Functional Significance of Collateral Circulation in Patients with Total Coronary Occlusion

Functional significance of collateral circulation was evaluated in 125 patients with total coronary occlusion. Patients were classified into 2 groups: group 1, patients without myocardial infarction; and group 2, patients with a first transmural myocardial infarction occurring within 3 months of symptom onset. There was a higher prevalence of well-developed collaterals and multivessel disease in patients without myocardial infarction than in those with myocardial infarction. The left ventricular ejection fraction, left ventricular enddiastolic pressure, and segmental wall motion scores were significantly better in group 1 than group 2. Despite total coronary occlusion, 61% of group 1 had a normal resting electrocardiogram; however, 96% of patients who underwent treadmill tests proved positive. The proportions of well-developed collaterals in 3 groups, divided according to the internal between onset of myocardial infarction and angiography (within 1 day of operation, 2 to 14 days, or 15 days to 3 months), were 13%, 54%, and 60%. There were no significant differences in left ventricular ejection fraction, segmental wall motion score, and left ventricular enddiastolic pressure in myocardial infarction patients with poorly developed collaterals and well-developed collaterals. The degree of collateral development is higher in myocardial infarction with right coronary artery occlusion compared with that of left anterior descending artery occlusion, without regarding the dominancy or length. Collateral circulation can prevent myocardial ischemia and present myocardial function in a significant number of patients without infarction; however, it does not provide protection against exercise-induced myocardial ischemia in the majority of patients from group 1. Although well-developed collaterals are not usually present within 1 day after myocardial infarction, they are generally present after 2 weeks. Collateral vessels in patients with myocardial infarction have no beneficial effects on preserving myocardial function.