Determinants of serum creatinine trajectory in acute contrast nephropathy

The aim of this study was to describe the trajectory of creatinine (Cr) rise and its determinants after exposure to radiocontrast media. Included were 98 subjects who underwent cardiac catheterization and were randomized to forced diuresis with i.v. crystalloid, furosemide, mannitol (if pulmonary capillary wedge pressure was < 20 mmHg), and low dose dopamine versus intravenous crystalloid and matching placebos. Baseline and postcatheterization serum Cr levels were analyzed in a longitudinal fashion, allowing for differences in the time between blood draws, to determine the different critical trajectories of serum Cr. The mean age, baseline serum Cr, and Cr clearance (CrCl) were 69.3 +/- 10.8 years, 2.5 +/- 0.9 mg/dL, and 31.4 +/- 12.1 mL/min, respectively. The clinically driven postprocedural observation time was 5.5 +/- 5.1 days (range 19 hours and one Cr value to 25.7 days and 18 values). The mean maximum Cr was 3.3 +/- 1.4, range 1.7-8.7 mg/dL). Longitudinal models support baseline Cr clearance predictions for the change in Cr at 24 hours, time as the determinant of Cr trajectory, and requisite monitoring. For any given individual, a rise in Cr of < or = 0.5 mg/dL in the first 24 hours after contrast exposure predicted a favorable outcome. Baseline renal function is the major determinant of the rate of rise, height, and duration of Cr trajectory after contrast exposure. Length of observation and frequency of laboratory measures can be anticipated from these models.