ISCHEMIC STROKE / CLASSIFICATION AND ETIOPATHOGENESIS

Created 16/12/2021, last revision 05/12/2022

• a progressive disease characterized by dilatation + tortuosity of the arteries; sometimes called dilated arteriopathy
  • the vertebrobasilar arteries are most commonly affected (⇒ vertebrobasilar dolichoectasia or megadolichobasilar artery)
  • ICA is also at high risk of being affected
• incidence 0.06-6% [Brutto, 2021]
• poses an increased risk of stroke recurrence (up to 19%/2 years) [Chen, 2019]
• may cause some “cryptogenic” strokes [Brutto, 2021]
• the characteristics listed below also apply to large fusiform aneurysms

Pathophysiology

Etiology

• atherosclerosis (atherosclerotic dolichoectasia)
  • affects both intra-/extracranial arteries
  • usually age > 40 years
  • typical vascular risk factors (e.g., hypertension) are present
• congenital disorders  (non-atherosclerotic dolichoectasia)
  • age < 40 years, more common in women, distal branches of the posterior circulation are affected
  • Marfan syndrome, Ehler-Danlos, Fabry disease
• dolichoectasia secondary to dissection

Clinical presentation

• ischemic stroke/TIA (30% in 5 years)
• intracranial bleeding, subarachnoid hemorrhage
• brainstem compression (basilar dolichoectasia), hydrocephalus
• neurovascular compression syndrome (NVCS)
  • compression of the optic nerve at the optic chiasma (ICA)
  • impairment of one or more cranial nerves is associated with a tortuous and elongated BA (n. VII, VIII, VI)

• factors affecting the clinical outcome:
  • the severity of arterial dilation and lateral shift
  • signs and symptoms at the time of the diagnosis
  • presence of mural thrombi
  • ectasia progression on follow-up imaging

Diagnostic evaluation

• CTA/MRA/DSA
  • enlargement and kinking of the artery with lateral shift
    • basilar arterial diameter > 4.5 mm
  • sometimes intraluminal thrombi can be detected
  • distinguish ectasia from fusiform aneurysm
• neurosonology
  • decreased flow velocity

Management

Prognosis

• from asymptomatic to malignant forms
• progression is more common in younger patients with ectasia in the anterior circulation
• a relatively high risk of stroke recurrence (up to 60% / 11 years)