Tissue plasminogen activator (tPA) is a drug given through a vein to help break up a blood clot so that blood flow can return to normal. It is used for the emergency treatment of ischemic stroke, which occurs when a blood clot interrupts blood flow to a region of the brain.
The timely administration of tPA can save lives. And because tPA restores blood flow by dissolving the clots in a blood vessel, it may limit the damage from a stroke and protect against quality of life impacts, like mobility loss or speech difficulties.
This article explains what tPA is and how it works to break down a clot. It discusses how healthcare providers make a decision about tPA administration, why it's not always possible to use the drug, and the side effects and complications that may arise from tPA use.
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What Does tPA Do in the Body?
A protein that naturally occurs in the body, tPA can be found on endothelial cells—the cells that line blood vessels.
It activates the conversion of plasminogen to plasmin, an enzyme responsible for the breakdown of clots. This helps restore blood flow that would otherwise remain impeded.
An experienced medical team can administer tPA in its powerful medication form when rapid clot-busting is needed.
Due to a range of factors, including the availability of tPA, the death rate from stroke in the United States fell 77% between 1969 and 2013. However, a 2019 analysis shows stroke rates are declining in people aged 75 and older but increasing in people aged 49 and younger.
Life After Stroke
Who Can Get tPA?
Prior to receiving treatment with tPA, you should expect your healthcare provider to review your medical history and order a brain computerized tomography (CT) scan. This is because there are several medical conditions that make it too dangerous for you to receive tPA.
If you have any of these conditions, not only would tPA not help you, it could cause significant harm to your health. You are ineligible to receive treatment if any of the following apply:
- Hemorrhagic stroke (bleeding in the brain)
- Brain aneurysm or AVM
- Previous intracranial hemorrhage
- Symptoms of a subarachnoid hemorrhage
- Recent history of surgical procedure
- Head injury/trauma
- History of stroke in the last three months
- Bleeding or blood clotting disorder
- Bleeding ulcer
- Pregnancy
- Use of blood-thinning medication
- Uncontrolled high blood pressure (above 185/110 mmHg)
- Low blood sugar (below 50 mg/dL)
Protocols have been established to rapidly identify whether you could be having a stroke, so that your testing and treatment can be prompt and efficient, allowing you to receive life-saving treatments in a timely manner.
In fact, some centers are making strides in diagnosing stroke sooner than ever before via mobile stroke units.
What Is the Success Rate of tPA for Strokes?
Studies in the mid-1990s showed tPA increased recovery from stroke symptoms by up to 50%. Today, studies show tPA used in combination with endovascular therapy (removal of clots by placing a catheter in the brain) gets even better results than tPA alone.
What Is the Timeline for tPA Administration?
Treatment with tPA has been effective for people with an ischemic stroke as long as it is received intravenously within up to 4.5 hours of the onset of symptoms.
In contrast, endovascular treatment to remove the clot or deliver tPA at the site of the clot is considered for up to 24 hours after a stroke.
Guidelines for the treatment of acute stroke published by the American Heart Association in 2018 strongly recommend IV alteplase (tPA) within 4.5 hours of stroke symptoms onset for eligible patients. This treatment approach has been shown to produce the best overall outcomes.
However, FDA approval states it should be administered within 3 hours, and faster treatment times are associated with a reduced rate of complications.
What Are the Side Effects of tPA?
While tPA has been shown to be beneficial in the treatment of stroke, there are risks associated with tPA treatment—even for people who have been medically cleared to receive it.
It is a powerful blood thinner, andserious side effects may occur, including the following:
- Hemorrhage (bleeding) affecting the brain: Causes headaches, weakness, confusion, loss of consciousness, seizures
- Hemorrhage of the digestive system: Causes blood in the stool or stomach pain
- Severe blood loss: Causes lightheadedness, low blood pressure, loss of consciousness
- Minor bleeding in the gums or nose
- Blood in the urine
If you experience any of these side effects, you should immediately inform your medical team.
How to Receive Prompt tPA Treatment
The best way to maximize the chances of receiving the most effective treatment for a stroke is to get to the emergency room as soon as possible if you believe a stroke may be occurring.
Symptoms of a stroke include:
- Trouble understanding words or speaking
- Numbness of the arm, face, or leg
- Blurred or blackened vision in one or both eyes
- Double vision
- Sudden, severe headache
- Vomiting
- Dizziness
- Difficulty walking
- Loss of balance or coordination
- Weakness of the face, arm, or leg
- Droopy face or eyelid
- Confusion
Note that a person having a stroke may not notice when they are experiencing symptoms. You may recognize these signs in someone else before they do, or vice versa.
Use the letters in FAST to recognize a stroke:
- F = Face drooping. Look for drooping on one side of the face. If unsure, ask the person to smile.
- A = Arm weakness. Numbness or weakness in one arm can be a sign of a stroke. Ask the person to raise both arms to see if one arm drifts downward.
- S = Speech difficulty. A stroke can cause slurred speech.
- T = Time to call 911. A stroke is an emergency (every minute counts). Note the time when symptoms first appeared.
Don’t wait for the symptoms to disappear. The sooner you get help, the more likely you'll be in the window for tPA treatment (if applicable). You'll also likely have fewer the long-term effects.
Signs and Symptoms of Stroke
Summary
The use of tPA medication to break up clots in blood vessels has offered benefits to thousands of people since its use was first approved, but it can't be used in all cases.
It's important to recognize the signs and symptoms of stroke to ensure treatment begins as quickly as possible.
Frequently Asked Questions
What kind of drug is tPA?
As a thrombolytic, tPA is part of a drug class that also includes agents such as TNKase (tenecteplase) and Streptase (streptokinase). These drugs are used to induce thrombolysis, or the dissolving of blood clots.
Learn MoreWhat Is Thromboembolism?
What is tPA used for?
Tissue plasminogen activator (tPA) is used to treat ischemic stroke, pulmonary embolism, and heart attack.
Why is tPA not given after 4.5 hours?
Research suggests tPA administered after 4.5 hours is not beneficial and may increase the risk of death. Some studies are investigating if tPA administration after 4.5 may provide benefits in certain situations.
Stroke Recovery and Rehabilitation
