Flow diverters versus stent-assisted coiling in unruptured intracranial vertebral artery dissecting aneurysms

OBJECTIVE Flow diverters (FDs) have been used in unruptured intracranial vertebral artery dissecting aneurysms (IVADAs) with seemingly more favorable outcomes compared with stent-assisted coiling (SAC). However, the benefits of FDs over SAC in unruptured IVADAs need further evaluation. METHODS This was a propensity score-matched, retrospective cohort study. Consecutive patients with unruptured IVADAs treated with FDs or SAC at the authors' hospital between January 2016 and December 2020 were reviewed. Propensity score matching at 1:1 was based on age, significant stenosis adjacent to aneurysmal dilatation, maximum diameter, and posterior inferior cerebellar artery involvement. Periprocedural cerebrovascular complications and angiographic and clinical outcomes were compared between the two matched groups. RESULTS A total of 124 unruptured IVADAs in 123 patients (median age 53 [interquartile range 47-59] years; 101 men) were included. The FD and SAC groups included 65 and 59 IVADAs, respectively. Propensity score matching resulted in 47 matched pairs. The rates of immediate complete occlusion were significantly lower in the matched FD group than in the matched SAC group (6.4% vs 68.1%, p < 0.001). The rates of periprocedural cerebrovascular complications were comparable between the two matched groups (6.4% vs 6.4%, p > 0.99). At last follow-up, the rates of complete occlusion (89.4% vs 80.9%, p = 0.39) and favorable clinical outcomes (100.0% vs 97.9%, p > 0.99) were comparable, whereas the rate of recanalization was significantly lower in the matched FD group than in the matched SAC group (0.0% vs 12.8%, p = 0.03). Although the difference between the rates of in-stent stenosis was not statistically significant (17.0% vs 6.4%, p = 0.18), the difference in the effect measures was considerable. CONCLUSIONS In unruptured IVADAs and compared with SAC, FDs provide comparable rates of periprocedural cerebrovascular complications, favorable clinical outcomes, and follow-up complete occlusion, lower rates of immediate complete occlusion and follow-up recanalization, and likely higher rates of in-stent stenosis.