Asnafi, Solmaz

AbstractShape memory polymer (SMP) foam‐coated coils (FCCs) are new embolic coils coated with porous SMP designed to expand for increased volume filling and enhanced healing after implantation. The purpose of this study was to compare chronic aneurysm healing after treatment with SMP FCCs to bare platinum coil (BPC) controls in the rabbit elastase aneurysm model. BPCs or SMP FCCs were implanted in rabbit elastase‐induced aneurysms for follow‐up at 30 days (n = 10), 90 days (n = 5), and 180 days (n = 12 for BPCs; n = 14 for SMP FCCs). Aneurysm occlusion and histologic healing, including a qualitative healing score, neointima thickness, collagen deposition, and inflammation were compared between the two groups. The mean neointima thickness was significantly greater in groups treated with SMP FCCs for all three time points. Histologic healing scores and collagen deposition quantification suggested that aneurysms treated with SMP FCCs experience more complete healing of the dome by 90 days, but the differences were not statistically significant. More progressive occlusion and recanalization were observed in aneurysms treated with SMP FCCs, but neither difference was statistically significant. Additionally, the SMP foam used in the FCCs was found to degrade faster in the rabbit elastase model than expected based on previous studies in a porcine sidewall aneurysm model. This study suggests that SMP FCCs can promote neointima formation along the aneurysm neck, and may lead to more complete healing of the dome and neck. These findings indicate potential benefits of this device for aneurysm occlusion procedures. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B:2466–2475, 2019.

Background: Flow diverters (FD) are increasingly used in the treatment of intracranial aneurysms. The risk of distal thromboembolic complications with FD is high, even in patients treated with dual antiplatelet therapy. The aim of the study was to understand the downstream vascular wall changes, by measuring the pulse wave velocity and vascular contractility following flow diverter treatment in a rabbit model. Methods: FD (Pipeline Embolic Device, Medtronic) were implanted in normal rabbits and sham-operated aorta were used as controls (n=5 for each group). Pulse wave imaging with ultra-fast ultrasound at 1600 frames per second (Vantage, Verasonics, Inc.) was performed in the vessel wall distal to FD, prior to device implantation and at 8 weeks follow up to measure the pulse wave propagation. Force contraction studies were conducted in the aortic rings using organ bath to assess the vascular functions. Results: The difference in pulse wave velocity (PWV) in the follow-up compared to pre-implantation was significantly higher (p=0.03,Fig 1A) in the distal vessels compared to sham controls (mean difference of PWV was 1.18 m/s and -0.37m/s, respectively as shown in Fig 1B). Conversely, the distal aortic segments to FD exhibited 55% increase in the level of vascular contractility compared to that of proximal segments (p=0.002). There is a significant positive correlation between mean PWV and mean vascular contractility. Conclusion: Our study found changes in the PWV after implantation of the FD, which correlated with vascular contractility. These results could explain vascular wall changes downstream following FD implantation.