Is contrast-related vasodilatation after intra-coronary iodixanol and iopromide in vivo endothelium-dependent?

AIMS Goals of the study were the assessment of the correlation between flow-dependent and contrast-related vasodilatation, comparison of iodixanol to iopromide and evaluation of the impact of plaque on vasodilatation in coronary arteries. METHODS AND RESULTS A controlled randomized paired cross-over comparison between iodixanol (320mgI.ml(-1)) and iopromide (300mgI.ml(-1)) was performed in 10 consecutive patients. Vessel area (Visions Five-64 F/X intra-vascular ultrasound-catheter, Endosonics and blood flow velocity measurements (0.014inches Doppler guide wire, Cardiometrics were recorded simultaneously at an identical position, at baseline, after i.c. bolus injection of 10ml physiologic saline (flow-dependent vasodilatation), and after application of contrast agent 1 and contrast agent 2 as randomized. The action of iodixanol and iopromide on the vascular wall did not differ and was equal to local flow-dependent vasodilatation induced by a saline bolus (correlation 0.95-- 0.98). The increase in local luminal area after injection of saline, iodixanol and iopromide in morphologically normal vessels (approximately 2.5mm(2)) was absent in atherosclerotic segments. Both contrast agents and saline demonstrated a nearly identical flow increase. CONCLUSION If iodixanol or iopromide are used as contrast agents, contrast-related vessel area increase in vivo seems to be endothelium-dependent.