Aspirin Is Potential Alternative to Traditional Anticoagulants

Aspirin may reduce the risk of blood clots in patients who cannot use traditional anticoagulants, new research suggests.

New research published in Circulation, the American Heart Association journal, suggests that aspirin might be an alternative anticlotting therapy for patients who cannot use anticoagulant drugs long-term.

A combined analysis of 2 similar independent studies, published online August 25, 2014, determined that aspirin reduced the risk of recurring blood clots in patients who experienced their first unprovoked venous thromboembolism (VTE) by up to 42%, when adjusted for nonadherence. That corresponds to 32 patients treated per year to prevent a single VTE event.

“If a million patients worldwide could be treated with aspirin each year, a hundred thousand events might be prevented with a minimal increase in bleeding, and with a treatment that would also be cost saving” the researchers wrote. “Additional potential benefits of aspirin in treated patients would include a reduction in arterial vascular events, and cancer-related events, each known to be associated with VTE.”

In addition, aspirin reduced symptomatic deep vein thrombosis, pulmonary embolism, and similar major vascular events by more than one-third.

The studies involved 1224 patients who received 100 mg of aspirin daily, and who were monitored for at least 2 years for VTE, myocardial infarction, stroke, bleeding, and death.

Patients with unprovoked VTE face a 10% risk of clot recurrence in the year after they first discontinue common anticoagulant therapy, and a 5% recurrence risk in each subsequent year, an American Heart Association press release noted. However, continuing treatment with the typical vitamin K antagonist therapies increases the risk of bleeding, and requires laboratory monitoring and dose adjustments.

“Aspirin does not require laboratory monitoring, and is associated with about a 10-fold lower incidence of bleeding compared with oral anticoagulants,” Cecilia Becattini, MD, study co-author said in a press release. “We are convinced that it will be an alternative for extended prevention of venous thromboembolism after 6 to 12 months of anticoagulant treatment.”

The findings show a net clinical benefit that favors aspirin over placebo, however, treatment effect is still significantly less than that of traditional anticoagulants.

Despite the findings, researchers recommend that patients speak to their physician about taking aspirin after stopping anticoagulation therapy, researchers noted. The therapy should only be regarded as a reasonable treatment in patients who would not otherwise receive anticoagulation therapy.

“It is not recommended that aspirin be given instead of anticoagulant therapy, but rather be given to patients who are stopping anticoagulation therapy, or for whom such treatments are considered unsuitable,” John Simes, MD, the study’s lead author, said in a press release. “Although less effective, aspirin is inexpensive, easily obtainable, safe, and familiar to patients and clinicians worldwide. If cost is the main consideration, aspirin is a particularly useful therapy. The cost of treating future thromboembolic events is greater than the cost of the preventive treatment.”