Pulmonary Embolism

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Pulmonary Embolism

• Michael Lee, M3

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PE Stats

• Incidence 0.5-1 per 1000
• 3rd leading cause of death in US (50K-100K
  deaths/year)
• Leading cause of unexpected deaths in
  hospitalized patients
• More than 50 of fatal PE cases unsuspected
  antemortem
• PE in 25-35 of those suspected of PE

Laack TA, Goyal DG. Emerg Med Clin North Am, Nov
2004.
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PE Pathophys

• Virchows triad leading to intravascular
  coagulation
• (1) local trauma to vessel wall
• (2) hypercoagulability and
• (3) stasis

Goldhaber SZ. Pulmonary Embolism. 2005.
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PE Pathophys

• Hypercoagulable State
• Inherited (Primary)
• Factor V Leiden, Antithrombin III deficiency
  (resistance to heparin), Antiphospholipid
  antibodies
• Acquired (Secondary)
• Long-haul air travel, surgery/immobilization/
  trauma, obesity, age, smoking, diabetes mellitus,
  OCP/pregnancy/postpartum state, cancer, HRT,
  raloxifene (SERM)

Goldhaber SZ. Pulmonary Embolism. 2005.
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PE Pictures

• Top Picture Saddle embolus at pulmonary artery
  bifurcation
• Bottom Picture PE in left lower lobe pulmonary
  artery

Godleski JJ. Path of DVT and PE, 1985.
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PE Consequences

• Increased pulmonary vascular resistance that can
  lead to right ventricular dysfunction
• Impaired gas exchange
• Alveolar hyperventilation
• Increased airway resistance d/t
  bronchoconstriction
• Decreased pulmonary compliance

Goldhaber SZ. Pulmonary Embolism. 2005.
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PE Risk Factors

• Hypercoagulable state (inherited, acquired)
• History of previous thromboembolic dz
• Malignancy (lung, brain, ovaries, pancreas)
• Surgeries (orthopedic, neurosurgical)
• Trauma (PE is 3rd most common cause of death)

Laack TA, Goyal DG. Emerg Med Clin North Am, Nov
2004.
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PE Clinical Presentation
Most Common Sx/Si Among 2454 Pts in International
Cooperative Pulmonary Embolism Registry
Goldhaber SZ, et al. Lancet 1999.
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Miniati M, et al. Am J Respir Crit Care Med 1999.
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PE Differential Diagnosis

• Myocardial infarction
• Pneumonia
• Congestive heart failure ("left-sided")
• Cardiomyopathy (global)
• Primary pulmonary hypertension
• Asthma

• Pericarditis
• Intrathoracic cancer
• Rib fracture
• Pneumothorax
• Costochondritis
• "Musculoskeletal pain"
• Anxiety

Goldhaber SZ. Pulmonary Embolism. 2005.
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PE Clinical Probability Assessment
Bounameaux H, et al. Curr Opin Hematol, 2006.
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PE Diagnostic Evaluation

• Plasma D-dimer ELISA - gt 500ug/L
• ECG - neg T waves in precordial leads V1-V4
  S1Q3T3 RBBB r/o MI
• CXR - Hamptons hump, Westermarks sign
  (decreased vascularity)
• Chest CT
• V/Q lung scintigraphy largely replaced by
  helical CT scan

Goldhaber SZ. Pulmonary Embolism. 2005. Tapson
V. CECIL Textbook of Medicine. 2004.
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PE Diagnostic Evaluation

• MRI
• Echo
• Pulmonary angiography
• Venous USG
• Contrast venography

Goldhaber SZ. Pulmonary Embolism. 2005.
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PE Treatment
Tai MRM, et al. Br J Surg, 1999.
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PE Prevention

• Heparin (binds antithrombin III, does not
  directly dissolve existing clots)
• Unfractionated (UFH)
• Low molecular weight (LMWH) - fragments of
  unfractionated heparin ie, Lovenox
• Warfarin (Coumadin)
• Often overlap heparin and warfarin for 5 days to
  counteract thrombogenic potential created by
  unopposed warfarin
• IVC Interruption - prevents PE, not DVT

Goldhaber SZ. Pulmonary Embolism. 2005.
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PE UFH vs LMWH

• LMWH has greater bioavailability, more
  predictable dose response, and longer half-life
  than UFH.
• LMWH has greater impact on mortality rate.

Goldhaber SZ. Pulmonary Embolism. 2005. Gould
MK, et al. Ann Intern Med. 1999.
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Conclusions

• PE is a common complication seen in hospitalized
  pts.
• Clinical presentation of PE is nonspecific and
  difficult to interpret.
• There are many diagnostic tools that complement
  clinical assessments.
• To better improve early diagnosis of PE,
  preventive measures should be in place that
  counter the risk factors, and clinicians should
  have a greater awareness for early signs/symptoms
  of PE.

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References

• Laack TA, Goyal DG. Pulmonary embolism an
  unsuspected killer. Emerg Med Clin North Am. 2004
  Nov 22(4) 961-983.
• Goldhaber SZ. Pulmonary Emoblism. Zipes DP, Libby
  P, Bonow RO, Braunwald E eds Braunwalds Heart
  Disease A Textbook of Cardiovascular Medicine.
  7th ed. Philadelphia, Elsevier, 2005, chapter 66.
  
• Godleski JJ Pathology of deep vein thrombosis
  and pulmonary embolism. In Godhaber SZ ed
  Pulmonary Embolism and Deep Vein Thrombosis.
  Philadelphia, WB Saunders, 1985, p. 17.
• Goldhaber SZ, Visani L, De Rosa M, for ICOPER
  Acute pulmonary embolism Clinical outcomes in
  the International Cooperative Pulmonary Embolism
  Registry (ICOPER). Lancet 3531386, 1999.
• Miniati M, Prediletto R, Fromichi B, et al.
  Accuracy of clinical assessment in the diagnosis
  of pulmonary embolism. Am J Respir Crit Care Med
  1999159866.
• Tapson V. Pulmonary Embolism. Goldman L, Ausiello
  D eds CECIL Textbook of Medicine. 22nd ed.
  Philadelphia, WB Saunders, 2004, chapter 94.
• Gould MK, Dembitzer AD, Doyle RL, et al Low
  molecular weight heparins compared with
  unfractionated heparin for treatment of acute
  deep venous thrombosis A meta-analysis of
  randomized, controlled trials. Ann Intern Med
  130800, 1999.
• Bounameaux H, Perrier A. Diagnosis of pulmonary
  embolism in transition. Curr Opin Hematol. 2006
  Sep 13(5) 344-50.
• Tai MRM, Atwal AS, and Hamilton G Modern
  management of pulmonary embolism, Br J Surg
  86853, 1999.