Main findings
Histological examination of prepared vein samples demonstrated an increase in lumen diameter and decrease in wall thickness after high-pressure distension of veins without a pedicle. This is consistent with nonelastic distension of the veins at high pressure and has been shown to result in injury to the vein endothelium and medial layer. By contrast, the veins with a pedicle were protected, implying less overdistension and by implication less damage. The increases in wall thickness and values obtained at 12 months are consistent with other recent studies.[16, 25] Low pressure veins without a pedicle tended to suffer less wall thickening than high pressure ones, consistent with a reduction in neointima formation. Pedicled grafts showed similar thickening irrespective of distension pressure. Importantly, low pressure grafts without a pedicle had similar wall thicknesses to pedicled grafts at either pressure. Low pressure grafts without a pedicle were associated with fewer post-operative complications and less pain compared to pedicled grafts. Our results imply that the simpler, less complicated low-pressure vein distension protocol is at least as effective at reducing wall thickening as vein harvesting with a fat pedicle.