Pipeline Stent Research Articles

Abstract No. 173: The Willis stent grafts placement in the treatment of intracranial aneurysm: a prospective, non-randomized multicentre trial with extremely long-term follow-up

Purpose: For the treatment of fusiform and wide-neck intracranial aneurysms, flow-diverting stents such as the pipeline embolization device (PED; ev3, Irvine, California) were developed. This type of stent is designed to divert the flow in the parent artery, hereby reducing inflow in the aneurysm causing thrombosis. We present a series of patients with follow-up up to 1 year after pipeline stent placement. Materials and Methods: We retrospectively identified all cerebral aneurysm patients treated at the University Medical Center Utrecht with a flow diverting pipeline stent who had imaging follow up before September 2011. We collected data on age, aneurysm type and location, treatment indication and occurrence of procedural complications. On the follow up imaging data we evaluated the patency of the stent and residual filling of the aneurysm. From clinical follow up and imaging we evaluated the occurrence of ischemia. Results: 12 patients (age 20-68; average age 50) had a total of 13 aneurysms (4 previously ruptured, 2 dissecting, 5 asymptomatic and 2 symptomatic aneurysms; 3 internal carotid artery, 4 verterbral artery, 4 basilary artery, 1 PICA, and 1 proximal middle cerebral artery). In case of previous rupture, treatment with the PED was performed between 47 and 270 days after initial aneurysm coiling. No procedural complications were reported. Stent patency and post procedural aneurysm filling was evaluated at an average of 130 days (range 36-183) after treatment. No residual filling of the aneurysm and one temporary stent occlusion were reported. One patient (7%) developed ischemia in the flow territory of the treated artery (vertebral artery stent with ischemia in the pons and cerebellum). Conclusion: Treatment with the PED in our hospital shows good results with no residual filling or permanent stent occlusion. One patient developed ischemia in the flow territory of the treated vessel.

Successful treatment of a traumatic carotid pseudoaneurysm with the Pipeline stent: Case report and review of the literature

Background:Traumatic intracranial pseudoaneurysms remain one of the most difficult vascular lesions to treat. In the case of traumatic pseudoaneurysms that may not be treated with parent vessel sacrifice, some flow diversion strategy such as stent-assistance or use of a flow diversion device is usually necessary.Case Description:In this study we describe endovascular parent vessel wall-remodeling/endoluminal reconstruction and traumatic pseudoaneurysm thrombosis through the use of the Pipeline stent and review recent reports concerning indications, safety, and efficacy for alternative pathology.Conclusion:Although currently not routinely employed in the treatment of traumatic pseudoaneurysms, the Pipeline stent may represent a safe and effective treatment alternative achieving complete endoluminal reconstruction of the damaged vessel wall.

Can a Self-Expanding Aneurysm Stent Be Clipped? Emergency Proximal Control Options for the Vascular Neurosurgeon

If a self-expanding stent has been placed during endovascular treatment of an aneurysm and subsequently an open aneurysm surgery becomes necessary in the same or an adjacent area, is it possible and safe to obtain proximal control by placing a temporary clip on the artery at a point where it contains the stent? To evaluate the effect of temporary clip application to 3 separate stent systems in an in vitro flow model with the stated hypothesis that clip application to these stents will result in permanent stent deformation. This is an in vitro flow model study using an accepted synthetic blood vessel substitute. The Neuroform(3) (Boston Scientific), Enterprise (Cordis/Codman), and Pipeline (ev3) stents were deployed within the flow model; temporary clips were applied; and angiographic measurements subsequently made. Two 4 × 30-mm Neuroform(3) stents, two 4.5 × 28-mm Enterprise stents, and two 3.75 × 20-mm Pipeline stents were successfully deployed and clipped repeatedly (4 iterations). Two- and 3-dimensional angiograms were obtained. After repeated clip occlusion, the Neuroform(3) and Enterprise stents returned to their original configuration and diameter. Clip application to both also resulted in immediate flow arrest. In contrast, initial clip application to the Pipeline stents did not result in flow arrest, but the second single clip application did. The Pipeline stents were also irreversibly deformed after the experimental protocol, with an average luminal diameter reduction of 26.85% (P < .05). The Neuroform(3) and Enterprise stents responded favorably to temporary clip application, returning to their original diameter after clip removal and showing no sign of permanent structural modification. The Pipeline flow-diverting stent, however, was irreversibly deformed by clip application. These data indicate that temporary clip application to certain stents is possible. Further in vivo study is required.

Position statement on the coverage of anticonvulsant drugs for the treatment of epilepsy

<h3>Introduction/purpose</h3> Flow-diverting Pipeline stents are commonly used for endovascular treatment of cerebral aneurysms but can be associated with delayed ipsilateral intracerebral hemorrhage. Although intra-aneurysmal hemodynamic changes have been studied, parent vessel and intracranial hemodynamics after Pipeline stenting are unknown. Here, we examine the impact of Pipeline stenting on parent artery and distal intracranial hemodynamics. <h3>Materials and methods</h3> Records of patients with internal carotid cerebral aneurysms treated with Pipeline stenting at our institution were retrospectively reviewed. Patients were included if flows were obtained after stenting using quantitative magnetic resonance angiography. Flow volume rate and mean, systolic, and diastolic flow velocities were measured in the internal carotid artery (ICA, cervical segment) and middle cerebral artery (MCA, M1 segment). Pulsatility index [(systolic - diastolic flow velocity)/mean flow velocity], resistance index [(systolic - diastolic flow velocity)/systolic flow velocity], and wall shear stress (WSS) were calculated for each vessel. Means were compared between ipsilateral and contralateral ICA and MCA using two-tailed Wilcoxon signed-rank tests. <h3>Results</h3> Nine patients were included, mean age 51 years. All aneurysms were located in the cavernous or paraclinoid segments of the ICA. Within the parent vessel, mean flow velocity (18.1 vs. 23.4 cm/s, <i>P = 0</i>.04) and diastolic velocity (15.4 vs. 20.2 cm/s, <i>P = 0</i>.04) were significantly lower than in the &nbsp;contralateral ICA, and systolic velocity was also lower (20.8 vs. 26.9 cm/s, <i>P = 0</i>.06) but not as significantly (Figure 1A). These lower flow velocities were accompanied by higher, although non-significant, pulsatility (0.31 vs. 0.29, <i>P = 0</i>.93) and resistance indices (0.26 vs. 0.25, <i>P = 0</i>.87) and slightly lower flow (248.1 vs. 277.6 mL/min, <i>P = 0</i>.61) in the parent vessel. In the ipsilateral MCA, however, pulsatility (0.19 vs. 0.30, <i>P = 0</i>.06) and resistance indices (0.17 vs. 0.25, <i>P = 0</i>.04) were significantly lower, and flow higher (152.1 vs. 135.6 mL/min, <i>P = 0</i>.17), than in the contralateral MCA (Figure 1B). These lower resistances were accompanied by a higher trend in ipsilateral versus contralateral MCA mean flow velocity (29.9 vs. 26.8 cm/s, <i>P = 0</i>.37), systolic velocity (32.9 vs. 31.3 cm/s, <i>P = 0</i>.86), diastolic velocity (27.3 vs. 23.5 cm/s, <i>P = 0</i>.17), and WSS (26.8 vs. 23.9 dynes/cm², <i>P = 0</i>.44). <h3>Conclusion</h3> After Pipeline stenting, there appears to be alteration in the elasticity of the stented ICA segment, with significantly lower flow velocities in the ipsilateral versus contralateral ICA. Conversely, there was an increase in flow velocities and WSS and significantly lower resistance in the ipsilateral MCA, suggesting the possible role of altered distal hemodynamics in delayed ipsilateral hemorrhages. <h3>Disclosures</h3> S. Shakur: None. V. Aletich: None. S. Amin-Hanjani: None. F. Charbel: None. A. Alaraj: None.