Background: Coronary lesion angiographic morphology of the complex type is associated to enhanced susceptibility to ischemia during vasodilator adenosinergic stress testing and attributed to the reduced vasodilatory capacity of the damaged endothelium. Whether coronary lesion morphology can also influence the results of adrenergic pharmacologic stress test remains unknown. The aim of our study was to assess the relationship between coronary plaque morphology and dobutamine-atropine stress echocardiography (DASE) results.
Methods and results: We analyzed DASE (up to 40 mcg/kg/min plus atropine) and coronary angiography data of 42 patients with single vessel disease and no totally occluded vessel at angiography. 7 patients had angina, 35 had previous infarction. A diagnostic DASE was performed in all patients within 1-10 (mean 4.7 +/- 3.4) days before 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 the angiographic lesion morphology (Ambrose classification), 2 groups were identified: Group I, with simple lesion; Group II with complex lesion. The two groups were similar for number of patients (n = 21), age (I = 55 +/- 11 vs II = 53 +/- 7 years, p = ns), coronary stenosis severity expressed as % diameter reduction (I = 77 +/- 14 vs II = 78 +/- 15%, p = ns), presence of previous infarction (I = 17 vs II = 18 pts, p = ns). No difference was found in the prevalence of positivity between the two groups (I = 72 vs II = 62%, p = ns). The two groups achieved a similar peak dobutamine dose (I = 32 +/- 9 vs II = 33 +/- 9 mcg/kg/min, p = ns) and peak Wall Motion Score Index (I = 1.5 +/- 0.26 vs II = 1.45 +/- 0.28, p = ns).
Conclusions: In patients with non occlusive single vessel disease, coronary morphology of complex type is not associated with greater vulnerability to dobutamine induced ischemia.