COMPLEX CORONARY-ARTERY LESION MORPHOLOGY INFLUENCES RESULTS OF STRESS ECHOCARDIOGRAPHY

Background The likelihood of a positive response with dipyridamole stress echocardiography (DSE) is directly related to the extent and severity of angiographically assessed coronary artery disease. Whether coronary lesion morphology-a known predictor of adverse cardiac events-may also modulate stress echo results remains unknown. The objective of our study was to assess the relation between stenosis lesion morphology and stress echocardiographic results. Methods and Results High-dose (up to 0.84 mg/kg over 10 minutes) DSE and coronary angiographic data of 68 in-hospital patients (39 with stable angina, 29 with angina at rest) with nonoccluding, single-vessel disease at angiography and no previous myocardial infarction were analyzed. DSE was performed in all patients within 3 days of coronary angiography. An angiographic lesion was considered complex when irregular borders and/or intraluminal lucencies suggestive of ulcer and/or thrombus were present. According to angiographic lesion morphology, two groups were identified: group 1, with simple coronary lesions, and group 2, with complex coronary lesions. The two groups were matched for number of patients (n=34 in each group), age (group 1, 59+/-9 versus group 2, 59+/-10 years, P=NS), and coronary artery stenosis severity by quantitative coronary angiography (group 1, 60+/-7% versus group 2, 58+/-6% diameter reduction, P=NS). The sensitivity of DSE was lower in patients of group 1 when compared with group 2 (53% versus 85%, P<.001). Among positive DSE, the low-dose (0.56 mg/kg over 4 minutes) positivity was less frequent in group 1 than in group 2 patients (17% versus 62%, P<.01). Exercise ECG was completed in 66 patients, and it was positive (>.1 mV ST-segment shift from baseline) in 20 out of 33 group 1 and in 22 out of 33 group 2 patients (61% versus 67%, P=NS). The peak rate-pressure product tended to be higher in group 1 than in group 2 patients (257+/-52 versus 240+/-64 mm HgXbeats per minuteX10(2), P=NS). Conclusions In patients with single-vessel disease without coronary occlusion or previous myocardial infarction, coronary lesion morphology of the complex type is associated with a higher DSE sensitivity and with a greater prevalence of low-dose, positive responses. Presence of irregular plaque contours, not only plaque geometry, is important in modulating stress responses in the presence of angiographically assessed coronary artery disease.