Ischemic Stroke (Clots)

What is an Ischemic Stroke?

An ischemic stroke occurs when a vessel supplying blood to the brain is obstructed. It accounts for about 87% of all strokes.

Illustration of a stroke
The main cause of ischemic stroke is atherosclerosis, or fatty deposits (plaque) that line the vessel walls. Fatty deposits can cause two types of obstruction:

  • Cerebral thrombosis is a thrombus (blood clot) that develops at the site of fatty plaque within a blood vessel that supplies blood to the brain.
  • Cerebral embolism is a blood clot that forms in the heart or large arteries of the upper chest or neck, or at another location in the circulatory system. Part of the blood clot breaks loose, enters the bloodstream and travels through the brain’s blood vessels until it reaches vessels too small to let it pass. A main cause of embolism is an irregular heartbeat called atrial fibrillation. It can cause clots to form in the heart, dislodge and travel to the brain.

View a detailed animation of an ischemic stroke

Ischemic Stroke Treatment

The urgent treatment for ischemic stroke is clot removal. Doctors can accomplish this with medication and mechanical treatments.

Medication Treatment with Alteplase IV r-tPA

Tissue plasminogen activator, r-tPA, (known as alteplase) is approved by the Food and Drug Administration to treat ischemic stroke. Doctors administer Alteplase IV r-tPA through an IV in the arm, dissolving the clot and improving blood flow to the part of the brain that’s deprived.

Many people don’t arrive at the hospital in time to receive the medication, which can save lives and reduce long-term effects of stroke. So it’s important to identify stroke and seek treatment immediately.

Mechanical Treatment to Remove the Clot

A mechanical thrombectomy removes a clot in eligible patients with a large vessel occlusion, or LVO. In this procedure, doctors use a wire-cage device called a stent retriever. They thread a catheter through an artery in the groin up to the blocked artery in the brain. The stent opens and grabs the clot. Special suction tubes may also remove the clot.

The procedure:

  • Is usually done within six hours of the onset of acute stroke symptoms but can be done up to 24 hours after symptoms begin if imaging tests show undamaged brain tissue.
  • May include Alteplase IV r-tPA treatment in eligible patients.


Additional Stroke Treatments

Individualized hospital care for stroke focuses on many aspects of recovery, including:

  • Monitoring and observing to detect and prevent complications
  • Finding the cause of the stroke
  • Identifying and initiating treatment to prevent further strokes
  • Starting the recovery process, including determining rehabilitation needs
  • Providing instruction and guidance for next steps, including a follow-up plan to prevent another stroke


Silent Stroke

You could have a stroke and not know it. Silent cerebral infarction (SCI), or silent stroke, is a brain injury without obvious symptoms that can be seen on diagnostic images. It’s likely caused by a blood clot that interrupts blood flow in the brain. It’s a risk factor for future strokes and a sign of progressive brain damage.

Other conditions related to SCI:

Atrial fibrillation (AFib) is the most common significant irregular heartbeat. It increases the risk of SCI more than three-fold. As we age, our risk for both atrial fibrillation and SCI increases.

Risk factors for silent stroke are also risk factors for AFib.

High systolic blood pressure (the top number in a measurement) is a risk factors for SCI. Diagnosing and preventing hypertension early are important steps to reduce silent stroke risk.

Silent strokes can decrease cognition (mental functions including memory, thinking, judgment and the ability to learn).

Man standing with his finger to his month, signalizing silence
woman with wheelchair at home

Support Network

Want to share recovery and rehabilitation experiences with other survivors? Find reassurance or offer your own words of wisdom on the American Heart / American Stroke Association's Support Network.