Last year at Parkland Memorial Hospital the primary adult teaching hospital for UT Southwestern faculty physicians only 19 percent of 349 patients diagnosed with the most common form of stroke arrived within three hours of the initial attack, Dr. Unwin said. Three hours is the crucial window of time in which the fast-acting, clot-busting drug called tissue plasminogen activator (tPA) must be administered. The drug dissolves blood clots in the brain, greatly reducing the risk of death or severe disability.
In June 2003 UT Southwestern launched a trial of Desmoteplase, a second-generation clot-buster made from the saliva of vampire bats that can be administered up to nine hours after the onset of a stroke. But only 16 percent of 252 stroke patients screened for the study since its inception arrived within nine hours of the onset of stroke, and of those 40 patients, none qualified for the treatment. Some arrived in time to receive tPA, and others failed to qualify because they had high blood pressure, were over 85, or had taken an anticoagulant.
"Here we have this opportunity to triple the window of time in which we can treat patients with an effective, fast-acting drug, and we haven't been able to use it in this study largely because people don't know the signs of stroke, and they don't treat it like an emergency," Dr. Unwin said. "It's amazing the number of people we encounter who suddenly can't use their arm one night, and they'll just go to bed and hope it's better by morning."
Stroke is the third-leading cause of death and a leading cause of severe disability in the United States. It affects 750,000 Americans of all ages each
Contact: Rachel Horton
UT Southwestern Medical Center