Contrast-induced nephropathy after a second contrast exposure

Background: The risk of contrast-induced nephropathy (CIN) after repeated contrast exposure has not been evaluated. Methods: We prospectively evaluated the effects of two contrast exposures during an investigational study of a new computerized tomography (CT) scanner. Adult subjects who underwent a variety of contrast- enhanced imaging procedures with conventional apparatus, as part of routine care, were invited to undergo a second contrast-enhanced research scan. Subjects were required to have an estimated glomerular filtration rate (eGFR) >60 mL/min/1.73 m(2) and a serum creatinine (sCr) value measured immediately prior to the second contrast exposure that was <125% of that measured prior to the first imaging study. Results: Twenty-eight subjects underwent a second contrast exposure after a mean interval of 20 +/- 13 days (75% males, 89% Caucasians, 21% diabetics, mean age 60.6 +/- 6 years, mean contrast volume 130 +/- 42 mL). There was a significant increase in mean sCr and decline in eGFR after the second contrast exposure (sCr 0.93 +/- 0.14 vs. 0.86 +/- 0.15 mg/dL prior, p = 0.027; eGFR 83.9 +/- 13.5 vs. 89.8 +/- 13 mL/min/1.73 m(2) prior, p = 0.028). Four subjects (14.3% of the population) developed CIN. Conclusion: Even in subjects with relatively preserved renal function there is a notable risk of CIN after repeated contrast exposure. This conclusion was unaltered by several sensitivity analyses.