Pulmonary embolism!

GUIDELINES & KEY LITERATURE: 

  • ACP offers best practice advice in the evaluation of acute PE!
  • Wells PE score is designed to help you predict the pretest probability for PE (not diagnosis!) so it should only be used in the presence of clinical suspicion
    • Did you know there’s a Wells score for PE and another for DVT?
    • What may be BETTER than Wells? The YEARS algorithm Study!
  • If a patient is low risk by Wells criteria, then “PERC out!”
  • PESI (or the simplified sPESI) classifies 30-day mortality risk in patients with acute PE
  • CHEST guidelines for antithrombotic therapy in VTE disease can help us choose therapy type (including when to give tPA and whether to treat subsegmental PE) and long-term duration, but none of the recommendations are based on high-quality evidence

FUN FACTS!

  • You don’t have to be a radiologist to learn how to read a CT pulmonary angiogram!
  • Approximately 50% of patients with PE have no known risk factors for VTE
  • Reproducible chest pain does NOT rule out PE
  • Fat embolisms from bone marrow necrosis may be the most common cause of acute chest syndrome in adults with sickle cell disease
  • Among patients with COPD exacerbation of unknown cause, 16% had PE.
  • RIH has a PE Response Team (PERT) coordinated by the MICU (see algorithm below, which is also available on Canvas under the RIH page). 

PEARLS!

  • Most PE arise from the proximal veins in the LE, especially the iliac, femoral, and popliteal veins
  • Complete duplex US is the preferred US test for diagnosing DVT. It assesses the deep veins from the inguinal ligament to the ankle with compression performed at 2-cm intervals. 
  • D-dimer increases with age, so use an age-adjusted level for patients ≥50yo by multiplying their age by 10
    • ex: 62yo patient has D-dimer cutoff of 620
  • CT pulmonary angiography is NOT specific for PE–it simply assesses filling defects in the pulmonary vasculature. Filling defects can be seen not only in PE (both acute and chronic) but also with poor patient positioning, inadequate contrast infusion, anatomical defects, and scars. 
  • The majority of VTE can be treated with direct oral anticoagulants (DOACs) including patients with cancer (SELECT-D, Hokusai cancer study).
  • Unprovoked VTE does not warrant cancer work-up (SOME Investigators NEJM 2015).
  • Female patients with first unprovoked VTE who want to discontinue anticoagulation, can be risk stratified using the HERDOO2 calculator (Rodger 2017).

QUESTIONS TO PONDER!

  • What is the difference between massive vs submassive PE? segmental vs subsegmental? provoked vs unprovoked? acute vs subacute vs chronic?
  • What are the risk factors for VTE? Do the risk factors differ in kids? 
  • What ECG findings occur in PE? What is the most common ECG finding? 
  • How does PE lead to cardiac arrest?
  • Are there patient populations or settings in which the Wells DVT/PE scores are not validated? What about the PERC and PESI scores?
  • When should we consider getting a V/Q scan instead of (or in addition to) a CT scan? What patient population is a poor substrate for V/Q?