Newspapers have devoted less space to recent findings about treatments with aspirin plus Plavix than they have to current sporting events. Yet this combination of two anti-clotting drugs has generated clinical results every bit as exciting as a 90-yard punt return.
Because both aspirin and Plavix prevent blood platelets from clumping up and blocking a major artery supplying blood to the heart or brain, they can be used to lower heart attack risk. But now, findings of the CHARISMA trial indicate that when aspirin and Plavix are combined they can be even more beneficial to some.
The CHARISMA trial compared cardiovascular outcomes in two groups of patients: one group had multiple risk factors but no known vascular disease; the other group had known vascular disease involving the coronary, cerebral, or peripheral arteries. Subjects from both groups were treated over a 30-month period either with aspirin alone or with aspirin plus Plavix.
Among the high-risk/no-disease participants taking the aspirin-Plavix combination, there was a trend toward worse cardiovascular outcomes, as well as a significant increase in episodes of moderate bleeding.
By contrast-and here's the payoff-the risk for cardiovascular events was significantly lower among those with known vascular disease who were taking both drugs in combination.
Although it may be dangerous to reach general conclusions from the results of a single study, the findings suggest that the antiplatelet combination is useful for, and should be continued in, people with known vascular disease. On the other hand, aspirin alone, rather than the combination of aspirin plus Plavix, appears a better choice for people who have risk factors but no known vascular disease.
The newspaper articles have correctly warned people not to stop their medications without consulting their doctors if they've been placed on a combination of antiplatelet drugs.
A somewhat different but related issue concerns healthy younger people, say under the age of 50, who are self-medicating with aspirin to prevent cardiovascular disease. Available evidence suggests that these individuals are more likely to suffer side effects, such as bleeding in the intestinal tract and even into the brain, from taking aspirin than they are to benefit from fewer cardiovascular events. These findings are not surprising considering the relatively low incidence of cardiovascular events in people under the age of 50 compared with the rather high frequency of bleeding in people taking aspirin.
Studies have shown that placement of a drug-eluting stent at the time of angioplasty increases the risk of late cardiovascular events and death caused by blood clots when the combination of aspirin plus Plavix is stopped 6 months after the procedure. Despite the increased costs and risk of bleeding, new recommendations indicate that this drug combination should be continued in these patients for at least a year after angioplasty.