Venous Thromboembolism

Abstract

Abstract-Patients who have a first episode of venous thromboembolism (VTE) have an elevated risk of a recurrent episode, and this necessitates secondary prophylaxis. Anticoagulant therapy is a double-edged sword, however, as it reduces the risk of recurrent VTE but increases the risk of hemorrhage. This balance must be taken into account when assessing the risk-benefit ratio of long-term anticoagulation. , is a common and preventable disease. The incidence of VTE in industrialized countries is around 1 to 2 cases per 1000 person-years. 1-3 DVT mostly arises in the lower extremities but may also occur in the arms, cerebral sinuses, and viscera. DVT restricted to the calf veins is associated with smaller clots and fewer long-term sequelae. By contrast, proximal DVT involving the popliteal, femoral, or iliac veins frequently leads to pulmonary embolism and often produces the post-thrombotic syndrome. Each year around 300 000 people in the United States die from acute PE, many cases only being diagnosed at autopsy. 4 A recent epidemiological study confirmed that VTE is a major public health burden, with an estimated 370 012 related deaths in 2004 in a group of 6 European countries. 5 Patients with a first episode of VTE are at an increased risk of new episodes. The risk of recurrence varies with time after the incident event, being highest during the first 6 to 12 months and never falling to zero. 1 The cumulative rate of recurrence is about 25% at 5 years and 30% at 10 years. 6,7 VTE should thus be considered a chronic rather than an acute illness. Recurrent DVT is associated with a substantially higher likelihood of the postthrombotic syndrome, 8 -10 and recurrent PE is fatal in about 4% to 9% of cases. 11,12 Recurrent VTE also predisposes patients to chronic pulmonary hypertension. 13 Thus, anticoagulant treatment should aim not only to prevent thrombus extension but also to prevent both early and late recurrences.Inadequate anticoagulant therapy leaves the patient with VTE at an elevated risk of early recurrence. Two randomized controlled trials have shown the need for secondary prophylaxis after a first VTE. Patients with proximal DVT who receive low-dose subcutaneous unfractionated heparin (5000 U bid) have a 47% risk of recurrent VTE within 3 months, 14 and 20% of patients with symptomatic calf vein thrombosis who receive a 5-day course of heparin without relaying oral anticoagulation have a recurrence within 3 months. 15 By contrast, the recurrence rate in patients with VTE is less than 1% during the period of treatment if they receive adequate anticoagulation. 16 -19 Secondary prophylaxis (ie, long-term anticoagulant treatment) has some drawbacks, however, such as the need for frequent laboratory monitoring and vitamin K antagonist (VKA) dose adjustment and an increased risk of major hemorrhage. The annual risk of anticoagulant-related major bleeding is around 1% to 3% and hemorrhagic risk increases in older patients, the very group at higher risk for VTE. 20 In addition, even chronic treatment loses its...

Outpatient Use of Low Molecular Weight Heparin Monotherapy for First-Line Treatment of Venous Thromboembolism in Advanced Cancer

“…Physicians may be more likely to prescribe LMWH monotherapy in NSCLC patients because of increased awareness of vascular events in these patients [25,26]. We found that patients with stage III cancer diagnosis and increasing age were less likely to receive LMWH.…”

Clinical outcomes of prolonged anticoagulation with rivaroxaban after unprovoked venous thromboembolism

“…The two major subtypes of VTE are deep vein thrombosis (DVT) and pulmonary embolism (PE). Patients who have had their first VTE episode have increased risk of recurrence,5, 6, 7, 8, 9 with the risk being highest in the first few months after the initial episode and remaining high through the first year 10. About a quarter of patients will have a recurrent episode within 5 years of their initial VTE episode and 30% are expected to have a recurrent episode within 10 years 10…”

“…However, since patients with unprovoked VTE are known to have a higher risk of recurrent VTE compared to those with provoked VTE (ie, VTE caused by transient risk factors such as surgery),5, 6, 8 the extent to which the finding in the overall VTE population could be applicable to the subset of patients with unprovoked VTE remains unclear.…”

Direct oral anticoagulants and venous thromboembolism

“…Fatal PE, the most serious consequence of VTE, ranges from 0.01% among low-risk surgical patients to 5% among hospitalised medical patients with multiple risk factors, and is currently considered the commonest avoidable cause of hospital death [4,5]. VTE is associated with a high risk of recurrence after a first event and, on cessation of anticoagulant therapy, approximately 10% of patients experience a recurrence within 1 year and up to 30% have a recurrence within 10 years [6,7]. In addition, VTE is associated with long-term clinically significant complications, which include the post-thrombotic syndrome and chronic pulmonary hypertension [4].…”