The occurrence of neointimal hyperplasia after flow-diverter implantation is associated with cardiovascular risks factors and the stent design

BackgroundNeo-intimal hyperplasia (NIH) is frequently observed after flow-diverter stent (FDS) implantation. Although mostly asymptomatic, this vascular response can sometimes lead to delayed ischemic strokes. This study intended to evaluate the factors potentially influencing the rates of NIH following FDS treatment.Material and MethodsAll aneurysm treatments performed with a Pipeline embolization device (PED) or a SILK stent from May 2011 to May 2015 were collected in a prospectively maintained database. Patient demographics, clinical, and angiographic outcomes including both digital subtraction angiography and C-arm cone-beam CT were registered. Two blind reviewers rated the presence of NIH on a binary scale (present/absent).ResultsFrom 148 patients, 63 datasets were available for analysis. Inter-reader agreement was excellent (Kappa=0.88). NIH was positively correlated with smoking, dyslipidemia, and high blood pressure, but not with aneurysm characteristics. At early follow-up (<12 months), NIH was more frequently associated with the use of the SILK stent (68%) rather than the PED (38%): P<0.02. At long-term follow-up, the NIH rate in the total population dropped from 55% to 26% with no more significant difference between the two stents. The complete occlusion rate as seen in early follow-up was higher in the SILK group with 76% vs 65% but without statistical significance (P=0.4).ConclusionNIH is a dual-vessel reaction after FDS implant. When planning a treatment in locations at risk of ischemic complications if severe NIH would occur, then the stent design should be considered. However, minimal NIH might also be needed as it is involved in aneurysm healing. Before treatment patients should be recommended best medical management of their cardiovascular risks factors to prevent an excessive NIH reaction.

Flow-Diverting Stents for the Obliteration of Symptomatic, Infectious Cavernous Carotid Artery Aneurysms

BACKGROUND Intracavernous aneurysms constitute up to 9% of all intracranial aneurysms and 6% are infectious (IIA). First line therapy is a protracted antibiotic course, yet with failure, surgery and endovascular parent vessel sacrifice have been utilized. Reconstructive endovascular therapies have emerged for aneurysm control and may demonstrate a safer therapeutic alternative. OBJECTIVE To present an IIA treated with a flow-diverting Pipeline stent (ev3 Neurovascular, Irvine, California). METHODS A 41-yr-old female presented with visual loss, ophthalmoplegia, and cavernous sinus thrombosis with an associated phlegmon. Transsphenoidal evacuation was performed without complication or bleeding and she continued on medical therapy. Two weeks postoperatively, she developed a worsening right third cranial nerve palsy and MRA demonstrated a 1-cm right IIA, not evident on postoperative MRI. Three days of dual antiplatelet therapy preceded successful pipeline embolization. Angiography demonstrated aneurysm obliteration at 3 mo and her right ophthalmoplegia resolved. RESULTS A literature review identified 6 reported cases of IIAs treated with stent embolization. Only 1 documented a flow-diverting Silk stent used in a child. All lesions were obliterated at follow-up without neurological sequelae. No complication arose with implantation in the setting of infection, and as few as 3 d of dual antiplatelet therapy was sufficient for preprocedural prophylaxis, although in Vivo antiplatelet activity may be more significant. CONCLUSION We report the first case of an IIA treated with a flow-diverting pipeline stent. These devices preserve native vasculature and neurological function compared to surgical and endovascular vessel sacrifice strategies. They appear to be safe management options for the treatment of IIAs.

Neurovascular reconstruction with flow diverter stents for the treatment of 87 intracranial aneurysms: Clinical results

Background Flow diverter stents represent a new endovascular tool to treat complex aneurysms, such as giant, large, wide-necked and fusiform. The highly dense mash of these stents reduces inflow and outflow inside the aneurysm, resulting in intra aneurysmal thrombosis and stent endothelialization. Objectives To present the results of treatment of intracranial aneurysms with flow diverter stents in a single center. Methods Retrospective review of 77 patients with 87 aneurysms treated using two different types of flow diverter stent, the Pipeline Embolization Device and SILK stent, between October 2010 and September 2013 in an interventional neuroradiology center. Results Flow diverter stent placement was successful in 98% of the lesions and resulted in an immediate major stasis within most of the treated aneurysms. The overall aneurysm occlusion rate at six months and 18 months was 80% and 84% respectively. Symptomatic complications occurred in 11 patients (14.3%) with morbidity in eight (10.4%) and mortality in three patients (3.9%). Conclusion Flow diversion is a promising technique for treatment of challenging intracranial aneurysms with acceptable morbidity. A high rate of complete occlusion for small large necked aneurysms, a low morbidity and mortality rate and no recanalization encourage their use in these aneurysms. Further studies accessing long-term aneurysm occlusion and recanalization are required.

Treatment of Complex Intracranial Aneurysms Using Flow-Diverting Silk® Stents An Analysis of 32 Consecutive Patients

This study describes the peri-procedural and late complications and angiographic follow-up results of 32 patients with 34 complex aneurysms treated with flow diverter Silk stents in a single centre. In this retrospective study, 40 Silk stents (SS) were implanted in 34 complex intracranial aneurysms in 32 patients. In our series, 20 (58.8%) carotid-ophthalmic internal carotid artery (ICA), six (17.6%) cavernous ICA, two (5.9%) supraclinoid ICA, two (5.9%) petrosal ICA (the same patient- bilateral) and four (11.8%) posterior circulation aneurysms were treated. One of the posterior circulation lesions was a fenestrated-type aneurysm. Twenty wide-necked, saccular; eight neck remnant; four fusiform and two blister-like aneurysms were included in our series. SS were successfully implanted in all patients (100%). Misdeployment occurred in 17.6% of patients. In two of these patients adequate stent openness was achieved via Hyperglide balloon dilatation. Coil embolization in addition to SS placement was utilized in four aneurysms. One patient (3%) experienced transient morbidity due to a thromboembolic event and there was one mortality (3%) due to remote intraparenchymal haemorrhage. Complete occlusion of 27/33 (81.8%) and 29/33 (87.9%) aneurysms was achieved six and 12 months after the procedure, respectively. In-stent intimal hyperplasia was detected in 6.1% patients. Flow-diverter Silk stent implantation is an effective method of treating complex aneurysms with acceptable mortality and morbidity rates. Complete occlusion is achieved in most of the complex aneurysms.

Treatment of Intracranial Aneurysms Using Flow-Diverting Silk Stents (BALT): A Single Centre Experience

The Silk stent (Balt, Montmorency, France) is a retractable device designed to achieve curative reconstruction of the parent artery associated with an intracranial aneurysm. We present our initial experience with the Silk flow-diverting stent in the management and follow-up of 25 patients presenting with intracranial aneurysms. Twenty-five patients (age range, 34–81 years; 24 female) were treated with the Silk flow-diverting device. Aneurysms ranged in size from small (5), large (10) and giant (10) and included wide-necked aneurysms, multiple, nonsaccular, and recurrent intracranial aneurysms. Nine aneurysms were treated for headache, 14 for mass effect. None presented with haemorrhage. All patients were pretreated with dual antiplatelet medications for at least 72 hours before surgery and continued taking both agents for at least three months after treatment. A total of 25 Silk stents were used. Control MR angiography and/or CT angiography was typically performed prior to discharge and at one, three, six and 12 months post treatment. A follow-up digital subtraction angiogram was performed between six and 19 months post treatment. Complete angiographic occlusion or subtotal occlusion was achieved in 15 patients in a time frame from three days to 12 months. Three deaths and one major complication were encountered during the study period. Two patients, all with cavernous giant aneurysms, experienced transient exacerbations of preexisting cranial neuropathies and headache after the Silk treatment. Both were treated with corticosteroids, and symptoms resolved completely within a month. In our experience the Silk stent has proven to be a valuable tool in the endovascular treatment of intracranial giant partially thrombosed aneurysms and aneurysms of the internal carotid artery cavernous segment presenting with mass effect. The time of complete occlusion of the aneurysms and the risk of the bleeding is currently not predictable.