Large Extracranial Artery Diseases and Stroke

Aortic arch atheromatous plaque thickness directly relates to the risk of stroke. The recurrence rate for stroke is 11.9 per 100 person years when aortic wall thickness reaches 4 mm, in comparison to 3.5 per 100 person years in patients with aortic wall thickness less than 4 mm. Transesophageal echocardiography has substantially improved the detection of aortic arch disease, which had previously been very difficult to assess without angiography.

Extracranial carotid artery disease is an important cause of stroke. Carotid stenosis becomes more likely with advancing age and occurs in approximately 2-7% of individuals aged 50 or older. However, carotid stenosis of over 80% affects only 1% of the general population. Carotid artery dissection and giant cell arteritis may also lead to extracranial stenosis and stroke. Arterial dissection occurs most frequently in the setting of minor or major trauma but may occur spontaneously. The vessel wall develops a hemorrhage, which expands and narrows the lumen. The smooth lining within the vessel (endothelium) often becomes irregular and serves as a nidus for clot formation. The hemorrhage may grow sufficiently to cause stenosis and occlusion of blood flow through the damaged artery, or the clots that form at the site of the endothelial damage may embolize to the brain. In giant cell arteritis, inflammation within the wall of extracranial vessels, most often the carotid arteries, leads to ischemia and stroke. Permanent blindness results in 40-50% of cases because the blood supply to the eye is compromised, and strokes occur in approximately 10% of cases. Headache and jaw pain induced by chewing (jaw claudication) are important clues to the possibility of giant cell arteritis. An elevated erythrocyte sedimentation rate is typically found, but confirmation of the diagnosis requires temporal artery biopsy. The disorder increases in incidence with age, affecting 2.6 per 100,000 persons 50-59 years of age each year and 44.6 per 100,000 over 80 years of age each year. Whites are seven times more likely to be affected than African Americans, and women are three times more likely to have the disease than men.

The vertebral arteries may be affected by both dissection and giant cell arteritis. In addition, verteb-robasilar insufficiency may result from subclavian steal syndrome. This disorder most often occurs in the setting of severe stenosis of the subclavian artery, proximal to the origin of the left vertebral artery, due to atherosclerotic plaque. Blood may be "stolen" from the left vertebral artery, which supplies blood to the left arm rather than to the brain. Transient ischemic attacks and episodic loss of consciousness (syncope) are frequent symptoms of the disorder; large differences in blood pressures are typically encountered when the right and left arms are compared. Surgical correction of the stenosis may prevent stroke and cure the syncope.

Fibromuscular dysplasia is an uncommon disorder affecting young women more often than men. A muscular band constricts large extracranial arteries, leading to ischemia or infarction. Several areas of narrowing may occur within a single vessel, leading to an appearance resembling a string of beads on catheter angiography. The renal arteries are often involved, and renovascular hypertension may result.

Blood Pressure Health

Blood Pressure Health

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...

Get My Free Ebook

Post a comment