Outcomes After Off-Label Use of the Pipeline Embolization Device for Intracranial Aneurysms: A Multicenter Cohort Study

Objective: To examine outcomes of Pipeline embolization device (PED) use for treatment of intracranial aneurysms outside of U.S. Food and Drug Administration–approved indications. Methods: Data from patients with aneurysms treated with off-label use of PED were pooled from 4 centers in a retrospective multicenter cohort study. Primary endpoints were decline in modified Rankin Scale score by at least 1 point and angiographic aneurysm occlusion at follow-up. Results: The study cohort comprised 109 patients. Mean aneurysm size was 8.4 ± 7.4 mm, 20.2% of aneurysms were located in the posterior circulation, and 11.9% of aneurysms were ruptured. The most common reasons for off-label use were aneurysm size (50.5%), aneurysm location (25.7%), and both size and location (10.1%). Mean follow-up was 9 months. Complete occlusion was achieved in 82.5% of cases at last angiographic follow-up. Modified Rankin Scale score decline was found in 18.8% of cases. On univariate analysis, age, aneurysm size, aneurysm morphology, aneurysm location, reason for off-label use, and rupture status were not associated with clinical decline or aneurysm occlusion on angiography. On multivariate analysis, treatment of a ruptured aneurysm with PED was found to be an independent predictor of postoperative decline in modified Rankin Scale score, and size as the only reason for off-label PED use was found to be an independent predictor of complete occlusion on final angiography. Conclusions: Off-label use of PED has a reasonable risk-to-benefit profile for appropriately selected aneurysms. Posterior circulation location and fusiform morphology do not appear to be associated with worse clinical or angiographic outcomes.