Diagnostic Methods Coronary Artery Disease

S The results of previous work from this laboratory have shown a poor correlation between percent stenosis (determined visually with calipers) and the coronary reactive hyperemic response (an index of maximal coronary vasodilator capacity) determined during cardiac surgery. This study was performed to determine whether other parameters of lesion severity could predict the reactive hyperemic response and thus the hemodynamic significance of coronary stenoses in human beings. Twenty-three patients with lesions in the proximal left anterior descending coronary artery were studied. To account for differences in expected vessel size, patients with large diagonal branches (greater than one-half the diameter of the left anterior descending artery) arising before the lesion were excluded. Computer-assisted quantitative coronary angiography was used to measure percent diameter stenosis, percent area stenosis, and minimal stenosis cross-sectional area. With a pulsed Doppler velocity probe, reactive hyperemic responses were recorded after a 20 sec coronary occlusion of the left anterior descending artery at cardiac surgery before cardiopulmonary bypass and were quantified by the peak/resting velocity ratio (normal greater than 3.5:1). Percent area stenosis ranged from 7% to 54% for vessels with normal reactive hyperemic responses and from 27% to 94% for vessels with abnormal reactive hyperemic responses. With both percent diameter stenosis and percent area stenosis there was substantial overlap between vessels with normal and abnormal reactive hyperemic responses. In contrast, nine of nine vessels with normal reactive hyperemic responses had lesion minimal crosssectional areas of greater than 3.5 mm2 and 13 of 14 vessels with abnormal reactive hyperemic responses had minimal cross-sectional areas of less than 3.5 mm2. We conclude that (1) the hemodynamic significance of a coronary stenosis in patients with coronary atherosclerosis is not accurately predicted by percent area or percent diameter stenosis, even when the angiograms are analyzed with quantitative coronary angiography and (2) minimal cross-sectional area can identify vessels with normal vs abnormal reactive hyperemic responses and thus can be used to predict the hemodynamic significance of stenosis of the proximal left anterior descending coronary artery. Circulation 69, No. 6, 1111-1119, 1984. CORONARY ARTERIOGRAPHY is widely accepted as a useful clinical and investigative tool. Despite this, there exist substantial data suggesting that the traditional methods of analysis of the coronary arteriogram are inadequate, and several investigators have shown that there is considerable intraobserver and interobFrom the University of Iowa Cardiovascular Center and the Veterans Administration Hospital, Iowa City. Supported by NIH grants HL20827 and IROI HL29976-01. Address for correspondence: David G. Harrison, M.D., Cardiovascular Division, Department of Internal Medicine, University of Iowa Hospitals, Iowa City, IA 52242. Received March 7, 1983; revision accepted Feb. 16, 1984. Dr. Harrison is the recipient of Clinical Investigator Award 1K8NL01046-01 from the NHLBI. Vol. 69, No. 6, June 1984 server variability. 1-3 The results of postmortem studies have shown a poor correlation between angiographic findings and anatomic findings. 6Although there is little controversy regarding the usefulness of coronary arteriography in separating patients with entirely normal coronary arteries from those with severe highgrade obstructions (greater than 95% diameter stenosis), the potential of the coronary arteriogram in predicting the hemodynamic significance of lesions that angiographically appear mild to moderate remains controversial. In the experimental animal the physiologic significance of artificially produced arterial stenoses has been extensively studied.7-9 Gould et al.9 produced varying 1111 by gest on July 5, 2017 http://ciajournals.org/ D ow nladed from