The most common cause of stroke is the distal embolization of an atherosclerotic plaque within the carotid artery. As early as childhood, a collection of lipid-laden cells known as a fatty streak can be found in the aorta. Over time, and in conjunction with the risk factors mentioned previously, a central core of lipids and cell debris becomes surrounded by a fibrous cap of thickened intima and medial smooth muscle cells. Eventually, this plaque can ulcerate and embolizes to the intracranial circulation (Fig. 8). Also common are emboli from a cardiac mural thrombus in the setting of atrial fibrillation.
Thrombosis may affect both large and small vessels. Thrombosis of large vessels may occur extracranially (e.g., cervical carotid artery occlusion) or intracra-nially (e.g., MCA occlusion), with resulting systems predictable based on the region served by the affected vessel. Disruption of small penetrating arteries gives rise to lacunar infarction, which typically affects deep brain structures. Lacunar infarctions are thought to arise from chronic hypertension eventually leading to hyalinization and sclerosis of small arteries feeding deep brain neurons.
3. Global Ischemic CVA
Systemic hypoperfusion, as seen during prolonged cardiac arrest, results in diffuse forebrain injury not referable to a discrete vascular territory. Damage is most evident in watershed regions between neighboring vascular territories (e.g., between the ACA and MCA territories).
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Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...