EFFECT OF ISOLATED PROXIMAL CORONARY STENOTIC LESIONS ON DISTAL MYOCARDIAL PERFUSION DURING EXERCISE

[摘要] This study tested the hypothesis that the absolute dimension of a coronary stenotic lesion is a more important determinant of its hemodynamic effect on regional myocardial perfusion during exercise than is relative percent stenosis. In 31 patients with an isolated lesion of the left anterior descending coronary artery, regional myocardial perfusion was determined from thallium-201 scans recorded in the left anterior oblique projection after symptom-limited treadmill exercise. Thallium-201 uptake in the distribution of the left anterior descending coronary artery was expressed as a ratio of thallium-201 uptake in the left circumflex artery distribution. Percent area stenosis, minimal cross-sectional area and mean diameter of each stenotic lesion were measured by computer-assisted cinevideodensitometric analysis of projected coronary arteriograms digitized in a 512 .+-. 512 pixel matrix with 256 gray levels. Thallium-201 uptake in the left anterior descending coronary artery distribution, expressed as a ratio, correlated poorly (r = 0.65) with relative percent stenosis, but correlated significantly (r = 0.83; p < 0.05) with absolute lesion area. For all 16 patients with reduced regional perfusion in the left anterior descending coronary artery distribution during exercise, lesion cross-sectional area was < 1.8 mm2 (mean 0.9 .+-. 0.6); for 13 of the 15 patients with normal distal perfusion, the area of the stenotic lesion was > 1.8 mm2 (mean 2.7 .+-. 0.7; p < 0.001). Percent coronary stenosis failed to predict flow-limiting lesions. Thus, exercise-induced thallium-201 perfusion defects correlate better with absolute dimensions of a coronary stenotic lesion than with relative coronary stenosis expressed as a percent, which is a less precise predictor of the hemodynamic effects of a stenotic lesion.

[发布日期] 1988-07-01