Complex Coronary Artery Lesion Morphology Influences Results of Stress Echocardiography

Abstract

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 Hg×beats per minute×10 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.