From the Guidelines
For patients with subsegmental pulmonary embolism (PE) and no proximal DVT, clinical surveillance over anticoagulation is suggested for those with a low risk for recurrent VTE, while anticoagulation is suggested for those with a high risk for recurrent VTE. This approach is based on the latest guidance from the Chest guideline and expert panel report 1. When considering treatment, it's essential to assess the patient's risk for recurrent VTE and to exclude proximal DVT with bilateral leg ultrasound or at another location if clinically suspected.
- Key factors in decision-making include:
- The risk of recurrent VTE
- The presence of proximal DVT
- The patient's understanding of clinical signs and symptoms worrisome for progressive thrombosis
- The likelihood of progressive thrombosis
- Clinical surveillance involves patient education to recognize signs and symptoms of progressive thrombosis, allowing for prompt reassessment if necessary 1.
- The decision to withhold anticoagulation should be made cautiously, considering the potential for ISSPE to be a true positive finding and the likelihood of progressive thrombosis, as detailed in the online supplement to the guideline 1.
From the Research
Treatment Options for Subsegmental Pulmonary Embolism (PE)
The treatment for subsegmental pulmonary embolism (PE) is a topic of ongoing debate, with some studies suggesting that anticoagulation may not always be necessary, especially in low-risk patients. The following points summarize the current evidence:
- Approximately 10% of all diagnosed pulmonary embolism are isolated to the subsegmental vessels 2.
- The risk of recurrent venous thromboembolism (VTE) in patients with acute subsegmental pulmonary embolism (SSPE) managed with or without anticoagulant therapy remains poorly understood 2.
- Most patients diagnosed with an acute SSPE receive anticoagulation, but the incidence of recurrent VTE detected over time is relatively high, especially in patients with cancer 2.
- Guidelines suggest considering a management strategy without anticoagulation in selected patients with SSPE at low risk of recurrent VTE, in whom proximal deep vein thrombosis is excluded 3.
- A large prospective study among low-risk patients with SSPE who were left untreated showed a higher VTE recurrence risk than initially deemed acceptable by the investigators 3.
- The risk-benefit ratio of anticoagulation for low-risk patients with SSPE remains unclear, and results from randomized trials are needed to answer the question about their optimal management 3, 4.
- A multicentre randomised placebo-controlled non-inferiority trial (SAFE-SSPE) is currently underway to evaluate the efficacy and safety of clinical surveillance without anticoagulation in low-risk patients with isolated SSPE 4.
- Initial anticoagulation in patients with pulmonary embolism can be achieved with thrombolysis, unfractionated heparin, LMWH, fondaparinux, or DOACs, with DOACs becoming the agents of first choice due to their practicability 5.
- A wait-and-see approach should only be considered in patients who are not at risk for new venous thromboembolism and in whom deep venous thrombosis has been ruled out 6.
Key Considerations
- The decision to treat or not treat subsegmental PE should be made on a case-by-case basis, taking into account the individual patient's risk factors and medical history 2, 3, 6.
- Further research is needed to determine the optimal management strategy for patients with subsegmental PE, particularly in low-risk patients 3, 4.