Preliminary outcomes of single antiplatelet therapy for surface-modified flow diverters in an animal model: analysis of neointimal development and thrombus formation using OCT

OBJECTIVE: To evaluate the rate of neointimal development and thrombus formation of surface-modified flow diverters in single antiplatelet therapy (SAPT) using optical coherence tomography (OCT) in a porcine model. METHODS: We divided 10 experimental pigs into two groups. One group (n=6) received dual antiplatelet therapy (DAPT) and the other group (n=4) received SAPT. Four stents (two per carotid artery) were implanted in both groups. The stents used were the Pipeline Flex embolization device (PED Flex), Pipeline Flex with Shield technology (PED Shield), and the Solitaire AB stent. All animals underwent weekly angiography and OCT. The OCT data were analyzed using the following measurements: neointimal ratio ((stent – lumen area)/stent area), stent-coverage ratio (number of stent struts covered by neointima/total stent struts), and the presence or absence of thrombus formation per 1 mm cross-section. RESULTS: PED Flex and Shield in the SAPT group had higher neointimal ratios than in the DAPT group (P<0.001, respectively). In the DAPT group, the speed of endothelial growth on day 7 in the PED Shield group was higher than that in the PED Flex group (P<0.001). In the SAPT group, PED Flex demonstrated significantly more thrombus formation on day 7 than PED Shield (P<0.001). CONCLUSIONS: The PED Shield stent showed faster endothelial growth than the other devices and comparable neointimal volume. There was significantly less thrombus formation on PED Shield than PED Flex when using SAPT in a porcine model.