Abstract 15827: Impact of Harvesting Techniques on Coronary Bypass Conduit Endothelial Cells and Collagen Exposure Using Ligand-Based Targeting

Abstract

Background: Coronary bypass is a mainstay therapy for coronary artery disease (CAD). Conduit options include the internal thoracic artery (ITA), radial artery (RA), and great saphenous vein (GSV). Long-term patency rates are >95% (ITA), 75% (RA), and 50% (GSV) at 10 years. The impact of harvesting techniques on endothelial cells is not well understood. Hypothesis: We hypothesized that observed differences in patency rates could potentially be explained by differences in endothelial cell response to a harvesting technique. Aims: 1) Determine degree of endothelial cell damage between different conduits and various harvesting techniques. 2) Assess ability of a specific collagen binding peptide SILY to bind to exposed collagen in GSV. Methods: De-identified human graft samples of ITA, RA, and GSV were collected and analyzed from September 2021 through February 2023. The harvesting techniques were open for ITA and GSV, endoscopic for RA, and endoscopic for GSV. The samples were fixed and stained with anti-CD31 antibody to identify endothelial cells on the luminal surface with enface imaging. Binding of SILY peptide to GSV was tested at different concentrations and incubation times. Results: 51 specimens were obtained, 18 open ITA, 10 open GSV, 18 endoscopic GSV, and 5 endoscopic RA. Luminal surface covered by endothelial cells was 86.6±8.1% for ITA, 76.7±14.7% for RA, 58.3±14.0% for endoscopic GSV, and 59.0±5.5% for open GSV. Endothelial coverage area on ITA samples was significantly higher compared to endoscopic GSV, open GSV, and RA (p<0.05). Endothelial coverage area on RA samples was significantly higher compared to endoscopic GSV and open GSV (p<0.05). There was no statistically significant difference in endothelial coverage area between open and endoscopic GSV (p=0.43). Testing of SILY binding revealed colocalization with collagen fibers on luminal surface of GSV samples. Conclusions: Microscopic examination showed greatest preservation of endothelial cells on ITA followed by RA and GSV with no difference between open and endoscopic GSV. Targeting of exposed collagen with SILY in the areas of damaged endothelium might be a good approach for therapeutics in the future.