Stroke is the number three cause of death in the United States. Its appearance can be sudden and its effects life threatening. Joining us for Martha Jefferson Healthwise today is Dr. Alex Grunsfeld, Director of Stroke and NeuroCritical Care, to talk about tPA, the only drug approved by the U.S. Food and Drug Administration for the acute treatment of stroke.
BD: Can you share some details with us on the tpa drug?
AG: tPA stands for Tissue plasminogen activator which is a thrombolytic agent, or clot-busting drug. It has been used for some time to treat heart attacks and in 1996 it was approved by the US Food and Drug Administration for use in selected patients for the treatment of acute ischemic stroke.
BD: how does tpa help someone having a stroke?
There are two main types of stroke. Ischemic stroke occurs when a blood vessel feeding the brain is blocked by a blood clot and a hemorrhagic stroke occurs when a blood vessel ruptures and bleeds into the brain. tPA can be effective for the treatment of an ischemic stroke by literally dissolving the clot that is blocking blood from reaching the brain. Studies have shown that the sooner the tPA is given the better the likelihood of a good or full recovery. Currently the time window for giving this drug intravenously is quite narrow – 3 hours from the start of the stroke symptoms. Evidence from recent studies suggest that in fact intravenous tPA may be beneficial as far out as four and a half hours, but the FDA has not yet to approved it beyond the 3 hours. So the take home message is, therefore, it is very important for people who think they're having a stroke to seek help immediately and call 911.
BD: Are other options available for treating stroke?
AG: Under special circumstances, tPA can be targeted directly at the clot using an intra-arterial catheter that is snaked up through the femoral artery into the blood vessels feeding the brain instead of through an intravenous injection. The FDA has approved the use of a cork screw like device attached to a catheter that is able to mechanically retrieve a clot from the blood vessel where it is lodged. Other types of devices to remove or break up clots are also out there, but all of these can only be used under special circumstances and are available only at large specialized stroke centers and their ability to reverse the effects of a stroke have not yet been conclusively demonstrated. What we do know is that once a stroke has occurred, the best outcomes are possible if a patient is treated at a hospital that has a specialized stroke unit. Treatments are directed to find and address the cause of the stroke, to prevent complications occurring as a result of the stroke and to provide aggressive rehabilitation.