Cress, Marshall C.

Abstract Background Flow diversion is a common endovascular treatment for cerebral aneurysms, but studies comparing different types of flow diverters are scarce. Objective To perform a propensity score matched cohort study comparing the Pipeline Embolization Device (PED) and Flow Redirection Intraluminal Device (FRED) for posterior circulation aneurysms. Methods Consecutive aneurysms of the posterior circulation treated at 25 neurovascular centers with either PED or FRED were collected. Propensity score matching was used to control for age, duration of follow-up imaging, adjunctive coiling, and aneurysm location, size, and morphology; previously ruptured aneurysms were excluded. The two devices were compared for the following outcomes: procedural complications, aneurysm occlusion, and functional outcome. Results A total of 375 aneurysms of the posterior circulation were treated in 369 patients. The PED was used in 285 (77.2%) and FRED in 84 (22.8%) procedures. Aneurysms treated with the PED were more commonly fusiform and larger than those treated with FRED. To account for these important differences, propensity score matching was performed resulting in 33 PED and FRED unruptured aneurysm pairs. No differences were found in occlusion status and neurologic thromboembolic or hemorrhagic complications between the two devices. The proportion of patients with favorable functional outcome was higher with FRED (100% vs 87.9%, p=0.04). Conclusion Comparative analysis of PED and FRED for the treatment of unruptured posterior circulation aneurysms did not identify significant differences in aneurysm occlusion or neurologic complications. Variations in functional outcomes warrant additional investigations.

Abstract BACKGROUND The Pipeline Embolization Device (PED; Medtronic) has been used off-label for the treatment of challenging posterior circulation aneurysms. Data on this modality are primarily limited to small retrospective single-center series. OBJECTIVE To assess safety and efficacy of this treatment by establishing an international, multicenter collaboration. METHODS Consecutive posterior circulation aneurysms treated with the PED from 2012 to 2019 across 11 neurovascular centers were retrospectively reviewed. Baseline demographics, aneurysm and treatment characteristics, complications, occlusion status, and functional outcome were assessed. RESULTS There were 149 posterior circulation aneurysms treated with PED in 146 patients. A total of 24 (16.4%) patients presented with subarachnoid hemorrhage. Most aneurysms were dissecting/blister (36.2%) in morphology, followed by saccular (35.6%) and fusiform (28.2%). The most common locations were the vertebral (51.7%) and basilar arteries (22.8%). Complete or near-complete occlusion (>90%) was achieved in 90.9% of aneurysms at a median follow-up of 12 mo. Dissecting/blister aneurysms were most likely to occlude ( P = .06). Symptomatic neurologic complications occurred in 9.4% of aneurysms, associated with larger size, ruptured presentation, presentations with brain stem compression, cranial nerve palsy, or stroke. Favorable functional outcome (modified Rankin Score 0-2) was achieved in 86.2% of patients. There were 6 fatalities of which 4 occurred in aneurysmal subarachnoid hemorrhage patients. CONCLUSION This multicenter study shows that PED for the treatment of posterior circulation is preferentially used for the treatment of fusiform and dissecting/blister aneurysm morphologies. Despite the challenges presented by these less-common morphologies, flow diversion may be performed with a neurologic complication rate of about 10% and favorable long-term aneurysm occlusion rates.

Abstract BACKGROUND Neck remnants are not uncommon after endovascular treatment of cerebral aneurysms. Critics of endovascular treatments for cerebral aneurysms cite neck remnants as evidence in favor of microsurgical clipping. However, studies have failed to evaluate the true clinical significance of aneurysm neck remnants following endovascular therapies. OBJECTIVE To assess the clinical significance of residual aneurysm necks and to determine the rate of subsequent rupture following coiling or stent-assisted coiling of cerebral aneurysms. METHODS We retrospectively reviewed the records of 1292 aneurysm cases that underwent endovascular treatment at 4 institutions. Aneurysms treated by primary coiling or stent-assisted coiling were included in the study; those treated by flow diversion were excluded Aneurysms with residual filling (i.e., Raymond–Roy Occlusion Classification II, neck remnant; or III, residual aneurysm filling) were assessed for their risk of subsequent rupture. RESULTS A total of 626 aneurysms were identified as having residual filling immediately posttreatment. Of these, 13 aneurysms (2.1%) ruptured during the follow-up period (mean 7.3 mo; range 1-84 mo). Eleven of the 13 (84.6%) were ruptured at presentation. Rupture at presentation, the size of the aneurysm, and the increasing age of the patient were predictive of posttreatment rupture. CONCLUSION We found that unruptured aneurysms with residual necks following endovascular treatment posed a very low risk of rupture (0.6%). However, patients presenting with ruptured aneurysms had a higher risk of rerupture from a neck remnant (3.4%). These results highlight the importance of achieving complete angiographic occlusion of ruptured aneurysms.