1031. Balloon-Mounted Stents for Treatment of Refractory Wall Malapposition in Flow Diverters

Authors: Peter Kan, MD, FAANS; Jacob Cherian; Mahsa Dabagh; Visish Srinivasan; stephen Chen; Jeremiah Johnson; Ajay Wakhloo; Vipul Gupta; J Macho; Amanda Randles (Houston, TX)

Introduction: Inadequate device opening and insufficient device to wall apposition are sources of long-term failure for parent vessel reconstruction with flow diversion (FD).Attempts with balloon angioplasty may fail and in these cases, deployment of balloon-mounted stents (BMS) can be useful. Methods: Patients undergoing FD for treatment of intracranial aneurysms were identified in a multi-institutional registry. Cases complicated by refractory device wall malapposition managed with use of BMS were reviewed retrospectively. We examined the impact of BMS deployment on blood flow distribution, flow structure, wall shear stress, and oscillatory shear index by simulating pulsatile blood flow in computational models of pre and post-BMS deployment stages from one of our cases. Results: Four patients undergoing FD treatment complicated by device wall malapposition addressed by use of BMS were identified. All cases demonstrated unruptured fusiform-type aneurysms of likely dissecting etiology.In all four cases, a region of parent vessel stenosis was noted near the region of the aneurysmal dilation. Deployment of flow diverters were complicated in these cases by failure of the device to fully open in the regions of parent vessel stenosis with resulting device malapposition. In all four cases, placement of a BMS within the area of stenosis resulted in opening of the flow diverter and improved wall apposition. All aneurysms occluded at follow-up. Computational modelsuggests that BMS deployment leads to better distribution of blood flow and more uniform distribution of blood velocity over the aneurysm. Conclusion: In cases of FD device deployment complicated by flow-limiting stenosis refractory to conventional techniques, a BMS deployed within the flow diverter can provide sufficient scaffolding to open both the stenotic device and parent artery. This improves device wall apposition and portends greater long-term success of flow diversion.