Intracranial arterial occlusion is a major cause of stroke. Basilar artery thrombosis is particularly morbid. While we aim to treat middle cerebral artery and anterior cerebral artery occlusions within 3-4 hours of symptom presentation using tissue plasminogia activator thrombolysis.

Treatment of basilar artery thrombosis is generally approached differently from other intracranial thromboses due to the grave prognosis if blood flow is not reestablished. Published mortality exceeds 90% with major morbidity almost invariable in the survivors. Although the dictum that the sooner treatment is initiated, the greater likelihood of a favorable outcome still holds, the six hour window for treatment is largely not applied as the risk of cerebral hemorrhage is weighed against the prognosis if untreated. Treatment is therefore more often dictated by the possibility of recovery and the morbidity of the treatment (i.e. a stable patient who has been "locked in" for twelve hours is probably not a good candidate for possible PCA embolization). Interestingly, hemorrhagic complications are less common than in other distributions. Generally, the milder the deficit, the better collateral circulation and the younger the patient, the better the outcome. Unfortunately, these are the patients in whom treatment is less likely to be entertained.

Basilar artery thrombosis should be considered a different entity from MCA or other intracranial arterial occlusions for the purposes of endovascular intervention. Not only is the untreated risk considerably higher, but meaningful improvement can be seen in the patients who are treated several hours and occasionally more than a day following their ictus.