The Source for Neurovascular News and Education

July 28, 2021


A small study has demonstrated safety and efficacy, with no serious complications.


Selected bifurcation aneurysms can be successfully treated using a flow-diverter stent, according to a small retrospective study.


Commenting on the findings for Neurovascular Exchange, Laurent Pierot, MD (Hôpital Maison-Blanche, Reims, France), pointed out that “the use of flow diversion in the treatment of bifurcation aneurysms is controversial. Indeed, it implies the coverage of some branches of the bifurcation, with a risk of occlusion and stroke.”


The new findings were published online December 21, 2018, ahead of print in the Journal of Neurosurgery.


In the paper, researchers led by Caterina Michelozzi, MD (Hôpital Pierre-Paul Riquet, CHU de Toulouse, France), report on their results with 29 patients (14 female) with 30 aneurysms who were treated using a flow-diverter stent between January 2010 and September 2017.


Overall, 21 aneurysms were located in the middle cerebral artery bifurcation, eight in the anterior communicating artery region, and one in the pericallosal artery. A total of 35 cortical branches were covered. All patients were treated using a single flow-diverter stent. Devices used included the Pipeline embolization device (ev3/Covidien) in 15 patients; the flow redirection endoluminal device (MicroVention) in 12 patients; and the SILK flow diverter (Balt Extrusion) in two patients.


Follow-up time was 21 ± 14.5 months for digital subtraction angiography (DSA) and 19 ± 16 months for MRI. In the 24 patients with available data, the mean time to aneurysm sac occlusion, including stable remodeling, was 11.8 (median 13).


The occlusion rate was 82.1% (23/28) in the overall group and 91.7% (22/24) in the subset of patients with at least two DSA control sequences. One recanalization occurred at 41 months posttreatment.


At the latest follow-up, seven of 35 covered branches (20%) were occluded, 51.4% showed a decreased caliber, and the remaining 28.5% were unchanged.


No patients experienced permanent complications with poor prognosis (mRS score > 2). One patient, however, did have permanent morbidity (stroke) due to a jailed branch occlusion, with an mRS score of 2 at last follow-up.


MRI T2-weighted sequences showed complete sac reabsorption in seven out of 29 aneurysms (24.1%). The remaining lesions were either smaller (55.2%) or unchanged (17.2%). MRI revealed asymptomatic ischemic events in perforator territories in seven out of 28 patients (25%) and symptomatic events in four patients (14.3%); these were reversible within 24 hours.


Better Than Prior Outcomes


“The same team published a preliminary experience a few years ago showing relatively [poor] results,” noted Pierot. “In this paper, they analyze a larger series of patients [and showed] good safety and efficacy with the technique.


“These results show that, in selected bifurcation aneurysms, flow diversion is a good option with good safety and efficacy,” he continued. He acknowledged, however, that the findings are limited by the retrospective, single-center design of the study and the small number of patients.


Unanswered questions, said Pierot, include which factors are associated with ischemic complications and what the respective roles are for the different endovascular techniques in the management of complex bifurcation aneurysms.


He also recommended that outcomes of aneurysms treated in the middle cerebral and anterior communicating arteries be evaluated separately, since the safety and efficacy of flow diversion is potentially different in these two locations.




Michelozzi C, Darcourt J, Guenego A, et al. Flow diversion treatment of complex bifurcation aneurysms beyond the circle of Willis: complications, aneurysm sac occlusion, reabsorption, recurrence, and jailed branch modification at follow-up. J Neurosurg. 2018;Epub ahead of print.



Michelozzi and Pierot report no relevant conflicts of interest.