Aspirin may be a promising treatment for those who can’t take anti-clotting drugs long term to prevent blood clots in the veins, according to new research.

Known as venous thromboembolism, the clots are typically in the deep veins of the legs and can break off, travel to the lungs and block lung arteries, a condition known as pulmonary embolism, which can be fatal.

Researchers found that aspirin reduced the risk of recurring blood clots by up to 42 percent.

In a combined analysis of two different studies, 1,224 patients received 100 mg of aspirin a day to treat blood clots and researchers monitored them for at least two years.

Although the study yielded clear results, researchers advise patients to talk to their doctor about taking aspirin after stopping treatment with anticoagulants.

“It is not recommended that aspirin be given instead of anticoagulant therapy, but rather be given to patients who are stopping anticoagulant therapy or for whom such treatments are considered unsuitable,” said John Simes, M.D., lead author of study and director of the National Health and Medical Research Council Clinical Trials Centre and professor at the University of Sydney in Australia.

According to researchers, without treatment, people who have blood clots in their veins with no obvious cause have on average a 10 percent risk of another clot within the first year and a 5 percent risk per year thereafter.

“The treatment is warfarin or a newer anticoagulant usually given for at least six to 12 months to prevent a further blood clot,” Simes said. “However, these people continue to be at risk.”

Co-author Cecilia Becattini, M.D.,  explained the benefits of aspirin. “Aspirin does not require laboratory monitoring, and is associated with about a 10-fold lower incidence of bleeding compared with oral anticoagulants. We are convinced that it will be an alternative for extended prevention of venous thromboembolism after 6 – 12 months of anticoagulant treatment.”

More than 250,000 people in the United States are hospitalized annually with deep vein thrombosis, the third most common cardiovascular illness.

The article was published in the American Heart Association’s journal Circulation.

 Additional Resources: