We conducted a nationwide study over a one year period (July 1, 1995-June 30, 1996) to elucidate the incidence, clinical and radiological features, outcome, and factors influencing the poor outcome in intracranial arterial dissection.
The subjects of the study were 357 patients with intracranial arterial dissection reported from 208 neurosurgical institutes. Those were divided into two groups: a hemorrhagic group of 206 patients (58%) presenting with subarachnoid hemorrhage, and a nonhemorrhagic group of 151 patients (42%) manifesting brain ischemia, headache or, asymptomatic. In addition, 322 patients (90%) had a single lesion, and 35 (10%) had multiple lesions. Among 322 patients in the single-lesion group, 299 (93%) had a lesion in the vertebrobasilar system, and only 23 (7%) in the carotid system.
Results: 1) Age and sex: Patients were younger in the nonhemorrhagic group, and in the group with lesions in the carotid system. Males were predominant in both the hemorrhagic and nonhemorrhagic groups, and in the group with lisions in the vertebrobasilar system. 2) Location of arterial dissection: the vertebral artery was most frequently affected in 84% of the hemorrhagic group, and in 77% of the nonhemorrhagic group. 3) Angiographical findings: Dilatation with or without contrast media retention was the most common finding in both the hemorrhagic and nonhemorrhagic groups. Narrowing or occlusion with or without retention was most prevalent in the carotid system, whereas dilatation with or without retention was most common in the vertebrobasilar system. 4) Treatment: Sixty-one percent of the patients was surgically treated in the hemorrhagic group, while 82%were conservatively managed in the nonhemorrhagic group. 5) Outcome: Fifty-three percent of the patients recovered well, and 27% died in the hemorrhagic group. Seventy-nine percent made a good recovery and only 3%died in the nonhemorrhagic group. The outcome did not significantly differ between those with lesions in the carotid and vertebrobasilar systems. 6) Causes of poor outcome: Rebleeding and primary brain damage were the leading causes of poor outcome in the hemorrhagic group, whereas brain infarction was the main cause in the nonhemorrhagic group.
These results were, on the whole, consistent with the data, accumulated from the literature. It could be said that the data in the present study would have established the clinical pictures of the intracranial arterial dissection.