5 Questions: Albers on stroke treatment
An occasional feature in which a medical expert answers five questions on a science or policy topic of interest to the Stanford community
Ten years ago a clot-busting drug was shown to be effective for limiting the damage caused by a stroke. But today only about 3 percent of stroke patients receive the drug, called tPA. Amy Adams, a science writer in the Office of Communication & Public Affairs, turned to Gregory Albers, MD, professor of neurology and neurological science and director of the Stanford Stroke Clinic, to explain this discrepancy.
1. What does tPa do?
Albers: The drug breaks down blood clots that cause 85 percent of strokes and restores blood flow to regions of the brain injured by stroke. If people receive treatment within 90 minutes they are three times more likely to have a complete recovery. However, there is also a small risk of serious bleeding associated with this therapy.
2. If it works so well, why do so few people get tPa?
Albers: It's only approved for use up to three hours after stroke onset. Patients frequently don't get to a hospital within that time frame. Even if patients do arrive at an emergency room, not all clinicians are adequately trained to deliver tPA. Also, there is a fear of giving tPA to the wrong patients and causing serious harm. We've been working to increase the number of hospitals that can rapidly offer tPA to appropriate patients.
3. How do you hope to increase the number of people who get tPa?
Albers: We published a study last year showing that stroke patients can benefit from tPA up to 4.5 hours after stroke onset. We want to get the word out about that so more people receive the drug while it can still help their recovery. Also, the Joint Commission on Accreditation of Healthcare Organizations, which accredits hospitals, is now accrediting stroke centers and one of the criteria is the ability to offer tPA treatment. Stanford was the second academic hospital in the country to be accredited. This should allow more people access to a hospital where they can receive tPA treatment. In Santa Clara County, the paramedics will start diverting stroke patients to hospitals that have already been or are soon likely to be accredited. In Houston, where there has been a big push to improve tPA delivery and divert patients to stroke-ready hospitals, 11 percent of stroke patients receive the drug throughout the city. Hopefully this strategy will spread across the country and more people will get appropriate treatment.
4. How does Stanford Hospital stack up in terms of tPa treatment?
Albers: More than 10 percent of stroke patients who come to Stanford get tPA treatment, but most eligible people don't get here in time. We are having a community stroke awareness fair on March 5 to help more people in the community recognize stroke symptoms. We also have a grant to study tPA treatment up to six hours after the stroke occurs to see if we can widen the window for effective therapy. We use MRI to determine the size and location of the blood clot and amount of salvageable brain tissue. But the drug doesn't work well on very large clots, so for those people we can use an alternate device that removes the clot in the same manner that a corkscrew removes a wine cork. With the information provided by MRI we can tailor the treatment for the individual patient.
5. Are there any new stroke treatments around the corner?
Albers: Yes. We helped design a clinical trial that tested a new drug that appears to be effective up to nine hours after the stroke occurs. This may allow many more stroke patients to receive treatment. The drug comes from a chemical in bat saliva that can dissolve blood clots. The drug was shown to be effective for patients who were selected using the new MRI technique that we have been using at Stanford Hospital for many years now.