Flow Diverter Devices for the Treatment of Unruptured Vertebral Artery Dissecting Aneurysm

Abstract

Objective: Vertebral artery dissecting aneurysm (VADA) is a very rare subtype of intracranial aneurysms; when ruptured, it is associated with significantly high rates of morbidity and mortality. Despite several discussions and debates, the optimal treatment for VADA has not yet been established. In the last 10 years, flow diverter devices (FDD) have emerged as a challenging and new treatment method, and various clinical and radiological results have been reported about their safety and effectiveness. The aim of our study was to evaluate the clinical and radiological results with the use of FDD in the treatment of unruptured VADA.

Methods: We retrospectively evaluated the data of all patients with unruptured VADA treated with FDD between January 2018 and February 2021 at our hybrid operating room. Nine patients with unruptured VADA, deemed hemodynamically unstable, were treated with FDD. Among other parameters, the technical feasibility of the procedure, procedure-related complications, angiographic results, and clinical outcomes were evaluated.

Results: Successful FDD deployment was achieved in all cases, and the immediate follow-up angiography showed intra-aneurysmal contrast stasis with parent artery preservation. A temporary episode of facial numbness and palsy was noted in one patient; however, the symptoms had completely disappeared when followed up at the outpatient clinic 2 weeks after the procedure. The 3-6 months follow-up angiography (n=9) demonstrated complete/near-complete obliteration of the aneurysm in seven patients, and partial obliteration and segmental occlusion in one patient each. In the patient who achieved only partial obliteration, there was a sac 13 mm in size, and there was no change in the 1-year follow-up angiography. In the patient with segmental occlusion, the cause could not be determined. The clinical outcome was modified Rankin Scale 0 in all patients.

Conclusion: Our preliminary study using FDD to treat hemodynamically unstable unruptured VADA showed that FDD is safe and effective. Our study has limitations in that the number of cases is small, and it is not a prospective study. However, we believe that the study contributes to evidence regarding the safety and effectiveness of FDD in the treatment of unruptured VADA.

Keywords: Aneurysm, dissecting; Endovascular procedures; Intracranial aneurysm; Vertebral artery.

Fig. 1.

Case No. 6. A : digital subtraction angiography (dSA) shows a vertebral artery dissecting aneurysm (23×11 mm). B : A small posterior inferior cerebellar artery originating at dissecting segment, but a connection with the anterior inferior cerebellar artery is observed. C : A Pipeline embolization device (Ped) was appropriately deployed to adequately cover the dissecting segment without crossing the contralateral vertebrovasilar junction. The arrows indicate the distal/proximal tip position of the Ped. d : dSA follow-up 15 minutes after the procedure shows no abnormalities. e : A diffusion weighted image performed the day after the procedure shows a small infarction at the medulla oblongata. f : Three months follow-up dSA shows that the lesion where the Ped was deployed is completely occluded. The size of the vertebral artery is also reduced due to the occluded lesion. g and h : Blood flow through the contralateral vertebral artery and retrograde collateral flow through the posterior communicating artery fills the occluded right vertebral artery territory.

Fig. 2.

Case No 1. A : digital subtraction angiography (dSA) showing a vertebral artery dissecting aneurysm (8×6 mm). B : flow Redirection endoluminal device (fRed; 2.5×18) was deployed across the aneurysm neck. C : Six-month follow-up dSA shows marked reduction in the size of the aneurysm. however, until the venous phase, the contrast stagnation is retained in the part of the aneurysm. d : Twelve-month follow-up dSA demonstrates a completely remodeled normal vertebral artery.

Fig. 3.

Case No. 3. A : Contrast magnetic resonance imaging to confirm brain metastasis of lung cancer shows a thrombosed aneurysm. B : In digital subtraction angiography (dSA), a dissecting aneurysm is observed with a large sac involving the origin of the posterior inferior cerebellar artery. C : flow Redirection endoluminal device (fRed) was deployed without crossing the contralateral vertebrobasilar junction and including across the aneurysm neck. d : The size of the aneurysm was reduced in dSA at 3-month follow-up dSA. however, it has reduced by more than 50%, and a large amount of contrast agent still fills the aneurysm. e : Twelve-month follow-up dSA, shows no difference compared to the previous exam.