Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, March 20, 1990 TAG: 9003202919
SECTION: NATIONAL/INTERNATIONAL PAGE: A/1 EDITION: EVENING
SOURCE: Associated Press
DATELINE: NEW ORLEANS LENGTH: Medium
Even when hospitals are prepared to offer this treatment, hours may pass before patients reach the emergency ward, are evaluated by heart specialists and eventually hooked up to lines that drip the medicine into their bloodstreams.
The new research supports the growing belief that for this approach to work well, it must be offered fast, perhaps even before heart attack victims leave their homes.
The research found that 92 percent of clogged arteries could be reopened if the medicine were given immediately as a shot. Currently hospitals administer the medicine as a continuous drip infusion, which takes longer to set up and is impractical for use by paramedics.
In past studies, clot-dissolving drugs have been about 60 to 70 percent effective in opening up clot-blocked heart arteries.
The new study, meant to simulate administration of the drug tissue plasminogen activator, or TPA, by ambulance crews was conducted by Dr. George McKendall of Rhode Island Hospital. He presented the findings Monday at a meeting of the American College of Cardiology.
"They achieved what appears to be a startling patency," or reopening of closed arteries, of more than 90 percent, said Dr. Carl Pepine of the University of Florida. "This is striking."
Ambulance crews in Providence will begin carrying TPA within a few weeks, McKendall said. Emergency teams in at least seven other cities are already doing this or are planning similar programs.
Dr. Richard Conti, president of the college of cardiology, said that in light of the latest research, "we ought to think about giving the first dose in the home by paramedics."
Heart attacks usually occur when an obstruction, typically a blood clot, gets stuck in an artery that feeds the heart muscle. Unless the blockage is removed within a few hours, a section of muscle is starved of oxygen and dies, permanently weakening the heart.
While TPA and similar drugs are effective, they also are risky because they can cause uncontrolled bleeding. If the bleeding occurs in the brain, the result can be a crippling stroke.
To make sure that during emergencies the medicines are given only to people who truly are having heart attacks, the ambulance crew typically sends electrocardiogram readings back to the hospital over a cellular telephone. A doctor there gives instructions about what medicines to administer.
Several clot-dissolving drugs are on the market, and others are being tested. Many studies are under way to determine which is the best.
In the United States, many physicians consider TPA to be the preferred drug. This medicine, produced through genetic engineering, costs a hospital about $2,300 for a single dose. A competing drug, streptokinase, which is made from bacteria, costs $87.
An Italian study concluded that streptokinase works just as well as TPA. However, another new study, also presented at the meeting Monday, suggests that a combination of the two may be the best approach.
Dr. Cindy Grines of the University of Kentucky compared the combination with straight TPA in 111 heart attack patients. She found that clogged arteries reopened in 70 percent of those who got the combination, combined with 58 percent in those getting TPA alone.
by CNB