CVPR Week 6: Pulmonary embolism Flashcards
Objectives
Pulmonary embolism description
- usually refers to a blood clot which has migrated from the leg to the lung
- but can also originate from the upper extremity, pelvis or the abdominal cavity
- Also
- embolisms of air, amniotic fluid,, tumor and fat can cause similar symptoms but are much less common
Pulmonary embolism prevalence
Clinical manifestations of Pulmonary embolism
7 listed
Diagnostic testing in Pulmonary embolism
6 listed
CT angiogram of pulmonary arteries description
CT angiogram of pulmonary arteries measures?
RV dilation and specifically
RV/LV ratio and an
RV/LV > 1 is associated with RV strain and an increased risk of death
RV/LV ratio
RV/LV > 1 is associated with RV strain and an increased risk of death
Positive study of CT angiogram of pulmonary arteries
in a positive study, filling defects are seen within the pulmonary arteries
What does a CT angiogram look like?
What does an RV/LV ratio > 1 look like?
Ventilation-Perfusion scanning
VQ scan AKA
Ventilation-Perfusion scanning
VQ scan mechanism
A nuclear medicine test where radiolabled xenon is inhaled while Technectium-99 labeled colloid is injected into the venous system
VQ scan for PE
Areas in the lung which have perfusion defects without ventilation defects suggest PE
VQ scan sensitivity and specificity
Much less specific and sensitive than the CT angiogram
VQ scan clinical use
usually reserved for patients with renal failure or to diagnose chronic PE
VQ test results which are non-diagnostic of PE
can indicate normal perfusion which essentially rules out PE
VQ test results suggesting PE
Diffusion defect is suggestive of PE
Multiple perfusion defects
Lower Extremity Doppler for DVT
Case: Does this patient have risk factors for PE?
Classic risk factors for PE
3 listed
Virchow’s Triad
- Hypercoaguability
- Stasis
- Endothelial damage
Risk factors for PE
- Factor V ledien
- Prothrombin gene mutations
- Protein C and S deficiencies
- Antithrombin III deficiencies
- Cancer
- Surgeries (Particularly orthopedic)
- Neurosurgeries
- Pregnancy
- immobilization
Question
What diagnostic test for this patient?
in this case VQ scan because of the renal insufficiency!!
why not a D-dimer?
What is a D-dimer?
a quantitative measure of degraded crosslinked fibrin in the blood associated with blood clot formation
Why isn’t D-dimer very diagnostic of PE?
- Because it can be elevated in patients post-surgery, pneumonia, CHF, cirrhosis, cancer and HIV
- also it is not recommended in hospitalized patients