (CIN 2).
Methods and Results We prospectively evaluated CIN according to two different definitions in 150 patients who underwent percutaneous coronary intervention (PCI) in simple lesions employing a low-medium dose of contrast media. Incidence of CIN was higher using the CIN 2 definition than CIN 1 (9.3% vs. 4%; p=0.0133). Patients with CIN 1 had a higher incidence of chronic kidney disease (CKD) (66.7% vs. 13.9%; p=0.006), higher mean serum creatinine levels (1.35±0.42 vs. 0.98±0.35; p=0.001) and lower mean eGFR levels (58.3±19.6 vs. 84±25.9; p=0.002). Patients with CIN 2 had a higher incidence of anemia (57.1% vs. 30.9%; p=0.049) and a higher mean contrast media volume was used (142.6±62.2 mL vs. 110.6±57.2 mL; p=0.05). In the multivariate analysis the only significant variable associated with CIN (CIN 2) was a higher volume of contrast media (OR=1.01; p=0.04). There were no differences in the major in-hospital events, but patients with CIN (both definitions) had a longer in-hospital stay. A persistent rise in serum creatinine at discharge occurred in only one patient. There were no differences between patients with and without CIN in events at the follow-up, with the exception of an increased risk of new hospitalization in patients with CIN 2.
Conclusion After PCI employing low-medium dose of contrast media the incidence of CIN varied according to the definition used. Neither of the two definitions offers additional information compared with the other. Chronic kidney disease and baseline parameters of renal function are the risk factors associated with CIN 1; anemia and higher volume of contrast media are associated with CIN 2.