Pulmonary embolism

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See Pulmonary Embolism in Pregnancy for pregnancy specific information.[1]

Background

Clinical Spectrum of Venous thromboembolism (VTE)

Only 40% of ambulatory ED patients with PE have concomitant DVT[2][3]

Types

Symptoms

Signs

  • Tachycardia (HR>100), Tachypnea (RR>20), Hypoxemia (SpO2<95%) are seen ~50% of the time
  • Hypotension (SBP<90) only seen 10% of the time, but largest predictor of mortality
  • Unilateral calf tenderness or edema, suggestive of a DVT
  • Other signs may include accentuated pulmonic component of second heart sound, JVD, or decreased breath sounds

Differential Diagnosis

Chest pain

Critical

Emergent

Nonemergent

Acute dyspnea

Emergent

Non-Emergent

Diagnostic Evaluation

Wells Criteria

  • Symptoms of DVT - 3pts
  • No alternative diagnosis better explains the illness - 3pts
  • HR > 100 - 1.5 pts
  • Immobilization within prior 4wks - 1.5pts
  • Prior history of DVT or PE - 1.5pts
  • Active malignancy - 1pt
  • Hemoptysis - 1pt

Wells Score

  • 0-1 point: Low probability (3.4%)
  • 2-6 points: Moderate probability (27.8%)
  • 7-12 points: High probability (78.4%)

Workup by Probability

Low Probability

  • Avoid CT pulmonary angiography in low probability pts that are either PERC rule negative or have a negative d-dimer
  • If low prob and PERC Rule negative, then no workup
  • If low prob and PERC Rule positive, then d-dimer
  • Age-adjusted D-Dimer in patients <50 yrs old (Age x 10) has increased specificity without changing sensitivity[4][5]

Moderate Probability

  • D-dimer
    • However, it is unclear whether d-dimer alone is sufficient to rule-out PE[6]

High Probability

  • Consider anticoagulation before imaging!
  • CTA if GFR >60
  • V/Q if GFR <60

Bedside Ultrasound

  • Ultrasound can help diagnosis in equivocal cases
  • Assess for right ventricular strain (RVS) and McConnell's sign
  • RVS is associated with statistically significant worse outcome[7]

Treatment

Supportive care

  • Give IVF to increase preload

Anticoagulation

  • Indicated for all patients with confirmed PE or high clinical suspicion (don't wait for imaging)
  • Treatment options:
    • LMWH SC
      • 1st line for most hemodynamically stable pts
      • contraindicated in renal failure
      • Enoxaparin 1 mg/kg SC q12h
      • Dalteparin 200 IU/kg SC q24h, max 18,000 IU
    • Unfractionated Heparin
      • Consider in pts w/:
        • Persistent hypotension
        • Increased risk of bleeding
        • Recent sx/trauma
        • Renal failure (GFR <30)
        • Morbid obesity or anasarca (poor sc absorption)
        • Thrombolysis is being considered
      • 80 units/kg bolus; then 18 units/kg/hr
        • Check PTT after 6hr; adjust infusion to maintain PTT at 1.5-2.5x control

Thrombolysis

  • Major controversy exists regarding thrombolytic therapy in submassive PE. Therapy should be individualized to patients.[8][9][10] 'The mortality benefit may be greatest in patients with right ventricular dysfunction. [11]
  • Bleeding risk is increased with increasing age especially in the group ≥ 65 yo[12]

Indications

  • Patients with massive PE and acceptable risk of bleeding complications
  • Pt w/ submassive PE w/ evidence adverse prognosis + low risk of bleeding complications
    • Hemodynamic instability
    • Worsening respiratory insufficiency
    • Severe Right Ventricular dysfunction
    • Major myocardial necrosis

Thrombolytic Instructions

  • Review contraindications
  • Discontinue heparin during infusion
  • tPA 100mg over 2hr OR 0.6 mg/kg over 2min
  • After infusion complete measure PTT
    • Once value is <2x upper limit restart anticoagulation

Absolute contraindications

  • Any prior intracranial hemorrhage,
  • Known structural intracranial cerebrovascular disease (e.g. AVM)
  • Known malignant intracranial neoplasm
  • Ischemic stroke within 3mo
  • Suspected aortic dissection
  • Active bleeding or bleeding diathesis
  • Recent surgery encroaching on the spinal canal or brain
  • Recent closed-head or facial trauma w/ radiographic evidence of bony fx or brain injury

Relative contraindications

  • Age >75 years
  • Current use of anticoagulation
  • PE in Pregnancy
  • Noncompressible vascular punctures
  • Traumatic or prolonged CPR (>10min)
  • Recent internal bleeding (within 2 to 4 weeks)
  • History of chronic, severe, and poorly controlled hypertension
  • Severe uncontrolled HTN on presentation (sys BP >180 or dia BP >110)
  • Dementia
  • Remote (>3 months) ischemic stroke
  • Major surgery within 3 weeks

IVC Filter

  • Indications
    • anticoagulation contraindicated in pt with PE
    • failure to attain adequate anticoagulation during treatment

See Also

Thrombolytics for pulmonary embolism

Disposition

  • Patients with significant clot burden generally require admission for anticoagulation
  • Consider discharge in low risk patients with peripheral PE[13]

External Links

References

  1. ↑ D-Dimer Concentrations in Normal Pregnancy: New Diagnostic Thresholds Are Needed. Kline et all. Clinical Chemistry May 2005 vol. 51 no. 5 825-829 http://www.clinchem.org/content/51/5/825.long
  2. ↑ Righini M, Le GG, Aujesky D, et al. Diagnosis of pulmonary embolism by multidetector CT alone or combined with venous ultrasonography of the leg: a randomised non-inferiority trial. Lancet. 2008; 371(9621):1343-1352.
  3. ↑ Daniel KR, Jackson RE, Kline JA. Utility of the lower extremity venous ultrasound in the diagnosis and exclusion of pulmonary embolism in outpatients. Ann Emerg Med. 2000; 35(6):547-554.
  4. ↑ Schouten, HJ, et al. Diagnostic accuracy of conventional or age adjusted D-dimer cut-off values in older patients with suspected venous thromboembolism: systematic review and meta-analysis. BJM. 2013; 346:f2492.
  5. ↑ Adams, D, et al. Clinical utility of an age-adjusted D-dimer in the diagnosis of venous thromboembolism. Ann Emerg Med. 2014; 64:232-234.
  6. ↑ ACEP Clinical Policy. http://www.acep.org/Content.aspx?id=80787
  7. ↑ Taylor, RA, et al. Point-of-care focused cardiac ultrasound for prediction of pulmonary embolism adverse outcomes. The Journal of Emergency Medicine. 2013; 45(3):392–399.
  8. ↑ Elliott C. et al. Fibrinolysis of Pulmonary Emboli — Steer Closer to Scylla.
  9. ↑ Sharifi M et al. Moderate pulmonary embolism treated with thrombolysis (from the “MOPPETT trial). J Cardiol 2013; 111: 273-7
  10. ↑ Meyer G. Fibrinolysis for patients with intermediate-risk pulmonary embolism. NEJM 2014; 370(15): 1402-1411
  11. ↑ Chatterjee. S et al. Thrombolysis for pulmonary embolism and risk of all-cause mortality, major bleeding, and intracranial hemorrhage: a meta-analysis. JAMA 2014; 311(23):2414-21. PubMed ID: 24938564.
  12. ↑ Thrombolysis_in_Pulmonary_Embolism_Metanalysis*Outcomes
  13. ↑ Vinson DR, Zehtabchi S, Yealy DM. Can selected patients with newly diagnosed pulmonary embolism be safely treated without hospitalization? A systematic review. Ann Emerg Med. 2012; 60:651-662.
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