What is the recommended time frame for administering tPA to improve outcomes in stroke patients?

Administering tissue plasminogen activator (tPA) within three hours of symptom onset is crucial for improving outcomes in patients experiencing an acute ischemic stroke. Clinical studies have demonstrated that the likelihood of significant recovery and reduced disability is greatly enhanced when tPA is given promptly after the onset of symptoms.

The reason for this narrow time frame stems from the rapid progression of ischemic brain injury during a stroke; neurons begin to die within minutes due to the lack of blood flow and oxygen. The earlier tPA is administered, the more likely it is to dissolve the clot obstructing blood flow to the brain, thereby preserving brain tissue and increasing the chances of a better functional recovery.

While tPA can be administered up to 4.5 hours after symptom onset in certain patients under specific guidelines, the most favorable outcomes, particularly regarding reduced mortality and long-term disability, are most strongly correlated with treatment provided within the three-hour mark.