That means the closest ER may be the best one when a stroke strikes — but only if the ER team is prepared to give special thrombolytic drugs called tissue plasminogen activators, or tPA, that can break up a clot and cut the risk of brain damage.
The study also shows too many minutes are lost between the time a stroke hits and the time a stroke victim reaches the ER. That delay reduces the number of patients eligible for tPA, which should only be delivered in the first three hours after a stroke occurs. More education of both the public and ER teams could help reduce delays and increase the chance that patients will get tPA.
These findings, from a four-hospital retrospective study of tPA treatment for ischemic stroke led by researchers from the University of Michigan Health System, will be presented May 20 at the annual meeting of the Society for Academic Emergency Medicine in St. Louis, MO.
“Despite all the proof that tPA works, emergency physicians have hesitated to use it because of concerns about achieving results similar to centers with specialized stroke teams, and the perceived liability they might face if it causes the patient to hemorrhage,” says lead author Phillip Scott, M.D., FAAEM, director of the UMHS Emergency Stroke Team and assistant professor in the U-M Department of Emergency Medicine. “But what we have shown is that with diligent use of stroke treatment protocols, and specialty neurologist consultation as needed, the complication rate for patients treated by an ER team is the same as for those treated by specialized stroke teams.”
The study looked at data from 140 patients treated with tPA from 1996 to 2001 by emergency physicians at community, university and urban teaching hospitals, and a community non-teaching hospital. All the hospitals used acute stroke treatment guidelines, and patients were treated by board-certified or board-eligible emergency physicians.
The rate of serious bleeding complications (intracranial hemorrhage) in patients treated in the four ERs was 7 percent — the same as in previous studies of tPA use by dedicated stroke teams.
This kind of bleeding is a known risk of tPA use, but despite the risk, treatment within three hours of symptom onset still improved clinical outcomes at three months.
The class of drugs called tPA are the only agents proven to reverse the effects of ischemic stroke. By breaking up clots and unclogging blood vessels near and within the brain, tPA restores blood flow to the brain areas that had been starved of their normal blood supply, and can reduce the permanent damage done by the stroke.
In major clinical trials, tPA therapy has been shown to reduce death and disability greatly in stroke victims over the long term, though the short-term risk of hemorrhage means physicians must carefully select the patients who receive tPA. Many organizations have prepared treatment guidelines for doctors to follow; they’re available at www.stroke-site.org/guidelines/guidelines.html.
The U-M study looked at the records of the 140 patients to see how they fared before and after tPA treatment by what Scott calls a “distributed stroke team.” Forty-four percent of the patients entered the ER with mild to moderately severe neurological impairment, as measured by the National Institutes of Health Stroke Scale, and another 32 percent had severe impairment.
The tPA did its job in most cases — 59 percent of the patients left the ER in better condition than they went in, and an additional 9 percent left the ER feeling like their normal selves.
This positive result is probably due to the fact that the ER teams treated the patients with proper speed, giving tPA within an hour and a half of the patient’s arrival at the ER, on average. Most patients were treated within the recommended three-hour window from stroke onset; 22 patients were treated despite having gone past the three-hour mark, though the median number of minutes over the deadline was 12. Some patients asked for tPA despite being over the time limit.
Even if they don’t have a stroke team at their hospital, ER physicians don’t have to go it alone when making the decision about whether a patient is a candidate for tPA, Scott says. “In 65 percent of the patients in our study, the ER physician consulted with a neurologist before giving tPA, and half of those consultations took place over the phone,” he explains. “Making the call about stroke diagnosis and tPA treatment can be tough, but with the proper support an ER physician can do it with confidence.”
But even if ERs are ready to help patients receive tPA when they’re appropriate candidates for it, they can’t deliver the treatment if the patients don’t get to the ER in time. That delay in onset-to-ER time was a big factor in the study findings. On average, it took an hour from the time the stroke occurred until the victim reached the ER.
In many cases, Scott says, that was due to a patient’s own decision to delay seeking treatment or failure to recognize what was happening to them. Recent surveys show that many people don’t know the symptoms of stroke, or what to do if they or someone nearby experiences them.
“Pre-hospital delays are still our biggest problem. This shows us how far we still have to go in educating the public that any sudden change in speech, sensation or strength might mean they’re having a stroke, and that they must call 911 and get to the emergency room as quickly as possible,” he says. “And, once they’re there, they should ask the doctor to give them clotbusters, if clotbusters are right for them.”
Scott estimates that the vast majority of stroke victims, especially in Michigan, who could receive tPA never do. But if more hospitals established stroke treatment protocols for their ER teams, he says, the odds for patients could improve.
Besides Scott, the study’s authors include research associates Lisa A. Davis, RN, MSN, CCRC and Shirley Frederiksen, M.S., RN, CCRC; and Rodney Smith, M.D., an adjunct clinical assistant professor of emergency medicine.
In addition to this study, UMHS stroke researchers are exploring stroke prevention, epidemiology, experimental treatments such as neuroprotective agents and hypothermia, and the basic science of what leads to and happens during a stroke.
Signs of stroke:
• Weakness, numbness or tingling in any part of the body, especially half of the body
• Difficulty producing speech, getting speech out, or understanding what others say
• Disruption of vision, loss of vision in one eye or sudden double vision
• Sudden onset of dizziness, usually accompanied by other symptoms
• Sudden, unexpected headache
Risk factors for stroke:
• Family history of stroke
• Diabetes
• Personal history of high blood pressure
• High cholesterol
• Cigarette smoking
• Heart rhythm irregularities, especially atrial fibrillation.