Historically, patients diagnosed with pulmonary embolism (PE) initially have been managed as inpatients. This practice stemmed from two primary issues: a reported mortality of 18 percent following PE and the need to titrate anticoagulation to therapeutic levels. However, more recent studies report that PE-related mortality is actually only around 3 percent, albeit still a high figure.¹ Additionally, direct oral anticoagulants (DOACs) such as rivaroxaban and apixaban do not require injections or coagulation testing to monitor for therapeutic levels. As a result, many professional society guidelines, including those from ACEP and the American College of Chest Physicians, now recommend that select patients with low-risk PE can be managed as outpatients.^2,3

Low-risk patients are typically classified as those with no hemodynamic instability, no significant cardiopulmonary comorbidities, and no evidence of significant myocardial strain or acute damage. Based on this, it is estimated that 30 to 50 percent of patients with acute PE diagnoses may be eligible for outpatient management.^2,4 Are you discharging 30 to 50 percent of your acute PEs? Doing so has advantages. Outpatient management is associated with lower costs—the median hospital cost among patients discharged from U.S. emergency departments with acute PEs between 2016 and 2018 was $986 compared to $6,130 for those admitted to the hospital.⁵ Other benefits of outpatient management include reduced risk of hospital-acquired conditions and reduced hospital capacity strain.

Outpatient Management of Patients with Low-Risk PE Is Safe

Randomized trials and several observational studies demonstrate that patients with low-risk PE can be managed safely as outpatients.^4,6–8 A systematic review of the outpatient management of PE found that both all-cause and PE-related mortality at 30 days was less than 1 percent among high-quality studies.⁸

Who Is Eligible for Outpatient Management?

Multiple protocols for the outpatient management of PE exist and typically integrate risk-stratification scores as well as clinical and social factors. Commonly used risk-stratification scores for outpatient management include the PE Severity Index (PESI), the Simplified PESI (sPESI), and the Hestia criteria (see Tables 1–3). The PESI and sPESI include vital signs and comorbidities that predict mortality following the diagnosis of PE. Those who have a PESI falling within Class I or II or an sPESI of 0 are potential candidates for outpatient management. In addition to clinical criteria, the Hestia criteria also incorporate medical or social reasons for admission. Validation studies found each of these scores can safely identify low-risk patients but may classify nonoverlapping proportions of patients. Importantly, in addition to having a low-risk PE, patients must lack other conditions requiring hospitalization, lack contra­indications to anticoagulation, and be able to obtain medications promptly and attend a follow-up appointment.

Table 1: Pulmonary Embolism Severity Index

Scoring
≤65: Class I, very low risk
66–85: Class II, low risk
86–105: Class III, intermediate risk
106–125: Class IV, high risk
>125: Class V, very high risk

Table 2: Simplified Pulmonary Embolism Severity Index

Scoring
0:.Low risk
≥1: High risk

Table 3: Hestia Criteria

Scoring
0: 0: Low risk
≥1: High risk

Many protocols also incorporate cardiac biomarkers such as troponin and brain natriuretic peptide (BNP) levels, although the cutoff value for BNP is not consistent (<600 pg/mL has been suggested).⁹ The value of using CT or ultrasound evidence of right ventricular (RV) heart strain in the disposition decision is less clear. Some studies suggest that CT may overestimate RV strain, particularly if using an RV/LV ratio of 0.9 rather than 1.0.^9–12

Treatment

DOACs have made it easier for patients to take anticoagulants and achieve reliable anticoagulation both as inpatients and outpatients. Rivaroxaban and apixaban are commonly used DOACs for PE and demonstrate similar safety and efficacy in real-world settings. Despite the ease of administration, however, insurance companies may require preauthorization or have a preferred DOAC, which can be a headache to sort out in the emergency department. Many clinicians and emergency departments take advantage of the coupons for free or significantly discounted medications from the pharmaceutical company to initiate treatment, then inform the patient that their primary care physician may switch the anticoagulant in the future (for example, www.eliquis.com/eliquis/hcp/resources and www.janssencarepath.com/hcp/xarelto/savings-program-overview ).

In the age of DOACs, the benefits of hospitalization for a substantial fraction of patients with low-risk PE are minimal or nonexistent. Interestingly, despite professional society guidance and a decade of safety data, outpatient management of PE in the United States varies widely, with signals that the practice is largely institution- rather than patient-dependent.^5,14 Institutions and clinicians should work to implement protocols to identify and treat appropriate patients with low-risk PE in the outpatient setting.

Dr. Westafer (@Lwestafer) is an attending physician and research fellow at Baystate Medical Center, clinical instructor at the University of Massachusetts Medical School in Worcester, and co-host of FOAMcast.

References

1. Jiménez D, de Miguel-Díez J, Guijarro R, et al. Trends in the management and outcomes of acute pulmonary embolism: analysis from the RIETE registry. J Am Coll Cardiol. 2016;67(2):162-170.
2. Kearon C, Akl EA, Ornelas J, et al. Antithrombotic therapy for VTE disease: CHEST guideline and expert panel report. Chest. 2016; 149(2):315-352.
3. Wolf SJ, Hahn SA, Nentwich LM, et al. Clinical policy: critical issues in the evaluation and management of adult patients presenting to the emergency department with suspected acute venous thromboembolic disease. Ann Emerg Med. 2018;71(5):e59-e109.
4. Aujesky D, Roy PM, Verschuren F, et al. Outpatient versus inpatient treatment for patients with acute pulmonary embolism: an international, open-label, randomised, non-inferiority trial. Lancet. 2011;378(9785):41-48.
5. Westafer LM, Shieh M-S, Pekow PS, et al. Outpatient management of patients following diagnosis of acute pulmonary embolism. Acad Emerg Med. 2021;28(3):336-345.
6. den Exter PL, Zondag W, Klok FA, et al. Efficacy and safety of outpatient treatment based on the Hestia clinical decision rule with or without N-terminal pro-brain natriuretic peptide testing in patients with acute pulmonary embolism. A randomized clinical trial. Am J Respir Crit Care Med. 2016;194(8):998-1006.
7. Piran S, Le Gal G, Wells PS, et al. Outpatient treatment of symptomatic pulmonary embolism: a systematic review and meta-analysis. Thromb Res. 2013;132(5):515-519.
8. Maughan BC, Frueh L, McDonagh MS, et al. Outpatient treatment of low‐risk pulmonary embolism in the era of direct oral anticoagulants: a systematic review. Acad Emerg Med. 2021;28(2):226-239.
9. Elias A, Mallett S, Daoud-Elias M, et al. Prognostic models in acute pulmonary embolism: a systematic review and meta-analysis. BMJ Open. 2016;6(4):e010324.
10. Quezada CA, Bikdeli B, Villén T, et al. Accuracy and interobserver reliability of the simplified pulmonary embolism severity index versus the Hestia criteria for patients with pulmonary embolism. Acad Emerg Med. 2019;26(4):394-401.
11. Zongdag W, Mos ICM, Creemers-Schild D, et al. Outpatient treatment in patients with acute pulmonary embolism: the Hestia study. J Thromb Haemost. 2011;9(8):1500-1507.
12. Peacock WF, Singer AJ. Reducing the hospital burden associated with the treatment of pulmonary embolism. J Thromb Haemost. 2019;17(5):720-736.
13. Aryal MR, Gosain R, Donato A, et al. Systematic review and meta-analysis of the efficacy and safety of apixaban compared to rivaroxaban in acute VTE in the real world. Blood Adv. 2019;3(15):2381-2387.
14. Vinson DR, Mark DG, Chettipally UK, et al. Increasing safe outpatient management of emergency department patients with pulmonary embolism: a controlled pragmatic trial. Ann Intern Med. 2018;169(12):855-865.