Objective: Delayed spontaneous aneurysm rupture is an uncommon but well recognized complication following flow diverter placement for the treatment of intracranial aneurysms. Concurrent coil embolization of the aneurysm along with flow diverter deployment is commonly used, under the assumption that coiling reduces the risk of delayed rupture. However, concurrent coiling adds expense and time to the procedure, and it is not known whether concurrent coiling actually reduces the risk of delayed rupture.
Methods: This is a retrospective case-control study. Twelve centers provided data on patients with unruptured internal carotid artery aneurysm ≥10mm undergoing treatment with flow diversion. Cases were identified as those experiencing delayed spontaneous aneurysm rupture ≤ 30 days after treatment and each case was matched to five control patients not experiencing rupture. The rate of coil placement as well as data on demographics, medical history, aneurysm characteristics, and procedural details were collected.
Results: Seven cases of delayed spontaneous rupture were identified, four of which were fatal. The interval between procedure and rupture ranged from 0-10 days, with a mean of 2.7 days. Cases and controls did not differ significantly in sex, smoking history, family history of aneurysm, aneurysm laterality, or size. Patients with delayed ruptures were more likely to have aneurysm occlusion at the end of the case (p=0.049). The rate of coil usage was 22% for both cases and controls. The odds ratio that coils protect against delayed rupture is 1.00 [CI 0.24, 4.96].
Conclusions: This study suggests that concurrent coil embolization does not reduce the risk of delayed rupture of aneurysms treated with flow diversion.