Stroke attributable to acute basilar occlusion

The Presence of Communicating Arteries in the Circle of Willis Is Associated with Higher Rate of Functional Recovery after Anterior Circulation Ischemic Stroke

Acute ischemic stroke (AIS) is the world's second leading cause of mortality. An established method for treating stroke patients in acute settings is endovascular therapy (EVT). However, the correlation of the successful endovascular treatment of AIS with the presence of communicating arteries in the circle of Willis needs to be proven. Our study examined clinical and radiological data of 158 consecutive patients treated with mechanical thrombectomy (MT) at our comprehensive stroke center. We analyzed their CT angiograms and digital subtraction angiography (DSA) to assess anatomical variants of Willis' circle and formed two groups-collateral-negative and collateral-positive group. The first group included patients with aplasia of both anterior (ACoA) and posterior communicating Artery (PCoA). The second group included patients that have at least one communicating artery (either anterior or posterior). We evaluated their reperfusion outcomes and functional recovery three months later. Our results showed that patients with communicating arteries had smaller areas of infarction on post-interventional CT and higher rates of functional recovery (Modified Rankin Score). The ACoA had a higher impact on early and late outcomes, confirmed by lower control CT scores and more favorable functional recovery. Therefore, anatomic variants of Willis' circle should be considered as a significant prognostic factor in AIS.

The Pathophysiology of Collateral Circulation in Acute Ischemic Stroke

Cerebral collateral circulation is a network of blood vessels which stabilizes blood flow and maintains cerebral perfusion whenever the main arteries fail to provide an adequate blood supply, as happens in ischemic stroke. These arterial networks are able to divert blood flow to hypoperfused cerebral areas. The extent of the collateral circulation determines the volume of the salvageable tissue, the so-called "penumbra". Clinically, this is associated with greater efficacy of reperfusion therapies (thrombolysis and thrombectomy) in terms of better short- and long-term functional outcomes, lower incidence of hemorrhagic transformation and of malignant oedema, and smaller cerebral infarctions. Recent advancements in brain imaging techniques (CT and MRI) allow us to study these anastomotic networks in detail and increase the likelihood of making effective therapeutic choices. In this narrative review we will investigate the pathophysiology, the clinical aspects, and the possible diagnostic and therapeutic role of collateral circulation in acute ischemic stroke.

Posterior circulation stroke: animal models and mechanism of disease

Posterior circulation stroke refers to the vascular occlusion or bleeding, arising from the vertebrobasilar vasculature of the brain. Clinical studies show that individuals who experience posterior circulation stroke will develop significant brain injury, neurologic dysfunction, or death. Yet the therapeutic needs of this patient subpopulation remain largely unknown. Thus understanding the causative factors and the pathogenesis of brain damage is important, if posterior circulation stroke is to be prevented or treated. Appropriate animal models are necessary to achieve this understanding. This paper critically integrates the neurovascular and pathophysiological features gleaned from posterior circulation stroke animal models into clinical correlations.

Endovascular revascularization of chronic symptomatic vertebrobasilar occlusion

BACKGROUND AND PURPOSE

Acute basilar artery occlusion is associated with a high risk of stroke, mortality, and poor outcome in survivors. Timely vessel revascularization is critical to improve the clinical outcome in this condition. A subset of patients survives acute occlusion with mild or no disability and some of these individuals develop recurrent ischemic events despite optimal medical therapy. The strategy for management of these patients is unknown.

CASE SUMMARY

We described 3 patients with chronic intracranial vertebrobasilar occlusions who presented with recurrent ischemic symptoms and progressive disability. All 3 patients were treated successfully with angioplasty and stenting. One patient experienced headache postprocedure and was found to have subarachnoid hemorrhage, which was self-limiting without need for intervention or result in permanent neurological sequela. All 3 patients have been free of recurrent symptoms for up to 30 months.

CONCLUSIONS

Revascularization of chronic vertebrobasilar occlusions is technically feasible. Due to the high-risk nature, it should be reserved as an option only for selected group of patients with recurrent ischemic symptoms and progressive disability despite maximal medical therapy. Further prospective study is helpful to clarify the role of this intervention.