Endpoint Attachment of Unfractionated vs. Low Molecular Weight Heparin: A Comparative Study on Blood Compatibility

Stephan Harm ^1* Jennifer Zottl ¹ Claudia Schildböck ¹ Christoph Bauer ¹ Denisa Cont ^1,2 Viktoria Weber ¹

• ¹ University for Continuing Education Krems, Krems an der Donau, Austria
• ² Karl Landsteiner University of Health Sciences, Krems an der Donau, Lower Austria, Austria

Blood compatibility is crucial for medical materials to avoid adverse reactions. Heparin, a natural anticoagulant, is used to coat medical devices such as catheters and stents to mimic the endothelial glycocalyx and prevent thrombus formation. Despite the successful application of endpoint attached (EPA) heparin surfaces in medical devices, reports linking heparin-induced thrombocytopenia (HIT) to heparin-bonded prostheses have emerged. The aim of this study was to evaluate the blood compatibility of surfaces functionalized with low molecular weight heparin (LMWH) compared to unfractionated heparin (UFH), given the lower risk of HIT associated with LMWH. Conventional 96-well plates and adsorbents were functionalized with UFH and LMWH. Coagulation, platelet adhesion, and leukocyte adhesion were evaluated to compare blood compatibility between LMWH- and UFH-functionalized surfaces. While LMWH-functionalized surfaces demonstrated no significant antithrombin III (AT-III) binding, they exhibited comparable blood compatibility to UFH-functionalized surfaces. We showed that the activation of coagulation by foreign surfaces is prevented by both types of heparins. No increase in blood cell adhesion was observed on LMWH-functionalized surfaces compared to UFH-functionalized surfaces. This study provides insights into the use of LMWH for surface functionalization, demonstrating comparable blood compatibility to UFH.