THE COLLATERAL CIRCULATION IN ACUTE MYOCARDIAL-ISCHEMIA

Recent studies in patients, receiving trombolytic therapy for acute myocardial infarction, have indicated that the presence of collateral vessels is important for both infarct size reduction and prevention of aneurysm formation. The collateral vascular supply to the myocardium at risk exerts a beneficial effect on left ventricular function that is comparable to the effect of successful trombolysis. In spite of these important clinical observations, there is limited information regarding factors influencing collateral vascular development. In patients with single vessel disease and normal left ventricular function, spontaneously visible and recruitable collateral vesels are particularly related to the combination of percent diameter stenosis (greater-than-or-equal-to 70%) and duration of angina (greater-than-or-equal-to 3 months). It is expected, that in a few years more data will be available regarding the functional significance of collateral circulation in obstructive coronary artery disease, as other techniques than coronary angiography are currently under investigation.