Functional significance of coronary collateral vessels in patients with previous ‘Q’ wave infarction: relation to aneurysm, left ventricular end diastolic pressure and ejection fraction

Abstract

The importance of coronary collateral circulation in relation to the left ventricular function, aneurysm formation and size was investigated in 100 patients with previous ‘Q’ wave myocardial infarction who underwent coronary angiography. Aneurysms were present in 20% of patients. The majority of these (80%) patients had severe or total occlusion of the left anterior descending artery. Thirty four percent of patients without aneurysm had significant collaterals whereas 25% of patients with aneurysms had collaterals ( P > 0.05). However, the size of the aneurysm was smaller when adequate collateral circulation was present (Collateral Index 2 or above). The incidence of hypertension and diabetes was similar in both groups. Collateral circulation was more frequently seen in the anterior (60%) as compared to inferior myocardial infarction (40%), but Collateral Index was higher in right coronary artery disease. The number of patients with an elevated left ventricular end-diastolic pressure (> 12) or poor ejection fraction was similar in the two groups with and without collaterals. Thus, there was no beneficial effect of collateral circulation on left ventricular function. The incidence of aneurysm was not significantly lower, although the size of the aneurysm was significantly smaller in the presence of collateral circulation.