Patient selection: primary percutaneous coronary intervention (PCI) with nonionic iso-osmolar contrast agent; creatinine clearance >= 60 mL per minute
Outcome: contrast-induced nephropathy (defined as increase in serum creatinine >= 25% from baseline at 48 hours after infusion of the contrast material
Risk factors for contrast-induced nephropathy on multivariate analysis:
(1) volume of contrast infused
(2) TIMI risk index from the InTIME trial (Morrow et al)
Volume of contrast media used:
(1) without nephropathy: 232 +/- 66 mL
(2) with nephropathy: 290 +/- 89
Parameters for the TIMI risk index:
(1) age in years (mortality increases with age)
(2) heart rate in beats per minute (mortality increases with heart rate)
(3) systolic blood pressure in mm Hg (mortality higher with low blood pressures)
risk index =
= (heart rate) * (((age) / 10)^2) / (systolic blood pressure) =
= (heart rate) * ((age)^2) / (100 * (systolic blood pressure)
Interpretation:
• A TIMI risk index >= 25.8 was 67% sensitive and 80% specific for contrast-induced nephropathy (area under the ROC curve 0.74).
• In the implementation risk for contrast volumes interpreted as: <= 200 mL as low risk; 201 to 290 some risk; > 290 high risk.
