Date: March 16th, 2021

Guest Skeptic: Dr. Corey Heitz is an emergency physician in Roanoke, Virginia. He is also the CME editor for Academic Emergency Medicine.

Reference: Westafer et al. Outpatient Management of Patients Following Diagnosis of Acute Pulmonary Embolism. AEM March 2021

Case: You are evaluating a 48-year-old female for pleuritic chest pain. She is low risk by Wells Criteria but PERC Rule positive because of an appendectomy last month. Her d-dimer comes back elevated, so you order a CT-PA to evaluate for pulmonary embolism (PE). The radiologist notes a distal sub-segmental PE on the right. The patient has normal vital signs and no comorbidities.

Background: Historically most patients with PEs have been admitted to the hospital in the USA. This is in contrast to Canada where papers in the early 2000 demonstrated the safety of out-patient management of PEs (Kovacs). A study from 2010 showed that half of PE patient from one centre in Ontario were safely being treated as outpatients (Kovacs).

Dr. Jeff Kline

PE guru, creator of the PERC Rule and Editor-in-Chief of Academic Emergency Medicine, Dr. Jeff Kline, was senior author on a paper that looked at treating VTE with outpatient management using a DOAC (Bean et al AEM 2015). This relatively small study (n=106) reported successfully treating 51% of DVT patients and 27% of PE patients with rivaroxaban (SGEM#126).

Literature from the USA reports that 90% of patients diagnosed with PE are admitted (Singer et al 2016). Another study showed less than 10% of PE patients are discharged home from the ED for out-patient therapy (Vinson et al 2017).

A couple of international guidelines support the outpatient treatment of ED patients with low-risk PE. This includes the European Cardiology Society (ECS 2019) and the British Thoracic Society (Howard et al 2018).

The American College of Emergency Physicians (ACEP) has a clinical policy that addresses this issue (Wolf et al 2018). The ACEP policy give outpatient management of PE patients a Level C recommendation:

“Selected patients with acute PE who are at low risk for adverse outcomes as determined by PESI, simplified PESI (sPESI), or the Hestia criteria may be safely discharged from the ED on anticoagulation, with close outpatient follow-up.”

PESI (Pulmonary Embolism Severity Index) is a risk stratification tool based upon studies by Donzé et al 2008 and Choi et al 2009.  The PESI consists of eleven criteria with a different number of points awarded for each variable. This can be complicated and there is an online calculator to help (MDCalc PESI Score).

The PESI score has been made even easier to use with the creation of the Simplified PESI. It only has six criteria, each has only one point and can also be computed online using MDCalc sPESI.

The Hestia Criteria is another scoring system to identify low risk PE patients that could be considered for outpatient PE treatment. Like the PESI score it has eleven criteria and an online calculator (MDCalc Hestia Criteria). If all eleven criteria are negative the patient is low risk with a predicted mortality of 0% and VTE recurrence of 2%. However, if any one of the criteria is positive the patient is not low risk. These patients are not considered eligible for outpatient management based on this score and it is recommended they be admitted for inpatient therapy.

Clinical Question: What are the current disposition practices, and outcomes, for patients with PE in US hospitals?

Reference: Westafer et al. Outpatient Management of Patients Following Diagnosis of Acute Pulmonary Embolism. AEM March 2021

  • Population: Patients 18 years of age or older between July 2016 and June 2018 presenting to one of 740 acute care hospitals and receiving a diagnosis of PE based upon ICD-10 codes
    • Exclusion: Patients diagnosed with PE in the previous 90 days, and those patients who expired during the ED visit
  • Intervention: Outpatient management
  • Comparison: Inpatient management
  • Outcome:
    • Primary Outcome: Initial disposition from the ED
    • Secondary Outcomes: Costs, return visits to the ED (chest pain, shortness of breath, bleeding) and rehospitalization withing 30 days

Dr. Lauren Westafer

This is an SGEMHOP episode which means we have the lead author on the show. Dr. Lauren Westafer is an Assistant Professor in the Department of Emergency Medicine at the University of Massachusetts Medical School – Baystate. She is the cofounder of FOAMcast and is a pulmonary embolism and implementation science researcher. Dr. Westafer serves as the Social Media Editor and a research methodology editor for Annals of Emergency Medicine and is an Associate Editor for the NEJM Journal Watch Emergency Medicine. She is also the newest member of the SGEMHOP faculty.

Authors’ Conclusions: Despite guidelines promoting outpatient management, few patients are currently discharged home in the US; however, practice varies widely across hospitals. Return visit rates were high but most did not result in hospitalization.”

Quality Checklist for Observational Study:

  1. Did the study address a clearly focused issue? Yes
  2. Did the authors use an appropriate method to answer their question? Yes
  3. Was the cohort recruited in an acceptable way? Yes
  4. Was the exposure accurately measured to minimize bias? Yes
  5. Was the outcome accurately measured to minimize bias? Yes
  6. Have the authors identified all-important confounding factors? Unsure
  7. Was the follow up of subjects complete enough? Yes
  8. How precise are the results? Fairly precise
  9. Do you believe the results? Yes
  10. Can the results be applied to the local population? Unsure
  11. Do the results of this study fit with other available evidence? Yes

Results: The cohort of patients identified in the database was 61,070. The mean age was 62 years with slightly more females (53%). About two-thirds of patients had Medicare (51%) or Medicaid (12%) while 29% had private insurance. The top three comorbidities were hypertension (60%), chronic pulmonary disease (25%) and obesity (25%).

Key Result: The vast majority of patients diagnosed with PE were admitted to hospital.

  • Primary Outcome: Initial disposition from the ED
    • 4% discharged from the ED at the index visit and 96% admitted
  • Secondary Outcomes:
    • Outpatient charge was $1,214 while the total cohort was $9,225
    • 28% of those discharged had a return visit
    • 11% of those discharged were subsequently admitted on a return visit
      • Factors associated with admission: Respiratory failure/hypoxia (OR 0.06, 95% CI 0.04-0.07), Shock (OR 0.17, 95% CI 0.00-0.48), Hypotension (OR 0.07; 95% CI 0.00-0.14), Heart failure (OR 0.24; 95% CI 0.18-0.34) and malignancy (OR 0.45; 95% CI 0.36, 0.53)
    • 1.9% of admitted patient died
    • 1.3% of patients returning within 30 days were for a bleeding associated diagnosis

Here are the five nerdy questions we asked Lauren to help us better understand her study. Listen to her respond to each question on the SGEM podcast.

1. Database: You used the Premier Healthcare Database (PHD) for this retrospective cohort study. This is a publicly traded company. Can you tell us a bit more about this resource and why you are confident in the fidelity of the data?

2. Risk Stratification: Did you consider calculating a risk score (PESI, sPESI or Hestia) for the patients and would it have been useful in interpreting the results?

3. Size and Location: We did not see any discussion about the size or location of the PEs. The ACEP clinical policy gives a level C recommendation whether or not to withhold anticoagulation in adult patients with subsegmental PE.

“Given the lack of evidence, anticoagulation treatment decisions for patients with subsegmental PE without associated DVT should be guided by individual patient risk profiles and preferences.” [Consensus recommendation]

4. Subgroup Analysis: You did some subgroup analyses based on the hospital location, size, teaching and rural or urban. Did you find anything interesting and what is your interpretation for any differences?

5. Concordance: Why do you think clinicians are still admitting the vast majority of patients (96%) when data exists that this number could safely be cut in half? In fact, the number is even higher because you excluded 212 hospitals that admitted 100% of PE patients. What is driving this clinical practice in the USA when in Canada we discharge 50% of PE patients for outpatient management.

Comment on the Authors’ Conclusion Compared to SGEM Conclusion: We agree with the authors’ conclusion.

SGEM Bottom Line: Patients with PE, given the right criteria, can be discharged home from the ED. US healthcare systems should consider decreasing the number of patients who are admitted, with the understanding that the risk of return visits is high.

Case Resolution: You discuss anticoagulation outpatient management with your patient. She prefers to be discharged and has close follow up with her primary care clinician in two days. Using shared decision making, you and the patient agree to discharge her home on oral anticoagulants.

Clinical Application: Consider using risk score systems and having shared decision-making discussions with your patients to determine who can be safely managed as an outpatient.

What Do I Tell My Patient? You have a small blood clot in your right lung. Your vital signs are normal, and all other risk factors are minimal. There is some weak evidence that you do not need to be treated with blood thinners. However, most people still decide to be treated for their blood clot. This treatment can be either in the hospital or as an outpatient. There is a 1 in 4 chance that if you decide to be treated at home you will return to the hospital and 1 in 10 patients need to be admitted when they return. What would you like to do?

Keener Kontest: Last weeks’ winner was another win for Dr. Steven Stelts from New Zealand. He knew that approximately 3-5% of Americans have a brain aneurysm at some point in their lifetime (NINDS).

Listen to the podcast on iTunes for this weeks’ keener question. If you think you know the answer then send an email to with “keener” in the subject line. The first correct answer will receive a cool skeptical prize.

SGEMHOP: Now it is your turn SGEMers. What do you think of this episode on the outpatient management of PE patients? Tweet your comments using #SGEMHOP.  What questions do you have for Lauren and her team? Ask them on the SGEM blog. The best social media feedback will be published in AEM.

Those of you who subscribe to Academic Emergency Medicine can get CME credit for this podcast and article.

  • Go to the Wiley Health Learning website
  • Register and create a log in
  • Search for Academic Emergency Medicine – “March”
  • Complete the five questions and submit your answers
  • Please email Corey ( with any questions or difficulties.

You can also get CME credit for this episode even if you are not a member of AEM. All the SGEM episodes are now accredited for CME. The content is always free but there is a small fee for the CME. This small fee will help support the SGEM and keep this free open access knowledge translation project going. Why not get credit for what you are already doing…listening to the SGEM.

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics’ Guide to Emergency Medicine.