Pulmonary Embolism

Matthew Alonso

Background

  • A thrombus originating in a deep vein (LE > UE) embolizing to the pulmonary arterial circulation
  • Risk Factors = Virchow’s Triad
    • Stasis: immobilization, hospitalization, spinal cord injury, or long travel
    • Hypercoagulable state: cancer, prothrombotic genetic conditions, OCPs, nephrotic syndrome, peri-partum, infection, autoimmune disease, etc.
    • Endothelial Injury: surgery, trauma, CVC, recent major infection/sepsis
  • Most originate from a DVT in the iliac, femoral, and popliteal veins

Presentation

  • Dyspnea and tachypnea
  • Respiratory alkalosis on blood gas from hyperventilation
  • Hypoxemia
  • Sinus tachycardia or atrial arrhythmias
  • Hypotension
  • Hemoptysis
  • Lower extremity pain, swelling, and redness – occurs in 50% of pts with DVT
  • RV Failure (large PE) – elevated JVP, hypotension, syncope, R parasternal heave, accentuated P2, hepatomegaly
  • Other: S3/S4, pleural friction rub, decreased breath sounds, wheezing, fever

Evaluation

  • If hemodynamically unstable and PE suspected, provide hemodynamic support (ie. O2, pressors, etc.) and perform emergent bedside TTE
    • If no RV strain evident on TTE, low likelihood of hemodynamically significant PE. Consider other causes of shock.
    • Signs of RV strain: D-sign (flattened interventricular septum during systolic) and McConnell’s sign (hypokinetic mid-free wall of RV with preserved contractility of RV apex)

Hemodynamically stable

  • EKG
    • Most commonly sinus tachycardia, but could see a fib vs flutter
    • Less commonly and indicative of large PE: Right axis deviation, RVH, RBBB, RA enlargement, S1Q3T3 (deep S in lead I, deep Q and inverted T in lead III), TWI in V1-V3
  • CXR: Typically normal
  • Labs: ABG, troponin, BNP, lactate, coags
  • May consider lower extremity dopplers o Imaging vs d-dimer based on pre-test probability:
    • Low pre-test probability (use Wells Criteria) → d-dimer
    • For moderate to high pre-test probability→ CTA Chest PE protocol
      • If high pre-test probability or moderate pre-test probability with >4h delay in work-up, start empiric anticoagulation if bleeding risk is acceptable while work-up is ongoing
  • TTE
  • Risk stratification: PE Severity Index (PESI): Predicts 30-day outcome of patients with pulmonary embolism

Management

Categorization of PE

Low Risk

Intermediate-Low Risk

Intermediate-High Risk

High Risk
Definition

Hemodynamic stablility

No evidence of right heart strain on TTE or CT or myocardial necrosis (hs-TnT) or ventricular streatch and pressure overload (BNP) on labs

Hemodynamic stablility

Either elevated cardiac biomarkers (hs-TnT & BNP) or evidence of RV strain on imaging (TTE or CT)

 Either elevated cardiac biomarkers (hs-TnT & BNP) or evidence of RV strain on imaging (TTE or CT)

Hemodynamically unstable (ex:SBP<90)

Elevated cardiac biomarkers (hs-TnT & BNP)

Imaging evidence of RV dysfunction (TTE or CT)
Management

Start AC: LMWH or heparin gtt (if renal impairment)

Rivaroxaban & apixaban can be used as initial management. Edoxaban & dabigatran can be used after 5-10d of parenteral therapy

Provide hemodynamic support(cautious IVF,O2: HFNC), monitor for decompensation

Start AC w/unfractionated heparin gtt

Consult cardiology for consideration of catheter directed thrombolysis (EKOS) or embolectomy

Transition to LMWH when clinically appropriate if renal function allows

Provide hemodynamic support(cautious IVF, O2: HFNC), monitor for decompensation

Start AC w/unfractionated heparin gtt. Consult Cardiology for consideration of catheter directed thrombolysis (EKOS) or embolectomy

Transition to LMWH when clinically appropriate if renal function allows

Provide hemodynamic support (cautious IVF, vasopressors, inotropes, O2:HFNC)< /p>

STAT page CCU fellow

Discuss with PERT team systemic thrombolytic therapy vs catheterbased thrombolysis, thrombectomy and/or surgical embolectomy

If impending circulatory collapse, discuss ECMO

AC: LMWH vs UFH (w/ bolus)

tPA Considerations

  • Most effective within 24 hours but effective up to 14d
  • Contraindications:
    • Absolute:
      • CNS Pathology: hemorrhagic or ischemic CVA within 3mo, AVM, CNS neoplasm, recent surgery
      • Trauma: Recent head trauma w/ fx or injury
  • Relative
    • Surgery: surgery w/in 3wks
    • Heme: active bleeding, bleeding diathesis, plt < 100, oral AC
    • Age: >75yo, dementia

Long-term management

  • Anticoagulation
    • NOAC - Remember to give initial loading dose (duration of load varies with each agent)
    • Warfarin (Coumadin): Goal INR 2-3, requires frequent monitoring
      • Need to bridge with heparin or lovenox
      • Pharmacy consult, and will need to be set up with coumadin clinic at the time of discharge
  • IVC filter: only if AC is contraindicated, bleeding risk unacceptably high, recurrent VTE despite optimal AC, patients undergoing major surgery with recent VTE and require temporary interruption in AC
  • Placed by IR or Interventional cards

Duration of Anticoagulation:

  • Major reversible/transient risk factors (surgery, trauma): 3-6 months
  • Idiopathic, unprovoked, or with less compelling risk factors: 12 months
  • Major permanent risk factors (cancer, homozygote F5L or prothrombin gene mutation, APLS, protein C/S deficiencies, AT III deficiency): At least 1 year, preferably lifelong.
  • Recurrent DVT/PE: lifelong (consider etiology)
  • Chronic Thromboembolic Pulmonary Hypertension (CTEPH): lifelong
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