ASH Annual Meeting
SAN DIEGO — Aspirin, when administered 6 to 12 months after
anticoagulant therapy, was associated with a significant reduced risk for
recurrence of unprovoked venous thromboembolism, according to results from the
As many as 20% of patients with unprovoked
VTE have recurrence within 2 years of discontinuing treatment
with oral anticoagulants.
Cecilia Becattini, MD, assistant professor of internal medicine
in the internal and cardiovascular medicine and stroke unit at Italy’s
University of Perugia, said the results show that aspirin can be a valid
alternative to oral anticoagulants for the extended treatment of VTE.
“With aspirin, a drug that is low-cost, safe and available
worldwide, we can reduce incidence of recurrence of by 40%,” she said.
“For its safety, practicality and low cost, aspirin is a valid alternative
to oral anticoagulants for the extended treatment of venous
Becattini noted that Warfasa researchers did not observe an increase in
major bleeding associated with aspirin. She added that aspirin is a very
well-known drug that does not require lab monitoring, and it is safer than oral
anticoagulation with a risk for bleeding complications of less than 1% per
Warfasa is a double-blind randomized placebo-controlled event-driven
study. Patients with a first-ever unprovoked VTE who had completed 6 to12
months of oral anticoagulant treatment were randomized to receive 100 mg daily
aspirin (n=205) or placebo (n=197) for at least 2 years.
Eleven percent of patients had recurrence in the placebo group vs. 6.3%
for patients assigned to aspirin (HR=0.57; 95% CI, 0.35-0.93) during the study
period. While on study treatment, 10.7% of patients assigned to placebo had
recurrence compared with 5.7% of the placebo group (HR=0.54; 95% CI,
0.32-0.91). The mean on-treatment period was 22 months.
One patient in each treatment group had a major bleed, with a similar
incidence of clinically relevant non-major bleeding. – by Jason
Disclosure: Dr. Becattini reported no relevant financial
There's always uncertainty about what to do after the first 6 months to 18 months on warfarin. Ideally, we'd like to treat all patients with warfarin to prevent recurrent thrombosis, but there are some patients who may be at increased risk for bleeding, such as elderly patients. Aspirin offers a safer alternative, especially when it is unclear whether the patient should be treated. The standard of care is to treat initial DVT with warfarin or some other anticoagulant for 3 to 6 months and then evaluate the patient to determine if further anticoagulation is indicated. For patients in the "gray" area, this study demonstrates that aspirin indeed reduces the risk of recurrent thrombosis; while its efficacy is not as great as that of warfarin, its safety profile in terms of bleeding risk is superior. So this study establishes aspirin as an agent with the potential to reduce venous thrombosis over the long term, although additional confirmation of these results is warranted.
Keith McCrae, MD
Staff physician in hematologic
oncology and blood disorders
Cleveland Clinic Taussig Cancer Center
Disclosure: Dr. McCrae reports no relevant financial disclosures.
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