Pulmonary Embolism Q&A (ACEP 2018 Policy)

The following is a summary of the ACEP Clinical Policy on VTE, updated May 20181.

1) In adults with suspected PE, can a prediction rule be used to identify patients at VERY low risk, for which no further testing is required? Yes, the PERC rule for patients at low risk (Level B)
  • Why PERC? It focuses on excluding PE instead of screening patients for appropriate use of D-dimer. In addition, it has been prospectively validated.
  • The threshold for PERC initial studies and subsequent validation is 2%. The presumption was that a risk <2% obviates the need for further testing.
  • If the patient is not deemed to be “low” risk prior to applying the PERC rule, then performance of the test is not as good and may be insufficient for the 2% threshold.
2) In adults with low to intermediate risk, does a negative, age-adjusted D-dimer allow us to forgo any further testing? Yes, age-adjusted D-dimer over age 50 is sufficient. (Level B)
  • PE prevalence increases with age as do comorbid conditions. D-dimer levels also increases with age.
  • Studied calculations include:
    • D-dimmer cut off equal to age after 50 (age x 10 ug/L FEU or age x 5 ug/L DDU)
    • D-dimer cutoff that increases by decade
    • Set higher d-dimer cut off for patients between 50-70

3) In adults with sub-segmental PE, is it safe to withhold anticoagulation? Unknown

  • There is insufficient evidence to make a recommendation.
  • Decision should be guided by individual patient risk profile and preference.
  • This assumes there is no DVT present.
4) In adults with PE, is anticoagulation and discharge from the ED safe? Possibly. PESI,  sPESI and Hestia criteria have been studied. (Level C)
  • More than 95% of PE patients are “hemodynamically stable”
  • Associated mortality in HD stable patients is 1-15%
  • PESI studied 30 day mortality, Hestia studied to identify “low risk of adverse outcomes”
  • Traditional hospitalization demonstrates 1% incidence recurrent VTE, 2% major hemorrhage, and 2% all-cause mortality. These are the threshold levels used for comparison to outpatient treatment protocols.
  • Some guidelines2 recommend screening echocardiography to determine right ventricular strain. This is not included in the PESI, sPESI, or Hestia criteria. Retrospective application of RV dysfunction criteria has shown that up to one-third of Hestia low risk patients would have required admission despite their good outpatient outcomes.
  • In addition, current studies used LMWH and Warfarin instead of NOACs, and did not exclusively use ED populations. More studies are warranted to make a higher level evidence recommendation.
5) In adults with lower extremity DVT who are discharged from the ED, is use of a NOAC instead of LMWH and Vit K antagonist safe? Yes. (Level B)
  • Current Novel Oral Anticoagulants (NOACs) have been studied and shown to be non-inferior to Low molecular weight heparin (LMWH)
  • No comparison studies among NOACs to determine their respective performance.
  • Dabigatrain (Pradaxa) and Edoxaban (Savaysa) studies started patients on IV heparin prior to starting NOACs making their utility on the undifferentiated ED patient less useful.
  • Rivaroxaban (Xarelto) and Apixaban (Eliquis) were studied without IV heparin pretreatment.
Why follow a clinical policy?
  • Reduce test related complications
  • Reduce healthcare costs
  • Reduce time in ED
  • Better utilization of resources
  • Improve patient satisfaction with efficiency
Recommendations:
  • Listen to the Cam Berg discussion on a PE Accelerated Diagnostic Protocol that utilizes a WELLs score to categorize patients and then apply the PERC rule. (EM:RAP episode)
  • Use a clinical calculator (MDCalc) for your calculations
References:
  1. 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. PDF
  2. Bledsoe JR, Woller SC, Stevens SM, et al. Management of Low-Risk Pulmonary Embolism Patients Without Hospitalization: The Low-Risk Pulmonary Embolism Prospective Management Study. Chest. 2018 PubMed

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