Proximal occlusion of the vertebral artery is regarded as a safe and effective method of treating
aneurysms of the vertebral artery or the vertebrobasilar junction unsuitable for treatment by neck clipping. Complications known to develop after this procedure include ischemic lesions of the perforators and other areas. There are only a limited number of reports on early
rupture of
aneurysm following proximal occlusion of the vertebral artery for the treatment of unruptured
aneurysm. We recently encountered a case of large
aneurysm of the vertebral artery identified after detection of brainstem compression. This patient underwent proximal occlusion of the vertebral artery with a coil and developed a fatal
rupture of the
aneurysm ten days after proximal occlusion. The patient was a 72-year-old woman who had complained of
dysphagia and unsteadiness for several years. An approximately 20 mm diameter
aneurysm was detected in her left vertebral artery. She underwent endovascular treatment, that is, her left vertebral artery was occluded with coils at a point proximal to the
aneurysm. Her initial post-procedure course was uneventful. However, she suddenly developed right-side
hemiparesis nine days after procedure. At that time, CT scan suggested sudden
thrombosis of the
aneurysm. Right vertebral angiography revealed a small part of the
aneurysm. She was treated conservatively. Ten days after the procedure, she suffered massive subarachnoid haemorrhage. Both the present case and past reports suggest that proximal occlusion of the vertebral artery is effective in treating relatively large
aneurysms unsuitable for treatment by neck clipping or trapping. However, when the bifurcation of the posterior inferior cerebellar artery (
PICA) is distal to the occluded point in cases where the
PICA bifurcates from the
aneurysm or the neck region, blood supply to the
aneurysm may persist because anterograde blood flow to the
PICA may be preserved. Therefore, clinicians must consider the possibility of
aneurysm rupture after proximal occlusion in the following cases: 1) when the
aneurysm is large or giant, but non-thrombosed; 2) when
thrombosis occurs soon after the procedure; 3) when postoperative angiography shows partial filling of the
aneurysm with
contrast agent through the contralateral vertebral artery of basilar artery or the cervical muscle branches.