7:42 a.m. Abstract 2 – Warfarin-aspirin stroke prevention trial's final results coming. Investigators will report final results of the Wafrarin-Aspirin Symptomatic Intracranial Disease (WASID) Trial, which compared warfarin to aspirin for preventing stroke and vascular death in patients with symptomatic narrowing of a major brain artery. A secondary goal was identifying high-risk patients for a later trial comparing stenting and medical therapy. Patients with verified artery stenosis causing transient ischemic attack or minor stroke were randomized to warfarin or aspirin. The trial began in 1998 and was stopped by the sponsoring National Institute of Neurological Diseases and Stroke last July on recommendation of its performance and safety monitoring committee. Primary and secondary analysis of 569 patients will be presented.
2:50 p.m. Abstract LBP6 – What's the best bat dose? German researchers report they may have determined the optimal dose at which a clot-buster dervived from vampire bat saliva may work. The DIAS (Desmoteplase In Acute Ischemic Stroke) trial tested the potent new clotbuster Desmodus rotundus salivary plasminogen activator (DSPA), or desmoteplase. It was originally derived from vampire bat saliva. In the double blind, placebo controlled trial, 104 patients were randomized to DSPA or placebo, three to nine hours after stroke onset. The initial phase of the study involving 47 patients was terminated early because of excess intracranial hemorrhages at higher doses. The remaining 57 patients randomly got placebo or varied reduced doses of DSPA. After 90 days, the researchers found that the optimal clinical outcome as reflected in improved neurological function scores came with a DSPA dose of 125 micrograms per kilogram of weight. That dosage will be used in the trial's third phase.
4 p.m. Abstract P10 Cheap four-minute medical tests could save billions of dollars. Three relatively simple medical tests that can be accomplished in four minutes and cost only $20 may help assess the risk of stroke in the elderly, and could help determine treatment aimed at reducing the annual number of strokes, which may have the potential for great savings in healthcare costs. A "quick scan" of the carotid arteries in the neck, electrical measurement of the heart rhythm via electrocardiogram and blood pressure measurement were studied as a cluster of tests to be used in screening for stroke risk factors in seniors, the investigator said. The study screened 2,532 seniors over age 60 in Central California and found neck artery blockages obstructing more than 50 percent of the artery in 7.5 percent (189 subjects) of those screened. Five percent (128 subjects) were found to have atrial fibrillation and 29.5 percent (746 of the seniors) had high blood pressure. An additional 3,514 seniors were screened at Madigan Army Hospital, New York University and American Vascular Association screenings with similar yields for a total of 6,046 patients. Researchers estimate that these carotid artery screenings may have prevented 30 strokes and saved $1,944,210 in stroke care costs. The investigators attempted to prevent strokes by either removing the carotid blockages by an operation called carotid endarterectomy before a stroke occurred or by treating them medically depending on the severity of the block. Researchers believe that if all 40 million Medicare recipients were to receive similar stroke prevention screening, more than 200,000 strokes and 30,000 deaths could be prevented annually, for a savings of more than $12 billion annually.
4 p.m. Abstract P66 – New device detects tiny clots during carotid artery stenting. A new technology called multi-frequency transcranial Doppler (TCD) ultrasound has shown it can tell doctors whether microscopic particles created during carotid artery procedures are merely gas bubbles or dangerous tiny clots that can reach the brain, causing small but damaging strokes. Houston researchers tested the ability of TCD, which uses both high and low frequency sound waves, to differentiate between solid and gaseous emboli during carotid artery stenting and angiography. "Microembolization" frequently occurs during stenting even with deployment of a distal protection device, the researchers found. More solid emboli (clots) were seen during manipulations that crossed artery lesions. "In this pilot study, multi-frequency TCD for automated emboli detection registered a high number of events," the researchers reported. They said further evaluation is needed to determine the true nature, size and number of emboli seen.