Subsegmental PE – Hold the Anticoagulation?

August 29, 2023

Written by Samuel G. Rouleau

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Structured surveillance without anticoagulation of patients with isolated subsegmental pulmonary embolism (ssPE) rarely occurs in community practice. After applying CHEST guidelines, ~5% of patients with isolated subsegmental PE are eligible for surveillance.

Small PE? Fat chance…of surveillance without anticoagulation
Pulmonary emboli confined to the subsegmental arteries comprise about 8% of all acute PE. As CT scan technology has improved, we are now able to detect PE isolated to the subsegmental arteries. This has led to an effort to identify which patients with isolated ssPE may be observed without anticoagulation to avoid potential bleeding risk. The American College of Chest Physicians (CHEST) published guidelines in 2016 and 2021 outlining which patients may be candidates for structured surveillance.^1-3

This was a retrospective cohort study of 21 Kaiser Permanente emergency departments over 5 years. Researchers identified 666 outpatients with isolated ssPE, and 229 were determined to be low-risk based on vital signs and comorbidities. Authors applied the CHEST guidelines to determine how many were eligible for surveillance without anticoagulation and then identified which patients actually underwent surveillance. Structured surveillance was defined as repeat imaging (either compression ultrasonography of the lower extremities or CTPA) within 2 weeks of diagnosis.

Thirty-five patients (15.3% of lower-risk patients with ssPE; 5.3% of all patients with ssPE) were eligible for structured surveillance without anticoagulation. Six patients (2.6%) underwent surveillance without anticoagulation, but only 1 patient (0.4%) underwent structured surveillance with follow-up and repeat imaging.

How will this change my practice?
Prior observational cohort data have reported higher than-expected recurrence rates of venous thromboembolism in patients with ssPE managed without anticoagulation.⁴ It is logistically cumbersome to apply all the eligibility criteria and difficult to ensure timely follow-up imaging. In the absence of results from two ongoing clinical trials (SAFE-SSPE & STOPAPE), it is difficult to see a path forward for ssPE surveillance without anticoagulation.

Edited and peer reviewed by Bo Stubblefield. Congrats to lead JAMA author and JF author Sam Rouleau on this publication.

Source
Samuel G Rouleau, Mahesh J Balasubramanian, Jie Huang, Tad Antognini, Mary E Reed, David R Vinson. Prevalence of and Eligibility for Surveillance Without Anticoagulation Among Adults With Lower-Risk Acute Subsegmental Pulmonary Embolism. JAMA Netw Open. 2023;6(8):e2326898. Published 2023 Aug 1. doi:10.1001/jamanetworkopen.2023.26898

Works Cited

1. Kearon C, Akl EA, Ornelas J, et al. Antithrombotic Therapy for VTE Disease: CHEST Guideline and Expert Panel Report. Chest 2016;149:315-52.
2. Stevens SM, Woller SC, Baumann Kreuziger L, et al. Executive Summary: Antithrombotic Therapy for VTE Disease: Second Update of the CHEST Guideline and Expert Panel Report. Chest 2021;160:2247-59.
3. Stevens SM, Woller SC, Kreuziger LB, et al. Antithrombotic Therapy for VTE Disease: Second Update of the CHEST Guideline and Expert Panel Report. Chest 2021;160:e545-e608.
4. Le Gal G, Kovacs MJ, Bertoletti L, 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;175:29-35.