Risk for Recurrent VTE in Patients With Subsegmental PE

Quick Takes

  • Patients who had isolated subsegmental pulmonary embolism (PE) without proximal deep venous thrombosis on repeated bilateral ultrasonography and were managed without anticoagulation had higher-than-expected rates of recurrent venous thromboembolism over the 90-day follow-up.
  • These results support the use of anticoagulation in patients with subsegmental PE at this time.

Study Questions:

What is the rate of recurrent venous thromboembolism (VTE) in patients with subsegmental pulmonary embolism (PE) managed without anticoagulation?

Methods:

The investigators conducted a multicenter prospective cohort study. (ClinicalTrials.gov: NCT01455818) at 18 sites between February 2011 and February 2021. Patients with isolated subsegmental PE were enrolled. At diagnosis, patients underwent bilateral lower extremity venous ultrasonography, which was repeated 1 week later if results were negative. Patients without deep venous thrombosis (DVT) did not receive anticoagulant therapy. The primary outcome was recurrent VTE during the 90-day follow-up period. The Kaplan–Meier method was used to calculate the survival estimates. These estimates were used to calculate the cumulative incidence rate and the associated 95% confidence interval (CI). A cumulative incidence plot was created for graphical presentation of the time to the primary outcome.

Results:

Recruitment was stopped prematurely because the predefined stopping rule was met after 292 of a projected 300 patients were enrolled. Of the 266 patients included in the primary analysis, the primary outcome occurred in eight patients, for a cumulative incidence of 3.1% (95% CI, 1.6-6.1%) over the 90-day follow-up. The incidence of recurrent VTE was 2.1% (95% CI, 0.8-5.5%) and 5.7% (95% CI, 2.2-14.4%) over the 90-day follow-up in patients with single and multiple isolated subsegmental PE, respectively. No patients had a fatal recurrent PE.

Conclusions:

The authors concluded that patients with subsegmental PE who did not have proximal DVT had a higher-than-expected rate of recurrent VTE.

Perspective:

This study reports that patients who had isolated subsegmental PE without proximal DVT on repeated bilateral ultrasonography and were managed without anticoagulation had higher-than-expected rates of recurrent VTE over the 90-day follow-up. This study can inform patients and clinicians about the risks of managing isolated subsegmental PE without anticoagulation. While a subgroup of patients with lower risk for recurrent events might be identifiable in future studies, these results support the use of anticoagulation in patients with subsegmental PE.

Clinical Topics: Anticoagulation Management, Cardiovascular Care Team, Noninvasive Imaging, Prevention, Pulmonary Hypertension and Venous Thromboembolism, Vascular Medicine, Anticoagulation Management and Venothromboembolism, Echocardiography/Ultrasound

Keywords: Anticoagulants, Diagnostic Imaging, Primary Prevention, Pulmonary Embolism, Risk, Ultrasonography, Vascular Diseases, Venous Thromboembolism, Venous Thrombosis


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