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Deep venous thrombosis and pulmonary embolism 

Deep venous thrombosis and pulmonary embolism

Chapter:
Deep venous thrombosis and pulmonary embolism
Author(s):

Paul D. Stein

, and Fadi Matta

DOI:
10.1093/med/9780199204854.003.161601_update_004

Update:

Management – enhanced discussion of approach to patients with isolated subsegmental PEs, also use of inferior vena cava filters. See Chapter 16.16.2 for updates on use of oral direct inhibitors of thrombin and factor Xa.

Updated on 29 Oct 2015. The previous version of this content can be found here.
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date: 30 March 2017

Deep venous thrombosis

Deep venous thrombosis (DVT) is diagnosed in 1 to 2% of hospitalized patients, but is often silent and is found much more frequently at autopsy. Patients typically complain of pain and/or swelling of the leg, but often the diagnosis will be considered only when the physician detects unilateral leg swelling.

Investigation—given the sinister nature of untreated DVT, it is important to confirm or refute the diagnosis with appropriate investigations whenever clinical suspicion is aroused, unless the general condition of the patient makes this inappropriate. Management algorithms have been developed to guide strategy for investigation. These typically use scoring systems to stratify the clinical probability that the particular patient has a DVT (or pulmonary embolism). Those with a low clinical probability proceed to D-dimer testing, with further investigation not pursued if this is negative. Patients with either a high clinical probability, or a low clinical probability but elevated D-dimer, proceed to tests for the presence of thrombus in the leg veins, typically by ultrasonography.

Management—a first episode of proximal DVT, diagnosed by noninvasive testing, should be treated with anticoagulation for 3 months. Longer duration of treatment may be recommended for those whose thrombosis occurred in the absence of a reversible risk factor or in those with a thrombophilic condition or cancer. Treatment is initiated with heparin (low molecular weight or unfractionated) or fondaparinux for ≥ 5 days and warfarin (or other vitamin K antagonist), with the heparin or fondaparinux stopped when the international normalized ratio (INR) is greater than 2.0 for ≥ 24 h. There is increasing experience and use of extended therapy with an oral factor Xa inhibitor (rivaroxaban, apixaban, edoxaban) or direct thrombin inhibitor (dabigatran) as alternatives to heparin/warfarin (see Chapter 16.16.2).

DVT carries extensive morbidity irrespective of pulmonary embolism: severe postphlebitic syndrome occurs in 9% of patients by 5 years.

Pulmonary embolism

Acute pulmonary embolism (PE) is the third most common cardiovascular problem after coronary heart disease and stroke. It is a complication of DVT, with emboli originating in the legs in 80% or more of cases. Immobilization, irrespective of the cause, is the most frequent predisposing factor.

Common symptoms are dyspnoea (c.75%), pleuritic chest pain (c.50%), cough (c.35%), and calf or thigh pain or swelling (c.40%). Circulatory collapse (systolic blood pressure <80 mmHg or loss of consciousness) is an uncommon (8–15%) mode of presentation in patients entered into clinical trials, but likely to be more frequent in routine clinical practice. Tachypnoea (respiratory rate ≥20 cycles/min or greater) is the most common physical sign (50–70%), and abnormalities may be found on respiratory (30–50%) or cardiac (20–30%) examination.

Investigation—algorithms similar to those used to guide management of patients with suspected DVT are used when PE is suspected or needs to be excluded. Patients with a low, ‘unlikely’, or moderate clinical probability and negative D-dimer are not investigated further. Patients with a high clinical probability, and those with an elevated D-dimer, proceed to tests for the presence of pulmonary emboli, typically by contrast-enhanced spiral CT, perhaps in combination with CT venous phase imaging.

Management—treatment with anticoagulants while awaiting the outcome of diagnostic tests may be appropriate, particularly if the tests cannot be obtained immediately. All patients who are hypoxic should be given supplementary oxygen at high concentration. Anticoagulation is as described for DVT. Thrombolytic therapy is not indicated for routine treatment, but is advised for those who are hypotensive or require ventilatory support.

Inferior vena cava filter—this is recommended for patients with proximal DVT or PE if anticoagulants are contraindicated, PE has recurred while on adequate anticoagulant therapy, or PE is severe and any recurrent PE may be fatal. Administrative data show a lower in-hospital all-cause mortality with vena cava filters in patients with PE if they are haemodynamically unstable (in shock or on ventilatory support), require thrombolytic therapy or pulmonary embolectomy, have solid malignant tumours or chronic obstructive pulmonary disease.

A very few survivors of acute PE (0.1–0.2%) develop chronic pulmonary thromboembolic hypertension.

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