I am often asked by stroke patients I see if they could have been candidates for the “clot busting ” medication known as Tissue Plasminogen Activator (t-PA), a thrombolytic drug approved by the U.S. Food and Drug Administration for the urgent treatment of ischemic stroke—the type of stroke that impedes arterial blood flow in the brain due to a narrowing or clot (blood or cholesterol plaque).
When stroke symptoms are observed, (facial drooping, slurred speech or leg and/or arm weakness, to name a few for instance) a radiological study of the brain called “CT scan” is quickly ordered to be sure the stroke is not due to a bleeding vessel. t-PA is never given for bleeding strokes..
t-PA is a weight based medication that is administered through an intravenous (IV) line. In order to qualify for this treatment doctors who treat stroke follow a very detailed list of inclusion/exclusion criteria. The physician has a detailed list of conditions or procedures that can exclude a patient from treatment due to the increased risk of bleeding. The single most important criteria for t-PA eligibility is presentation to the emergency department when stroke symptom onset--self reported or witnessed--occurred in less than 3 hours.
Why 3 hours?
A stroke causes the surrounding tissues where the initial insult has occurred to become oxygen starved. Lack of oxygen over minutes and certainly hours will cause this brain tissue to die or become “infarcted.” The infarcted tissues can then become irritated and swollen increasing the risk for bleeding in and around the area of damaged tissue.
That is why it is very important to know exactly when patients were last known to have stroke symptoms. It is unfortunate that all too often, stroke symptoms are dismissed. At times, it saddens me that I cannot console patients or family members who feel regret at not having made the call to 911. I urge them to tell others—family, friends and strangers—to make the 911 call at the first signs of stroke. Three hours can seem like a lot of time, but it may not compare with the burden of facing the remainder of one’s life with disability.