Risk stratification of PE
- Well's criteria objectifies risk of pulmonary embolism.
- PERC (pulmonary embolism rule-out criteria) is used to rule out PE in those with low pre-test probability (Wells < 3) if ALL 8 PERC criteria are true.
| Well's criteria |
PERC |
| |
age < 50 |
| Clinical s/sx of DVT (3) |
no unilateral leg swelling |
| PE is most likely diagnosis (3) |
SaO2 ≥ 95% |
| HR > 100 (1.5) |
HR < 100 |
| Immobilization x 3d or surgery in last 4wks (1.5) |
no surgery/hospitalization in last 4wks |
| Previously diagnosed DVT or PE (1.5) |
no prior VTE |
| Hemoptysis (1) |
no hemoptysis |
| Malignancy with treatment in last 6mo or palliative (1) |
no estrogen use |
CXR
- Most frequently normal, but can see Westermark's sign (wedge-shaped hyperlucency/decreased pulmonary markings: dilation of proximal pulmonary vessels and collapse of distal vessels), Hampton's hump (opacity at pleural edge 2/2 infarction)
CT angiogram
- Test of choice in most cases - sensitive and specific
V/Q scan
- Use if: pregnant/want to reduce radiation in young pts, severe renal disease (Cr > 2.0)/contrast allergy precluding contrast CT
- Still have fetal radiation with V/Q = screen pregnant women with lower extremity duplex first if leg symptoms are present
- Sensitive but less specific (false positives)
- Reports out probability of PE - low, intermediate (non-diagnostic), high.
- If chest x-ray abnormal (pulmonary edema, atelectasis, etc.), more likely to have "intermediate" read and should go for CTA instead
Anticoagulation
- Heparin
- Unfractionated - IV or subQ
- Low-molecular weight - subQ
- NOACs
- Some require LMWH/UFH bridge (dabigatran (Pradaxa))
- Apixaban (Eliquis), Rivaroxaban (Xarelto) do not require bridging
- Caution in renal insufficiency (CrCl < 30) (dabigatran most dependent on renal function; apixaban least dependent)
- Emergent/hemodynamically unstable - tPA
- Failed anticoagulation or v large clot burden - IVC filter
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last edited: March 8, 2018, 11:53 p.m. | pk: 17
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