Influence of Iodixanol-270 and Iopentol-150 on the microcirculation in man: influence of viscosity on capillary perfusion

Purpose, Material and Methods: The aim of this study was to investigate the influence of direct intraarterial application of the contrast agents Iodix anol-270 and Iopentol-150 on the capillary perfusion. This was accomplished through continuous recording of the capillary perfusion in the nailfold ca pillaries of the right hand before and after a bolus injection of 20 ml of contrast agent into the right axillary artery. Results: After injecting 20 ml of Iodixanol-270, which has a high viscosity compared to the plasma viscosity, a statistically significant decrease in the erythrocyte velocity of 60.8% from 0.439 +/- 0.273 mm/s to 0.172 +/- 0. 090 mm/s was observed already 10 s after the injection (p = 0.0001). The de creased velocity was maintained until the end of the observation period of 6 min. In contrast to this finding, no change in the erythrocyte velocity w as observed after injection of 20 ml of the low-viscous Iopentol-150 (p = 0 .1508). Conclusions: The erythrocyte velocity in cutaneous capillaries therefore st rongly depends on the viscosity of the contrast agent.