Stanford study expands window for effective stroke treatmentMay 29, 2009STANFORD, Calif. - Once symptoms start, there's only a tiny window of time for stroke victims to get life-saving treatment. Now, research from the Stanford University School of Medicine has cracked that window open a bit wider. If a patient arrives at the emergency room within three hours of experiencing stroke symptoms, doctors can administer a potent clot-busting medication and often save critical brain tissue. But if more than three hours have passed, current clinical guidelines say the medication should not be used. But the new study suggests that the traditional three-hour time window is too short. By combining data from multiple clinical trials, Maarten Lansberg, MD, PhD, assistant professor of neurology and neurological sciences at Stanford, and colleagues from Belgium and Germany showed that treatment can benefit patients up to 4.5 hours after they experience their first symptom. Their findings will be published online May 28 in the journal Stroke. Every year, more than 750,000 Americans experience a stroke, or brain attack, due to a sudden drop in blood flow to the brain. Most strokes are ischemic, meaning they're caused by a blocked artery. For these strokes, a medication called tissue plasminogen activator, or tPA, can open blocked blood vessels and help restore blood flow to the brain. "We've known that this treatment works for ischemic stroke since 1995," said Lansberg, the lead author of the study. "But in the United States, only about 3 percent of stroke patients end up getting treated. Most of them are ineligible because they come to the hospital after the three-hour time window." The timing of treatment is important, because giving a strong blood thinner like tPA during a stroke can cause bleeding inside the brain. The longer a patient waits to get treatment, the more likely it is that the risks of treatment will outweigh the benefits. "Doctors from all over the world have tried to increase the treatment time window," Lansberg said. But evidence from individual clinical trials has been confusing: Some studies demonstrated a benefit from treatment after three hours, while others were inconclusive or reported no benefit. "Individually, the studies were too small to be convincing," said Greg Albers, MD, professor of neurology and neurological sciences and director of the Stanford Stroke Center, who was not involved in the study. "Most of the studies showed a trend but weren't statistically significant." But when Lansberg and colleagues combined data from all four of the major tPA stroke trials to date, they saw a much clearer picture. Among a total of 1,622 patients who arrived at the hospital between three and 4.5 hours after their symptoms started, treatment with tPA improved the odds of a favorable outcome by 31 percent. "A favorable outcome means that patients are either completely back to normal or they have minimal symptoms, like some numbness or a slight facial droop," Lansberg said. "But they can do everything in their normal life that they were able to do before the stroke happened." The study, funded by grants from the National Institutes of Health, found no change in the death rate among patients treated with tPA during the three- to 4.5-hour window. In other words, treatment improved outcomes without negatively affecting mortality. Lansberg collaborated with Vincent Thijs, MD, PhD, professor of neurology at the University Hospitals of Leuven in Belgium, and Erich Bluhmki, PhD, who works for Boehringer Ingelheim Pharma GmbH & Co. Boehringer Ingelheim manufactures tPA for use in Europe. A second study, also led by Lansberg and published online in Stroke on April 16, further supports these findings. Using data from six previous trials, the researchers calculated the likelihood that patients would benefit or be harmed by tPA treatment. Out of 100 patients treated three to 4.5 hours after the onset of stroke, the study estimated 16.9 patients would benefit and only 3.4 would be harmed. "Although this is not as good as treatment at an earlier time, it is still a highly significant benefit for patients treated in this group," Lansberg said. Stanford doctors have already started to incorporate the new data into their clinical decision-making, Albers said. Although the FDA has not approved tPA for use more than three hours after the onset of symptoms, physicians can offer the treatment to patients as an "off-label" use. "Until these data came out, we were treating patients up to three hours," Lansberg said. "Now, after carefully explaining the risks and benefits, we give patients the option to get treatment up to 4.5 hours after their symptoms start." Albers estimates that roughly 15 percent of patients at Stanford come in during the three- to 4.5-hour time window. "It varies by location," he said, "because if you live in a remote area, you're less likely to get to the hospital in time. But with 750,000 strokes happening every year in the United States, it's quite a large number of patients who could potentially benefit." Despite a longer window for treatment, Lansberg stressed the classic mantra of stroke researchers: "'Time is brain' still holds true," he said. "When your brain doesn't get the sugar and oxygen it needs, your brain cells die. For every minute you wait, your chances of getting better from the treatment drop." Stanford University Medical Center |
|||||||||||||||||||||
| Related Stroke Current Events and Stroke News Articles New understanding about mechanism for cell death after stroke leads to possible therapy Scientists at the Brain Research Centre, a partnership of the University of British Columbia Faculty of Medicine and Vancouver Coastal Health Research Institute, have uncovered new information about the mechanism by which brain cells die following a stroke, as well as a possible way to mitigate that damage. Surgery not linked to memory problems in older patients For years, it has been widely assumed that older adults may experience memory loss and other cognitive problems following surgery. But a new study from researchers at Washington University School of Medicine in St. Louis questions those assumptions. Pushing the brain to find new pathways Until recently, scientists believed that, following a stroke, a patient had about six months to regain any lost function. After that, patients would be forced to compensate for the lost function by focusing on their remaining abilities. Night Beat, Overtime and a Disrupted Sleep Pattern Can Harm Officers' Health A police officer who works the night shift, typically from 8 p.m. to 4 a.m., already is at a disadvantage when it comes to getting a good "night's" sleep. Vitamin B niacin offers no extra benefit to statin therapy in seniors already diagnosed with CAD The routine prescription of extended-release niacin, a B vitamin (1,500 milligrams daily), in combination with traditional cholesterol-lowering therapy offers no extra benefit in correcting arterial narrowing and diminishing plaque buildup in seniors who already have coronary artery disease, a new vascular imaging study from Johns Hopkins experts shows. The benefits of exercise Physical exercise is one of the most effective methods of preventing disease. The current issue of Deutsches Arzteblatt International is devoted to this important topic. Heart and bone damage from low vitamin D tied to declines in sex hormones Researchers at Johns Hopkins are reporting what is believed to be the first conclusive evidence in men that the long-term ill effects of vitamin D deficiency are amplified by lower levels of the key sex hormone estrogen, but not testosterone. New study links vitamin D deficiency to cardiovascular disease and death While mothers have known that feeding their kids milk builds strong bones, a new study by researchers at the Heart Institute at Intermountain Medical Center in Salt Lake City suggests that Vitamin D contributes to a strong and healthy heart as well - and that inadequate levels of the vitamin may significantly increase a person's risk of stroke, heart disease, and death, even among people who've never had heart disease. Early end to key study on benefits of niacin, a B vitamin, in keeping arteries open was premature Heart experts at Johns Hopkins are calling premature the early halt of a study by researchers at Walter Reed Army Medical Center and Washington Hospital Center on the benefits of combining extended-release niacin, a B vitamin, with cholesterol-lowering statin medications to prevent blood vessel narrowing. Study finds many people with hemianopia have difficulty detecting pedestrians while driving, advocates for individual testing Schepens Eye Research Institute scientists have found that--when tested in a driving simulator--patients with hemianopia (blindness in one half of the visual field in both eyes) have significantly more difficulty detecting pedestrians (on their blind side) than normally sighted people. More Stroke Current Events and Stroke News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||