IMPACT OF CHRONIC PATENCY OF INFARCT-RELATED CORONARY-ARTERY ON PREVALENCE OF MYOCARDIAL-ISCHEMIA DURING THE PHARMACOLOGICAL AND EXERCISE STRESS TEST

Background: Even late restoration of anterograde coronary flow may hav e beneficial effects on left ventricular function, electrophysiology, and survival in postinfarction patients. Hypothesis: The patency or oc clusion of an infarct-related coronary artery in the chronic phase may also be associated with myocardial ischemia provoked by pharmacologic and physiologic stress tests. Methods: High-dose dipyridamole echocar diography test (DET) (up to 0.84 mg/kg over 10 min), exercise electroc ardiography (EET), and coronary angiographic data in a group of 127 in -hospital patients who had survived an acute myocardial infarction wer e analysed. Patients who had only angiographic evidence of infarct-rel ated single artery disease (greater than or equal to 50% luminal diame ter reduction) and no previous revascularization were enrolled in the study. DET and EET were performed (DET in all, EET in 118 patients) wi thin 5 days before coronary angiography. Fifty-seven patients had tota l occluded infarct arteries (Group 1) with various degrees of collater al circulation (2.6 +/- 1.1 collateral score, by a 3 grading system), whereas the other 70 patients had patent infarct arteries (Group 2) wi th significant residual stenoses (82 +/- 13% diameter reduction). Resu lts: The prevalence of rest angina or effort angina and topography of the infarct-related coronary artery did not differ between the two gro ups (all p = NS). There were more patients with Q wave in Group 1 than in Group 2 (72 vs. 57%, p = 0.08) compared with non-Q wave infarction (Group 1 = 28 vs. Group 2 = 43%, p = 0.08). Ischemia in the infarct-r elated artery territory detected by DET (defined as new wall motion dy ssynergy or marked worsening of resting hypokinesia) was 61% in Group 1 and 41% in Group 2 (p = 0.025). EET was positive in 26 of 54 (48%) G roup 1 and in 21 of 64 (33%) Group 2 patients (p = 0.09). Conclusions: Patients with occluded infarct-related arteries have a higher prevale nce of ischemia during DET and EET regardless of the presence of colla teral flow. These results suggest that the presence of partial anterog rade flow in the prolonged period could have a favorable influence on prevalence of residual ischemia in these patients.