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Stroke study examines aspirin and warfarin (4/21/98)

The April 22 issue of the Journal of the American Medical Association (JAMA) is devoted to stroke and highlights a decade of nationwide stroke research led by the neurology team at The University of Texas Health Science Center at San Antonio.

Included are the results of SPAF III, the recently-completed third national study funded by the National Institutes of Health, of "Stroke Prevention in Atrial Fibrillation." Over the past 10 years, three major SPAF studies directed by San Antonio researchers and conducted at 25 medical centers in the United States and Canada have pointed to specific prevention measures that are already saving tens of thousands of patients from strokes and hundreds of millions of dollars in health care costs.

An estimated 2 million Americans have the abnormal heart rhythm known as atrial fibrillation, which can cause clots to be formed in the upper chambers of the heart. These clots can be pumped into the blood stream and carried to the brain to cause stroke. People with atrial fibrillation have, on average, six times the risk of stroke as people of the same age without the rhythm.

According to Robert G. Hart, MD, professor of medicine/neurology, who headed the SPAF studies nationwide, the third and final portion of SPAF followed 892 people with atrial fibrillation to show that carefully selected patients with the rhythm have a low stroke rate if taking aspirin, postponing for many the need for anticoagulation therapy (the use of blood thinners such as warfarin), with its attendant risk of bleeding and need for frequent medical monitoring.

"This study should guide doctors in identifying those with atrial fibrillation who benefit the most and the least from anticoagulation therapy, influencing the care of hundreds of thousands of Americans with this irregular heart rhythm," Dr. Hart said.

More than 35 scientific publications have appeared from the SPAF studies. In the April 15 Annals of Internal Medicine, results of the transesophageal echocardiography component contributed to understanding how and why strokes occur so frequently in people with atrial fibrillation. Sluggish flow of blood in the upper chambers of the heart and cholesterol buildup in the aorta were identified as factors associated with stroke.

Most researchers agree that effective stroke prevention for people with atrial fibrillation has been the most important clinical advance in medical stroke prevention during the past decade.

"As the SPAF studies draw to a close, appreciation and thanks are due to the many patient volunteers, doctors in South Texas, our own team including research nurse Anne Leonard and Dr. David Sherman, the South Texas Veterans Health Care System and the University Health System, who all helped take a big step forward in prevention of strokes," Dr. Hart said.

Contact: Mike Lawrence (210) 567-2570