Extended anticoagulation beneficial after pulmonary embolism
Patients who experience a first pulmonary embolism may benefit from anticoagulation therapy for up to 2 years after the unprovoked episode, although the benefits of treatment do not appear to continue after therapy is stopped, the results of study findings in the Journal of the American Medical Association show.
An initial pulmonary embolism not preceded by a transient risk factor such as surgery may “require long-term secondary prevention measures” to reduce the risk for additional blood clots or major bleeding, with the lack of an inciting risk factor putting patients at “a much higher risk of recurrence,” according to researchers.
Francis Couturaud, MD, PhD, of the Université de Bretagne Occidentale in France, and colleagues examined 371 adult patients with no major risk factor for a blood clot who experienced an initial pulmonary embolism. All participants completed 6 months of uninterrupted treatment with a vitamin K antagonist after the episode; patients were then randomly assigned warfarin therapy or placebo for 18 months.
The investigators primarily sought the composite of recurrent venous thromboembolism at 18 months. Secondary outcomes included the composite at 42 months, as well as each component of the composite and unrelated deaths at both 18 and 42 months. Median follow-up was 24 months.
In the 18 months after randomization, six of 184 patients treated with warfarin (3.3%) and 25 of 187 in the placebo group (13.5%) experienced the composite of recurrent VTE or major bleeding (HR = 0.22; 95% CI, 0.09-0.55). This translates to a relative risk reduction of 78% in favor of warfarin, according to study results.
Recurrent VTE was experienced by three patients with warfarin vs. 25 patients with placebo (HR = 0.15; 95% CI, 0.05-0.43); major bleeding occurred in four patients with warfarin vs. one patient with placebo (HR = 3.96; 95% CI, 0.44-35.89).
The benefit of anticoagulation was lost after therapy stopped. During 42 months, the composite outcome occurred in 33 patients (20.8%) with warfarin and in 42 patients (24%) with placebo (HR = 0.75; 95% CI, 0.47-1.18).
No between-group differences were seen regarding the rates of recurrent VTE, major bleeding and unrelated death.
The results suggest the need for long-term, secondary prevention in patients who experience an initial, unprovoked pulmonary embolism, according to researchers.
“Whether these should include systematic treatment with vitamin K antagonists, new anticoagulants or aspirin or be tailored according to patient risk factors needs further investigation,” the researchers wrote. – by Julia Ernst, MS
Disclosure: Couturaud reports receiving research grant support from Pfizer; honoraria for board memberships or symposia from AstraZeneca and Bayer; and travel support from Actelion, Bayer, Daiichi Sankyo, Intermune and Leo Pharma. Please see the full study for a list of all other authors’ relevant financial disclosures.