Kidney enhancement on X-rays following emergency percutaneous coronary procedure predicts poor short- and long-term clinical outcomes.

BACKGROUND We assessed radiographic kidney enhancement following an emergency coronary procedure as a predictor of contrast-induced nephropathy (CIN) and poor long-term outcome. METHODS AND RESULTS We enrolled 126 consecutive patients who underwent an emergency coronary procedure and abdominal X-ray within 24h. We defined kidney enhancement as positive when the density of the kidneys was equal to or higher than that of the lumbar vertebrae. Of the 126 patients, 11 showed kidney enhancement and 115 did not. There were no significant differences in the baseline characteristics of patients with and without kidney enhancement. The incidence of CIN was significantly higher in patients with than in those without kidney enhancement (91% vs. 6%, P<0.01). During a mean follow-up of 21±16 months, 5 of 11 patients with kidney enhancement had poor outcomes, such as renal replacement therapy or death, whereas poor outcomes were observed in only 12 of 115 patients without kidney enhancement. Kaplan-Meier analysis revealed a significant difference in the probability of a poor outcome between patients with and those without kidney enhancement (46% vs. 10%, P<0.01). CONCLUSIONS Radiographic kidney enhancement following a percutaneous coronary procedure predicts the occurrence of CIN and poor clinical outcome.