WALL SHEAR AND CIRCUMFERENTIAL STRESS CHANGES IN A PORCINE DOUBLE-LAYER VEIN GRAFT

摘要

This study aimed to evaluate short-term changes of wall shear stress and circumferentialnstress in a self-designed double-layer vein graft in a porcine vein graft model. In thisnstudy, left and right hind femoral arteries of 40 white pigs were randomly divided into annexperimental group (double-layer vein graft) and a control group (single-layer vein graft).nAt one hour and then at one, two and four weeks after venous bypass grafting, sets of tennanimals underwent Doppler-ultrasonic and electromagnetic flowmeter examinations toncalculate wall shear stress in middle sections of the vein grafts. Then, the vein grafts werenexcised and subjected to mechanical tests to assess the circumferential stress. As a result,nthe double-layer vein grafts showed an increase in wall shear stress by 43.5% comparednwith the control group at one hour after venous bypass grafting. With time wall shearnstress gradually increased, the intimal circumferential stress gradually decreased in thentwo groups. Intimal circumferential stress in the experimental group was significantlynlower than that in the control group at each observational time-point. Hence, the doublelayernsupport of the vein graft may have contributed towards a rise in wall shear stressnand reduction in circumferential stress in the true vein graft over the four-week periodnafter venous bypass grafting, and thus conferring some protection to the true vein graft.