New Emergency Stroke Treatments

by Brian Carty, MD, MSPH
06-17-2008

In ancient Greece stroke was called apoplexy, which means “struck down by violence.” Stroke is a sudden and often catastrophic impairment of brain function. It is one of the most dreaded of all diseases, in part because many people fear a lifetime of disability even more than death.

Stroke symptoms

A stroke can cause a variety of symptoms, such as sudden weakness or numbness of the face, arm or leg, especially on one side of the body, sudden confusion, trouble speaking or understanding, or trouble seeing. Other symptoms are sudden difficulty walking, dizziness, loss of balance or coordination, and sudden severe headache.

New Treatments Are Available

Until just a few years ago medicine had little to offer a stroke patient except to let nature take its course and to provide supportive care such as oxygen, fluids, aspirin, and the like. But in the past 10 years, new and more effective emergency treatments have significantly improved outcomes for stroke patients.

Types of stroke

There are two main types of stroke: ischemic, caused by a clot in a brain artery, and hemorrhagic, caused by bleeding from a ruptured artery in the brain. In an ischemic stroke, the clot in the brain artery stops blood flow. When brain or any other tissue is deprived of blood flow, the tissue dies. Early restoration of blood flow decreases the amount of brain tissue lost.

The emergency stroke treatments discussed here are for ischemic stroke, not hemorrhagic stroke. Hemorrhagic stroke and other less common types of stroke will not be discussed further here. Hemorrhagic stroke will be covered in an upcoming Hot Medical News article.

Transient Ischemic Attack (TIA)

A note about transient ischemic attack (TIA), a neurologic deficit such as paralysis or speech disturbance which resolves in a few minutes or hours. A TIA often precedes a full blown stroke. Recent research shows that most patients with TIAs should be immediately admitted to the hospital for a rapid evaluation and treatment. This approach markedly reduces the risk of a disabling stroke.

IV-tPA

tPA is drug which dissoves blood clots. Intravenous tPA (IV-tPA), has been shown to improve the outcome from ischemic stroke when given within 3 hours of stroke onset. The time since the onset of the stroke is the time elapsed since the patient was last seen to be normal. For example, if the patient went to bed and was normal at 10 PM and woke at 2 AM paralyzed on one side, for treatment purposes, the time since the onset of the stroke is 4 hours.

Before IV-tPA is given, bleeding in the brain must be ruled out with a CT scan, and other conditions must be met. Intravenous tPA for stroke should be available in most community hospitals.

The MERCI device and IA-tPA

View Video

An animated video of the use of the MERCI device for removing a clot which has caused an ischemic stroke.
-with permission Concentric Medical

In these two treatments, a catheter is inserted into a peripheral artery and then threaded directly into the artery which is blocked by a clot which has caused the stroke. The MERCI clot retriever device is then used to grasp and remove the blood clot (see video). This device must be used within 8 hours.

Intra-arterial tPA (IA–tPA) involves injecting the clot-busting drug tPA directly into the clot to attempt to dissolve it. IA-tPA must be given within 6 hours. Usually the MERCI device is used first. If the MERCI device is unsuccessful or only partially successful in removing the clot, then IA-tPA is used. The MERCI device and IA-tPA are usually available only at large stroke centers with an interventional neuroradiologist. For example, in California, the MERCI device and IA-tPA are available only in Los Angeles, Sacramento, and in the San Francisco area.

Treatment summary

Here is a summary of the emergency treatments for stroke and the times since stroke onset within which they must be given:

    0 to 3 hr – intravenous tissue plasminogen activator (IV-tPA)
    0 to 6 hr – intra-arterial tPA (IA-tPA)
    0 to 8 hr – MERCI device

Summary

A stroke is a medical emergency, and every minute counts. Call 911 immediately if anyone has stroke symptoms. “Time lost is brain lost.” The sooner treatment is given the better the outcome. For a thrombotic stroke, after an emergency CT scan has ruled out bleeding and after other conditions have been met, IV-tPA within 3 hours is standard therapy. At a major stroke center with an interventional neuroradiologist, the MERCI device and/or IA-tPA may be even more effective.

 

 

 

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