What is the recommended routine follow-up investigation timeline after the acute period of a pulmonary embolism (PE)?

Routine Follow-Up After Acute Pulmonary Embolism

All patients should undergo routine clinical evaluation at 3-6 months after acute PE to assess for symptoms, VTE recurrence, bleeding complications, and potential chronic thromboembolic complications. 1

Timeline and Core Assessment at 3-6 Months

The 3-6 month follow-up visit is a Class I recommendation with Level B evidence and serves multiple critical purposes 1:

• Assess for persistent or new-onset dyspnea and functional limitation using standardized scales (Medical Research Council dyspnea scale or WHO functional class) 1
• Screen for VTE recurrence, occult malignancy, and bleeding complications from anticoagulation 1
• Decide on anticoagulation duration and dose after the initial treatment period 1
• Evaluate for chronic thromboembolic pulmonary hypertension (CTEPH) risk factors and symptoms 1, 2

Risk-Stratified Approach to Further Investigation

For Symptomatic Patients (Dyspnea or Functional Limitation Present)

If patients report persistent or new dyspnea/exercise limitation at 3-6 months, further diagnostic evaluation should be pursued 1:

1. Consider transthoracic echocardiography (TTE) if ≥1 symptom is present 1
2. Obtain NT-proBNP levels - elevated levels warrant further workup 1
3. Perform V/Q scan as the key diagnostic test 1, 2
4. If mismatched perfusion defects are found on V/Q scan >3 months after PE, refer to a pulmonary hypertension/CTEPH expert center (Class I recommendation) 1

For Asymptomatic Patients

Routine follow-up imaging (CT pulmonary angiography) is NOT recommended for asymptomatic patients after completing appropriate anticoagulation 2:

• The pulmonary arterial bed is restored in the majority of patients within the first few months 2
• However, consider further evaluation in asymptomatic patients with high-risk features for CTEPH 1:
  • Advanced age
  • Cardiac or pulmonary comorbidity
  • Higher body mass index
  • History of smoking
  • Higher systolic pulmonary arterial pressure at diagnosis
  • Right ventricular dysfunction at initial presentation
  • Residual pulmonary vascular obstruction at discharge 2

Integrated Care Model

An integrated model of patient care involving hospital specialists, appropriately qualified nurses, and primary care physicians is recommended (Class I, Level C) 1:

• Ensures optimal transition from hospital to community care 1
• Includes standardized treatment protocols and regular monitoring 1
• Facilitates early detection of complications including CTEPH, which can develop in up to 4% of patients 3

Key Pitfalls to Avoid

• Do not lose patients to follow-up - systematic follow-up is essential as up to 47% of PE patients may have reduced maximal aerobic capacity at one year 2
• Do not routinely image asymptomatic patients - this leads to unnecessary radiation exposure and healthcare costs 2
• Do not delay referral to CTEPH centers when V/Q scan shows mismatched perfusion defects, as early detection improves outcomes 1
• Do not forget to reassess anticoagulation decisions at 3-6 months, as there is lifelong VTE recurrence risk except in cases provoked by strong transient factors 1

Beyond 6 Months

After the initial 3-6 month evaluation, recommend regular follow-up examinations (e.g., yearly intervals) for patients on extended anticoagulation 1:

• Reassess bleeding risk versus VTE recurrence risk
• Monitor for late complications including post-PE syndrome
• Adjust anticoagulation dose if continuing beyond 6 months (consider reduced-dose apixaban or rivaroxaban) 1

Incomplete reperfusion persists in approximately 19-26% of patients even after 24 months, emphasizing the importance of sustained clinical vigilance 3.