Vertebrobasilar Vasospasm after Aneurysmal Subarachnoid Hemorrhage: Review

Abstract

In the present review we outline the clinical data, diagnosis and prognosis of vertebrobasilar (VB) vasospasm (VS) after subarachnoid hemorrhage (SAH). Aneurismal SAH is associated with high rates of morbidity and mortality. Although a major advancement has been made in recent years in diagnosis and treatment of aneurysmal SAH, 30% of the patients who survived the initial bleeding show further deterioration as a results of delayed cerebral ischemia (DCI) that traditionally was associated with large arteries lasting vasospasm (VS). The diagnosis of cerebral VS is based on clinical presentation, transcranial Doppler (TCD) evaluation and perfusion imagines as significant arterial narrowing is associated with reduced cerebral perfusion in the affected territories, DCI and cerebral infarcts. Although cerebral VS in the anterior circulation was intensely studied, little is known about VS in the posterior cerebral circulation.The incidence of posterior circulation VS and basilar artery (BA) VS is lower than the incidence reported for the anterior circulation, however it is associated with worst outcome. The diagnosis of posterior circulation and BA-VS is mainly based on measurement of TCD intracranial/extracranial (IC/EC) flow velocities FVs ratio that have been correlated with arterial narrowing on computerized tomography (CT) angiography, cerebellar hypoperfusion and outcome. Within the past decade, there has been very little scientific activity to follow up on the research outlined above although TCD grading criteria for BA-VS are in widely used on daily clinical practice for the diagnosis of posterior circulation VS. The purpose of the present review is to increase clinician awareness and knowledge of posterior circulation VS after aneurysmal SAH and other intracranial pathology as for it major impact on outcome of patients with cerebral VS. Keywords: