Findings may provide benefit for nearly 1.5 million Americans each year
BOSTON - Researchers at Brigham and Women's Hospital (BWH) have discovered the combination of abciximab, an antiplatelet drug that prevents the formation of blood clots, and a low-dose clot-busting therapy may provide heart-attack patients with a new and more effective treatment option, according to a study published in the June 1, 1999 issue of Circulation: Journal of the American Heart Association. The finding is based on results of the Thrombolysis in Myocardial Infarction (TIMI) 14 Trial, which is the first to demonstrate the potential benefits of combining these two therapies in the treatment of heart attack.
The study showed that 72 percent of heart-attack patients who received abciximab plus half the standard dose of the clot-buster alteplase (tissue plasminogen activator, or t-PA) achieved optimal blood flow in their arteries within 60 minutes of treatment, compared with only 43 percent of patients treated with alteplase alone. Within 90 minutes, 77 percent of patients treated with combination therapy achieved this level of blood flow, compared with 62 percent given alteplase alone.
"Beginning with the initial TIMI studies over 15 years ago, we demonstrated the importance of rapidly opening obstructed coronary arteries in heart attack patients," said Eugene Braunwald, MD, vice president for academic affairs at Partners HealthCare System and chairman of the TIMI study. "Results from the TIMI 14 study bring us closer to finding the ideal treatment regimen for restoring blood flow in heart-attack patients, and may help set new standards of care for treating these patients. We know from many previous studies that there is a correlation between improving blood flow in the coronary artery and survival."
Every year, about 1,500,000 Americans suffer a heart attack. Nearly all heart attacks are caused by a blood clot that obstructs the flow of blood to the heart, thereby depriving it of oxygen and nutrients. Clot-busting drugs, also known as thrombolytics, currently are the standard therapy for treating heart attacks. These drugs have been shown to be effective in breaking down the clots, restoring blood flow, and reducing the risk of death. However, thrombolytics restore blood flow in only 30 to 60 percent of patients, and may be associated with major bleeding in the brain. Moreover, the blood vessel treated with a clot-buster often becomes blocked again.
"Although the use of thrombolytic therapy has clearly benefited heart-attack patients, these drugs may have reached their limit of success," said lead study author Elliott M. Antman, M.D., director of the Coronary Care Unit at Brigham and Women's Hospital and an associate professor of medicine at Harvard Medical School. "Our data show that abciximab can enhance the benefits of clot-busting therapy by improving its ability to open blocked arteries and restore optimal blood flow in significantly more patients."
- TIMI-14 was a randomized, open-label, multi-centered, international trial involving 888 heart-attack patients who arrived at the hospital within 12 hours of experiencing chest pain. Patients were treated with one of the following therapies: alteplase (tPA) alone or abciximab (ReoPro TM) alone of abciximab with reduced doses of alteplase. The primary objective of the study was to determine the percentage of patients achieving optimal blood flow (referred to as TIMI 3 flow) through the blocked artery at 90 minutes after treatment began.
- The TIMI 14 investigators have also evaluated the combination of abciximab with reduced doses of reteplase, a clot dissolving drug given in two injections separated by 30 minutes. Preliminary data show encouraging results with the combination of alteplase and reduced doses of reteplase as well.
About Brigham and Women's Hospital (BWH)
BWH is a 663-bed nonprofit teaching affiliate of Harvard Medical School and a founding member of Partners HealthCare System, an integrated health care delivery network. Internationally recognized as a leading academic health care institution, BWH is committed to excellence in patient care, medical research, and the training and education of health care professionals. The hospital's preeminence in all aspects of clinical care is coupled with its strength in medical research. A leading recipient of research grants from the National Institutes of Health, BWH conducts internationally acclaimed clinical, basic, and epidemiological studies.