Stroke Prevention: Can Ischemic Strokes Be Avoided?

Ischemic stroke, also known as brain ischemia or cerebral ischemia, is a medical emergency caused by a blockage in a blood vessel supplying blood to the brain. It is the most common type of stroke, accounting for about 87% of all cases. Ischemic strokes are life-threatening and can lead to permanent brain damage and death. Therefore, recognising the signs and seeking immediate medical attention is crucial.

The main cause of ischemic stroke is atherosclerosis, or fatty deposits (plaques) that line the vessel walls. These fatty deposits can cause two types of obstruction: cerebral thrombosis, where a blood clot develops at the site of fatty plaque, and cerebral embolism, where a blood clot forms in the heart or large arteries and travels to the brain. Other causes include clotting and bleeding disorders, congenital heart defects, and heavy alcohol misuse.

The signs of an ischemic stroke include sudden numbness or weakness on one side of the body, trouble speaking or seeing, dizziness, loss of coordination, and severe headaches. To recognise the warning signs, remember the acronym BE FAST: balance, eyes, face, arms, speech, and time. If you or someone you know is experiencing these symptoms, call emergency services right away.

Ischemic strokes are caused by blood clots or fatty deposits blocking blood vessels in the brain

Ischemic strokes are a medical emergency and the most common type of stroke, accounting for about 87% of all stroke cases. They occur when a blood vessel supplying blood to the brain is blocked. This blockage is often caused by blood clots or fatty deposits (also known as plaque) inside the blood vessel.

Blood Clots

Blood clots usually start in the heart and travel through the circulatory system. They can break up on their own or become lodged in an artery. When a clot blocks a brain artery, the region of the brain doesn't get enough oxygen-rich blood, and cells start to die. This is a life-threatening situation that requires immediate medical attention.

Fatty Deposits

Fatty deposits, or plaque, can cause two types of obstruction:

• Cerebral thrombosis: A thrombus (blood clot) that develops at the site of fatty plaque within a blood vessel that supplies blood to the brain.
• Cerebral embolism: A blood clot that forms in the heart, large arteries of the upper chest or neck, or elsewhere in the circulatory system. This clot then breaks loose, enters the bloodstream, and travels through the brain's blood vessels until it reaches vessels too small for it to pass through.

Risk Factors and Prevention

Circulatory conditions are the main risk factor for ischemic stroke as they increase the likelihood of blood clots or fatty deposits. However, not everyone with these conditions will experience a stroke. The conditions include clotting and bleeding disorders and congenital heart defects. Other factors that increase the risk of ischemic stroke include heavy alcohol misuse and excess abdominal and visceral fat.

Quitting smoking is the most powerful way to prevent ischemic stroke. Maintaining a healthy lifestyle by managing blood pressure, cholesterol, and weight can also reduce the risk.

They can be further classified into thrombotic and embolic strokes

Ischemic strokes, which account for 80-87% of all strokes, occur when blood flow to the brain is blocked. They can be further classified into thrombotic and embolic strokes.

Thrombotic strokes are caused by a blood clot that develops in the blood vessels inside the brain. This type of stroke is often linked to health conditions that lead to the buildup of fatty deposits, which narrow and harden blood vessels, making it easier for clots to form. Atherosclerosis, a condition in which the artery lining becomes thickened and narrowed by plaque, is the most common risk factor for thrombotic strokes. Thrombotic strokes are usually seen in older persons, especially those with high cholesterol, atherosclerosis, or diabetes. They may be preceded by one or more "mini-strokes," called transient ischemic attacks (TIAs).

On the other hand, embolic strokes are caused by a blood clot that forms elsewhere in the body and then travels to one of the blood vessels in the brain through the bloodstream. The clot, called an embolus, travels until it becomes lodged in a blood vessel inside the brain, blocking blood flow and oxygen from reaching the brain. Embolic strokes often result from heart disease, atrial fibrillation, or heart surgery and occur rapidly without any warning signs.

While thrombotic and embolic strokes have different causes, they share similar symptoms, including sudden weakness or numbness on one side of the body, difficulty speaking or understanding speech, and trouble walking. Recognizing the signs of a stroke and seeking immediate treatment is crucial, as strokes are a leading cause of death. Treatment for ischemic strokes involves immediate action to restore blood flow and long-term management to prevent future strokes.

Risk factors include clotting and bleeding disorders, congenital heart defects, alcohol misuse, and excess abdominal and visceral fat

Ischemic strokes occur when a blood clot blocks a blood vessel in the brain. They are medical emergencies and can be fatal.

Clotting and Bleeding Disorders

Blood clots are the most common cause of ischemic strokes. Many health conditions can cause blood clots, including clotting and bleeding disorders.

Congenital Heart Defects

Heart defects, such as atrial septal defects or ventricular septal defects, can also cause blood clots and increase the risk of ischemic stroke.

Alcohol Misuse

Alcohol misuse is a risk factor for ischemic stroke. Heavy alcohol consumption increases the risk of ischemic stroke, with the risk being transiently elevated for up to two hours after drinking. However, frequent light to moderate alcohol intake may decrease the risk.

Excess Abdominal and Visceral Fat

Abdominal obesity measures, such as waist circumference and waist-height ratio, are independent predictors of ischemic stroke in women but not in men. These measures were found to be better predictors of stroke risk than general obesity measures, such as Body Mass Index (BMI).

Visceral fat, which is often associated with abdominal obesity, is metabolically active and releases inflammatory markers that can contribute to the development of atherosclerotic diseases like ischemic stroke.

Symptoms include facial drooping, limb weakness, and slurred speech

A stroke is a medical emergency that requires immediate attention. Ischemic strokes, in particular, are caused by a blockage in a blood vessel supplying blood to the brain and account for about 87% of all strokes.

The symptoms of an ischemic stroke depend on the region of the brain affected, but they typically occur without warning and may be intense. Facial drooping, limb weakness, and slurred speech are among the most common symptoms.

Facial drooping may be observed when smiling or talking, with one side of the face appearing to droop or feel numb. This may also be accompanied by a drooping eyelid.

Limb weakness is usually experienced on one side of the body and may manifest as difficulty raising one arm, or a feeling of weakness or numbness.

Speech difficulties, such as slurred speech, can also occur, making it challenging to speak or repeat a complete sentence.

If you or someone you know is experiencing these symptoms, it is crucial to act F.A.S.T:

• Face: Check for facial drooping.
• Arms: Check for arm weakness.
• Speech: Listen for slurred speech.
• Time: Call emergency services immediately if any of these signs are present.

Acting quickly can significantly improve the chances of survival and reduce the likelihood of permanent symptoms.

Treatment involves medication or surgery to remove blood clots and prevent further blockages

Treatment for ischemic stroke focuses on restoring blood flow to the brain as soon as possible to reduce the risk of permanent brain damage and death. The two most common treatments are thrombolytic therapy and thrombectomy.

Thrombolytic Therapy

Thrombolytic therapy involves the use of medications that dissolve blood clots. The most commonly used drug is alteplase, which is injected intravenously to improve blood flow to the affected area of the brain. Alteplase must be administered within a short time window, usually fewer than four hours from the onset of stroke symptoms, as it can increase the risk of dangerous internal bleeding.

Thrombectomy

Thrombectomy is a surgical procedure to remove a blood clot. During this procedure, a surgeon inserts a small, thin tube called a catheter into a blood vessel and threads it up to the clot in the brain. The clot is then either vacuumed up in one piece or broken into smaller pieces and sucked up. Thrombectomy can be performed within six hours of the onset of acute stroke symptoms or up to 24 hours if imaging tests show undamaged brain tissue.

Other Treatments

In addition to thrombolytic therapy and thrombectomy, other treatments may be necessary to manage ischemic stroke and prevent further blockages. These include:

• Blood thinners: Anticoagulant medications that thin the blood to prevent it from clotting too easily.
• Oxygen therapy: The administration of extra oxygen to make breathing easier and help restore oxygen to the brain.
• Blood sugar management: Monitoring and controlling blood glucose levels to aid in brain recovery.
• Mild intentional hypothermia: Safe lowering of body temperature to slow down brain damage during and after a stroke. This is a rare treatment option.

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