Endovascular management of vertebrobasilar dissecting aneurysms

Abstract

Background and purpose: Several approaches to the treatment of dissecting aneurysms of the vertebrobasilar system have been used. We evaluated our endovascular experience, which includes trapping and proximal occlusion.

Methods: Thirty-five patients with intradural vertebrobasilar dissecting aneurysms presented to our institution between 1992 and 2002. Twenty-six were treated by endovascular means and two with surgery. In the endovascular group, 14 were in a supra-posterior inferior cerebellar artery (PICA) location, and three of these extended to the vertebrobasilar junction on the initial angiogram. Ten were located in an infra-PICA location, or no antegrade flow was seen in the PICA or anterior spinal artery. Two were located at the PICA with antegrade flow preserved in the branch. Twelve lesions were treated with trapping; another 14 were initially treated with proximal occlusion techniques, two of which eventually required trapping procedures. Follow-up images were obtained within 1 year of initial treatment in 24 patients. Mean follow-up for these patients was 3.5 years.

Results: Initial treatments were technically successful and without complication in all 26 patients. Follow-up examinations showed complete cure in 19 of 24 patients. One patient died of global ischemia after presenting as Hunt and Hess grade 5 with subarachanoid hemorrhage. Two recurrent hemorrhages occurred in patients in the proximal occlusion group; one died, and the other underwent a trapping procedure. One patient developed contralateral vertebral dissection 24 hours after occlusion of a dissecting aneurysm of the dominant vertebral artery and died of a brain stem infarct. Another died of probable vasospasm, and the last died of an unknown cause 1 month after treatment. Two patients had recanalization despite an initial trapping procedure, both underwent further treatment. Mortality rate was 20% in the treated group (including the two patients treated surgically), with four of five deaths occurring during the initial hospital course. Mortality rate was 50% in the six patients in the untreated group who were available for follow-up.

Conclusion: Dissecting aneurysms of the vertebrobasilar system remain high-risk lesions because of their natural history. They can be managed by endovascular methods according to aneurysm location, configuration, collateral circulation, and time of presentation. Trapping results in better prevention of rehemorrhage. Proximal occlusion can achieve occlusion without manipulation of the affected segment when more direct endovascular occlusion or stent placement cannot be performed.

Fig 1.

Patient 25. A, Anteroposterior and B, lateral diagnostic angiograms demonstrate a dissecting aneurysm of the dominant left vertebral artery involving the supra-PICA segment and proximal basilar artery (arrow). Arrowhead indicates the pseudoaneurysm. C, Lateral view of the left internal carotid artery injection shows good collateral circulation to the basilar artery (arrow) through the posterior communicating artery after proximal occlusion of the left vertebral artery. Arrowhead indicates the tip of the distal balloon. D, Two-year follow-up left internal carotid artery angiogram in the lateral projection shows interval thrombosis of the pseudoaneurysm and dissected segment of the left vertebral artery. The basilar artery (arrow) appears less irregular.

Fig 2.

Patient 27. A, Anteroposterior angiogram of the left vertebral artery shows irregular narrowing of the supra-PICA segment (arrow) and a pseudoaneurysm at the vertebrobasilar junction (arrowhead). The anterior spinal artery and left PICA are not included in the abnormal segment. B, Anteroposterior angiogram of the right vertebral artery shows a codominant vessel with full delineation of the vertebrobasilar junction pseudoaneurysm (arrowhead). The dissection extends in the basilar artery to include the AICA origins (arrow). C, Posttreatment angiogram of the right vertebral artery shows coil occlusion of the vertebrobasilar junction pseudoaneurysm (arrowhead). D, Posttreatment angiogram of the left vertebral artery shows proximal occlusion of the supra-PICA segment of the vessel with preservation of flow in the anterior spinal artery (arrow) and PICA.

Fig 3.

Patient 11. A, Anteroposterior angiogram of the left vertebral artery demonstrates irregularity of the lumen (arrow) and a 4–5-mm pseudoaneurysm (arrowhead) near the PICA origin. B, Lateral angiogram of the left vertebral artery shows the small pseudoaneurysm (arrow). C, Lateral angiogram of the right vertebral artery at the time of rehemorrhage 2 weeks after proximal occlusion of the left vertebral artery shows that the pseudoaneurysm (arrow) has not enlarged and the left PICA remains patent. D, Anteroposterior angiogram of the right vertebral artery after delivery of coils across the vertebrobasilar junction into the pseudoaneurysm shows the lesion is occluded (arrow), with the PICA filling antegrade

Fig 4.

Patient 22. A, Anteroposterior angiogram of the right vertebral artery shows a dissection of this codominant vertebral artery (black arrow) and psuedoaneurysm (arrowhead). Note the fenestration in the basilar artery (white arrow). B and C, Follow-up angiograms of the right (B) and left (C) vertebral arteries, respectively, show no residual aneurysm. D, Follow-up angiogram 1 year later shows recurrence of the dissecting aneurysm (arrow) proximally in the left vertebral artery to involve the PICA. The coil mass has compacted (arrowhead).