Do we treat subsegmental pulmonary embolism?

From the Guidelines

For patients with subsegmental pulmonary embolism and no proximal DVT, we suggest clinical surveillance over anticoagulation in those with a low risk of recurrent VTE, and anticoagulation over clinical surveillance in those with a high risk of recurrent VTE. This approach is based on the most recent guidelines from the Chest journal, which emphasize the importance of individualizing treatment decisions based on patient risk factors 1. The management of subsegmental pulmonary embolism (SSPE) should consider the risk of clot propagation or recurrence against the bleeding risks from anticoagulation.

Key Considerations

• The decision to treat SSPE should be based on the patient's overall clinical presentation, including the presence of symptoms, cardiopulmonary reserve, and risk factors for recurrent VTE 1.
• Patients with a high risk of recurrent VTE, such as those with active cancer, reduced mobility, or a history of VTE, should be considered for anticoagulation therapy 1.
• The use of direct oral anticoagulants (DOACs) such as apixaban or rivaroxaban may be considered for patients with SSPE who require anticoagulation therapy 1.
• Close surveillance without anticoagulation may be considered for select low-risk patients with isolated SSPE who have no cancer, no symptoms, good cardiopulmonary reserve, and no DVT 1.

Treatment Approach

• For patients who require anticoagulation therapy, the treatment duration is generally 3 months 1.
• Patients who are not anticoagulated should be educated on the signs and symptoms of recurrent VTE and instructed to return for reevaluation if symptoms persist or worsen 1.
• Serial imaging may be considered to monitor for clot progression in patients who are not anticoagulated 1.

From the Research

Treatment of Subsegmental Pulmonary Embolism

The treatment of subsegmental pulmonary embolism (SSPE) is a topic of ongoing debate. Several studies have investigated the risks and benefits of anticoagulation therapy in patients with SSPE.

• The study by 2 found that withholding long-term anticoagulation therapy in patients with SSPE diagnosed by V/P SPECT resulted in a 4% risk of recurrence of venous thromboembolism (VTE) during 90 days of follow-up.
• In contrast, the study by 3 reported a relatively low long-term incidence of VTE in patients with isolated SSPE managed without anticoagulation, with an incidence of 1.9 per 100 patient-years.
• The study by 4 found that the risk of recurrent VTE was comparable after subsegmental and more proximally localized incidental pulmonary embolism (IPE), and that low molecular weight heparins were associated with a lower risk of major hemorrhage compared to vitamin K antagonists.
• The study by 5 highlighted the importance of clinical context in deciding whether to anticoagulate patients with SSPE, and found that anticoagulation was more commonly used in patients with a higher risk of recurrent VTE and other clinical factors.

Anticoagulation Therapy

The use of anticoagulation therapy in patients with SSPE is influenced by several factors, including the risk of recurrent VTE, the risk of anticoagulant-related bleeding, and the presence of other clinical conditions.

• The study by 6 discussed the use of anticoagulant agents, including unfractionated heparin, low molecular weight heparins, and oral anticoagulants, in the prevention and treatment of pulmonary embolism.
• The study by 4 found that low molecular weight heparins were associated with a lower risk of major hemorrhage compared to vitamin K antagonists in patients with cancer-associated IPE.
• The study by 5 found that anticoagulation was more commonly used in patients with SSPE who had a higher risk of recurrent VTE and other clinical factors, such as recent surgery, elevated serum D-dimer, and lung parenchymal abnormalities.

Clinical Context

The clinical context of patients with SSPE plays a crucial role in deciding whether to anticoagulate.

• The study by 5 found that patients with SSPE who received anticoagulation had a different clinical context compared to those who did not receive anticoagulation, including a higher risk of recurrent VTE and other clinical factors.
• The study by 3 reported that the long-term incidence of VTE in patients with isolated SSPE managed without anticoagulation was relatively low, but that future studies were needed to assess the risk-benefit ratio of anticoagulation in this patient population.