NEURINTSURG4499 340..343

Background The Enterprise (EN) vascular reconstruction device is a self-expanding nitinol stent used as adjunctive support in wide-necked aneurysm coiling. We sought to evaluate the effect of deployment technique on how well the EN stent conforms to the vessel wall around a curve. Methods A flow model consisting of a 3.5 mm diameter silicone tube forming a 7 mm radius curve was visualized using high-resolution flat-panel CT (FPCT; DynaCT). EN stents (4.5 mm322 mm) were deployed using three methods: (1) microcatheter pull-back, (2) delivery microwire push and (3) a combination of both methods so as to keep the microcatheter tip centered within the lumen during deployment. FPCT images were visualized using multiplanar reconstruction for evidence of incomplete stent apposition (ISA). Results FPCT revealed a critical role for deployment method in stentewall apposition as noted by the development of a crescent-shaped gap between the stent and the wall. Specifically, the manufacturerrecommended microcatheter pull-back unsheathing technique (method 1) resulted in outer curve ISA, while the microwire push technique (method 2) led to inner curve ISA. Using method 3 in a dynamic pushepull manner minimized both inner and outer curve ISA. Conclusion The deployment method used to deliver the EN vascular reconstruction device plays a critical role in determining how well its struts appose the vessel wall in vitro. This characteristic must be taken into account when deploying this flexible low-profile stent to avoid ISA in even mildly tortuous anatomy given the possible link between stent malapposition and thromboembolic complications. INTRODUCTION The Enterprise vascular reconstruction device (EN) is a closed-cell design intracranial stent that is designed for treatment of wide-necked aneurysms 2 (figure 1A). The EN stent offers a number of features that provide it with advantages, including a low-profile delivery microcatheter (0.021-inch), resheathability for repositioning and smaller cell size to decrease risk of coil protrusion, as compared with the open-cell design Neuroform stent (figure 1B). Conventional angiography and 3D rotational angiography have not been able to clearly visualize the fine structure of the EN stent in clinical use to assess how well the stent apposes the vessel wall in tortuous anatomy. Recent advances in high-resolution imaging with C-arm flat-panel angio-CT (FPCT) have improved the ability to resolve the stent structure. 5 This technique has been successfully used to determine the in vitro behavior of self-expanding intracranial stents around bends. These studies were, however, conducted in vitro by externally altering the angle of a straight silicone tube containing the already deployed stent. Although these studies are very informative, they do not reflect the reality of deploying a stent in an already tortuous vessel, and do not address the effect of deployment technique on the interaction of the stent with the vessel wall. In the current study, we used FPCT to evaluate the interaction of the EN stent with the wall in an in vitro silicone model, and describe a critical effect of the deployment technique on the development of incomplete stent apposition (ISA) 7 to the wall and present a method of deployment that aims to mitigate this undesirable property.