Predictors of cerebral aneurysm persistence and occlusion after flow diversion: a single-institution series of 445 cases with angiographic follow-up

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>Flow diversion requires neointimal stent overgrowth to deliver aneurysm occlusion. The existing literature on aneurysm occlusion is limited by heterogeneous follow-up, variable antiplatelet regimens, noninvasive imaging modalities, and nonstandard occlusion assessment. Using a large, single-center cohort with low attrition and standardized antiplatelet tapering, the authors evaluated outcomes after flow diversion of anterior circulation aneurysms to identify predictors of occlusion and aneurysm persistence.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>Data from a prospective, IRB-approved database was analyzed for all patients with anterior circulation aneurysms treated by flow diversion with the Pipeline embolization device (PED) at the authors’ institution. Follow-up consisted of catheter cerebral angiography at 6 and 12 months postembolization. Clopidogrel was discontinued at 6 months and aspirin was reduced to 81 mg daily at 12 months. Occlusion was graded as complete, trace filling, entry remnant, or aneurysm filling. Multivariate logistic regression was performed to identify predictors of aneurysm persistence.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Follow-up catheter angiography studies were available for 445 (91%) of 491 PED procedures performed for anterior circulation aneurysms between August 2011 and August 2016. Three hundred eighty-seven patients accounted for these 445 lesions with follow-up angiography. The population was 84% female; mean age was 56 years and mean aneurysm size was 6.6 mm. Aneurysms arose from the internal carotid artery (83%), anterior cerebral artery (13%), and middle cerebral artery (4%). Morphology was saccular in 90% of the lesions, and 18% of the aneurysms has been previously treated. Overall, complete occlusion was achieved in 82% of cases at a mean follow-up of 14 months. Complete occlusion was achieved in 72%, 78%, and 87% at 6, 12, and 24 months, respectively. At 12 months, adjunctive coiling predicted occlusion (OR 0.260, p = 0.036), while male sex (OR 2.923, p = 0.032), aneurysm size (OR 3.584, p = 0.011), and incorporation of a branch vessel (OR 2.206, p = 0.035) predicted persistence. Notable variables that did not predict aneurysm occlusion were prior treatments, vessel of origin, fusiform morphology, and number of devices used.</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>This is the largest single-institution study showing high rates of anterior circulation aneurysm occlusion after Pipeline embolization. Predictors of persistence after flow diversion included increasing aneurysm size and incorporated branch vessel, whereas adjunctive coiling predicted occlusion.</jats:p></jats:sec>

Multimodal management of giant cerebral aneurysms: review of literature and case presentation

“…Further analysis revealed that at 12 months, adjunctive coiling predicted occlusion, whereas male sex, aneurysm size and incorporation of a branch vessel predicted aneurysm persistence. Prior treatments, vessel of origin, fusiform morphology and number of devices used did not predict aneurysm occlusion 39…”

“…Open microsurgery lends to immediate dome occlusion but may be fraught with high morbidity 45 46 48 51 52. In contrast, conventional endovascular treatment with endosaccular coil embolisation is associated with known risks of recurrence, whereas parent vessel remodelling through flow diversion with delayed complete aneurysm occlusion can lead to aneurysm growth 39 53. Additionally, a curative result from flow diversion treatment of the more fusiform and supergiant aneurysms becomes limited given the challenges of achieving endothelialisation along a longer length of device construct without a wall.…”

“…Flow diversion is fundamentally based on two concepts: (1) the placement of a high-density mesh device in the parent vessel disrupts blood flow into the aneurysm, resulting in progressive intra-aneurysmal thrombosis and (2) the device provides a scaffold for which endothelial cells can grow to isolate the aneurysm from the parent artery with subsequent radiographic obliteration of the aneurysm 34. Since the initial introduction of flow diversion in the 2000s, there have been a number of publications on the proven efficacy in durable curative treatments of giant aneurysms as well as safety with morbidity and mortality rates less than open microsurgical clipping 34–44…”

Single-stage flow diversion with adjunctive coiling for cerebral aneurysm: outcomes and technical considerations in 72 cases

“…We are hyper-vigilant in these cases, waiting a full 30 min post-embolization for final control angiography prior to ending the case. Siddiqui et al shared the case of a patient with a giant MCA aneurysm treated with flow diversion and dense coil packing in which the patient experienced acute post-procedural stent thrombosis and cautioned against densely packing the aneurysm with coils 24. We also use a light coil pack (14% packing density overall) and systemically heparinize these patients overnight following their procedure, all to limit the risk of acute stent thrombosis.…”

Pipeline Embolization for Salvage Treatment of Previously Stented Residual and Recurrent Cerebral Aneurysms

“…The Pipeline embolization device (PED) was approved with a similar indication for large and giant aneurysms of the internal carotid artery (ICA). The PED has low rates of major complication and complete occlusion of ∼80% of aneurysms 1 year after treatment, in creasing thereafter [3-5]. Recanalization and recurrence after coiling as well as aneurysm persistence after flow diversion (FD) are a problem in spite of these contemporary technologies [6].…”