Ischemic Stroke Care Timing, Team and tPA

Main Category: Stroke / Neuroprotection
Article Date: 18 May 2004 - 0:00 PDT

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Tissue plasminogen activator (tPA) is the thrombolytic agent approved in 1996 by the FDA for treating ischemic strokes, which account for about 80% of all strokes. Clinical studies have shown this clot-busting agent can reduce the effects of stroke and increase patients' chances of recovering from the event with little or no disability. However, the window of tPA opportunity is relatively narrow and the agent must be appropriately administered; not everyone is a tPA candidate.

"tPA is the only acute therapy that we have for stroke," says S. Claiborne Johnston, MD, PhD. "We have prevention therapies and supportive therapies, but we don't have any direct therapies for stroke other than tPA. Based on results of a single trial, but a very well-done trial, and also data from other trials, it looks like tPA has a solid impact on outcomes after stroke. It can extremely be difficult to give this agent, however. It carries a risk of hemorrhage, so patients must be properly screened and evaluated. It also needs to be given within three hours of symptom onset, at least according to how we understand it today."

Perhaps as a consequence of the timing issues and perceived clinical challenges, Dr. Johnston believes this agent is underutilized. "The reality is that we're not giving tPA to many people nationwide," he says. "There are a variety of different studies out there reporting anywhere from 1% to 4% in representative hospitals and populations. There are problems at all different levels. One is just trying to get people to come in rapidly after their stroke symptoms begin. Sometimes their stroke symptoms occur during sleep or the patient will wait until the symptoms go away before seeking treatment. At the physician level, we know that there are many people who are candidates for tPA and yet physicians do not always give it. We know we are currently undertreating, based on studies of patients who are candidates for tPA but don't get it.

"We don't really know the potential impact of tPA on a population or public health level," he continues. "Some centers have been able to get treatment rates up, at least for short periods of time, to where over 10% of ischemic stroke patients are receiving tPA. If we could do that on a national level, I believe there would be a major impact on the outcomes and costs of stroke care because of reduced long-term morbidity. Stroke is the number one cause of adult morbidity, so tPA does have a lot of potential. This potential is not being reached at present, and that is disappointing."

The Brain Attack Coalition (BAC), a multidisciplinary group representing major professional organizations, has developed recommendations for the establishment of primary stroke centers addressing 11 criteria for acute stroke care (fig1). The BAC recommendations define team members and their roles; availability of essential laboratory and diagnostic services; and the need for care protocols, outcomes tracking, and educational programs. The coalition suggests these recommendations have the potential to improve the care of stroke patients by increasing the use of appropriate diagnostic and therapeutic modalities.

Research conducted by Johnston and colleagues, presented at the American Stroke Association's 29th International Stroke Conference, suggests the BAC recommendations may indeed facilitate improved tPA utilization. To evaluate the impact of the individual BAC criteria on tPA use, Johnston and his team surveyed 34 academic medical centers to ascertain which of the 11 criteria each center met. They followed with a statistical comparison of the recommended criteria to the number of ischemic stroke patients treated with tPA at each facility.

Seven of the eleven were found to be associated with greater tPA use. Of those seven, Dr. Johnston says four were "statistically significant" predictors of increased use of the drug: written procedures for treating stroke, integrating emergency medical services (EMS) personnel into the treatment effort, an emergency department staff well-trained in recognizing stroke, and stroke education programs.

"Written care protocols were most strongly associated with giving tPA in hospitals," he explains. "The hospitals that tend to use them are the ones that have care organized in other ways and we can't take that apart in this study to determine whether the protocol itself is responsible. But there are data from other studies that suggest these care protocols really do improve utilization. The main reason people don't get tPA is because of timing issues. Written care protocols are in the emergency department, so that helps deliver rapid care for patients. The emergency department variable has to do with integrated and aware emergency department care for stroke, so that's obviously going to be a crucial component for time to treatment. The EMS piece has to do with integrating their activities to the emergency room, so that also makes sense because it reduces the time to treatment and improves treatment rates."

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