Matching the diameter of ePTFE bypass prosthesis with a native artery improves neoendothelialization

The undersizing of the bypass graft diameter compared to native artery changes blood flow characteristics and velocity which may affect conduit neo-endothelialization, intimal hyperplasia reaction and patency. The aim of this study was to evaluate conduit neoendothelialization, intimal hyperplasia reaction and patency results between undersized and matched ePTFE grafts.

In 16 male Sprague-Dawley rats, undersized (1-mm internal diameter) and matched (2-mm internal diameter) ePTFE grafts were anastomosed end-to-end in the infrarenal abdominal aorta. Blood flow volume per minute was measured and wall shear stress was calculated for each group. After 3 weeks of follow-up, angiography was performed via the left carotid artery just before sacrifice. Conduit neoendothelialization and intimal hyperplasia reaction were measured by computer-assisted morphometry.

Wall shear stress was 8 times higher for the undersized group (840.56 vs. 105.07 mPa). Three weeks after implantation, conduit neoendothelialization was better in matched grafts compared to undersized grafts (441 vs. 574 microm, p = 0.008). Intimal hyperplasia reaction was similar for both groups (8.7 vs. 6.7 microm(2)/microm for undersized and matched grafts, respectively). Patency rate was 7/8 for undersized and 8/8 for matched ePTFE grafts.

Although the graft patency and the intimal hyperplasia reaction were not different between the two groups after 3 weeks, matched grafts had a significantly better endothelialization compared to undersized grafts. This short-term beneficial effect may influence long-term patency results.