Long-term follow-up study of unruptured vertebral artery dissection: clinical outcomes and serial angiographic findings

Object. Although the spontaneous occurrence of an unruptured vertebral arte ry (VA) dissection has increasingly been recognized as a relatively common cause of stroke, and the clinical aspects of this lesion have gradually bee n determined, its natural course remains obscure. The main goal of this stu dy was to clarify the management protocol for this condition by examining s erial angiographic changes in patients with unruptured VA dissections. Methods. Seventeen patients with unruptured VA dissections, including 13 me n and four women, were clinically and angiographically examined between 199 3 and 1998. All patients were observed using serial angiography studies. Th e initial angiography examinations most frequently revealed stenotic lesion s (appearance of a pearl-and-string sign or string sign) in eight (47.1%) o f 17 cases. In 15 cases (88.2%), changes in the lesions were evident on fol low-up angiography studies. Stenotic lesions resulted in occlusion in four cases, normalization in three, and subsequent formation of an aneurysm in o ne case, which was treated successfully by proximal occlusion of the affect ed vessel performed using a detachable balloon. Occluded lesions, which wer e initially observed in three patients, recanalized in two patients and rem ained unchanged in one patient. Fusiform dilation alone was demonstrated in three patients during the initial angiography session; these lesions becam e normalized or were unchanged on follow-up studies. Saccular aneurysms wer e observed in two patients. In one of these cases, proximal ligation of the parent artery was successfully performed because of subsequent aneurysm en largement. A double lumen, which appeared in one patient with an extradural VA dissection, became occluded. Magnetic resonance T-2-weighted imaging st udies revealed infarction corresponding to the posterior circulation in sev en cases. During long-term observation in this series, good or excellent re covery was obtained in 14 (87.5%) of 16 patients, and moderate or severe di sability in two (12.5%); one patient was lost to follow up after the second angiography study. Conclusions. A follow-up angiography study must be performed during the ear ly stage (within approximately 3 weeks after onset of symptoms) to confirm the formation or enlargement of an aneurysm, because such conditions may be amenable to surgical treatment. Unruptured VA dissection could otherwise b e treated and followed conservatively. Although the majority of dissected l esions seem likely to stabilize within a few months, as evidenced on angiog raphy, in some cases a longer observation period is required.