A New Endoluminal, Flow-Disrupting Device for Treatment of Saccular Aneurysms

Abstract

Background and Purpose-We report a preclinical study of a new endoluminal device for aneurysm occlusion to test the hypothesis that the device, even without use of intrasaccular coil placement, could occlude saccular aneurysms without causing substantial parent artery compromise or compromise of adjacent, small branch arteries. Methods-The Pipeline Neuroendovascular Device (Pipeline NED; Chestnut Medical Technologies, Inc) is a braided, tubular, bimetallic endoluminal implant aimed at occlusion of saccular aneurysms through flow disruption along the aneurysm neck. The device was implanted across the necks of 17 elastase-induced aneurysms in the New Zealand white rabbit model and followed for 1 month (nϭ6), 3 months (nϭ5), and 6 months (nϭ6). In each subject, a second device was implanted in the abdominal aorta to cover the origins of lumbar arteries. Aneurysm occlusion rates by angiography (grade 1, complete occlusion; grade 2, near-complete occlusion; and grade 3, incomplete occlusion) were documented. Percent area stenosis of the parent arteries was calculated. Presence of distal emboli in the downstream vessels in the parent artery and branch artery stenosis or occlusion was noted. Results-Grades 1, 2, and 3 occlusion rates were noted in 9 (53%), 6 (35%), and 2 (12%) of 17 aneurysms, respectively, indicating an 88% rate of complete or near complete occlusion. No cases of branch artery occlusion or distal emboli in the downstream vessels of the parent artery, specifically the subclavian artery, were seen. Parent artery compromise from neointimal hyperplasia was minimal in most cases. Conclusions-The Pipeline NED is a trackable, bio-and hemocompatible device able to occlude saccular aneurysms with preservation of the parent artery and small, adjacent branch vessels.

Effect of Flow Diverter Porosity on Intraaneurysmal Blood Flow

“…Currently, stents are used to maintain coils inside the aneurysm. It is thought that stents alone would be able to treat such disease by acting more as a "flow diverter" rather than as a "mechanical support for coils" [8,9]. Indeed, stents may aspire at three potential purposes: the aneurysmal/arterial circulation disconnection, the aneurysmal in-jet redirection, and the establishment of a scaffold useful for vessel repair.…”

“…Some authors have also reported a stent-in-stent technique to increase the lateral hemodynamic resistance of the stent in dissecting or small wide-necked aneurysms [4][5][6][7]. New generation of intracranial stents and recent devices called flow diverters are thought to progressively become the current optimal minimally invasive treatment for intracranial aneurysms [8,9]. Such devices have a lower porosity and are used for stand-alone treatment.…”

Diffusion-weighted imaging–detected ischemic lesions associated with flow-diverting stents in intracranial aneurysms: safety, potential mechanisms, clinical outcome, and concerns

“…These are presumably associated with hemodynamic and not embolic factors. Recent studies, both in animals 11,12 and in clinical practice, 19 suggest that in the case of laminar flow, due to a high pressure gradient in the covered side branch, the side branch remains patent, even with multiple overlapping devices. 8 Thus, in cases in which an important collateral network exists or develops, a "competition" of flow may have as a result a decrease in pressure gradient between the covered ostium and the distal portion of the arterial branch, contributing in such a way to a hemodynamic "stagnation.…”

Small Pipes: Preliminary Experience with 3-mm or Smaller Pipeline Flow-Diverting Stents for Aneurysm Repair prior to Regulatory Approval

“…This topic has been widely discussed in the flow-diversion literature, with the consensus suggesting that branch occlusions are not uncommon but are often clinically silent. 5,11,12 It remains unclear whether small-diameter flow diverters have a greater propensity to cause occlusion or symptomatic flow reduction to covered arterial branches, but the series by Yavuz et al 4 showed relatively high rates of branch occlusion (3/21, 14%) and a reduced caliber of the covered branch (6/21, 29%) among 21 MCA bifurcation aneurysms treated. 12 Our series demonstrated 1 case (8%) of a jailed branch artery occlusion (frontopolar artery) with an associated area of diffusion restriction on MR imaging (postprocedure day 1) suggestive of infarct, but this was clinically silent.…”