Aspirin May Cut Risk of Unprovoked Blood Clots

Reduce blood clots with aspirin in patients by 40 percent

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Low dose aspirin may help prevent an additional blood clot in patients not considered at risk. Taking a course of aspirin for at least two years could reduce the risk to patients by as much as 40 percent.

Up to 20 percent of patients with unprovoked venous thromboembolism (VTE), a blood clot that forms in a vein despite a lack of risk factors such as age, diabetes or obesity; suffer another blood clot within two years of halting anticoagulant medications such as warfarin.

Though taking anticoagulants longer than two years is effective, it is linked to an increased risk of bleeding.

"Ask your physician about taking aspirin to prevent blood clots."

Dr. Cecilia Becattini, an assistant professor in the internal and cardiovascular medicine stroke unit at the University of Perugia in Italy, emphasized she wanted to test whether simple, affordable aspirin therapy could help protect patients. Previous trials had not suggested a significant benefit to taking aspirin to lower the risk of a blood clot recurrence.

The finding is significant because warfarin, the standard of care for blood clots, requires frequent monitoring, including blood tests and check ups, and can react poorly with other medications and foods.

During the double-blind randomized placebo-controlled Warfasa trial, 205 patients with a first-ever unprovoked VTE who had previously taken an oral antocoagulant for between six months and one year, received either 100 milligrams of aspirin daily or a placebo for at least two years.

In comparison a typical dose of aspirin is 325 milligrams.

A blood clot recurrence occurred in 27 patients, or 6.3 percent, who received aspirin as compared to 42 participants, 11 percent, who took a placebo during the study period. While on the research treatment, 22 patients taking aspirin and 38 who took the placebo reported a recurrence. In addition one patient in each study group suffered major bleeding.

"This is our first observation, but aspirin appears to be low cost and safe while reducing the incidence of venous thromboembolism by 40 percent, " said Dr. Becattini.

She said that additional trials will be needed before the therapy would be recommended as a treatment for preventing additional blood clots.

The research was presented today at the American Society of Hematology's annual meeting in San Diego, Calif.

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Review Date: 
December 10, 2011
Last Updated:
December 10, 2011