Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Predicting which stroke patients will be helped -- or harmed -- by clot-busting treatment

20.05.2014

Johns Hopkins researchers say they have developed a technique that can predict — with 95 percent accuracy — which stroke victims will benefit from intravenous, clot-busting drugs and which will suffer dangerous and potentially lethal bleeding in the brain.

Reporting online May 15 in the journal Stroke, the Johns Hopkins team says these predictions were made possible by applying a new method they developed that uses standard magnetic resonance imaging (MRI) scans to measures damage to the blood-brain barrier that protects the brain from drug exposure.

If further tests confirm their method's accuracy, it could form the basis of expanded and more precise use of intravenous tPA, a drug that is currently limited to patients who are within 4.5 hours of a stroke onset, in order to have the best chance of dissolving the blood clot causing the stroke without risking additional damage.

If doctors had a safe, reliable tool to determine which patients could still be safely treated outside that window, more patients could be helped, the researchers say.

... more about:
»CT »MRI »aggressive »damage »method »stroke »tPA

"If we are able to replicate our findings in more patients, it will indicate we are able to identify which people are likely to have bad outcomes, improving the drug's safety and also potentially allowing us to give the drug to patients who currently go untreated," says study leader Richard Leigh, M.D., an assistant professor of neurology and radiology at the Johns Hopkins University School of Medicine.

Leigh's method is a computer program that lets physicians see how much gadolinium, the contrast material injected into a patient's vein during an MRI scan, has leaked into the brain tissue from surrounding blood vessels. By quantifying this damage in 75 stroke patients, Leigh identified a threshold for determining how much leakage was dangerous. Then, he and his team applied this threshold to those 75 records to determine how well it would predict who had suffered a brain hemorrhage and who had not. The new test correctly predicted the outcome with 95 percent accuracy.

The blood-brain barrier is a unique shield of blood vessels that limits the passage of molecules from the bloodstream into the brain. Without it, the brain is open to infection, inflammation and hemorrhage. Ischemic stroke patients are at risk of bleeding into the brain when there is damage to the barrier. In an ischemic stroke, a blood clot is stuck in a vessel, cutting off blood flow to a portion of the brain, which will begin to die the longer the clot remains. When patients come to the hospital within a few hours of suffering an ischemic stroke, doctors quickly move to give intravenous tPA, hoping that it will dissolve the clot without causing additional damage.

In roughly 30 percent of patients, receiving tPA in a timely manner provides great benefit. In some people — roughly 6 percent of stroke patients— there is already too much damage done to the blood-brain barrier, and the drug causes bleeding in the brain, severe injury and sometimes death.

But doctors haven't known with any precision which patients are likely to suffer a drug-related bleed and which are not. In these situations, if physicians knew the extent of the damage to the blood-brain barrier, they would be able to more safely administer treatment, Leigh says.

Most stroke patients, Leigh notes, don't get to a hospital within the window for optimal tPA use, so physicians don't give them tPA, fearing dangerous complications. Sometimes, more aggressive treatment can be attempted, such as pulling the clot out mechanically via a catheter threaded from the groin area or by directly injecting tPA into the brain.

Typically, physicians do a CT scan of a stroke victim to see if he or she has visible bleeding before administering tPA. Leigh says his computer program, which works with an MRI scan, can detect subtle changes to the blood-brain barrier that are otherwise impossible to see. If his findings hold up, Leigh says, "We should probably be doing MRI scans in every stroke patient before we give tPA."

The biggest obstacle in successful stroke treatment has always been time, Leigh notes. The longer it takes for a patient to be treated, the less chance of a full recovery. An MRI scan does take longer to conduct in most institutions than a CT scan, Leigh concedes. But if the benefits of getting tPA into the right people — and most importantly, protecting the wrong people from getting it — outweigh the harms of waiting a little longer to get MRI results, doctors should consider changing their practice.

"If we could eliminate all intracranial hemorrhages, it would be worth it," he says.

Leigh is now analyzing data from patients who got other treatments for stroke outside the typical time window, in some cases many hours after the FDA-approved cutoff for tPA. It's possible, he says, that some people who come to the hospital many hours after a stroke can still benefit from tPA, the only FDA-approved treatment for ischemic stroke.

###

Media Contacts: Stephanie Desmon
410-955-8665; sdesmon1@jhmi.edu

Lauren Nelson
410-955-8725; lnelso35@jhmi.edu

The study was supported by grants from the National Institutes of Health's National Institute of Neurological Disorders and Stroke (R01NS47691), the National Institute on Deafness and Other Communication Disorders (R01DC05375) and the Seton Healthcare Family.

Other Johns Hopkins researchers involved in the study include Argye E. Hillis, M.D.; John W. Krakauer, M.D.; and Peter B. Barker, D.Phil. Shyian S. Jen, M.D., of Emory University also contributed to the study.

Johns Hopkins Medicine (JHM), headquartered in Baltimore, Maryland, is a $6.7 billion integrated global health enterprise and one of the leading health care systems in the United States. JHM unites physicians and scientists of the Johns Hopkins University School of Medicine with the organizations, health professionals and facilities of The Johns Hopkins Hospital and Health System. JHM's vision, "Together, we will deliver the promise of medicine," is supported by its mission to improve the health of the community and the world by setting the standard of excellence in medical education, research and clinical care. Diverse and inclusive, JHM educates medical students, scientists, health care professionals and the public; conducts biomedical research; and provides patient-centered medicine to prevent, diagnose and treat human illness. JHM operates six academic and community hospitals, four suburban health care and surgery centers, and more than 30 primary health care outpatient sites. The Johns Hopkins Hospital, opened in 1889, was ranked number one in the nation for 21 years in a row by U.S. News & World Report.

Stephanie Desmon | Eurek Alert!
Further information:
http://www.jhmi.edu

Further reports about: CT MRI aggressive damage method stroke tPA

More articles from Health and Medicine:

nachricht Millions through license revenues
27.04.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht New High-Performance Center Translational Medical Engineering
26.04.2017 | Fraunhofer ITEM

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>