Improvement and Aggravation of Spontaneous Unruptured Vertebral Artery Dissection

Abstract

Background: Intracranial vertebral artery dissection (VAD) is a well-recognized cause of stroke in young and middle-aged individuals, especially in Asian populations. However, a long-term natural course remains unclear. We investigated the long-term time course of VAD using imaging findings to examine the rate and predisposing factors for improvement.

Methods: We registered 56 consecutive patients (40 males; mean age, 51.8 ± 10.7 years) with acute spontaneous VAD and retrospectively investigated neuroimaging and clinical course within 1 month and at 3 months ± 2 weeks, 6 months ± 2 weeks, and 12 months ± 2 weeks after onset to ascertain predisposing factors and time course for improvement.

Results: The most common presenting symptoms were headache and/or posterior neck pain, seen in 41 patients (73%). Magnetic resonance imaging showed brainstem and/or cerebellum infarction in only 32 patients (57%). Of the 56 VADs, 16 (28%) presented with pearl and string sign, 5 (9%) with pearl sign, 15 (27%) with string sign, and 20 (36%) with occlusion sign. VAD occurred on the dominant side in 20 patients and on the nondominant side in the other 36 patients. The pearl and string sign was more frequently noted on the dominant side than on the nondominant side (50 vs. 17%, p = 0.008). On the other hand, occlusion occurred more often on the nondominant side than on the dominant side (47 vs. 15%, p = 0.016). Furthermore, the pearl and string sign was more frequently seen in the improvement group (41 vs. 15%, p = 0.028), whereas the occlusion sign was evident more frequently in the nonimprovement group (21 vs. 52%, p = 0.015). Follow-up neuroimaging evaluation was performed at 1 and 3 months in 91% each, and at 6 and 12 months in 82% each. VAD aggravation was identified within 1 month after onset in 14%, while VAD improvement was seen in 14, 38, 50, and 52% at each period, mainly within 6 months after onset. Older patients and current smoking were negatively associated with VAD improvement.

Conclusions: VAD improvement primarily occurs within 6 months after onset, and VAD aggravation within 1 month. It seems that older patients and current smoking are negative predictors of VAD improvement as risk factors, and as image findings, the pearl and string sign is a positive predictor and occlusion a negative predictor.

Keywords: Asian ethnicity; Risk factor; Smoking; Vascular imaging; Vertebral artery dissection.

Fig. 1.

The proportion and time course of achieving vertebral artery dissection (VAD) improvement at 1, 3, 6, and 12 months of follow-up is shown. Improvement mainly occurred up to 6 months after onset. * p < 0.05, McNemar test.

Fig. 2.

Changes in the right vertebral arterial angiographic findings during 6 months in a 36-year-old man who developed vertebral artery dissection with sudden-onset right occipital pain. a Angiogram 10 days after the onset demonstrated pearl and string sign, with dilation (arrowhead) of the right vertebral artery at the branching of the posterior inferior cerebellar artery with distal stenosis (arrow). b On day 21, there was no significant change. c On day 91, both dilation and stenosis improved. d The 6-month follow-up angiogram showed almost normal morphology of the right vertebral artery.