Collateral circulation in total occlusion of the left anterior descending or right coronary artery

Abstract

The functional significance of the collateral circulation was evaluated in 125 patients with total coronary occlusion. Patients were classified into two groups. Group 1:patients with angina pectoris (AP), Group 2:patients with a first transmural myocardial infarction (MI) within 3 months of the symptom onset. Clinical variables, resting and exercise electrocardiogram (EKG) were analyzed with angiographic findings. Collateral fillings were graded from 0 to 3: 0 = none; 1 = filling of side branches only; 2 = partial filling of the epicardial segment; 3 = complete filling of epicardial segment. The wall motion of each segment was scored from 1 to 5: 1 = normal; 2 = mild to moderate hypokinesia; 3 = severe hypokinesia; 4 = akinesia; 5 = dyskinesia. The scores of the 5 segments were added to yield a total LV score. There was a higher prevalence of good collaterals and multi-vessel disease in patients with AP than in those with MI (83% vs 53%, 54% vs 30%, respectively, p < 0.005). The left ventricular ejection fraction (LVEF), left ventricular end-diastolic pressure (LVEDP) and segmental wall motion score were significantly better in patients with AP than in those with MI (68.9 +/- 13.4%, vs 50.5 +/- 12.6%, 15.0 +/- 7.3 mmHg vs 20.3 +/- 8.8 mmHg, 6.5 +/- 2.2 vs 9.6 +/- 2.3, respectively, p < 0.05). In spite of total coronary occlusion, 61% of AP patients had normal resting EKG but (96% of AP patients who underwent treadmill test proved positive. The proportions of well-developed collaterals in 3 groups divided according to the interval between onset of MI and angiography (within 1 day, 2 to 14 days, 15 days to 3 months) were 13%, 54% and 60%. There were no significant differences in LVEF, segmental wall motion score and LVEDP in MI patients with poorly-developed collaterals and well-developed collaterals (49.1 +/- 15.7% vs 46.4 +/- 10.1%, 11.1 +/- 2.2 vs 10.9 +/- 1.4 and 24.3 +/- 9.7 mmHg vs 20.3 +/- 7.0 mmHg, p = NS). The degree of collateral development was higher in MI with right coronary artery occlusion compared with that of left anterior descending artery occlusion (1.1 +/- 1.0 vs 2.0 +/- 1.0, p < 0.05). In conclusion, collateral circulation can prevent myocardial ischemia and preserve myocardial function in a significant number of patients with AP but do not provide protection against exercise-induced myocardial ischemia in the majority of patients with AP.(ABSTRACT TRUNCATED AT 400 WORDS)