Comparison of potential risks between intracranial and extracranial vertebral artery dissections

Background/Aims: To better understand potential risks for vertebral artery (VA) dissection (VAD), we compared intracranial and extracranial VADs. Methods: We analyzed consecutively admitted VAD patients over a 9-year period in whom VAD was confirmed by angiography. All patients were categorized as having intracranial or extracranial VAD, and demographic and radiological characteristics of VAD were compared. We used multivariate analysis to predict the risks for intracranial and extracranial VADs. Results: The study population (n = 74) had a mean age of 46.0 ± 10.3 years. VAD was more frequent in the nondominant VA (n = 49, 66.2%). Vertical nidus of VAD was more common in the intracranial segment (81.1%), and more particularly it was most frequently located within a 2-mm perimeter of the posterior inferior cerebellar artery (PICA) orifice (60.0%). Absence of traumatic history (OR 13.1, 95% CI 1.6-107.4; p = 0.016), history of hypertension (OR 14.1, 95% CI 1.1-184.6; p = 0.043) and aging (OR 1.1 per 1-year increase, 95% CI 1.0-1.2; p = 0.038) were independent predictors of intracranial VAD. Conclusion: As compared to extracranial VAD, intracranial VAD was particularly frequent and particularly vulnerable at the perimeters of the PICA and nondominant VA and was associated with an absent trauma history, hypertension and aging. Formation of VAD appeared to be different according to intracranial or extracranial involvement.