CORONARY-ARTERY VASOMOTION IN CARDIAC TRANSPLANT PATIENTS WITH NORMALCORONARY ANGIOGRAMS

In 18 consecutive transplant patients with normal coronary angiograms and without calcium blocker therapy, and in 20 controls, we measured t he diameters of the left anterior descending artery using quantitative coronary angiography. Measurements were effected on the frames record ed 5 min or more after intravenous administration of 0.4 mg methylergo metrine, and 2 min after subsequent 2 mg bolus intracoronary isosorbid e dinitrate administration. The arterial vasodilatory capacity was def ined as the ratio of the difference of the largest and smallest arteri al diameters and the smallest diameter. We observed normal vasoconstri ction of the different coronary arterial segments. Coronary arterial d iameter decrease from basal state was about 8% and was more pronounced at the distal segments of the left anterior descending artery. There was no difference of vasodilatory capacity between transplant patients and controls for the proximal and middle portion of the left anterior descending artery, while the difference was highly significant for th e distal portion. In eight patients, the decrease of the vasodilatory capacity was beyond the lower limit of the normal range of values. The significance of those quantitative angiographic abnormalities is stil l unproven. They could be due to early vasomotor capacity blunting aft er transplantation and to late structural alterations of distal corona ry vessels in cardiac transplant patients.