Treatment of Unruptured Vertebral Artery Dissecting Aneurysms

We retrospectively investigated the clinical and angiographic follow-up results of intracranial vertebral artery (VA) dissection initially presented without subarachnoid hemorrhage (SAH) to clarify its management. Forty-one patients with VA dissection initially presenting without SAH were studied. Initial angiography revealed pearl and string sign in 18, double lumen sign in 4, aneurysmal dilatation with double lumen in 2, only aneurysmal dilatation in 6, occlusion in 7, and string-like stenosis in 4. Twenty patients, including 6 with subsequent SAH, underwent endovascular treatment (parent artery occlusion in 16 and stent-assisted coil embolization in 4). The other 21 patients were treated conservatively. The intervals between the onset and SAH were 1 day (2 patients), 3 days (2 patients), 14 days (1 patient) and 51 months (1 patient). One of the 16 patients treated by parent artery occlusion suffered from ischemic complications. Stent-assisted coil embolization was safely performed in all of the 4 patients. Follow-up angiography of the 37 patients showed deterioration in 14, complete resolution or improvement in 9, and no change in 14. Thirty-seven patients achieved good recovery, and 4 patients remained moderately disabled due to the initial ischemic attack. Although the natural history of unruptured VA dissection is still unknown, endovascular treatment should be considered for patients with a relatively large or growing aneurysmal dilatation because prognosis of the patients with subsequent SAH is poor.