In Vitro Investigation of Antithrombotic Performance of Bivalirudin and Aspirin Dual-Modified Polycaprolactone Vascular Grafts

The clinical application of small-diameter vascular grafts (SDVGs; <6 mm) is limited by thrombosis and mediated by protein adsorption, platelet activation, and coagulation. To address this, we develop a dual-modified polycaprolactone (PCL) graft via covalent conjugation of bivalirudin (BV), a direct thrombin inhibitor, and aspirin (ASA), a cyclooxygenase-1 suppressor. Compared with pure PCL, the BV/ASA-modified PCL graft reduces bovine serum albumin adsorption by 35.7% and fibrinogen adsorption by 36.2%, while maintaining mechanical properties and structural integrity. Platelet adhesion, assessed by LDH viability, is reduced by 42.6%, and the blood clotting index (BCI) is increased by 67.4%, indicating enhanced anticoagulation. The modified surface enhances anticoagulation and exhibits cell viability above 80%, confirming non-toxicity. These in vitro results demonstrate that BV and ASA dual functionalization effectively improves the antithrombotic performance of PCL vascular grafts, suggesting its potential as a candidate for further preclinical evaluation in SDVG applications.