Experimental Research On Competitive Flow After Simulated Coronary Artery Bypass Grafting In Modified Langendorff-perfused Model

There are two parallel blood flows at the distal side of anastomosis after coronary artery bypass grafting (CABG):the original coronary artery and the bypassed graft. The flows come from these two paths will absolutely pass through the same anastomosis together, so there have to be a competitive flow (CF) between them. CF from original coronary artery influences the blood flow in bypassed graft from various degrees, or leads to failure of a surgery. The purpose of this study was to evaluate the influence of competitive flow caused by different degrees of stenosis (0,33%,66%, over 90%)on the blood flow in bypassed graft.MethodsChoose 12 experimental rabbits, intravenous anesthesia, intravenous heparinization, get rabbits'hearts, perfuse with 4℃cardioplegia to stop the heart, Got thoracic aorta to build modified Langendorff-perfused model. Adjust different degrees of stenosis, and measure the transient time blood flow of bypassed grafts in different degrees of stenosis with transient time flow measurement (TTFM).ResultsWith no significant difference on average perfuse pressure (group A: 74.15±2.41mmHg, group B:76.92±2.47mmHg, group C:75.54±2.40mmHg, group D:75.92±4.92mmHg,P> 0.05), under the circumstance of different degrees of stenosis (0,33%,66%, over 90%), transient time blood flow of bypassed grafts are: 16.69±2.66ml-min-1,18.77±2.83ml-min-1,26.46±2.54ml-min-1,30.46±2.79ml-min-1 separately. The transient time blood flow is of minimum when there is no stenosis, while which is of maximum when the stenosis is over 90%. With increase of the degrees of stenosis, the blood flow in group 0,33%,66% and over 90% is increasing significantly.ConclusionsDue to the existence of the flow comes from original coronary artery after coronary artery bypass grafting, there causes competitive flow. Competitive flow makes the blood flow in bypassed graft decrease in different degree. Meanwhile, with decrease of the degrees of stenosis in original coronary artery, competitive flow increases, and the blood flow in bypassed graft decreases.