A nationwide study (VAD 2013) was conducted over a year (January 1 to December 31, 2011) to elucidate the recent trends of the clinical features, radiographic findings, treatment, and outcomes of non-traumatic intracranial arterial dissection in the vertebrobasilar system. Here, we present the outline of the study.
In this study, 632 patients from 172 neurosurgical institutes were enrolled. They were divided into 3 groups: (1) hemorrhage group consisting of 193 (30.5%) patients with subarachnoid hemorrhage; (2) ischemia group consisting of 209 (33.1%) patients with brain infarction or transient ischemic attack; and (3) headache group consisting of 230 (36.4%) patients. The following patient characteristics were recorded: age, sex, location of arterial dissection, initial radiographic findings, and serial changes in these findings, treatment, follow-up periods, and mid-term outcomes. The outcomes were evaluated using the modified Rankin scale (mRS), and a good outcome was defined as an mRS score of 0-2.
Results: (1) Age and sex: The median age of the patients was 53, 52, and 50 in the hemorrhage, ischemia, and headache groups, respectively. Men outnumbered women in all the 3 groups; especially, in the ischemia group, the number of men was remarkably higher than that of women. (2) Location of arterial dissection: The vertebral artery was affected in 85% of the patients in both the hemorrhage and ischemia groups, and in 97% of the patients in the headache group. (3) Radiographic findings: Fusiform dilatation and pearl-and-string sign were the common findings in the hemorrhage group, whereas tapering string and occlusion were more frequent in the ischemia group. Regarding serial changes of the radiographic findings, improvement of the finding was the most common, followed by no change in both the ischemia and headache groups.(4) Treatment: Surgical treatment was administered to 82% of the patients, and endovascular surgery was the main procedure adopted for the hemorrhage group. In contrast, conservative treatment was administered to a majority of the patients in the ischemia and headache groups. Antithrombotic therapy was administered to 79% of the patients in the ischemia group, and to 17% in the headache group. (5) Follow-up periods: The median follow-up period was 5, 10, and 12 months in the hemorrhage, ischemia, and headache group, respectively. (6) Mid-term outcomes: Good outcomes were observed in 57% of the patients in the hemorrhage group; however, 26% of the patients in this group died. Furthermore, good outcomes were observed in 85% and 98% of the patients in the ischemia and headache group, respectively; the mortality rate in these 2 groups was rather low.
These data were compared to those of the previous studies, such as the nationwide study in 1995-96 by Yamaura et al. The number of patients in the headache group was higher in this than in the previous studies. The number of patients with hemorrhage who received surgical treatment, especially endovascular surgery, was higher in this than in the previous studies. Furthermore, the number of patients in the ischemia and headache groups who received antithrombotic therapy was higher in this than in the previous studies. However, the clinical features, radiographic findings, and outcomes did not differ significantly between the present study and the previous studies.