Comparison of risks and clinical predictors of contrast-induced nephropathy in patients undergoing emergency versus nonemergency percutaneous coronary interventions.

BACKGROUND: Contrast nephropathy (CIN) increases adverse clinical outcomes. We examine risks and clinical predictors of CIN in patients undergoing percutaneous coronary intervention (PCI) and effectiveness of prophylactic therapy.

METHODS: A cohort of 8,798 patients who underwent PCI from May 2000 to April 2008 was enrolled. We divided patients into 3 groups. A: STEMI patient undergoing primary PCI; B: UA/NSTEMI patients undergoing early PCI; C: Patients without MI undergoing elective PCI. Pre-PCI saline hydration was given to group B and C if baseline glomerular filtration rate (GFR) <60 ml/min/1.73 m².

RESULTS: Mean age was 57.4 years; 35.9% was diabetics. Incidence of CIN were 12.0%, 9.2%, and 4.5%, in group A, B and C (P = <0.0005). CIN correlated with higher mortality (15.5% vs. 1.3%, P < 0.0005) at 1 month. The important predictors of CIN were age >70, female gender, anemia, low systolic BP < 100 mmHg, high creatinine kinase level, abnormal LVEF, baseline renal impairment, MI and insulin dependent diabetes. Incidence of CIN in patients with GFR >60 were 8.2%, 9.2%, and 4.3% in group A, B, and C respectively (p < 0.0005). Incidence of CIN in patients with GFR = 30-60 were 19.1%, 4.5%, and 2.4% (p < 0.0005) and in patients with GFR < 30 were 34.4%, 40.0%, and 25.9% (p = 0.510).

CONCLUSIONS: Pre-hydration prophylaxis was effective in preventing CIN in mild renal impaired patients (GFR 30-60) but are less so in more severely renal impaired patients (GFR < 30). STEMI patients undergoing primary PCI regardless of baseline GFR were at high risk. Accelerated prophylactic regime can be considered in this cohort.