UTHealth part of major NIH study on brain cooling and stroke
HOUSTON – (March 9, 2010)–Researchers at The University of Texas Health Science Center at Houston (UTHealth) are part of the largest clinical trial to date of hypothermia (brain cooling) for stroke. The $1.1 million study is funded by the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health.
James C. Grotta, M.D., the Roy M. and Phyllis Gough Huffington Distinguished Chair in Neurology at The University of Texas Medical School at
Brain cooling has been shown to decrease brain swelling and reduce loss of neurological function after an acute stroke. It has also been proven highly effective in saving lives and preventing neurological damage after cardiac arrest and after oxygen deprivation in newborns. This trial, called the ICTuS 2 study (Intravascular Cooling for Acute Stroke), will look specifically at whether hypothermia can be used safely in elderly stroke patients.
“Stroke is more prevalent in the elderly and this type of treatment is important in trying to minimize neurological damage and possible disability,” said Grotta, chief of Neurology Services and co-director of the Mischer Neuroscience Institute at Memorial Hermann-TMC. “We think this particular form of hypothermia using a catheter inserted into the vein will cool patients faster and more comfortably, as these patients are awake, versus the externally cooled patients who are typically comatose.”
In the ICTuS 2 trial, investigators will use an endovascular temperature modulation system from Philips Healthcare. Endovascular cooling provides rapid heat exchange and very fast cooling toward target temperature; in awake patients, endovascular cooling is generally superior to cooling blankets or ice packs in maintaining tight temperature control around the target temperature.
Cooling is achieved by inserting a special catheter into the inferior vena cava – the body’s largest vein. No fluid enters the patient; instead, an internal circulation within the catheter transfers heat out. Study participants are covered with a warming blanket to “trick” the body into feeling warm, and temperature sensors in the skin and a mild sedative help suppress shivering. In this study, body temperature will be cooled to 33 degrees C and maintained at that level for 24 hours.
At the conclusion of the cooling period, participants will be re-warmed over 12 hours.
Set to begin later this spring, the three-and-a-half-year study will enroll 400 patients. ICTuS 2 is a single-blind, randomized trial. To be included, patients must meet certain age and medical criteria, treatment must begin within three hours of stroke onset, and patients must receive intravenous injection of tissue plasminogen activator (tPA), a “clot-busting” medication.
“In animal models, cooling within the three-hour window has shown to be most effective, and you have to be able to get the artery open, which is why we try to cool patients who have received tPA,” Grotta said.
Stroke occurs when blood flow to the brain is interrupted by a blockage or a rupture in an artery, depriving brain tissue of oxygen. It is the third-leading cause of death behind heart disease and cancer. According to the American Stroke Association, nearly 800,000 Americans suffer a stroke each year – one every 40 seconds. On average, someone dies of stroke every three to four minutes.
Deborah Mann Lake
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