Background: It has been shown that suboptimal preparation of a vein graft prior to its insertion results in immediate morphological and functional damage to both endothelial cells and underlying smooth muscle cells. This study examines the influence of perioperative balloon catheter injury on the subsequent development of intimal hyperplasia and vasomotor function in experimental vein grafts. Methods: Twenty New Zealand White rabbits had a carotid vein bypass graft performed: 10 were controls and 10 had a balloon catheter passed through their lumen which resulted in deendothelialization and intramural injury (4Fr Fogarty catheter, 0.6-0.75 ml H2O inflation, three passes). All grafts were harvested after 28 days for either morphology (n = 6) or functional studies (n = 4; four 5-mm rings/graft). Results: Perioperative balloon injury of the vein graft resulted in a 23% increase in the intimal thickness (102 ± 7 μm vs 83 ± 2 μm, deendothelialized vs control; mean ± SEM, P < 0.01) and a 67% increase in medial thickness (144 ± 19 μm vs 86 ± 8 μm; mean ± SEM, P < 0.01) of the vein grafts. Both the sensitivity and maximal contraction of the responses elicited by norepinephrine, serotonin, and bradykinin were increased in the deendothelialized group compared to controls. Conclusion: Perioperative denuding balloon injury of the vein graft results in the increased development of intimal hyperplasia with an overall enhanced contractility. This study demonstrates the long-term structural and functional effects of perioperative balloon catheter injury on vein grafts that may contribute to decreased graft patency.
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