Twenty-seven patients (15 diabetics and 12 non-diabetics) with normal to moderately reduced renal function underwent femoral angiography with a low-osmolar contrast agent, iohexol (Omnipaque), under perexaminatory hydration. Fourteen patients were randomised to pretreatment with oral felodipine extended release (Plendil) 10 mg and 13 patients to placebo 3-4 h before angiography. GFR measured with [51Cr] EDTA-clearance decreased 24 hours after the angiography in the felodipine group from GFR 52.5 +/- 18.6 (mean +/- SD) to 46.2 +/- 16.5 ml/min (p < 0.01) and in the placebo group from 70.6 +/- 18.6 to 62.6 +/- 26.4 ml/min (p < 0.01). Serum creatinine increased significantly in the felodipine group from 128 +/- 61 to 139 +/- 67 mumol/l (p < 0.05) but not in the placebo group (122 +/- 54 to 125 +/- 51 mumol/l (ns)). The values of serum creatinine returned to baseline levels 7 days after angiography. During hydration there was only a slight reduction of GFR after angiography with iohexol. Thus, felodipine had no major effect on GFR after iohexol but, as baseline GFR tended to be lower in the felodipine pre-treated patients, it might have had some renoprotective effect in patients with more advanced renal failure.

Four patients reacting with acute renal failure despite using low osmolar contrast media are reported. They all had diabetic nephropathy and renal insufficiency. A retrospective study of 75 consecutive patients examined with angiography showed that 13% had both of these two risk factors.

The contrast media-induced renal effects of 3 different low osmolar contrast agents were prospectively evaluated with creatinine, beta-2-microglobulin, and urea in serum before and after femoral arteriography in 110 consecutive patients. Forty-two patients (38%) had at least one of the 2 major risk factors for contrast media-induced nephropathy; diabetes mellitus or renal dysfunction. Six patients (5%) had both risk factors. There were statistically significant increases of S-creatinine (6.5%, p < 0.001) and S-beta-2-microglobulin (7.4%, p < 0.001) but no increase of S-urea, in the total patient material. This effect was independent of preexaminatory renal function, the presence of diabetes mellitus and type of low osmolar contrast agent used in these patients who were properly hydrated before the examination. The amount of administered contrast medium did not correlate with the degree of contrast agent-induced renal function impairment.