Anti-clot drug powerless during some heart attacks
By Gene Emery
BOSTON, May 15 (Reuters) - The clot-busting drug t-PA, used for years to halt heart attacks, proved ineffective when given during cardiac arrests in which patients had no pulse, according to a study in Thursday's New England Journal of Medicine.
"We found no evidence that the administration of t-PA during CPR improved the likelihood of either survival to hospital discharge or a return of spontaneous circulation," researchers concluded.
The findings do not apply to t-PA's use in other types of heart attacks, where its effectiveness is well documented.
Also known by the brand name Activase, t-PA dissolves clots that block the flow of blood to the heart muscle.
Out-of-hospital cardiac arrest results in some 250,000 deaths annually in the United States and Canada.
The study was financed by Hoffmann-LaRoche, whose parent company, Roche Holding Ltd. (ROCZg.VX), owns 58 percent of Genentech Inc. (NYSE:DNA - News), the maker of t-PA.
Although it is still possible that t-PA might be effective in some circumstance, the editors of the Journal said, the new findings of Dr. Riyad B. Abu-Laban of the University of British Columbia in Vancouver offer "little reason for optimism regarding this therapeutic approach in cases of cardiac arrest."
The Abu-Laban team arranged to have t-PA or a placebo given to 233 patients who were getting CPR because their heart had largely stopped beating, a condition known as pulseless electrical activity, where only a small amount of blood is being pumped and 96 percent of patients never survive to be discharged from the hospital. It is found in 20 percent of the people with cardiac arrest.
Although the researchers found that the heart seemed to resume normal pumping in 21.4 percent of the t-PA recipients, the success rate was essentially the same -- 23.3 percent -- for the patients who received the placebo.
Ultimately, only one person, a t-PA recipient, survived to be discharged from the hospital |
