Reducing Door-to-Needle Time for tPA Use Remains an Elusive Goal in Stroke Care

Hospitals continue to experience delays in administering a potentially lifesaving drug to patients presenting with acute ischemic stroke.

At issue is tissue-type plasminogen activator (tPA), the only thrombolytic therapy proven to reduce ischemic stroke mortality and morbidity. But the drug is strongly time dependent. Some researchers estimate that among 100 patients given tPA within the 1- to 3-hour treatment window, every 10-minute delay in the start of therapy reduces by 1 the number of patients having an improved disability outcome.

In light of this time sensitivity, national initiatives, such as the American Heart Association/American Stroke Association Get With the Guidelines–Stroke, recommend that hospitals complete clinical and imaging evaluation of a patient and initiate tPA therapy, if appropriate, within 1 hour of patient arrival. The Joint Commission wants primary stroke centers to administer tPA within 1 hour of patient presentation in 80% of cases.

The reality is quite different. A study presented at the American Stroke Association's International Stroke Conference, held in Los Angeles in February, found that in 2009, only 29.1% patients treated with tPA had door-to-needle times of no more than 60 minutes, a slight improvement over the 19% figure from 2003 (Fonarow GC et al. Circulation. 2011;123[7]:750-758). The study looked at data from 25 504 patients with acute ischemic stroke treated with tPA within 3 hours of symptom onset in 1082 hospitals participating in the Get With the Guidelines–Stroke program.

Gregg C. Fonarow, MD, lead author of the study and professor of cardiovascular medicine at the University of California, Los Angeles, found the results disappointing, especially because the study focused on hospitals that had joined the stroke association's quality improvement efforts. “The results were in many ways surprising, as they also highlight a great opportunity for improvement,” Fonarow said. “We only saw modest improvements over time, plus we saw wide disparities across hospital and patient characteristics.”

The researchers found that hospitals treating patients with tPA in greater volume were better at meeting the 60-minute target than hospitals treating fewer patients. Patients had a higher probability of being treated within 60 minutes upon arrival at an emergency department if they were younger, male, or white; if they had not had a previous stroke; or if they arrived by ambulance.

Another factor affecting treatment speed is how quickly the patient arrives at the emergency department after first experiencing the symptoms of stroke. Current guidelines say tPA should be given only in the first 3 hours after stroke onset. After that point, increased bleeding risks associated with the drug begin to outweigh the clot-busting benefits. (Newer studies are suggesting benefit of tPA given up to 4.5 hours after stroke onset, but the US Food and Drug Administration has yet to approve use of tPA during this expanded window.)

Mathew J. Reeves, PhD, DVM, a coauthor of the study and an associate professor in the department of epidemiology at Michigan State University in East Lansing, said the 3-hour time frame makes clinicians work faster for patients presenting near the end of the window, while putting patients presenting quickly after stroke onset on the back burner. “The data are pretty compelling that the later you come in, the quicker you are treated, because everyone is focused on this 3-hour yes/no window,” Reeves said. “There should not be any difference in the speed, but it is human nature, and the hospital processes will take more time if more time is available.”

To minimize the human nature components and to maximize stroke care, systems and protocols need to be put in place that prevent such behaviors, said Eric E. Smith, MD, MPH, another coauthor and an assistant professor of neurology at the University of Calgary, Alberta, Canada. To help accomplish this, the heart and stroke association have launched Target: Stroke, a program aimed at reducing door-to-needle times to under 60 minutes. Target: Stroke identifies key time targets, such as performing the initial patient evaluation within 10 minutes of arrival in the emergency department, notifying the stroke team within 15 minutes of arrival, and initiating computed tomographic or magnetic resonance imaging scans to rule out hemorrhagic stroke within 25 minutes of arrival.

Smith added that the low percentages of patients being treated with tPA within 60 minutes of presentation also reflects a lack of consensus among national quality improvement organizations that this time frame represents quality care. “As a community, we have not focused on this as a target for quality improvement, and there are a lot of reasons for that,” Smith said. “It is achievable, but we need to increase our focus on systems and integration of care.”