Document resource
Introduction/Purpose Flow diverting stents (FDSs) are a first-line treatment for large and complex intracranial aneurysms, yet in-stent thrombosis remains a serious complication with potentially catastrophic neurological consequences. Mandatory dual antiplatelet therapy (DAPT) with aspirin and clopidogrel mitigates this risk but creates significant management challenges in patients presenting with ruptured aneurysms or requiring urgent surgery. A surface-modified FDS that intrinsically resists thrombosis could expand the treatable patient population and reduce procedural risk. This study evaluated four distinct surface coatings applied to the Pipeline Flex Embolization Device (PED) and compared their anti-thrombogenic performance.Materials and Methods PED (PED-375-16) stents were coated with one of four strategies: a fluorinated plasma polymer (ppC3F6) deposited via radio-frequency glow-discharge, a zwitterionic polycarboxylbetaine brush via silane chemistry (pCB-Silane), a zwitterionic copolymer deposited by UV-crosslinked rotational coating (pCB-Copolymer), or a commercially available zwitterionic coating (Shield). Uncoated PED segments served as controls. Anti-thrombogenic performance was assessed using an I-125 radiolabeled fibrinogen adsorption assay, a validated surrogate for surface thrombogenicity. Both adsorption (initial protein binding) and retention (stable anchoring after washing) were quantified in ng/cm2, as both metrics predict platelet activation and thrombus propagation.Results All coatings reduced fibrinogen adsorption relative to uncoated controls ( figure 1). The pCB-Silane coating outperformed all others, achieving the lowest adsorption (18.18 ng/cm2) and retention (8.26 ng/cm2) — approximately a 10-fold reduction in retained protein versus ppC3F6 (79.98 ng/cm2). The Shield commercial coating showed intermediate performance (adsorption 59.92 ng/cm2; retention 30.74 ng/cm2). The pCB-Copolymer showed moderate adsorption reduction (130.07 ng/cm2) but higher retention (57.05 ng/cm2). Notably, ppC3F6 reduced initial adsorption (108.47 ng/cm2) but demonstrated disproportionately high retention, suggesting adsorbed fibrinogen undergoes stable conformational changes that may augment thrombogenic signaling.Conclusion A zwitterionic pCB-Silane surface coating substantially reduces fibrinogen binding on the Pipeline FDS, outperforming both a commercially available anti-thrombogenic coating and a fluorinated plasma polymer. These preclinical results support a pathway toward an FDS that may reduce or eliminate DAPT dependence, offering particular benefit to patients with ruptured aneurysms or elevated bleeding risk. In vivo validation and platelet adhesion studies are ongoing.Disclosures M. McAvoy: None. K. Wu: None. K. Kim: None. B. Ratner: None.Abstract O-037 Figure 1Fibrinogen adsorption and retention on FDS with different coating methods