Only a small proportion of patients with subsegmental pulmonary embolism (PE) may be eligible for structured surveillance without anticoagulation as recommended by the American College of Chest Physicians (CHEST) guidelines, and despite the CHEST guideline on structured surveillance in these patients, it is rarely used in the community setting, according to research published in JAMA Network Open.

“[The 2016 CHEST guideline and expert panel report authors] suggested structured surveillance without anticoagulation for ambulatory patients with stable subsegmental PE without active cancer, [deep vein thrombosis (DVT)] (requiring bilateral compression ultrasonography regardless of DVT signs and symptoms), impaired cardiopulmonary reserve, marked symptoms, and increased risk of recurrent [venous thromboembolism (VTE)],” explained the researchers. “This cautious recommendation was reiterated in the subsequent 2021 CHEST guideline and expert panel report.”

The researchers conducted a retrospective cohort study across 21 US community hospitals to assess the prevalence of surveillance among outpatients with acute subsegmental PE and to estimate the proportion of outpatients in community practice eligible for structured surveillance using the modified CHEST criteria (excluding patients with higher-risk characteristics or right ventricular dysfunction) and a stricter set of criteria requiring an age <65 years and no more than 1 embolus.

Continue Reading

The study included 666 adult outpatients with acute subsegmental PE between January 1, 2017, and December 31, 2021. Of those, 229 (34.4%) had lower-risk characteristics. These patients had median age of 58 years (interquartile range, 42-68 years). This lower-risk cohort was 52.4% men and 55.9% self-identified as non-Hispanic White.

Among the lower-risk cohort, the researchers found that 6 patients (2.6%) were not treated initially with anticoagulants and only 1 patient (0.4%) underwent structured surveillance.

The analysis revealed that 15.3% and 6.6% of the lower-risk cohort and 5.3% and 2.3% of the full cohort were eligible for structured surveillance using the modified CHEST criteria and the stricter criteria, respectively.

“These findings suggest that there was almost no effect on surveillance practices attributable to the CHEST guideline in this large US health care system—a system that is conducive to structured surveillance, with ready access to VTE imaging, specialty consultation, and timely primary care follow-up,” stated the study authors. “Although trials are ongoing to define which patients with subsegmental PE can safely undergo surveillance, widespread uptake of any new surveillance practice will require more than passive diffusion.”

Limitations of the study included the retrospective design, a 5-year study period, potential bias of unblinded physician abstractors, incomplete case ascertainment, and inclusion of only northern California residents.


Rouleau SG, Balasubramanian MJ, Huang J, Antognini T, Reed ME, Vinson DR. Prevalence of and eligibility for surveillance without anticoagulation among adults with lower-risk acute subsegmental pulmonary embolism. JAMA Netw Open. 2023;6(8):e2326898. doi:10.1001/jamanetworkopen.2023.26898