Integrated evaluation of relation between coronary lesion features and stress echocardiography results: The importance of coronary lesion morphology

OBJECTIVES The aim of this study was to analyze, in the same group of patie nts, the relationship between multiple variables of coronary lesion and res ults of exercise, dobutamine and dipyridamole stress echocardiography tests . BACKGROUND Integrated evaluation of the relation between stress echocardiog raphy results and angiographic variables should include not only the assess ment of stenosis severity but also evaluation of other quantitative and qua litative features of coronary stenosis. METHODS Study population consisted of 168 (138 male, 30 female, mean age 51 +/- 9 years) patients, on whom exercise (Bruce treadmill protocol), dobuta mine (up to 40 mcg/kg/min) and dipyridamole (0.84 mg/kg over 10 min) stress echocardiography tests were performed. Stress echocardiography test was co nsidered positive for myocardial ischemia when a new wall motion abnormalit y was observed. One-vessel coronary stenosis ranging from mild stenosis to complete obstruction of the vessel was present in 153 patients, and 15 pati ents had normal coronary arteries. The observed angiographic variables incl uded particular coronary vessel, stenosis location, the presence of collate rals, plaque morphology according to Ambrose classification, percent diamet er stenosis and obstruction diameter as assessed by quantitative coronary a rteriography. RESULTS Covariates significantly associated with the results of physical an d pharmacological stress tests included for all three stress modalities pre sence of collateral circulation, percent diameter stenosis and obstruction diameter, as well as lesion morphology (p < 0.05 for all, except collateral s for dobutamine stress test, p = 0.06). By stepwise multiple logistic regr ession analysis, the strongest predictor of the outcome of exercise echocar diography test was only percent diameter stenosis (p = 0.0002). However, bo th dobutamine and particularly dipyridamole stress echocardiography results were associated not only with stenosis severity-percent diameter stenosis (dobutamine, p = 0.04; dipyridamole, p = 0.003) but also, and even more str ongly, with lesion morphology (dobutamine, p = 0.006; dipyridamole, p = 0.0 009). As all of stress echocardiography results were significantly associat ed with percent diameter stenosis, the best angiographic cutoff in relation to the results of stress echocardiography test was: exercise, 54%; dobutam ine, 58% and dipyridamole, 60% (p < 0.05 vs, exercise). CONCLUSIONS Integrated evaluation of angiographic variables have shown that the results of dobutamine and dipyridamole stress echocardiography are not only influenced by stenosis severity but also, and even more importantly, by plaque morphology. The results of exercise stress echocardiography, alth ough separately influenced by plaque morphology, are predominantly influenc ed by stenosis severity, due to a stronger exercise capacity in provoking m yocardial ischemia in milder forms of coronary stenosis. (C) 1999 by the Am erican College of Cardiology.