From the Guidelines
Pulmonary embolism (PE) typically presents with sudden onset dyspnea, chest pain, and syncope, which are the most common signs and symptoms that require immediate medical attention. The clinical presentation of PE can vary from haemodynamic instability to silent, and evaluating the likelihood of PE in an individual patient according to the clinical presentation is crucial in the interpretation of diagnostic test results and selection of an appropriate diagnostic strategy 1. In 90% of cases, suspicion of PE is raised by clinical symptoms such as dyspnea, chest pain, or syncope, either singly or in combination. The most frequent presentations of PE include pleuritic chest pain, isolated dyspnea of rapid onset, and syncope or shock, which is the hallmark of central PE with severe haemodynamic repercussions 1.
Some key points to consider in the diagnosis of PE include:
- Dyspnea, tachypnea, or chest pain are present in 97% of patients with PE without cardiac or pulmonary disease 1
- Recent onset dyspnea, chest pain, or syncope are present in as many as 97% of patients with PE, even in those with previous cardiac or pulmonary disease 1
- Pleuritic chest pain is one of the most frequent presentations of PE, usually due to distal emboli causing pleural irritation 1
- Isolated dyspnea of rapid onset is usually due to more central PE, not affecting the pleura, and may be associated with substernal angina-like chest pain 1
- Syncope or shock is the hallmark of central PE with severe haemodynamic repercussions, and is accompanied by signs of haemodynamic compromise and reduced heart flow 1
According to the most recent evidence, the diagnosis of PE has been facilitated by technical advancements and multidetector CT pulmonary angiography, which is the major diagnostic modality currently used 1. Ventilation and perfusion scans remain largely accurate and useful in certain settings, and MR angiography can be useful in some clinical scenarios 1.
In terms of risk factors, recent surgery, prolonged immobility, cancer, pregnancy, oral contraceptive use, and inherited clotting disorders increase suspicion of PE 1. Symptoms can range from mild to life-threatening, with massive PE potentially causing shock, loss of consciousness, or cardiac arrest 1. Anyone experiencing these symptoms should seek emergency medical care immediately, as prompt diagnosis and treatment significantly improve outcomes 1.
From the Research
Signs and Symptoms of Pulmonary Embolism
The signs and symptoms of pulmonary embolism (PE) may be non-specific, making diagnosis challenging 2. Common presentations include:
- Acute chest pain
- Shortness of breath
- Syncope
Diagnosis of Pulmonary Embolism
Diagnosis of PE relies on a combination of clinical assessment and objective diagnostic testing 2. The following steps can be used to evaluate a patient with possible PE:
- Assessment of the clinical probability of PE
- D-dimer testing if indicated
- Chest imaging if indicated
Clinical Probability of Pulmonary Embolism
The clinical probability of PE can be assessed using a structured score or clinical gestalt 3. Patients with a low probability of PE (<15%) may not require further testing if they have certain clinical characteristics, such as:
- Age <50 years
- Heart rate <100/min
- Oxygen saturation level >94%
- No recent surgery or trauma
- No prior venous thromboembolism event
- No hemoptysis
- No unilateral leg swelling
- No estrogen use
D-dimer Testing
A D-dimer level of <500 ng/mL is associated with a post-test probability of PE <1.85% 3. In patients with low or intermediate clinical probability, a normal D-dimer result can exclude PE without the need for chest imaging.
Chest Imaging
Chest imaging with computed tomography pulmonary angiogram (CTPA) is accurate and preferred for diagnosing PE 2. However, CTPA may detect asymptomatic PE of uncertain clinical significance. Ventilation-perfusion (VQ) scan is an alternative option, especially in younger patients and pregnancy, due to lower radiation exposure 2.
Risk Stratification
Patients with PE can be stratified into four risk classes: high, intermediate-high, intermediate-low, and low risk 4. This risk stratification has concrete therapeutic consequences, ranging from out-of-hospital treatment of low-risk patients to reperfusion treatment of (intermediate-) high-risk patients.
Treatment of Pulmonary Embolism
The initial therapy for patients with PE is anticoagulation 5. Direct oral anticoagulants (DOACs) are preferred for most patients with PE due to their lower risk of bleeding and practical advantages 2, 3. Systemic thrombolysis is recommended for patients with PE and systolic blood pressure <90 mm Hg 3, 5.