Vertebral artery hypoplasia and the posterior circulation stroke

Vertebral artery hypoplasia and vertebral artery dissection

“…12 In 1980, researchers noted that the smaller of a pair of arteries was more likely than the larger to occlude, and raised the question of whether congenitally hypoplastic vessels were more prone to occlusion. 1,[3][4][5][6][7] The observed relationship between VAH and sVAD, including the ipsilateral tendency, is similar to that between VAH and posterior circulation stroke. 1,[3][4][5][6][7] The observed relationship between VAH and sVAD, including the ipsilateral tendency, is similar to that between VAH and posterior circulation stroke.…”

“…13 Subsequent cohort studies verified this relationship, demonstrating that VAH is a risk factor for posterior circulation stroke, which tends to occur ipsilaterally. It may be related primarily to VA asymmetry, rather than subsequent obstruction of any etiology, and thus involve the physics of blood flow and sheer forces, 6,14 which would contribute to our understanding of the similarity of results. The mechanism underlying this relationship, however, remains incompletely understood.…”

“…18 Previous studies may have underestimated the frequency with which dissection causes VAH-related ischemic stroke. 6 VAH-related stroke may thus be associated with an etiology that tends to affect younger individuals, such as dissection. 6 VAH-related stroke may thus be associated with an etiology that tends to affect younger individuals, such as dissection.…”

Possible Morphological Pathomechanisms of Ischemic Stroke in the Posterior Circulation of Patients with Vertebral Artery Hypoplasia

“…[14][15][16] Emerging evidences suggest that vertebral artery hypoplasia may contribute to posterior circulation ischemic events, especially when other risk factors coexist. 8,9,17,18 As long as the collateral blood supply is preserved (via the circle of Willis, the sufficiency of the anterior circulation, the cervical collaterals, the compensatory hyperperfusion of the contralateral vertebral artery), the clinical severity of a congenital variation (hypoplasia) in the vertebral artery remains hidden. If the supplemental system fails and the compensatory mechanisms are exhausted, this can lead to stroke.…”

“…It is not negligible, that the vertebral artery hypoplasia in coexistence with known risk factors for stroke may increase their negative clinical impact. 17 Based on these findings the purpose of the current work is to try to find the possible pathomechanism of stroke in the vertebrobasilar territory in the presence of VAH.…”