Health and Stroke

Everything You Need to Know About tPA for Stroke

tPA is a drug that has revolutionized the way strokes are treated

May 17, 2022

Zeit Medical

When a stroke occurs, time is of the essence. In an acute stroke there is a 4.5-hour time window to administer tissue plasminogen activator (tPA) to treat the stroke. tPA is a drug that can halt the ongoing acute stroke induced damage and help reverse its effects. This blog post will describe what tPA is, how it works, and why it's so important to give the medication as soon as possible after a stroke occurs. We will also take some time to review the risks and potential downsides of tPA.

Key Points: Tissue plasminogen activator (tPA) is a drug that helps to dissolve blood clots in an acute ischemic stroke. It is recommended to give intravenous tPA within 4.5 hours of onset of stroke symptoms, but the earlier the medication is given the better.Studies show that eligible patients typically have improved clinical outcomes.

What is tPA?

Tissue plasminogen activator (tPA) is a purified solution of an enzyme that all humans have in their bodies to keep naturally occurring clotting in check. For example, under normal circumstances tPA prevents blood vessels  (or other parts where blood flows slowly) from getting clotted up. In concentrated form, this protein-based medication can be highly effective in dissolving blood clots in the brain. By dissolving the blood clot, blood flow is restored to the part of the brain that was affected by the stroke. It can be used to treat acute ischemic stroke when a victim fits certain screening criteria within a 4.5 hour window from the onset of symptoms.

tPA and the Evolution of Stroke Treatment

The FDA approved the use of tPA for acute ischemic strokes in 1996. Death and disability from stroke have dropped significantly with the use of tPA in combination with better diagnostics and care plans. In the early days of tPA treatment use, there were concerns that it could cause excessive bleeding and other complications in stroke patients. However, these risks have been largely mitigated with better patient selection and closer monitoring.

How tPA Works

When a stroke occurs, the blood flow to the brain is interrupted. This can cause damage to the brain cells. tPA works by dissolving the blood clot that is blocking the blood flow and restoring normal circulation. If tPA is indicated, it is administered via an intravenous line. The clot dissolving drug will then start attacking and dissolving blood clots everywhere in the body.

Why tPA and Timing Is Everything

Time is of the essence when it comes to treating strokes. The sooner treatment begins from stroke onset, the less damage is done to the brain. In many cases, tPA can restore blood flow to the blocked vessel and reverse the damage that has been done.This can significantly improve the patient's prognosis and lessen the stroke severity. However, it has to be administered within 4.5 hours (the less time has passed the better) by the hospital stroke team. The longer that delicate brain tissues are deprived of vital nutrients from a clot, the lesser the chance of survival or recovery from disabling stroke deficits.

How Strokes Were Managed Before tPA

Before the development of tPA, not much could be done to treat a stroke. Patients presenting with strokes were hospitalized and given bed rest until the acute phase of the stroke had passed. There was no safe or effective way to dissolve blood clots or restore blood flow to the brain. In some cases, surgery was performed to remove the clot, but this was risky and often unsuccessful.

Does tPA Have Any Downsides?

tPA is a safe and effective medication when used appropriately. However, there are some potential downsides to consider. tPA can cause bleeding in the brain, which can lead to further damage. It is also important to note that not all strokes are caused by blood clots. In these cases, tPA would not be effective or safe.

Possible serious side effects of tPA can include increased risk of bleeding, embolism, allergic reaction, prolonged bleeding. A patient also may experience weakness, easy bruising, lightheadedness, vision changes, nausea. Before tPA is given, the doctor consults a checklist to ensure the patient is a good candidate for treatment and to see if there are any contraindications. Such contraindications are: More than 4.5 hours has passed since onset of symptoms, being on a blood thinner, recent significant bleeding or surgery, history of hemorrhagic stroke, to name the most important ones.

Paving the Way to a Better Future for Stroke Victims

Unfortunately, between 80 and 90% of stroke patients are not receiving tPA, either due to late diagnosis or lack of infrastructure for a rapid evaluation. However, widespread campaigns for recognizing stroke symptoms, new technology, and ever-evolving evaluation techniques are gradually improving the odds of post-stroke recovery.

Thankfully, tPA was just the beginning for improving stroke outcomes. It has inspired the medical community to change clinical practice and to continue looking for new tools for treatment and assessment to optimize stroke recovery, such as mechanical clot removal. Overall, the approval of tPA has helped pave the way to better stroke treatment and recovery.

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