Delay in breaking up blood clots means worse stroke outcome

February 11, 2013, American Heart Association
Brain image. Credit: American Heart Association

Every 30-minute delay in breaking up a blood clot from a stroke was associated with a 10 percent decrease in the probability of a good outcome, regardless of other factors such as stroke severity, according to late-breaking research presented at the American Stroke Association's International Stroke Conference 2013.

The study, a subset from a larger trial, included patients who received both intravenous (tPA) and endovascular , and had blood flow restored within seven hours of stroke onset.

The patients were part of the Interventional Stroke Management III trial (IMS 3), presented earlier in the conference, in which intravenous tPA alone and with added endovascular therapy were compared, but neither proved superior. Delivered through a vein in the arm tPA is the only emergency proven to improve outcomes. It must be given within 4.5 hours of and faster start of treatment leads to better recovery.

Endovascular therapy involves inserting a catheter directly into a blocked artery in the brain to deliver clot-busting drugs or to use a device to remove the clot. This treatment is usually used after the 4.5-hour for intravenous tPA has closed, or for bigger or more stubborn clots that don't dissolve with other treatments.

The importance of timing using endovascular therapy hasn't been as well studied, said study author Pooja Khatri, M.D., M.Sc., director of acute stroke and associate professor of neurology at the University of Cincinnati in Ohio.

IMS 3 was a multicenter international trial in which about 900 participants with were to be randomly assigned to receive tPA alone or tPA plus endovascular therapy. Everyone received tPA within three hours of stroke onset. The trial was stopped in April 2012, with about two-thirds of intended patients enrolled, after an interim analysis determined the additional therapy was highly unlikely to benefit patients.

In the sub-study, researchers examined data on 240 patients who received both intravenous and endovascular therapy in IMS 3 who had major clots in brain arteries. Among these patients, blood flow was restored in 182 patients within seven hours from stroke onset. Patients were evaluated for level of disability 90 days after treatment.

Time proved critical regardless of other factors, such as absence of a disability prior to stroke, stroke severity, or the results of the patients' scans before treatment.

"We have effective endovascular treatments for unblocking arteries, but as far as actually making stroke patients clinically better, we need to move a lot faster," Khatri said. "There's a window of time that we have during a stroke and if we pass that point, it's the point of no return in terms of brain damage. For endovascular therapy to work we may need to deliver it more quickly, and that is what future trials need to test. If we had opened arteries faster in the IMS 3 trial, we might have had a positive trial that brought a more effective treatment to patients with severe strokes."

Delays, said Khatri, include patients not recognizing the signs of a stroke, family members driving patients to the hospital instead of calling emergency services (9-1-1), emergency departments being too slow in identifying or evaluating a for treatment, and delays in transferring to a hospital or facility with expertise in endovascular therapy.

"In the future, we may also be able to use MRI and CT scans to take images of a patient's brain to identify whose treatment window is closing, those who have a little more time, or those with the types of clots most likely to benefit from endovascular therapy. These approaches are under investigation. But, even for those with favorable scans, we can't get away from the fact that the clock is ticking and an patient needs to be managed with the highest level of urgency."

Explore further: Adding endovascular therapy to tPA didn't improve recovery after stroke

Related Stories

Adding endovascular therapy to tPA didn't improve recovery after stroke

February 8, 2013
Adding endovascular therapy to clot-busting therapy for stroke did not significantly improve stroke recovery at three months, according to a study presented in a special symposium at the American Stroke Association's International ...

'Clot-buster' drug may still be best stroke treatment

February 7, 2013
(HealthDay)—The standard medical care for patients having an ischemic stroke is to give powerful "clot-busting" drugs as soon as possible after the start of the stroke.

Clot-busting drug safe for stroke patients taking blood thinner

May 10, 2012
Acute ischemic stroke patients taking the blood thinner warfarin can be treated safely with the clot-busting drug tissue plasminogen activator (tPA), according to research presented at the American Heart Association's Quality ...

Recommended for you

A nanoparticle inhalant for treating heart disease

January 18, 2018
A team of researchers from Italy and Germany has developed a nanoparticle inhalant for treating people suffering from heart disease. In their paper published in the journal Science Translational Medicine, the group describes ...

Starting periods before age of 12 linked to heightened risk of heart disease and stroke

January 15, 2018
Starting periods early—before the age of 12—is linked to a heightened risk of heart disease and stroke in later life, suggests an analysis of data from the UK Biobank study, published online in the journal Heart.

'Decorated' stem cells could offer targeted heart repair

January 10, 2018
Although cardiac stem cell therapy is a promising treatment for heart attack patients, directing the cells to the site of an injury - and getting them to stay there - remains challenging. In a new pilot study using an animal ...

Two simple tests could help to pinpoint cause of stroke

January 10, 2018
Detecting the cause of the deadliest form of stroke could be improved by a simple blood test added alongside a routine brain scan, research suggests.

Exercise is good for the heart, high blood pressure is bad—researchers find out why

January 10, 2018
When the heart is put under stress during exercise, it is considered healthy. Yet stress due to high blood pressure is bad for the heart. Why? And is this always the case? Researchers of the German Centre for Cardiovascular ...

Heart-muscle patches made with human cells improve heart attack recovery

January 10, 2018
Large, human cardiac-muscle patches created in the lab have been tested, for the first time, on large animals in a heart attack model. This clinically relevant approach showed that the patches significantly improved recovery ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.