Pathways and Functional Significance of the Coronary Collateral Circulation

Two hundred coronary arteriograms and left ventriculograms of patients having significant coronary artery disease were reviewed. Collateral circulation was seen only when the degree of arterial narrowing exceeded 90%. Ten different collateral pathways were noted in patients having right coronary obstruction; seven different pathways were noted in left anterior descending obstruction; five different pathways were noted in left circumflex obstruction. The role of collateral circulation in preserving myocardial function was assessed by comparing regional left ventricular contractility in 86 instances of total arterial occlusion and adequate collateral circulation with that in 80 instances of total arterial occlusion and inadequate collateral circulation. Among the group with adequate collaterals, regional left ventricular contraction was normal in 43%, mildly impaired (hypokinetic) in 52% and severely impaired (akinetic or dyskinetic) in only 5%. Among the group lacking adequate collaterals, regional contraction was normal in 11%, mildly impaired in 16% and severely impaired in 73%. Chi square analysis reveals that the difference between the two groups is significant at the .01 level. These data indicate that collateral circulation plays an important role in preserving myocardial contractility in patients with coronary artery disease.