Sooner is much better than later when giving clot-busting medication to treat patients with ischemic stroke, confirms research appearing today in JAMA.
Intravenous tissue-type plasminogen activator (tPA), a medication that dissolves blood clots, is used to treat the hallmark of ischemic stroke, a clot in an artery that blocks blood flow to the brain. Imaging studies have shown that after blood supply to the tissue is interrupted, the amount of irreversibly injured brain tissue expands rapidly, with 2 million additional neurons lost each minute, so acting quickly to dissolve such a clot is essential for positive outcomes following a stroke.
In the JAMA study, researchers analyzed data from 58 353 patients with acute ischemic stroke who were treated with tPA within 4.5 hours of symptom onset. Patients were treated in 1395 hospitals participating in the Get With The Guidelines–Stroke registry launched by the American Heart Association and American Stroke Association. The researchers looked at outcomes associated with the speed (in 15-minute increments) with which treatment was initiated after the onset of stroke symptoms. They found that faster treatment was associated with reductions in in-hospital death and symptomatic intracranial bleeding and increases in the likelihood patients were walking independently at discharge and were discharged to home.
Lead author Jeffrey L. Saver, MD, David Geffen School of Medicine at the University of California, Los Angeles, discussed his team’s findings.
news@JAMA: Why did you do this study?
Dr Saver: There has been evidence that time is an important factor when using a clot buster, but the evidence base was fairly small and the degree of impact of time delay was not well quantified.
news@JAMA: What new insights does your study offer?
Dr Saver: It demonstrates the magnitude of the impact of timeliness for administering tPA; for every 15 minutes you reduce administration, 2 more patients out of 100 have an improved outcome.
news@JAMA: There has been concern by some clinicians treating ischemic stroke that administering tPA increases the risk of brain bleeding, but your study suggests otherwise.
Dr Saver: Our study shows for the first time that hemorrhage is increased the longer it takes to administer tPA, and it suggests the way to reduce the bleed risk is to treat earlier and to have organized emergency medicine and emergency neurology departments implement the changes in care in response to that data.
news@JAMA: In recent years, research has shown tPA to be to some degree effective in treating ischemic stroke up to 4.5 hours after symptom onset, and because of that, there is concern this larger window may subconsciously cause clinicians to forget about the urgency of treatment. What does your study say about that mind-set?
Dr Saver: Although data has come out showing that worthwhile degrees of benefit are obtained even after 3 hours following onset of stroke, the best benefit is obtained in the first hour. The real time difference in outcomes is 1 minute, so we can’t dawdle.
news@JAMA: Does your study remind patients and family members to act quickly if a stroke is suspected?
Dr Saver: It’s important that patients and family members know that stroke is now highly treatable but that every minute counts. So if symptoms occur suddenly, call 911 to get to the hospital right away. It takes up to 60 minutes in even the best hospitals to perform the needed imaging tests and blood work before administering tPA.