Effects of calcitonin gene-related peptide on normal and atheromatous vessels and on resistance vessels in the coronary circulation in humans.

BACKGROUNDCalcitonin gene-related peptide (CGRP) is a potent dilator of normal epicardial coronary vessels in humans, but its effects on myocardial blood flow and atheromatous coronary vessel diameter are unknown.METHODS AND RESULTSSeven patients were entered for study of the effects of CGRP on coronary blood flow and 13 for the comparison of its effects on normal and atheromatous coronary arteries. In the first seven patients, left anterior descending artery (LAD) diameter at an angiographically normal site, coronary sinus oxygen saturation (CSO2S), systemic blood pressure, and heart rate were measured during intracoronary infusion of increasing concentrations of CGRP (up to 200 ng/ml at 2 ml/min) followed by intracoronary adenosine (0.267 micrograms/ml at 2 ml/min) and finally intracoronary glyceryl trinitrate (GTN) (5 micrograms/ml at 2 ml/min). CGRP dilated the normal segment of the LAD by 22.6 +/- 8% (mean +/- 95% confidence interval), p less than 0.001, with only a small increase in CSO2S from 40.1 ...