['In Japan, prophylactic hemodialysis has been considered useful for preventing contrast-induced nephropathy (CIN).', 'To assess whether hemodialysis prevented CIN, 391 patients (age: 69 +/- 8 years, 63 females) with chronic renal insufficiency (CRI, serum creatinine level (Scr) > or = 1.3 mg/dl) who underwent cardiac catheterization, were retrospectively analyzed. Patients were divided into 3 categories based on Scr: L (1.3 > or = Scr < 2.0 mg/dl, n = 332); M (2.0 > or = Scr < 3.0 mg/dl, n = 49); and H (Scr > or = 3.0 mg/dl, n = 10). To prevent CIN, 35 category M patients and all category L patients received hydration alone, whereas 14 category M patients and all category H patients received hemodialysis. CIN developed in 48 patients. The incidence of CIN in category H was significantly higher than that in category L or M (H, 40% vs L, 11% or M, 16% (p < 0.05)). In category M patients treated with hemodialysis, Scr increased from 2.4 +/- 0.3 to 3.0 +/- 0.5 mg/dl (p < 0.05) within 7 days, and 29% of patients developed CIN. However, in category M patients who did not receive hemodialysis, the Scr did not change (pre, 2.3 +/- 0.2 mg/dl to post, 2.2 +/- 0.4 mg/dl), and the incidence of CIN was 11%.'] Does prophylactic hemodialysis prevent contrast-induced nephropathy after cardiac catheterization in patients with chronic renal insufficiency?