Association between elevated urinary levels of kidney injury molecule type 1 and adverse cardiovascular events at 12 months in patients with coronary artery disease

INTRODUCTION Contrast-induced nephropathy is associated with worse prognosis in patients with coronary artery disease (CAD); however, the prognostic role of urinary biomarkers of renal injury has not been fully established. OBJECTIVES We evaluated the clinical utility of urinary biomarkers for the prediction of major adverse cardiac and cerebrovascular events (MACCEs) in patients undergoing coronary angiography. PATIENTS AND METHODS This prospective study included 95 consecutive patients with stable and unstable CAD (men, 69.5%; median age, 65 years), referred for coronary angiography and monitored for MACCEs during 12-month follow-up. MACCEs were defined as cardiovascular death, myocardial infarction, myocardial revascularization, or stroke. Urine samples were collected 24 hours before and 6 hours after coronary angiography and assayed for kidney injury molecule type 1 (KIM-1), interleukin 18, liver fatty acid-binding protein, and renalase, using an enzyme-linked immunosorbent assay. The results were adjusted for urinary creatinine concentration. RESULTS MACCEs occurred in 10 patients (10.5%). These patients had a higher rate of postprocedural contrast-induced acute kidney injury than patients without MACCEs (30.0% vs 7.1%, P = 0.02), higher median SYNTAX score (25.5 points vs 11.5 points, P = 0.04), higher postprocedural KIM-1 concentrations (0.45 ng/mg vs 0.21 ng/mg, P = 0.03), and a larger absolute increase of urinary KIM-1 levels (Delta KIM-1; 0.41 ng/mg vs 0.10 ng/mg, P = 0.01). Preprocedural values of KIM-1 and other biomarkers were comparable between groups. Patients with Delta KIM-1 levels above the 75th percentile had worse 12-month prognosis (P = 0.0004). Delta KIM-1 levels were an independent predictor of 12-month MACCEs (P = 0.001). MACCEs were accurately predicted by Delta KIM-1 levels exceeding 0.093 ng/mg (area under the curve, 0.752; P = 0.0001). CONCLUSIONS Excessive increase of urinary KIM-1 levels after coronary angiography may help identify CAD patients with poor 12-month prognosis.