When is the best time to repeat Computed Tomography Pulmonary Angiography (CTPA) for a patient with pulmonary embolism on anticoagulation therapy to assess safety for air travel?

Timing of Repeat CTPA for Pulmonary Embolism Patients Before Air Travel

The optimal time to repeat CTPA for a patient with pulmonary embolism on anticoagulation therapy to assess safety for air travel is 3-6 months after the initial diagnosis, particularly if the patient has risk factors for developing chronic thromboembolic pulmonary hypertension (CTEPH). 1

Follow-up Imaging Recommendations

• Follow-up imaging is not routinely recommended for asymptomatic patients after pulmonary embolism (PE) according to the 2019 ESC Guidelines 1
• However, follow-up imaging may be considered in patients with risk factors for developing CTEPH, especially when evaluating fitness for air travel 1
• The 3-6 month timeframe aligns with the recommended routine re-evaluation period for all PE patients 1
• This timing allows for assessment of clot resolution and evaluation of potential chronic complications before air travel 1

Assessment Algorithm for Air Travel Safety

Step 1: Timing of Evaluation

• Schedule follow-up CTPA at 3-6 months after initial PE diagnosis and treatment initiation 1
• This timing allows for adequate assessment of clot resolution and potential development of CTEPH 1

Step 2: Clinical Evaluation

• Assess for persistent or new-onset dyspnea or functional limitation 1
• Check for signs of VTE recurrence, bleeding complications, or other comorbidities 1
• Evaluate risk factors for CTEPH development 1

Step 3: Imaging Assessment

• Perform CTPA to evaluate:
  • Resolution of pulmonary emboli 1
  • Signs of chronic thromboembolic disease 1
  • Right ventricular size and function 1

Step 4: Additional Testing (if indicated)

• Consider echocardiography to assess for pulmonary hypertension 1
• Measure natriuretic peptide levels if there are concerns about right heart function 1
• Consider cardiopulmonary exercise testing for patients with persistent symptoms 1

Special Considerations for Air Travel

• Long-duration air travel is a weak risk factor for VTE development (incidence of 1 in 4656 for flights >4 hours) 2
• Risk of travel-related thrombosis is higher in individuals with pre-existing risk factors, including history of PE 2
• For high-risk travelers undertaking journeys >3 hours, well-fitted below-knee compression hosiery is recommended 2
• VTE may be attributable to travel if it occurs up to 8 weeks following the journey 2

Important Caveats

• The decision to clear a patient for air travel should prioritize mortality and morbidity risk assessment 1
• Patients with persistent symptoms after PE should be referred to a pulmonary hypertension/CTEPH expert center for comprehensive evaluation before air travel clearance 1
• Patients with unprovoked PE have a higher risk of recurrence and may require more careful evaluation before air travel 3
• Maintaining mobility during flights is recommended to reduce risk of new or recurrent VTE 2

Anticoagulation Considerations

• Ensure the patient is on appropriate anticoagulation therapy before air travel 1
• For patients with first PE associated with temporary risk factors, anticoagulation for 3-6 months may be sufficient 1
• For unprovoked PE or persistent risk factors, extended or indefinite anticoagulation should be considered before air travel clearance 4, 5
• NOACs are preferred over traditional LMWH-VKA regimens unless contraindicated 1