Effect of endothelial dysfunction on regional perfusion in myocardial territories supplied by normal and diseased vessels in patients with coronary artery disease

Background, Endothelium-dependent regulation of coronary tone affects both conduit and resistance coronary arteries. However, little is known about the usefulness of myocardial perfusion imaging in evaluating coronary endothelial function. We evaluated the relation between invasive angiographic measurements of coronary vasomotion in response to intracoronary acetylcholine and the presence of regional perfusion abnormalities assessed by technetium 99m sestamibi imaging. Methods and Results. We studied 11 patients (9 men and 2 women) with suspected coronary artery disease (48 +/- 8 years, mean +/- standard deviation). We used quantitative coronary angiography to delineate the vasomotor response to increasing doses of acetylcholine given intracoronary, Regional myocardial perfusion was assessed by planar Tc-99m sestamibi imaging during and after the administration of acetylcholine. In the 11 patients, 23 coronary artery territories were analyzed: 13 were angiographically normal, and 10 showed varying degrees of luminal narrowing. Four (31%) of 13 angiographically normal coronary arteries had a positive vasomotor response to acetylcholine (greater than or equal to 20% reduction in luminal diameter) that was associated with a regional perfusion defect. Acetylcholine induced a positive vasomotor response, which was also associated with a regional perfusion defect in 1 of 3 coronary arteries with stenoses of intermediate severity (50% to 69%), Likewise, acetylcholine induced a positive vasomotor response in 6 of 7 coronary arteries with significant luminal narrowing (greater than or equal to 70%), 5 of which showed a corresponding regional perfusion defect. Conclusions. In patients with coronary artery disease, noninvasive measurements of regional myocardial perfusion by Tc-99m sestamibi correlate well with invasive measurements of coronary endothelial function. These findings may have implications for monitoring the effects of interventions designed to improve endothelial function and microvascular function in patients with coronary artery disease.