Opening of Coronary Collaterals by Repeated Brief Coronary Occlusions in Conscious Dogs

The collateral blood flow and regional myocardial function during a one- minute coronary occlusion were compared before and after multiple one-minute coronary occlusions. After repeated coronary occlusions, the collateral blood flow velocity increased significantly from 0.7 ± 0.1 (SE) to 2.0 ± 0.2 cm/sec (p < 0.05), and the blood flow debt repayment decreased from 326±26% to 189 ± 12 % (p < 0.05). The systolic segment shortening in the collateral depend ent zone improved slightly. Thus, the native coronary collateral vessels open in response to a repeated ischemic stimulus.