For decades doctors have prescribed two drugs, aspirin and warfarin, to heart disease patients to help prevent blood clots, and although both drugs are effective they have never been compared in a large clinical trial. An international study begun recently by researchers at the San Francisco Veterans Affairs Medical Center (SFVAMC) will match these two old drugs against each other, and against a newer drug called clopidogrel, to see which of them prevents more heart attacks, strokes, and deaths in patients with chronic heart failure.
Unlike most international clinical trials in recent years, the 4,500-patient study will not be predominantly funded by a pharmaceutical or biotech company, said the study's chairman Barry Massie, MD, UCSF professor of medicine, and chief of the cardiology division at the SFVAMC. All three drugs in the trial already are approved for patients with heart disease and several other conditions. But the VA, which is paying about half of the trial's cost through its cooperative study program, recognized that determining which drug is most effective could save patient lives and might also reduce costs.
"The results of this study have the potential to greatly affect practice," Massie said. "For instance, between 20 and 40 percent of heart failure patients now receive warfarin. That figure will either increase or decrease substantially depending on the results. Aspirin is widely used in patients with coronary heart disease, the leading cause of heart failure. However, there is some evidence that aspirin may have negative effects in heart failure patients under some circumstances. If this proves to be so, many of these patients will be switched to warfarin or clopidogrel."
When the study is completed, Massie said, doctors will be able to choose among the three medicines based on three important factors: efficacy, safety and cost.