Treatment Outcomes After Single-Device Flow Diversion for Large or Giant Aneurysms.

Objective: We aimed to evaluate the efficacy and safety of single-device flow diversion in patients with aneurysms measuring ≥15 mm in diameter.

Methods: For this retrospective study, we extracted medical record data for patients with unruptured intracranial aneurysms, who underwent flow diversion, at the authors' institution between July 2014 and August 2019. The primary effectiveness outcome was defined as angiographic occlusion of the target aneurysm within 18 months without major (>50%) parent artery stenosis, major adverse events, or additional treatment.

Results: Thirty-five aneurysms in 35 patients were analyzed. Most aneurysms (n = 29, 82.9%) involved the anterior circulation. The median aneurysmal diameter was 18.3 mm, and the median neck size was 7.6 mm. Eleven (31.4%) aneurysms were considered giant (≥25 mm). The primary effectiveness outcome was achieved in 20 (57.1%) patients at a median of 10 months (interquartile range, 4.3-12.5) after flow diversion. Major adverse events occurred in 6 (17.1%) patients, including remote intraparenchymal hemorrhages (n = 2), a major ischemic stroke (n = 1), a delayed rupture of the target aneurysm (n = 1), and clinical deterioration caused by aggravated mass effect (n = 2). Multivariate logistic regression analysis found 2 independent predictors of the primary effectiveness outcome: the aneurysmal diameter (odds ratio, 0.71; 95% confidence interval, 0.54-0.86; P = 0.004) and the parent-vessel angle (odds ratio, 0.97; 95% confidence interval, 0.93-0.99; P = 0.017).

Conclusions: Single-device flow diversion was shown to be ineffective for large or giant intracranial aneurysms with a high parent vessel angle.