[Changes in the blood and plasma volumes during diagnostic angiocardiography. Differences between high- and low-osmolality contrast media].

Changes in blood and plasma volumes were investigated in the course of diagnostic cardiac catheterizations, comparing the effect of a high and a low osmolar contrast medium in 30 patients (5 women and 25 men; mean age 53 [19-76] years) with coronary heart disease (n = 27) or valvular defect (n = 3). Using a randomized, double-blind protocol 15 patients received amidotrizoic acid (2.1 osmol/kg; mean dosage 166 +/- 68 or 2.2 +/- 1.1 ml/kg), while 15 patients received iopamidol (0.8 osmol/kg; mean dosage 154 +/- 78 ml or 2.1 +/- 1.0 ml/kg). The indocyanine-green method and the haematocrit were used to measure blood and plasma volumes immediately before and after the angiocardiography. Blood volume after amidotrizoic acid injection increased by a mean of 4.9% (228 +/- 242 ml) and by 0.4% (17 +/- 197 ml) after iopamidol (P less than 0.05). Plasma volume increased by a mean of 11.8% (331 +/- 150 ml) after amidotrizoic acid and 5.7% (157 +/- 97 ml) after iopamidol (P less than 0.01). The increase in plasma volume correlated with the dose of contrast medium: 2 ml per ml amidotrizoic acid (r = 0.93) and 1 ml per ml iopamidol (r = 0.82).--During angiocardiography blood and plasma volume may increase by up to 500 ml, an increase which depends not only on dosage but also on the osmolality of the injected contrast medium.