VASOMOTOR PROPERTIES OF RADIAL AND INTERN AL MAMMARY ARTERIES - APPLICATIONS IN CORONARY-BYPASS SURGERY

Satisfactory results were obtained with the radial artery used as a co nduit for coronary artery bypass. However, spasm of this conduit was o bserved. Human radial and internal mammary artery ring segments were s tudied in organ chambers. Potassium chloride, norepinephrine, serotoni n and thromboxane A2 mimetic were used to obtain dose-response curves, permitting assessment of force of contraction and sensitivity. The ra dial artery presents stronger contractions than the internal mammary a rtery. The two vessels have equal sensitivity to the vasoconstrictors used. These data emphasize the hyperreactivity of the radial artery an d the need for prevention of vasospasm when this vessel is use as a co nduit for coronary artery bypass.