Angiographic Evaluation of Coronary Collateral Circulation Patterns in Patients with Coronary Artery Disease Requiring Surgical Revascularization

Background: Coronary artery disease is highly prevalent in India with onset at a younger age. Coronary collateral circulation plays an important role in protecting myocardium from infarction, preserving myocardial contractility and reducing cardiovascular events. The objective of the present study is to assess the pattern of coronary collateral circulation in known cases of coronary artery disease with correlation to age, gender and degree of occlusion. Method: This is a retrospective study done on 200 preoperative angiograms in patients with coronary artery disease. Patients were classified according to age, gender and degree of obstruction in major vessels. Collateral vessels were graded according to the Rentrop classification. Patients with collaterals were further classified on the basis of intensity of collaterals into 3 groups: those with no collateralization (Grade 0), poor collateralization (Grade 1) and those with adequate collateralization (Grade 2 - 3). Results: Collateral development was seen in 175 (87.5%) angiograms. Collaterals were seen in 66% for left anterior descending (LAD), 44.5% for circumflex (LCx) and 70.5% for right coronary artery (RCA) block. Coronary collaterals between LAD and posterior descending artery (PDA) via ventricular septal branches were most common pathways. Adequate collaterals were seen in 53% males and 29.3% females (p 50 years and in 32% in cases with age p = 0.014) and 54.8% cases with arterial obstruction > 90%. Conclusion: Collateral circulation between LAD and PDA via ventricular septal branches is the commonest pathway to develop. Although prevalence of LAD occlusion is higher but collaterals develop more for RCA occlusion. Adequate collaterals develop more frequently in males, cases above 50 years and in vessels with >90% obstruction.