What the SWIFT and TREVO II Trials Tell Us About the Role of Endovascular Therapy for Acute Stroke” in both

Stroke.ahajournals.org: May 29, 2012

Revascularization of Collaterals for Hemodynamic Stroke

Insight on Pathophysiology From the Carotid Occlusion Surgery Study

Carotid atherosclerosis accounts for up to 15% of all strokes¹ and approximately 15 000 to 20 000 have symptomatic carotid occlusions in the United States each year.² Furthermore, recurrent ipsilateral stroke in unselected patients with carotid occlusion affects 2.1% to 3.8% on an annual basis.^3–5 The pathophysiology of stroke due to atherosclerotic plaque of the internal carotid artery may be distinct once the stenotic or narrowed vessel progresses to occlusion. Various mechanisms for cerebral ischemia in carotid occlusion have been described, including downstream clot propagation and stump embolism^6,7; however, impaired perfusion plays a major role, particularly once the distal stump of the occlusion develops mature endothelium. A combined effect of hypoperfusion and poor clearance of embolic material has also been described.⁸ Perfusion through collaterals to downstream territories of the brain is therefore pivotal. In fact, collaterals largely determine recurrence of symptomatic ischemia after hemodynamic stroke in carotid occlusion. The clinical observation of stereotypical events and those that occur with hypotension and initiation of antihypertensive agents, after a hot bath, or even with the upright position, support a hemodynamic process. Read More