Ischemic Stroke

What is Ischemic Stroke?

Ischemic strokes occur when blood vessels that supply blood to the brain are blocked by a clot. They account for 87 percent of all stroke cases.

What Causes It?

Ischemic stroke is most often due to atherosclerosis, a condition that causes fatty deposits to develop in the walls of the arteries (plaques). Other important risk factors for ischemic strokes are long-standing increased arerial blood pressure, diabetes, and atrial fibrillaton (irregular heart beat).

Types of Ischemic Stroke

Ischemic strokes are classified as one of the following:

  1. Embolic - An artery clot that forms somewhere in the body and travels to the brain through the bloodstream (and lodges there).
  2. Thrombotic – Occurs when a clot forms on a blood-vessel deposit and blocks blood flow in one or more arteries.
  3. Cryptogenic – An ischemic stroke that has no definable cause. Nearly 20 percent of all ischemic strokes are cryptogenic. Typically occurs in people 55 or younger.

Stroke Warning Sign

Transient ischemic attack (TIA), commonly referred to as a “mini stroke,” is similar to ischemic stroke except that symptoms are temporary, most only lasting five minutes or less.

TIAs should be taken seriously. Nearly 30 percent of people who have a TIA will go on to have a stroke within a year.

Primary Treatment

Ischemic and transient ischemic attacks (TIA) are treated with either medicines or medical procedures.


Medicines can be highly effective if given within four hours of when stroke symptoms first begin.

Medicines used to treat ischemic stroke

Tissue Plasminogen Activator (tPA)
Tissue plasminogen activator (tPA) is most common treatment medication. It is given through an IV in the arm, and works by dissolving arterial blood clots that block nourishment from getting to the brain. If tPA is delivered within 3 to 4.5 hours of an ischemic stroke, a person has a higher chance of recovery.

Blood Thinners
If the doctor is unable to use tPA, blood thinners can be administered to help keep platelets from clumping together in your veins and arteries.

The two main types of blood thinners used:

Other antiplatelets used to treat stroke include: Ticlopodine, Clopidogrel and Dipyridamole.

Medical Procedures

If tPA proves unsuccessful and/or in the event of acute ischemic stroke (e.g., plaque buildup from carotid artery disease) a medical procedure may be recommended.

Procedures used to clear blocked arteries

  • Carotid endarterectomy (CEA): Surgical removal of fatty plaque in the carotid artery.
  • Carotid artery stenting (CAS): Minimally invasive placement of a stent in the artery using catheters to prevent narrowing.
  • Angioplasty: A thin tube with a small attached balloon is threaded through a blood vessel (from arm or groin) to the blocked site. The balloon is then inflated, widening the artery and pushing the plaque to the sides of the wall.
  • Mechanical Thrombectomy: Our neurovascular surgeons use leading-edge retrieval devices (e.g., Solitaire) to remove blood clots. This therapeutic procedure has proved to be highly successful in treating embolic stroke.

Preventing Another Stroke


  1. Once you’ve had a stroke, the chance of having another one increases.
  2. One in every four strokes in the U.S. is recurrent. Recurrent strokes account for nearly 185,000 strokes in the U.S. every year.
  3. 80 percent of all strokes can be prevented with lifestyle modifications and by properly managing medical conditions that increase risk.

Lifestyle habits that reduce your risk for recurrent stroke

  • Eating a healthy diet that’s low in saturated and trans fats and cholesterol
  • Smoking cessation
  • Increasing physical activity
  • Limiting alcohol use

Condition Risk Factors

Acute stroke, left middle cerebral artery thrombus occlusion.

Controlling conditions that increase your risk for stroke is essential to preventing a recurrent stroke.

High blood pressure (hypertension) is one of the most important risk factors, as it increases risk of stroke one and a half times. High blood pressure damages arteries, creating weak spots that can rupture easily. You can control high blood pressure with a healthy diet, regular exercise, and medication (antiplatelets and antihypertensives).

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Diseases that increase risk of recurrent stroke:

Carotid Artery Disease

Also known as carotid stenosis, this occurs when the two large blood vessels in the neck that supply blood to the brain, become narrowed due to cholesterol buildup. Carotid disease is highly associated with stroke, as nearly 75 percent of all ischemic strokes occur in the distribution of the carotid arteries in the neck.

Carotid artery disease accounts for approximately 25 percent of ischemic stroke occurrences. More about carotid artery disease.

Intracranial Atherosclerotic Disease (ICAD)

Refers to the narrowing and hardening of arteries in the brain, restricting blood flow. ICAD accounts for approximately 10 percent of ischemic strokes.

You are at higher risk for ICAD if you:

  • Are Hispanic, African American or Asian
  • Smoke
  • Have a family member who has had a stroke or heart disease
  • Are overweight
  • Have diabetes
  • Have high cholesterol
  • Have high blood pressure

UC San Diego neurologists work closely with our endovascular neurosurgeons to provide aggressive medical management of this condition. When necessary, balloon angioplasty (widening of the arteries) or intracranial stenting is performed.

Heart Conditions

When cardiac conditions increase risk for stroke, this is known as cardiogenic embolism.

Conditions that increase risk include arrhythmia and patent foramen ovale (PFO), and account for approximately 20 percent of all ischemic strokes in the U.S.

Read more about our Electrophysiology Program.


People who have diabetes are four times more likely to have a stroke. This is because they are more inclined to have health problems that can increase their risk for stroke, like high cholesterol and atrial fibrillation. Careful regulation of blood sugar levels can help keep diabetes in check and prevent stroke from occurring.

Atrial fibrillation (irregular heartbeat)

Nearly 15 percent of people who have a stroke also have atrial fibrillation. Considered a major risk factor, people with atrial fibrillation are five times more likely to have a stroke. Atrial fibrillation-related strokes are preventable with monthly heart rhythm monitoring, medications, and electrical stimulation.

Blood disorders

Blood disorders keeps blood from clotting properly. Too much clotting can result in a heart attack or stroke. Blood disorders and cancers include:

High cholesterol

Too much "bad" cholesterol (LDL) and not enough "good" cholesterol (HDL) can lead to plaque build-up in the arteries. This build-up blocks normal blood flow, which can cause a stroke. High cholesterol also increases risk of atherosclerosis and heart disease. Manage high cholesterol by:

  • Avoiding foods that are high in saturated fats
  • Losing weight
  • Exercising on a regular basis

Contact Us


Stroke is a
Medical Emergency

If you have stroke symptoms, do not drive yourself to the hospital --- call 9-1-1.

Our Stroke Specialists

Meet Our Team


Administering tPA FAST

Read about UC San Diego Health System's record in getting tPA to ischemic stroke patients.