A watershed stroke or infarction is a type of ischemic stroke that occurs in the border zones between the territories supplied by major cerebral arteries. In other words, it is a stroke that affects the areas of the brain that receive blood supply from the end branches of two or more major cerebral arteries, where blood flow is already reduced due to low perfusion pressure.
Watershed strokes occur when blood flow to the brain is significantly reduced, typically as a result of low blood pressure, hypotension or severe stenosis or occlusion of large arteries that supply blood to the brain. As a result, brain cells in these border zones become ischemic and can be damaged or die if the condition is not treated promptly.
There are several factors that can contribute to the development of a watershed stroke:
Hypotension: Low blood pressure can reduce blood flow to the brain, which can increase the risk of a watershed stroke.
Atherosclerosis: A buildup of plaque in the arteries can narrow the blood vessels and reduce blood flow to the brain.
Cardiac disease: Conditions such as atrial fibrillation, heart valve disease, and cardiomyopathy can increase the risk of blood clots forming in the heart and traveling to the brain.
Blood disorders: Conditions such as sickle cell anemia, thrombophilia, and polycythemia vera can increase the risk of blood clots forming in the blood vessels.
Drug abuse: Certain drugs, such as cocaine and amphetamines, can increase blood pressure and reduce blood flow to the brain, which can increase the risk of a watershed stroke.
The treatment of a watershed stroke depends on the severity of the stroke and the underlying cause. In general, the goals of treatment are to prevent further damage to the brain, manage symptoms, and prevent future strokes.
Emergency treatment: If the stroke is severe, emergency treatment may be necessary. This can include medications to dissolve blood clots, surgery to remove a clot, or mechanical thrombectomy to remove a clot using a catheter.
Medications: Medications may be prescribed to manage symptoms and prevent future strokes. This can include antiplatelet drugs, anticoagulants, blood pressure medications, and cholesterol-lowering drugs.
Rehabilitation: Rehabilitation is an important part of stroke treatment, especially for patients who experience lasting effects from the stroke. Physical therapy, occupational therapy, and speech therapy may be recommended to help patients regain strength, mobility, and communication skills.
Lifestyle changes: Lifestyle changes can help reduce the risk of future strokes. This can include maintaining a healthy diet, exercising regularly, quitting smoking, and managing underlying medical conditions such as diabetes, high blood pressure, and high cholesterol.