From the Guidelines
For a patient with shortness of breath and a history of pulmonary embolism, initial testing should include a D-dimer blood test and a CT pulmonary angiogram (CTPA), as recommended by the most recent guidelines 1. The D-dimer test is used to detect the presence of a clot, and if elevated, it suggests possible clot formation. The CT pulmonary angiogram is the gold standard for diagnosing PE. Additional important tests include:
- Arterial blood gases to assess oxygenation
- Complete blood count to check for anemia or infection
- Basic metabolic panel to evaluate kidney function
- Chest X-ray to rule out other causes like pneumonia
- ECG to assess for cardiac strain patterns Depending on clinical suspicion, a lower extremity ultrasound may be performed to check for deep vein thrombosis as a source of emboli. Pulse oximetry should be continuously monitored to track oxygen saturation levels. These tests are crucial because patients with a history of PE have an increased risk of recurrence, and prompt diagnosis is essential for initiating appropriate anticoagulation therapy, as supported by previous studies 1. The combination of clinical assessment and these diagnostic tests allows for accurate diagnosis and appropriate management of potentially life-threatening recurrent pulmonary embolism. It is also important to use validated clinical prediction rules to estimate pretest probability in patients in whom acute PE is being considered, as suggested by best practice advice 1. In patients with a low or intermediate clinical likelihood of PE, normal results on D-dimer testing can obviate the need for PE imaging, as stated in the guidelines 1. However, in patients with a high pretest probability of PE, CT pulmonary angiography (CTPA) is commonly performed, as recommended by the guidelines 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Diagnostic Tests for Shortness of Breath with a History of Pulmonary Embolism
The following tests are recommended for a patient experiencing shortness of breath (SOB) with a history of pulmonary embolism (PE):
- Computed Tomography Pulmonary Angiography (CTPA) is the principal means of evaluating dyspnea in the emergency department 2
- CTPA is the most sensitive test for the diagnosis of pulmonary embolism and its use has been associated with a rising incidence of the condition 3
- A negative CTPA essentially rules out the diagnosis of pulmonary embolism without the need to routinely exclude the presence of deep vein thrombosis 3, 4
- Bedside echocardiography may be used to demonstrate signs of cor pulmonale and identify large central thrombi, but it has limitations 5
- Ventilation-perfusion (V/Q) scanning may be used as an alternative to CTPA in some patient populations, particularly those with a low risk of pulmonary embolism or those who cannot undergo CTPA 3
Additional Considerations
- Patients with a history of PE and SOB should undergo a thorough evaluation to rule out other causes of dyspnea, such as pneumonia, pulmonary edema, pleural effusion, or atelectasis 2
- Clinical outcome studies have demonstrated that pulmonary embolism can be safely ruled out in patients with a clinical probability indicating pulmonary embolism to be unlikely and a normal D-dimer test result 4
- Compression ultrasonography and ventilation-perfusion scintigraphy may be reserved for patients with concomitant symptomatic deep vein thrombosis or a stringent contraindication for CTPA, respectively 4