Introduction In vitro studies have shown that Pipeline Embolization Device+Shield Technology (Shield) with a surface modification of a 3 nm thick modified phosphorylcholine is less thrombogenic.1 We hypothesize that Shield has less thrombus formation in vivo as compared to Pipeline Embolization Devices (PED) regardless of dual antiplatelet therapy (DAPT).
Methods Forty rabbits with elastase induced aneurysms were randomly assigned to receive a Shield or PED. For each device, half of the animals received DAPT. In each of the four groups, 10 animals were enrolled for a period of 30 days. Herein, we report on 32 animals that have reached the study endpoint to date. Animals that received DAPT (10 mg/kg each of aspirin and clopidogrel) were started a 5 days prior to implant and continued until the endpoint at 30 days. At the time of implant optical coherence tomography (OCT, Dragonfly, St Jude) was performed before and after angioplasty, and repeated at terminal follow-up. Thrombus formation was assessed at 4 locations along the implant (distal end, at the level of the vertebral artery, at the aneurysm neck, and at the proximal end) as present or absent. Aneurysm occlusion was assessed on digital subtraction angiography after 30 days and according to the scale of Darsaut et al.2
Results Baseline characteristics (e.g., aneurysm size, neck size, parent vessel diameter) were not different between the four groups (p > 0.1). Animals receiving DAPT had a significant reduction in PRU values (69 ± 28 vs 247 ± 41, p < 0.0001) and no change in ARU (649 ± 31 vs 659 ± 9, p > 0.05). The Shield was more likely to have no thrombus or thrombus only at one of the four locations as compared to PED (OR 0.10 95% CI 0.02–0.56, p = 0.01). There was no difference in thrombus at the four locations as a function of DAPT (p > 0.05). There was no dependence on aneurysm occlusion on the device used or PRU value; however, achieving complete or near complete occlusion was negatively and marginally correlated with the aneurysm neck size (Spearman’s rho = 0.314; p = 0.049).
Conclusion The hypothesis that Shield technology reduces acute thrombus formation regardless of DAPT has been confirmed in vivo using OCT.
References 1 G Girdhar et al. J Thromb Thrombolysis 2015;40:437–4432.
2 TE Darsaut, et al. AJNR. 2012;33:2004–2009
Disclosures M. Marosfoi: None. E. Langan: None. S. Vedantham: None. F. Clarençon: None. R. King: None. J. Wainwright: 5; C; Medtronic Neurovascular. M. Gounis: 1; C; Medtronic Neurovascular. A. Puri: 1; C; Medtronic Neurovascular. 2; C; Medtronic Neurovascular.
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