What is an ischemic stroke?

An ischemic stroke is the blockage of an artery that leads to the brain. When the vessel becomes blocked, oxygen does not reach the blood and brain cells begin to die.

Common related conditions
Hemorrhagic Stroke Stroke

Types of ischemic strokes

Embolic strokes

An embolic stroke occurs when a blood clot that forms in another area of the body breaks free and travels to the brain. The blood clot can block blood flow in an artery to the brain and cause a stroke. This is a common occurrence in patients who also have atrial fibrillation.

Thrombotic strokes

A thrombotic stroke occurs when a blood clot forms in and blocks an artery that supplies the brain. Patients who have high cholesterol are most likely to have a thrombotic stroke. Thrombotic strokes are further classified as large vessel thrombosis or small vessel thrombosis.

Ischemic strokes account for more than 85 percent of all stroke cases.

Causes of an ischemic stroke

Causes of ischemic stroke include:


Atherosclerosis, when plaque builds up in the arteries, is the most common cause of ischemic stroke. As plaque builds up in the arteries, it can block the entire artery to the brain and stop blood flow to the brain.

Blood clot

A blood clot that lodges in a carotid artery and blocks the flow of oxygen-rich blood to the brain can lead to an ischemic stroke.

Risk factors for an ischemic stroke

There are a variety of modifiable and nonmodifiable risk factors that increase a person’s likelihood of suffering an ischemic stroke.

Risk factors for ischemic stroke that are modifiable include:

  • High blood pressure (hypertension) — primary risk factor for stroke
  • Diabetes — people with diabetes are four times more likely to suffer from carotid artery disease
  • Coronary heart disease
  • Smoking — can increase plaque buildup in the arteries, which can lead to stroke

Most cases of ischemic stroke can be prevented by your modifying lifestyle (exercise, stop smoking, lose weight and eat healthy) to live a healthier life.

Risk factors that are not modifiable include:

  • Age — you are more at risk to suffer from a stroke if you are over 55
  • Gender — men are more likely to suffer a stroke than women
  • Race — African Americans, Alaskan Americans and American Indians are more likely to suffer from a stroke

Symptoms of an ischemic stroke

Symptoms of an ischemic stroke include:

  • Dropping or numbness on one side of the face
  • Weakness in the arms — inability to lift an arm
  • Problems with speech
  • Confusion
  • Trouble walking
  • Problems with vision

Diagnosis of an ischemic stroke

If you or a family member is experiencing signs of a stroke, call 911 right away. As each minute passes before treatment, more brain cells die.

Once you are in the care of a medical professional, he or she will quickly evaluate you for signs of a stroke. The professional will perform a physical exam to test blood pressure, listen to your heart rate and check your eyes for signs of plaque. Other tests to your doctor may order to diagnose a stroke include:

  • Blood tests — blood tests can reveal other potential causes of your symptoms as well as determine how fast your blood clots.
  • MRI (magnetic resonance imaging) or CT (computed tomography) scan — an MRI or CT scan can take detailed images of the brain and carotid arteries to determine if there are blood clots blocking the arteries to the brain. These tests can be done with contrast dye to see the brain and potential clots in greater detail.
  • Carotid ultrasound — a carotid ultrasound can show any blockages of the carotid arteries in the neck that may be causing your symptoms.
  • Echocardiogram (echo) — an echo can show blood clots in the heart that may have broken off and traveled to the brain and blocked the carotid arteries and are causing your stroke symptoms.

Treatment for an ischemic stroke

Treatment can begin in an ambulance, so do not try to drive yourself or a loved one to the hospital.

Treatments for an ischemic stroke include:

  • Medication — tissue plasminogen activator (tPA) is a clot-busting medication used to treat ischemic strokes. tPA must be given within four hours of stroke symptoms starting, and the sooner it is given, the more effective it is.
  • Surgery — a mechanical thrombectomy can be performed within six hours of symptoms starting to remove the blood clot in the carotid artery; this procedure is completed after tPA is given.

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