The role of vein patch in distal anastomotic intimal hyperplasia: an histologic characterization.

Comparison of the cumulative patency of four types of Polytetrafluoroethylene (PTFE) grafts with and without a vein patch at the distal anastomosis in one hundred and twenty ilio-femoral by-passes of sixty dogs revealed: (i) Vein patch improved patency in standard PTFE graft 10/16 (62.5%) versus without a vein patch 6/16 (27.5%) (p < 0.1). (ii) The less rigid thin wall PTFE graft did not benefit from vein patching 22/45 (48.8%) versus those without a vein patch 28/45 (62.2%) (p < 0.2). (iii) DAIH was present in all grafts with and without a vein patch and occurred exclusively at the heel and the toe of the graft plus the floor of the host artery three months after implantation. (iv) An organized fibrocellular multilamination characterized the cytoarchitecture of the DAIH. (v) A process of gradual cell transformation and orientation occurred in DAIH that spanned between the graft and the lumen. Vein patch at the distal anastomosis improved the patency of the more rigid standard PTFE grafts, and adversely affected the less rigid thin walled PTFE graft in dogs. The formation and distribution of DAIH was not altered by a vein patch at the distal anastomosis of PTFE grafts.