Clinical question: What is the recurrence rate of venous thromboembolism (VTE) in patients with isolated subsegmental pulmonary embolisms (SSPE) managed without anticoagulation?
Background: Despite the increasing frequency of acute pulmonary embolism, the mortality rate has not changed. The clinical significance and need for anticoagulation in SSPE are unknown.
Study design: Multi-center prospective cohort study
Setting: 18 international sites between February 2011 and February 2021
Synopsis: This study enrolled patients with a new diagnosis of isolated SSPE without evidence of deep venous thrombosis. Those with distal thrombosis received anticoagulation at the treatment discretion of the physician. Patients with increased risk of thrombosis or alternative need for anticoagulation, such as active cancer, history of VTE, and pregnancy were excluded.
The primary outcome was recurrent VTE. The authors hypothesized that the recurrence rate would be 1%. This study found a cumulative reoccurrence rate of 3.1% (8 of 266 patients). Sub-analysis showed a recurrence rate of 2.1% for a single SSPE and 5.7% for multiple SSPEs. Those with distal venous thrombosis had a recurrence rate of 12.5%. The lowest reoccurrence rate was 1.8% in patients under 65 years old with a single SSPE identified. No patients had a fatal recurrent pulmonary embolism during the study period.
Bottom line: There were higher rates than expected of recurrent VTE after SSPE, especially in patients >65 years old or with distal venous thrombosis.
Citation: Le Gal G, et al. Risk for recurrent venous thromboembolism in patients with subsegmental pulmonary embolism managed without anticoagulation: a multicenter prospective cohort study. Ann Intern Med. 2022;175(1):29-35. doi: 10.7326/M21-2981.
Dr. Munoa is a hospitalist at Denver Health, Denver, and an assistant professor in the division of internal medicine, at the University of Colorado School of Medicine.