Pulmonary Embolism

Pulmonary Embolism

Pulmonary embolism (PE) occurs when a part of a thrombus, usually dislodged from a deep vein thrombosis (DVT), passes into the pulmonary circulation, occluding the pulmonary arteries. PE is a potentially life-threatening condition and is the most common reason for preventable hospital death. Rapid diagnosis is crucial, but a diagnosis of PE can often be missed because of its non-specific clinical symptoms. Long-term complications of PE include chronic thromboembolic pulmonary hypertension (CTEPH). The Wells’ score is one scoring system that is commonly used to predict the clinical probability of PE. Computed tomography (CT) pulmonary angiography has become the method of choice for diagnostic imaging in patients with suspected PE, although other diagnostic methods are now available. The 2014 update of the European Society of Cardiology (ESC) guidelines for the management of PE brings about new recommendations for prognosis and treatment.


Treatment of the complications of venous thromboembolism

Between 20% and 50% of patients who develop deep vein thrombosis (DVT) go on to develop post-thrombotic syndrome (PTS), a condition that is associated with substantial morbidity. Patients with PTS are generally managed using compression therapy and leg elevation, although surgical intervention may be appropriate in some cases. Chronic thromboembolic pulmonary hypertension (CTEPH) occurs as a complication in 3–4% of patients who survive pulmonary embolism (PE). Patients with CTEPH may be managed surgically via pulmonary endarterectomy or, if this is inappropriate, lung transplantation. Drugs approved for idiopathic pulmonary arterial hypertension may be useful for managing the symptoms of CTEPH in patients who are not appropriate for surgery.


Balancing the benefits and risks of treatment

Anticoagulants are effective in treating deep vein thrombosis (DVT) and pulmonary embolism (PE) but can be associated with an increased risk of bleeding and other adverse events. The balance between benefit and risk can depend on the duration of anticoagulant treatment. Longer-term treatment can increase the risk of bleeding and it should generally be given to patients at high risk of venous thromboembolism (VTE) recurrence. Other adverse events that should be considered include heparin-induced thrombocytopenia (HIT) and osteoporosis.


Deep Vein Thrombosis

Deep vein thrombosis (DVT) is usually the formation of a thrombus in the deep veins of the leg, although DVT may also occur in the veins of the upper limbs. DVT can occur spontaneously without a known underlying cause or after provoking events, such as trauma, surgery or acute illness. Complications of DVT include potentially life-threatening pulmonary embolism (PE), as well as post-thrombotic syndrome (PTS). DVT recurs with a relatively high frequency. The Wells’ score, a commonly used clinical score, quantifies the likelihood of an individual patient having DVT. Although a high Wells’ score indicates a clinical probability of DVT, an objective imaging technique, such as compression ultrasonography, must be used to confirm or rule out DVT.


Treatment of DVT and PE

Prompt diagnosis and treatment of deep vein thrombosis (DVT) is essential to decrease both the risk of recurrence and a potentially fatal pulmonary embolism (PE). Traditionally, treatment of DVT and PE begins with a parenteral anticoagulant, overlapping with and transitioning to longer-term treatment with a vitamin K antagonist (VKA). Novel oral anticoagulants (OACs) provide an alternative option for the treatment of DVT and PE, and overcome many of the practical limitations associated with VKAs. The updated 2014 European Society of Cardiology (ESC) guidelines now recommend the novel OACs rivaroxaban, dabigatran, apixaban and edoxaban as alternatives to traditional therapy for the treatment of PE in patients with a low/intermediate risk for early mortality. The use of compression stockings is an important adjunct to pharmacological treatment in patients with DVT. Other venous thromboembolism (VTE) treatment approaches may include surgery catheter-guided thrombectomy or thrombolytic therapy.


Extended Secondary Prevention of Venous Thromboembolism

Although the risk of recurrent venous thromboembolism (VTE) reduces after the first few months of treatment, a residual risk remains. For patients who have received anticoagulation treatment for up to 3 months after a first episode of symptomatic deep vein thrombosis, the cumulative risk of VTE recurrence is approximately 18% after 2 years, 25% after 5 years and 30% after 8 years. Despite this risk, physicians often terminate anticoagulation after 6–12 months because the risk of bleeding is believed to outweigh the risk of recurrent VTE. EINSTEIN CHOICE is currently evaluating the already established 20 mg once-daily dose of rivaroxaban, a reduced 10 mg once-daily dose of rivaroxaban and a 100 mg once-daily dose of acetylsalicylic acid for the long-term prevention of recurrent VTE. The findings may enable alignment of anticoagulant treatment with the benefit–risk profile of the individual patient.