Relation between exercise and dobutamine stress-induced wall motion abnormalities and severity and location of stenosis in single-vessel coronary artery disease

Background Quantitative coronary angiography has been shown to allow accura te assessment of coronary stenosis. Exercise and dobutamine stress echocard iography both are established methods for assessing the functional importan ce of coronary stenosis. The relation, however, between exercise and dobuta mine stress-induced wall motion abnormalities and the severity and location of stenosis remains controversial. Methods and Results Thirty patients with single-vessel coronary artery dise ase with greater than or equal to 50% minimal luminal reduction and stable angina participated in the study. Severity of coronary artery stenosis was assessed by means of computed angiography. During peak exercise echocardiog raphy 23 patients had wall motion abnormalities and 7 did not. A positive t est result was associated with severity of stenosis greater than or equal t o 80% for 65% of stenoses (P < .05 versus severity of stenosis <80%) and wi th a proximal location of 94% of stenoses (P < .01 versus middle and distal stenoses). A significant correlation was found between area of stenosis an d difference in wall motion score between rest and peak exercise (r = 0.53, P < .01). The proportion of positive exercise stress was greater among ste noses with severity <80% (62% versus 46% dobutamine stress, P < .05). Durin g dobutamine stress echocardiography 18 patients had wall motion abnormalit ies and 12 patients did not. A positive test result was associated with sev erity of stenosis greater than or equal to 80% in 72% of stenoses (P < .05 versus severity of stenosis <80%) and with a proximal location in 81% of st enoses (P < .01 versus middle and distal stenoses). A weak correlation was found between area of stenosis and difference in wall motion score between rest and peak dobutamine str ess (r = 0.37, P < .05). Conclusions Among patients with single-vessel coronary artery disease, posi tive stress echocardiographic test results usually are associated with prox imal greater than or equal to 80% stenosis. Patients with <80% stenoses are more likely to have a positive exercise stress test result than a positive dobutamine stress test result.