Clinical Evaluation of Venous Thromboembolism

Risk Factors

Risk factors for VTE can be both inherited and acquired ( Box 51.1 ). The Virchow triad of hypercoagulability, endothelial injury, and venous stasis holds true for more than 150 years after its initial description. More recently, inflammation has been identified as a key mechanistic driver in the development of VTE. Among one of the strongest risk factors for VTE is a history of prior VTE. There is a high risk of recurrence in patients with both provoked and unprovoked prior VTE: up to 50% over 10 years in those with a prior unprovoked event and up to 25% over 10 years in those with a prior provoked event. An individual patient’s risk factors should be considered when assessing likelihood of VTE as a possible cause of their clinical presentation.

Clinical Manifestation

In a large registry of patients presenting with DVT, the most common complaint was swelling of the extremity, present in 82% of outpatients and 59% of inpatients. Patients with lower extremity DVT also often complain of a cramping or pulling sensation in the calf that may be exacerbated by ambulation. Extremity discomfort was reported in 70% of outpatients, but only 37% of inpatients. Though much less prevalent, DVT can also occur in the upper extremities, most frequently in the setting of an indwelling catheter or pacemaker, or in the presence of venous outflow obstruction. Symptoms are similar with swelling and discomfort in the affected arm. Symptoms of an associated PE are also reported in patients presenting with a DVT.

The physical exam is often notable for swelling and tenderness, but warmth and erythema can also be present. The presentation is most often unilateral, although it can present bilaterally in those that are hypercoagulable or have the rare instance of inferior vena cava (IVC) thrombosis. A palpable cord or prominent superficial venous collaterals may also be present. Signs and symptoms tend to be more common in those patients diagnosed as an outpatient compared to those hospitalized at the time of diagnosis, with over 10% of inpatients having no signs or symptoms and compared to only 2% of outpatients. In rare, severe cases, patients may exhibit signs of impaired perfusion due to venous obstruction secondary to massive DVT resulting in diminished arterial flow. Phlegmasia alba dolens is the early stage of decreased perfusion as the leg will appear white. This may progress further to become phlegmasia cerulea dolens—frank venous gangrene of the limb.

The two most common presenting symptoms of PE are sudden onset dyspnea and chest pain, which is commonly described as pleuritic in nature. Other presenting symptoms include cough with or without hemoptysis, dizziness, or syncope, or upper abdominal pain. One-quarter to half of patients will also complain of symptoms of a concomitant DVT. Small PEs can also be asymptomatic and found incidentally on imaging performed for an alternative reason. The prognostic implications of these small asymptomatic PEs remain a matter of debate.

Presenting signs of PE include tachycardia, tachypnea, respiratory distress, diaphoresis, and clinical evidence of DVT. Rales, decreased breath sounds, an accentuated pulmonic component of the second heart sound, right ventricular (RV) heave, and jugular venous distension can also be seen. In patients with suspicion for PE, signs of DVT increase the pre-test probability. In the most severe cases, patients can present with hypotension, shock, active cardiac arrest, or respiratory failure. Overall, clinical signs and symptoms in isolation have poor specificity, thus further evaluation of risk factors and clinical risk stratification is required.

The signs and symptoms of DVT and PE are associated with a broad differential diagnoses, thus limiting the use of assessment of clinical presentation alone when making the diagnosis ( Boxes 51.2 and 51.3 ).