1. Home>
2. Specialty Care>
3. Oncology and Hematology>
4. Summary and Comment

Fatal Pulmonary Embolism After Venous Thromboembolism

Recurrent PE occurs infrequently after 6 months of anticoagulation therapy.

When managing patients with venous thromboembolism (VTE), clinicians’ main concern is new or recurrent pulmonary embolism (PE). To prevent death from PE, long-term anticoagulant therapy often is prescribed. However, this approach has several drawbacks, including risk for major hemorrhage, restrictions on activities that might incur bleeding, inconvenience of taking daily medication, and requisite frequent monitoring of prothrombin time. Shortening the duration of anticoagulation often is considered for patients whose initial VTE was provoked by surgery, trauma, hormonal therapy, pregnancy, or prolonged immobilization, but little data are available about whether risks for fatal PE are low enough to justify this practice.

Investigators from universities in Canada, Sweden, and Italy evaluated patients with VTE (provoked or idiopathic) who had been enrolled in two studies that had been designed to explore the optimal duration of anticoagulant therapy. More than 2000 patients received anticoagulants for a mean of 6 months (range, 3–39 months) and were followed for a mean of 54 months (range, 1–120 months) after discontinuing anticoagulants. During treatment and follow-up, 340 deep venous thromboses (DVT), 116 nonfatal PEs, and 45 fatal PEs (possible, probable, or definite cause of death) occurred.

The risk estimate for any fatal PEs was 0.49 (95% confidence interval, 0.36–0.64) per 100 person-years of follow-up. When risk was analyzed according to whether initial VTEs were provoked or idiopathic, the estimates were 0.23 and 0.72 per 100 person-years, respectively, and the CIs did not overlap. The case-fatality rates among patients with recurrent disease who presented initially with DVT, PE, or both were 8%, 12%, and 9%, respectively. Most fatal PEs occurred during the first year after discontinuing anticoagulants (incidence, 0.81%); after that, annual risk was 0.40. In regression analysis, increasing age (hazard ratio, 2.12) and idiopathic VTE (HR, 2.42) were associated with greater risk for fatal PE.

Comment: These data show that risk for fatal PE after 6-month courses of anticoagulant treatment is low (<1%), especially if initial VTE was provoked. However, among patients in whom VTE does recur, the case-fatality rate is of concern, and VTE recurrence also can lead to postphlebitic syndrome or chronic thromboembolic pulmonary hypertension. However, prolonging anticoagulation might not be feasible in patients with predisposition to bleeding, those who require frequent invasive procedures, or those with active lifestyles. Also, the outcomes of this study do not apply to VTEs that occur in patients with cancer, permanent immobilization, or high-risk thrombophilia (e.g., antiphospholipid antibody syndrome), who are most susceptible to recurrent events. In deciding on the duration of anticoagulation, many factors must be taken into account, but most patients can be reassured that risk for fatal PE after discontinuing anticoagulants is low.

— David Green, MD, PhD

Published in Journal Watch Oncology and Hematology January 8, 2008

Citation(s):

Douketis JD et al. The risk for fatal pulmonary embolism after discontinuing anticoagulant therapy for venous thromboembolism. Ann Intern Med 2007 Dec 4; 147:766.

• Original article (Subscription may be required)
• Medline abstract (Free)