Parent vessel occlusion for vertebrobasilar fusiform and dissecting aneurysms

Abstract

Background and purpose: Previous reports of outcome with permanent vessel occlusion (PVO) for large, giant, or fusiform aneurysms in the posterior circulation have been limited. We undertook this study to evaluate the perioperative (within 30 days) and follow-up outcomes for patients treated with permanent occlusion of the vertebral artery for vertebrobasilar fusiform and dissecting aneurysms.

Methods: Thirteen consecutive patients were studied. Two groups were defined for the study. Group I patients underwent PVO to achieve complete thrombosis of the aneurysm. Group II patients underwent PVO to reduce flow to the aneurysm where complete thrombosis was not desirable. Modified Rankin scores were obtained at presentation and at follow-up (follow-up range, 1-76 months; mean, 22.0 months).

Results: All group I aneurysms were shown to be thrombosed on the angiograms obtained at the immediate follow-up examinations. Improvement in outcome scores was achieved by all group I patients. Improvement in Rankin scores after endovascular treatment was statistically significant (P =.026). All group II patients had complete occlusion of the vertebral artery; however, continued filling of the fusiform aneurysm was still observed. Four patients in group II died during the follow-up period. Two of these deaths were attributable to the aneurysms. Of the remaining three patients, two experienced clinical worsening and one remained stable.

Conclusion: In this series, PVO for chronic fusiform and acute dissecting aneurysms of the vertebrobasilar system proved to be a useful therapeutic endovascular technique. Long-term outcomes suggest that patients with aneurysms involving only one vertebral artery, where complete thrombosis can be achieved, have better clinical outcomes than those who have aneurysms involving the basilar artery or both vertebral arteries, where complete thrombosis cannot achieved by using PVO.

Fig 1.

Images from the case of a 46-year-old man (patient 3 in group I) who suffered SAH from a fusiform aneurysm of the distal intracranial right vertebral artery. A, Anteroposterior projection angiogram of the right vertebral artery disclosed a fusiform aneurysm of the distal intracranial portion (arrow) that is proximal to the vertebrobasilar junction and distal to the right posterior-inferior cerebellar artery (PICA, arrowhead). B, Aneurysm and distal vertebral artery were embolized with coils. Lateral projection control angiogram of the right vertebral artery, obtained after embolization, shows preservation of flow to the right posterior-inferior cerebellar and basilar arteries. C, Anteroposterior projection angiogram of the left vertebral artery shows preservation of flow to the right posterior-inferior cerebellar and basilar arteries. The patient achieved complete recovery and remained neurologically normal.

Fig 2.

Images from the case of a 71-year-old man (patient 4 in group II) with a fusiform vertebrobasilar aneurysm with mass effect on the left medulla, causing referable symptoms. A, Initial T2-weighted MR image of the posterior fossa shows mass effect and compression of the left medulla (arrows) from the aneurysmally dilated distal left vertebral artery (arrowheads). Note the high signal intensity within the aneurysm, signifying slow disturbed flow. B, Anteroposterior projection angiogram of the left vertebral artery. C, Oblique projection angiogram of the left vertebral artery shows a fusiform aneurysm extending from the distal intracranial left vertebral artery into the proximal basilar artery (arrows). Contrast material refluxed into the right vertebral artery. Note that the origin of the left posterior-inferior cerebellar artery is from the proximal basilar artery (arrowhead). The patient tolerated a 30-min temporary balloon occlusion of the left vertebral artery just proximal to the vertebrobasilar junction. D, Lateral projection angiogram of the left vertebral artery, obtained after embolization, confirms coil occlusion of the artery. E, Follow-up MR angiogram, obtained at 24 hr, shows preservation of blood flow to the posterior fossa via the right vertebral artery with high signal intensity slow flow and/or thrombus within the distal left vertebral aneurysm (arrowhead). F, Patient’s symptoms improved after embolization. Axial view T2-weighted MR image obtained 18 months after embolization shows thrombosis of the proximal aneurysmal sac, as evidenced by low signal intensity (arrowhead). G, MR angiogram obtained 18 months after embolization shows thrombosis of the proximal aneurysmal sac, as evidenced by lack of flow-related enhancement (arrows). Continued flow-related enhancement can be seen in the basilar artery (arrowhead).