Certain eligible patients suffering from an ischemic stroke can safely receive recombinant tissue plasminogen activator (tPA) to dissolve a clot up to 4.5 hours from stroke onset, according to updated American Stroke Association (ASA) guidelines published Jan. 31 in Stroke.

The new guideline for tPA administration applies to patients younger than 80 years, not taking oral anticoagulants and with a National Institutes of Health Stroke Scale score of less than 25, wrote Edward Jauch, MD, director of the division of emergency medicine at the Medical University of South Carolina in Charleston, and colleagues.

The FDA previously declined to extend the approved window for tPA administration past three hours, but on the basis of information from European trials, particularly the ECASS trials, administration between three and 4.5 hours is now reasonable to consider according to guidelines, Jauch told Health Imaging. He added that older patients and those with more severe strokes were not included in this extension because effectiveness in these patient groups is not well established.

Decreasing time to treatment was another major focus of the updated guidelines. “The entire system of care needs to be streamlined so whatever the final tool you’re using for reperfusion—whether it be drug or device—you need to shorten that window and compress it as tightly as possible to maximize the amount of salvageable brain that’s still there," said Jauch.

ASA recommended integrating regional networks of comprehensive stroke centers, primary stroke centers, acute stroke-ready hospitals and community hospitals. If feasible, patients should be rapidly transferred to the closest available certified primary care stroke center or comprehensive stroke center.

Door-to-needle time guidelines were solidified at 60 minutes or less. While a one-hour time frame to receiving tPA after patient arrival had previously been a soft recommendation, Jauch says it’s now the benchmark to identify effective stroke centers. “It’s become clear that if you commit to doing things quickly, it is very achievable to have door-to-needle times less than 60 minutes,” he said. “It’s the responsibility of the hospital and the system to really squeeze and compress the time from arrival to the time of initiating treatment for appropriate patients.”

Earlier in the week, the Society of Interventional Radiology (SIR), working with seven other medical societies, unveiled a separate set of metrics and benchmarks for care of stroke patients that also emphasized a rapid treatment schedule, though they differed from ASA’s guidelines.

These benchmarks, to be published in February in the Journal of Vascular and Interventional Radiology, recommended a door-to-needle time of two hours or less. SIR’s guidelines also set a door-to-imaging time of 25 minutes, with the interpretation being completed within 45 minutes.