What is the pathophysiology of vertebral artery dissection (VAD)?

Updated: Feb 21, 2019
  • Author: Eddy S Lang, MDCM, CCFP(EM), CSPQ; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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This intramural hemorrhage can evolve in a variety of ways, resulting in any of the following consequences:

  • The hematoma may seal off and, if sufficiently small, remain largely asymptomatic.

  • If the dissection is subintimal, the expanding hematoma may partially or completely occlude the vertebral artery or one of its branches. Extensive dissections (those that extend intracranially and involve the basilar artery) result in infarctions of the brainstem, cerebellum or, rarely, the spinal cord. Subintimal dissections also may rupture back into the vertebral artery, thus creating a false lumen (pseudolumen).

  • Subadventitial dissections tend to cause pseudoaneurysmal dilation of the vertebral artery, which may compress adjacent neurologic structures. These subadventitial dissections are prone to rupture through the adventitia, resulting in subarachnoid hemorrhage. In an autopsy series of more than 100 patients with subarachnoid hemorrhage, 5% of the hemorrhages were deemed the result of VAD.

  • The intimal disruption and low flow states that arise in VAD create a thrombogenic milieu in which emboli may form and propagate distally. This results in transient ischemia or infarction.

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