Quantifying Thrombogenicity: A Bioanalytical Protocol for the Absorbance-Based Assessment of Vascular Implants with Plasma

Assessing thrombogenicity is crucial for evaluating biomaterials, especially those that interface with flowing blood, such as cardiovascular implants, including vascular stents, grafts, and stent-grafts. To standardize thrombogenicity assessments, we use human plasma and quantify the light absorbance associated with the biomaterial. For this evaluation, various tubular vascular implants from leading brands-such as bare-metal stents, drug-eluting stents, vascular grafts, and stent-grafts-are longitudinally sectioned into small pieces and placed in a low-adhesion 96-well plate. Using either platelet-rich plasma (PRP) or platelet-poor plasma (PPP), we measure the absorbance of light passing through the plate over an hour and plot the resulting curve. This method quantifies the thrombogenicity of a biomaterial under controlled conditions. Key factors examined include anticoagulants, platelet presence, and surface-coating molecules to assess their impact on thrombogenicity. Using this simple, reproducible protocol, we demonstrated (a) the relative efficacy of various anticoagulants in thrombogenicity assessments, and (b) the effectiveness of vascular coating molecules in reducing thrombogenicity on stents. This streamlined approach offers valuable insights for optimizing biomaterial performance in vascular implants. Unlike conventional clotting assays, which focus on standardized blood clotting mechanisms, this assay is tailored to evaluate biomaterials and external parameters influencing thrombogenicity. Key features • This protocol is a static, in vitro, quantitative assessment of thrombogenicity for both novel and commercial vascular biomaterials with flat or tubular geometries. • Thrombogenicity is assessed by evaluating the opaqueness of platelet-rich or platelet-poor plasma over time to measure fibrin formation. • Various anticoagulants such as sodium citrate, sodium ethylenediaminetetraacetic acid, and sodium heparin are compared to evaluate the efficacy of the protocol. • This protocol compares the thrombogenicity of various commercial stents, grafts, and stent-graft hybrids, as well as novel molecular coatings.