Definition: Tissue Plasminogen Activator from Wikipedia, the Free Encyclopedia.
Tissue plasminogen activator (abbreviated tPA or PLAT) is a protein involved in the breakdown of blood clots. It is a serine protease (EC 3.4.21.68) found on endothelial cells, the cells that line the blood vessels. As an enzyme, it catalyzes the conversion of plasminogen to plasmin, the major enzyme responsible for clot breakdown. Because it works on the clotting system, tPA is used in clinical medicine to treat embolic or thrombotic stroke. Use is contraindicated in hemorrhagic stroke and head trauma.tPA may be manufactured using recombinant biotechnology techniques. tPA created this way may be referred to as recombinant tissue plasminogen activator (rtPA).
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| A simplified illustration demonstrates clot breakdown (fibrinolysis), with blue arrows denoting stimulation, and red arrows inhibition |
Clinical Applications
tPA is used in diseases that feature blood clots, such as pulmonary embolism, myocardial infarction, and stroke, in a medical treatment called thrombolysis. To be most effective in ischemic stroke, tPA must be administered as early as possible after the onset of symptoms. Protocol guidelines require its use intravenously within the first three hours of the event, after which its detriments may outweigh its benefits. They can either be administered systemically, in the case of acute myocardial infarction, acute ischemic stroke, and most cases of acute massive pulmonary embolism, or administered through an arterial catheter directly to the site of occlusion in the case of peripheral arterial thrombi and thrombi in the proximal deep veins of the leg.The guideline in Ontario, Canada hospitals for ischemic strokes is that tPA must be given within 4.5 hours of the onset of symptoms. Because of this, only about 3% of patients qualify for this treatment, since most patients do not seek medical assistance quickly enough.
In the United States, the window of administration used to be 3 hours from onset of symptoms, but the newer guidelines also recommend use up to 4.5 hours after symptom onset. tPA appears to show benefit not only for large artery occlusions but also for lacunar strokes.
Since tPA dissolves blood clots, there is risk of hemorrhage with its use. tPA has also been given to patients with acute ischemic stroke above age 90 years old. Although a small fraction of patients 90 years and above treated with tPA for acute ischemic stroke recover, most patients have a poor 30-day functional outcome or die. Nonagenarians may do as well as octogenarians following treatment with IV-tPA for acute ischemic stroke. In addition, people with frostbite treated with tPA had fewer amputations than those not treated with tPA. In tPA overdose, aminocaproic acid works as an antidote.
See the full article Tissue Plasminogen Activator from Wikipedia, the Free Encyclopedia.
Katie Jerdee - Stroke Lobby Day (tPA)
Survivor Katie Jerdee tells her story about having a stroke while running during soccer practice and the importance of knowing the stroke warning signs.Stroke Specialists Regarding tPA (in Australia)
Unwitnessed Strokes
SSTattler: I saw the video (more than twice) and I'm convinced on simply logic. It is weird but true.The safety of intravenous thrombolytic therapy in patients with unwitnessed strokes surpassed the safety in patients with witnessed strokes when physicians based treatment decisions on the last time patients were seen normal. GMNN's Mitchel L. Zoler interviews Dr. Demetrios Sahlas.
Tissue Plasminogen Activator - tPA(Medical Animations )
Medical Animations by High Impact Graphics. Learn more at HighImpact.com or give us a call at 800-749-2184.Stroke Evaluation Simulation - tPA Consent and Order
In this clip, the patient is consented for tPA administration.Stroke Evaluation Simulation - tPA Delivery
In this clip, the patient receives an injection of t-PA.Target: Stroke - Mixing tPA Ahead of Time
Eric E. Smith, MD, MPH, FRCPC, FAHA, Chair - Get With The Guidelines Stroke Clinical Workgroup and Assistant Professor of Neurology, Department of Clinical Neurosciences of Hotchkiss Brain Institute at the University of Calgary discusses mixing tPA ahead of time.Treating Mild Strokes Could Yield Benefits using tPA
The use of clot-busting drugs in patients with mild stroke could save thousands of them from long-term stroke-related disability, and about $200 million each year in stroke-related health-care costs, explains Dr. Pooja Khatri.See as well the article Treating Mild Stroke Could Save Patients, Dollars in Internal Medicine News.
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