O-012 Acute clot formation on the surface of flow diverters can be reduced by using phosphoryl-choline surface modification

Introduction/Purpose Major ipsilateral ischemic stroke have been reported to range between 1.6%–4.3% 1,2 after flow diverter treatment. Patient-specific contributors to peri-procedural thromboembolic complications remain under investigation. Beyond understanding and correcting patient-specific factors, we seek device technology to decrease these unpredictable complications. By using high resolution intravascular imaging tool (optical coherence tomography – OCT) we sought to determine the rate of acute micro-clot formation on the surface of different flow diverters. Furthermore, we assessed the consequences of angioplasty (after FD implant) with respect to acute clot formation. We hypothesize that a new generation phosphoryl-choline surface modified flow diverter may reduce acute clot formation on the surface of the device. Materials and methods Thirty elastase induced aneurysms were created in rabbits and treated with 3 different types of flow diverters. Classic Pipeline (C-PED), Pipeline-Flex with Shield Technology (S-PED) and FRED devices were implanted in 10 animals in each group. Four days prior to implant animals received dual anti-platelet therapy (DAPT: 10 mg/kg aspirin and clopidogrel) and that was continued until the end of the study (30 days). OCT (Dragonfly, St Jude) was used to assess the acute clot formation on the surface of devices, after deployment, and repeated 20 min after angioplasty (Figure). Thrombus formation was analyzed and scored by looking at 3 different locations along the implant. In addition, clot formation at the origins of covered side branches (OSB) was separately scored. Results At the origin of side branches, the S-PED showed a significantly less amount of clot formation both pre- and post-angioplasty (10% and 20%, versus C-PED: 40% and 60% and FRED: 60% and 90%, respectively, p=0.0065). At the 3 other locations (OSB not included): the distal end of the device, proximal end (including the level of the aneurysm) and the location between the aneurysm and the vertebral artery there was no difference in clot formation between the 3 devices immediately after deployment. However, following angioplasty of the devices, a decrease of clot formation was seen only in the S-PED group versus an increase as expected with the other devices (S-PED: 20% decrease, C-PED: 30% increase, FRED: 20% increase). Conclusion Our preliminary study supported our hypothesis that using phosphoryl-choline surface modified flow diverter can be useful to decrease the occurrence of micro-clot formation, especially post-angioplasty. Importantly, S-PED reduced clot formation at the origin of covered side-branches. References . AJNR 2015;36:98–107. . J. Neurosurg 2016;1–6. Disclosures M. Marosfoi: None. F. Clarencon: None. E. Langan: None. R. King: None. O. Brooks: None. T. Tamura: None. M. Gounis: 1; C; Medtronic Neurovascular. A. Puri: 1; C; Medtronic Neurovascular.