Should a patient with low-risk pulmonary embolism (PE) be admitted to the hospital or treated as an outpatient?

Low-Risk Pulmonary Embolism: Outpatient Management Recommended

Patients with low-risk pulmonary embolism should be treated as outpatients rather than admitted to the hospital, provided they meet specific eligibility criteria and have access to appropriate follow-up care. 1

Risk Stratification is Essential

Before making the admission decision, you must first formally risk-stratify the patient using a validated clinical tool 1:

• Use PESI (Pulmonary Embolism Severity Index) class I/II - these patients have 30-day mortality rates of ≤1.6% and 3.6% respectively 2
• Use simplified PESI (sPESI) score of 0 - these patients have 30-day mortality of approximately 1.0-1.1% 2
• Use Hestia criteria - a pragmatic list of exclusion criteria 1

The 2021 CHEST guidelines provide a strong recommendation for outpatient treatment in low-risk PE, even though the certainty of evidence is low, because the panel placed very high value on avoiding hospitalization-related harms and costs while achieving similar clinical outcomes 1.

Mandatory Exclusion Criteria Before Outpatient Treatment

Even if risk scores indicate low risk, patients must NOT have any of the following 1:

Physiologic Instability

• Heart rate >110 bpm 1
• Systolic blood pressure <100 mmHg 1
• Oxygen saturation <90% on room air 1
• Severe pain requiring opiates 1

Medical Contraindications

• Active bleeding or recent major bleeding risk (recent GI bleed, surgery, previous intracranial bleeding, uncontrolled hypertension) 1
• Already on full-dose anticoagulation at time of PE diagnosis 1
• Severe renal failure (eGFR <30 mL/min or CrCl <30 mL/min) 1
• Severe liver disease 1
• Severe thrombocytopenia (platelet count <50,000-75,000/mm³) 1
• Heparin-induced thrombocytopenia within the past year 1

Social and Logistical Factors

• Inability to return home or inadequate home care 1
• Lack of telephone communication 1
• Concerns about medication compliance 1
• Patient does not feel well enough to go home 1
• Other medical comorbidities requiring hospital admission 1

Required Infrastructure for Safe Outpatient Management

You cannot simply discharge these patients without a system in place 1:

• Robust pathway for follow-up and monitoring must exist 2
• Access to prompt outpatient care if symptoms worsen 1
• Consultant or senior clinician review before discharge 2
• Access to medications - patients must be able to obtain anticoagulation immediately 1

Evidence Supporting Outpatient Management

The outcomes data strongly support this approach 1:

• 90-day all-cause mortality: No difference between outpatient vs inpatient (0 fewer events per 1,000) 1
• 90-day major bleeding: No difference (0 fewer events per 1,000) 1
• 90-day recurrent PE: No difference (0 fewer events per 1,000) 1

A landmark randomized controlled trial demonstrated that among 171 outpatients with low-risk PE, only 0.6% developed recurrent VTE within 90 days, with mean hospital stay of just 0.5 days compared to 3.9 days for inpatients 3. A systematic review of outpatient PE management showed major adverse outcomes occurred in <1% of patients at 90 days, including all-cause mortality (0.7%), PE-related mortality (0.06%), recurrent VTE (0.8%), and major bleeding (0.8%) 4.

Anticoagulation Choice for Outpatients

Use direct oral anticoagulants (DOACs) as first-line therapy rather than warfarin 1:

• Apixaban or rivaroxaban - single-drug regimens that can be started immediately 1, 2
• Dabigatran or edoxaban - require initial LMWH bridging 1, 2

The 2021 CHEST guidelines give a strong recommendation for DOACs over vitamin K antagonists for treatment-phase therapy, with moderate-certainty evidence showing similar efficacy but improved safety profile 1.

Common Pitfalls to Avoid

Do not rely solely on imaging findings: RV dilation on CT or echocardiography does NOT automatically exclude patients from outpatient management if they meet low-risk clinical criteria 1. However, if RV dilation is present in an otherwise low-risk patient, consider measuring cardiac biomarkers (BNP/troponin) for additional risk stratification 1.

Do not perform routine bleeding risk scores: No specific bleeding risk assessment beyond the exclusion criteria is required in patients deemed low-risk by PESI/sPESI/Hestia 1.

Do not discharge without same-day anticoagulation: Patients must have immediate access to anticoagulation medications before leaving the emergency department 1, 2.

Patient Satisfaction and Cost-Effectiveness

Outpatient management is strongly preferred by patients, with 96.6% indicating they would choose outpatient treatment again for a subsequent PE 5. The median hospital stay reduction is approximately 5 bed-days per patient 5, making this approach significantly more cost-effective while maintaining safety 1.