Neck Location on the Outer Convexity is a Predictor of Incomplete Occlusion in Treatment with the Pipeline Embolization Device: Clinical and Angiographic Outcomes

Abstract

BACKGROUND AND PURPOSE: With the increasing use of the Pipeline Embolization Device for the treatment of aneurysms, predictors of clinical and angiographic outcomes are needed. This study aimed to identify predictors of incomplete occlusion at last angiographic follow-up. MATERIALS AND METHODS:In our retrospective, single-center cohort study, 105 ICA aneurysms in 89 subjects were treated with Pipeline Embolization Devices. Patients were followed per standardized protocol. Clinical and angiographic outcomes were analyzed. We introduced a new morphologic classification based on the included angle of the parent artery against the neck location: outer convexity type (included angle, ,160°), inner convexity type (included angle, .200°), and lateral wall type (160°# included angle #200°). This classification reflects the metal coverage rate and flow dynamics.RESULTS: Imaging data were acquired in 95.3% of aneurysms persistent at 6 months. Complete occlusion was achieved in 70.5%, and incomplete occlusion, in 29.5% at last follow-up. Multivariable regression analysis revealed that 60 years of age or older (OR, 5.70; P ¼ .001), aneurysms with the branching artery from the dome (OR, 10.56; P ¼ .002), fusiform aneurysms (OR, 10.2; P ¼ .009), and outer convexitytype saccular aneurysms (versus inner convexity type: OR, 30.3; P , .001; versus lateral wall type: OR, 9.71; P ¼ .001) were independently associated with a higher rate of incomplete occlusion at the last follow-up. No permanent neurologic deficits or rupture were observed in the follow-up period. CONCLUSIONS:The aneurysm neck located on the outer convexity is a new, incomplete occlusion predictor, joining older age, fusiform aneurysms, and aneurysms with the branching artery from the dome. No permanent neurologic deficits or rupture was observed in the follow-up, even with incomplete occlusion.

Onset-to-treatment time and aneurysmal regression predict improvement of cranial neuropathy after flow diversion treatment in patients with symptomatic internal carotid artery aneurysms

“…Platelet function testing was routinely performed using the VerifyNow P2Y12 assay and the VerifyNow Aspirin assay (Accumetrics, San Diego, California, USA) on the day before. Antiplatelet medications were adjusted accordingly, as in previous reports 15. Dual antiplatelet therapy was continued for at least 6 months after the procedure, and single antiplatelet therapy was continued indefinitely thereafter.…”

“…Heparin anticoagulation was implemented throughout the procedure. Flow diversion treatment was performed using standard technique, as described previously 15 16…”

Fluid dynamics in intracranial aneurysms treated with flow-diverting stents: effect of multiple geometrical parameters

“…This location of the aneurysm with respect to the parent vessel has been identified as less favourable for successful embolization of the sac after FDS treatment (Sunohara et al. 2021). A study comparing the clearance of aneurysmal sac on the outer convexity versus the concave side of the parent vessel also observed significantly faster clearance for the aneurysm on the outer convexity (Epshtein & Korin 2018).…”

“…After having analysed the geometry and the outcomes after treatment with flow-diverting stents (FDS) of 105 aneurysms, Sunohara et al. (2021) concluded that an aneurysm neck located on the outer wall of the curved artery is a predictor for incomplete occlusion after treatment. Additionally, numerical simulation of 23 patient aneurysms (Larrabide et al.…”

“…The outcome of the treatment with FDS depends on numerous parameters such as location (Sunohara et al. 2021), aneurysm size or shape (Daou et al. 2019) and neck size (Cebral et al.…”