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Contrast induced nephropathy is associated with permanent renal dysfunction and increased mortality. Few data is available regarding its effect on event-free survival of patients with non-ST elevation myocardial infarction (NSTEMI).
Patients with NSTEMI who underwent early coronary angiography were analysed retrospectively. Exclusion criteria were previous exposure to contrast agents within 7 days, hemodynamic instability or emergent procedures, and end stage renal failure requiring chronic hemodialysis treatment. Contrast induced nephropathy (CIN) was defined as either 25% or 0.5 mg/dl increase in preprocedural serum creatinine within 72 hours of the procedure. Follow-up data of patients were acquired from hospital records. Patients without follow-up data were invited to hospital by phone call. Clinical endpoints of the study were mortality and nonfatal myocardial infarction (MI) in long term follow-up.
312 consecutive patients (mean age 59±12 years, 76% male) with complete serum creatinine measurements and long term clinical follow-up data (median 38 months) were included in the study. CIN developed in 9.6% (30) of patients. Independent predictors of CIN were contrast volume/estimated glomerular filtration rate ratio [odds ratio 1.294 (1.062-1.577), p=.011], left ventricular ejection fraction [odds ratio 0.950 (0.911-0.990), p=0.015] and hemoglobin concentration [odds ratio 0.755 (0.601-0.949), p=0.016]. Death or nonfatal myocardial infarction was observed more frequently in patients with CIN during the follow-up compared to patients without (43.3% vs 19.9% respectively, chi-square=10.4, log rank p=0.005). Independent predictors of long term mortality were left ventricular ejection fraction [X2=23,5, OR=0.930 (0.903-0.958), p<0.001], age [X2=4.3, OR=1.028 (1.002-1.056), p<0.038], and baseline creatinine [X2=4.2, OR=1.725 (1.021-2.913), p=0.042].
CIN after invasive procedures in patients with NSTEMI is associated with increased mortality and cardiac events. Patients who developed CIN during acute coronary syndromes should be considered as high-risk group and clinical follow-up should be done accordingly. However CIN is not an independendent predictor of long term mortality or recurrent events in patients with NSTEMI.