Safety and Effect of Flow Diverters in the Management of Large and Giant Unruptured Intracranial Aneurysms.

Purpose: To investigate the safety and effect of flow diverters in the management of large and giant unruptured intracranial aneurysms and risk factors for complete aneurysm occlusion at a long-term follow-up.

Materials and methods: Patients with large and giant unruptured intracranial aneurysms treated with flow diverters (Pipeline and Tubridge embolization devices) were retrospectively enrolled. The clinical data, peri-procedural complications, occlusion status of aneurysms, and factors affecting aneurysm occlusion were analyzed. Subanalyses between large and giant aneurysms or between saccular and fusiform aneurysms were also performed.

Results: Ninety-two patients with 95 intracranial aneurysms were enrolled. Most aneurysms involved the internal carotid artery (77.9%). The size of the aneurysm was 10-25 mm in 81 (85.3%) and > 25 mm in 14 (14.7%). The procedure was successful in all patients (100%). At discharge, the mRS was 0 in 72 (78.3%) patients, 1 in 15 (16.3%), 2 in three (3.3%), 3 in one (1.1%), and 6 in one (1.1%). Four patients (4.3%) who had undergone PED (Pipeline embolization device) implantation experienced post-procedural complications. Follow-up was performed in 77 (83.7%) patients 6-65 (median 39) months after embolization, and 55 (71.4%) patients with 56 aneurysms experienced imaging follow-up. At the last angiographic follow-up 6-62 months (median 37) after the procedure, four (7.1% or 4/56) patients had instent stenosis, and total aneurysm occlusion with OKM (O'Kelly-Marotta) grade D was in 45 aneurysms (80.4%). Flow diverter combined with coiling is a single independent factor affecting complete aneurysm occlusion (OR = 8.98, 95% CI 1.87-43.22, p = 0.006). In subanalysis, the treatment modality was significantly (p = 0.04) different in the large versus giant aneurysms, with diversion plus coiling being performed in all 14 giant aneurysms but only in 43 (53.1%) large ones. Follow-up angiographic occlusion of aneurysms was significantly (p = 0.04) better in giant aneurysms than in large ones.

Conclusion: The Pipeline and Tubridge flow diverting devices seem safe and effective in the treatment of large and giant unruptured intracranial aneurysms, and flow diverter combined with coiling is an independent risk factor for complete aneurysm occlusion at the long-term follow-up even though serious peri-procedural complications remain to be solved.