From the Guidelines
For patients with subsegmental pulmonary embolism (SSPE) on anticoagulants, routine follow-up CT angiography (CTA) is generally not recommended unless there are specific clinical indications. Most patients should have clinical follow-up at 3-6 months to assess symptom resolution without imaging. Consider repeat CTA only if the patient experiences persistent or worsening symptoms despite adequate anticoagulation therapy, develops new concerning symptoms, or if there's suspicion of recurrent PE. For patients with unprovoked SSPE, anticoagulation typically continues for at least 3-6 months with medications like apixaban (5mg twice daily), rivaroxaban (15-20mg daily), or warfarin (target INR 2-3) 1. The decision to discontinue therapy should be based on risk-benefit assessment rather than routine imaging. Repeat CTA exposes patients to unnecessary radiation and contrast while rarely changing management in patients responding well to treatment. Resolution of clots occurs at variable rates, with most showing significant improvement by 3 months, though complete resolution isn't necessary to discontinue therapy if the patient is clinically improved and has completed an appropriate treatment course.
Some key points to consider in the management of SSPE include:
- The presence of risk factors for recurrent or progressive VTE, such as active cancer, reduced mobility, or pregnancy, which may favor choosing anticoagulation or more aggressive surveillance 1.
- The importance of patient education to ensure an understanding of clinical signs and symptoms worrisome for progressive thrombosis that would require return for reassessment 1.
- The need for regular follow-up examinations to check for possible signs of VTE recurrence, cancer, or bleeding complications of anticoagulation, and to assess for persisting or new-onset dyspnoea or functional limitation 1.
- The consideration of the patient's preference in the decision to extend or discontinue anticoagulant therapy 1.
Overall, the management of SSPE should be individualized based on the patient's clinical presentation, risk factors, and preferences, with a focus on minimizing the risk of recurrent VTE and bleeding complications while optimizing quality of life.
From the Research
Rescanning with CTA in Patients with Subsegmental Pulmonary Embolism
- There is no clear evidence on when to rescan with CTA in patients with subsegmental pulmonary embolism who are now on anticoagulants 2, 3, 4.
- The decision to anticoagulate patients with subsegmental pulmonary embolism (SSPE) is controversial, and the clinical context plays a significant role in this decision 5.
- A systematic review and meta-analysis found that the frequency of bleeding, venous thromboembolism (VTE) recurrence, and death in patients with SSPE who received anticoagulation therapy was not significantly different from those who did not receive anticoagulation therapy 6.
- The lack of randomized controlled trials makes it difficult to draw conclusions about the effectiveness and safety of anticoagulation therapy in patients with SSPE 2, 3, 4.
- Clinical context, such as the presence of risk factors, alternative indications, and illness severity, should be taken into account when deciding whether to anticoagulate patients with SSPE 5.
Factors to Consider
- Clinical context, including risk factors, alternative indications, and illness severity 5
- Presence of symptoms, such as haemoptysis, pleuritic pain, acute dyspnoea, or circulatory collapse 2, 3, 4
- Results of diagnostic imaging, such as CTA 2, 3, 4
- Patient's overall health status and comorbidities 5
Limitations
- Lack of randomized controlled trials on the effectiveness and safety of anticoagulation therapy in patients with SSPE 2, 3, 4
- Limited data on the outcomes of patients with SSPE who receive anticoagulation therapy versus those who do not 6
- Clinical context and individual patient factors may influence the decision to anticoagulate, making it difficult to develop a one-size-fits-all approach 5