Abstract 15918: Comparison of Synthetic Small-Calibre Biodegradable vs. Stable ePTFE Vascular Prosthesis After Long-term Implantation in the Rat Aorta
Purpose: Shelf-ready, synthetic, small-calibre vascular prostheses are needed in cardiovascular surgery. We assessed the long term results of synthetic, biodegradable small-calibre vascular grafts compared to stable ePTFE for aortic replacement in the rat.
Methods: 14 anaesthetised Sprague Dawley rats received an infrarenal aortic graft (8-biodegradable; 6-ePTFE) replacement (end-to-end; 2mm ID) and 6 sex/age-matched rats served as controls. Biodegradable grafts (polycaprolactone=PCL) were produced by random micro/nano-fibre (porosity 80%) electro-spinning. After a mean survival of 15.5±3.0 months, in vivo ultra-sonography and angiography were performed to assess patency (%), stenosis, aneurysm formation, and compliance (%/100mmHg). After explantation micro-CT, histology, immuno-histology, scanning electron microscopy (SEM) and morphometry were carried out for assessing (%): calcification, cellularity, intimal hyperplasia.
Results: Patency was 100% for PCL and 67% for ePTFE. No aneurysmal dilatation or stenoses were found in the PCL or ePTFE group. Compliance was significantly lower for ePTFE compared to PCL (5.7±0.7 vs. 8.2±1.0; p<0.01) but markedly reduced compared to native aortas of the controls (21.2±2.8). Despite better compliance calcification was higher in PCL than ePTFE grafts (70.8±21.2 vs. 54.3±12.5;p<0.03) and absent in controls. Histologically, low cellular ingrowth was found in ePTFE whereas PCL showed significantly higher homogenous cellularity producing an autologous extra-cellular matrix, replacing the degrading (65% molecular weight reduction) PCL scaffold (10.8±4.0 vs. 32.1±9.2;p<0.0001). Morphometry showed 100% neoendothelialisation for both grafts. Intimal hyperplasia thickness, length and area were higher in ePTFE compared to PCL. SEM revealed a confluent endothelial coverage for PCL grafts.
Conclusions: Synthetic, biodegradable small-calibre nano-fibre polycaprolactone grafts show better patency, compliance, endothelialisation and less intimal hyperplasia compared to the clinically used ePTFE grafts after long-term implantation in the rat aorta. Thus, such novel in situ tissue engineered grafts could become a promising option for cardiovascular revascularisation procedures.
- © 2011 by American Heart Association, Inc.