Determinants of intracranial aneurysm retreatment following embolization with a single flow-diverting stent

Abstract

Purpose: Flow diverting stents have revolutionized the treatment of intracranial aneurysms through endoluminal reconstruction of the parent vessel. Despite this, certain aneurysms require retreatment. The purpose of this study was to identify clinical and radiologic determinants of aneurysm retreatment following flow diversion.

Methods: A multicenter flow diversion database was evaluated to identify patients presenting with an unruptured, previously untreated aneurysm with a minimum of 12 months' clinical and angiographic follow-up. Univariate and multivariate logistic regression modeling was performed to identify determinants of retreatment.

Results: We identified 189 aneurysms treated in 189 patients with a single flow-diverting stent. Mean age was 54 years, and 89% were female. Complete occlusion was achieved in 70.3% and 83.6% of patients at six and 12 months, respectively. Aneurysm retreatment with additional flow-diverting stents occurred in 5.8% of cases. Univariate analysis revealed that dome diameter $\ge$10 mm (p = 0.012), pre-clinoid internal carotid artery location (p = 0.012), distal > proximal parent vessel diameter (p = 0.042), and later dual antiplatelet therapy (DAPT) discontinuation (p < 0.001) were predictive of retreatment. Multivariate analysis identified discontinuation of DAPT $>$12 months (p = 0.003) as a strong determinant of retreatment with dome diameter $\ge$10 mm trending toward statistical significance (p = 0.064). Large aneurysm neck diameter, presence of aneurysm branch vessels, patient age, smoking history, and hypertension were not determinant of retreatment on multivariate analysis.

Conclusions: Prolonged DAPT is the most important determinant of aneurysm retreatment following single-device flow diversion. Abbreviating DAPT duration to only six months should be a consideration in this population, especially for patients with a large aneurysm dome diameter.

Keywords: Aneurysm; endovascular; flow diversion; retreatment.

Figure 1.

Patient recruitment and cohort development. PED: Pipeline Embolization Device.

Figure 2.

(a) and (b) 3D and Anteroposterior (AP) projection Digital Subtraction Angiography (DSA) images demonstrating a right M1 aneurysm (white arrow) with perforator lenticulostriate arteries arising from the aneurysm dome (black arrows). (c) Twelve-month follow-up after single Pipeline Embolization Device (PED) placement with residual filling of the dome. (d) Six-month follow-up after placement of second PED now with obliteration of the aneurysm sac (white asterisk) and preserved perforator flow (black arrows).