Stroke occurs when blood flow to the brain is disrupted. Disruption in blood flow is caused when either a blood clot or piece of plaque blocks one of the vital blood vessels in the brain (ischemic stroke), or when a blood vessel in the brain bursts, spilling blood into surrounding tissues (hemorrhagic stroke) (Neurology, 2005; 64: E1-E2).
Intravenous tissue plasminogen activator or tPA (also known as a “clot-buster” medication) is currently the only agent approved by the US Food and Drug Administration (FDA) for treating acute ischemic stroke. tPA should be administered within three hours of onset of acute ischemic stroke in patients who meet certain eligibility requirements (New England Journal of Medicine, September 7, 2000: 343(10); 712-722).
Nationwide, 10 to 20 percent of eligible ischemic stroke patients receive tPA (Stroke, November 2005: 36(11); 2500-2503).
Tissue plasminogen activator is not generally used for hemorrhagic stroke, or in those who may experience bleeding problems, because it may increase bleeding. A CT scan or MRI of the brain is needed to quickly determine if an individual is having an ischemic or hemorrhagic stroke.
The pooled results of three major tissue plasminogen activator (tPA) trials confirmed that early stroke treatment is strongly associated with favorable stroke outcomes (The Lancet, March 6, 2004: 363(9411); 768-74).