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
How can a D-dimer be used for PE?
In patients with a low to moderate suspicion of PE d-dimer has a negative predictive value of 98%
D-dimer for high clinical suspicion of PE
negative predictive value is only 70%
How to determine the probability of PE
- Modified Well’s Criteria
- Geneva Scoring System
Clinical predictions for PE
Modified Well’s Score
Case Modified Wells Score
Geneva scoring system for PE
Case
VQ scan
Case
How do we treat our patient?
Patient suddenly deteriorates
How do we treat his shock?
Treatment of massive pulmonary embolism: patients in shock
TPA AKA
Tissue Plasminogen activator (T-PA)
EKOS Catheter AKA
Catheter-directed thrombolysis
ECMO AKA
Extracorporeal membrane oxygenation
ECMO for PE
May be an option for patients who are severely unstable
Treatment option for PE for patients who are severely unstable
ECMO
EKOS catheter clinical use
can be useful particularly in patients with high-risk of bleeding
PE treatment for patients who are at a high-risk for bleeding
EKOS
Massive PE treatment for patients in shock
Thrombolytics (tissue plasminogen activator (T-PA) is the standard of care
Patient improves but returns a week later with hematemesis
Inferior vena caval filters clinical use
- Lower extremity DVT or PE in patients with contraindications to anticoagulation
- Patients with PE who have a recurrence while on anticoagulation
- certain patients with severe pHTN and PE
Inferior vena caval filters
Long-term anticoagulation options for PE
5 listed
- Warfarin
- Low molecular weight heparin
- Oral factor Xa inhibitors
- Direct thrombin initiator (dabigatran)
- Direct oral anticoagulants
Warfarin AKA
Coumadin
Warfarin considerations for PE
- needs monitoring and is somewhat difficult to control
- easily reversible
Low molecular weight heparin considerations for PE
Particularly in cancer patients
Oral factor Xa inhibitors for PE
Rivaroxaban or apixaban
Direct thrombin inhibitor for PE
Dabigatran
Dabigatran is a?
Direct thrombin inhibitor
Rivaroxaban or apixaban are?
Oral factor Xa inhibitors
Symptoms of PE
Symptoms of PE are somewhat non-specific
a high-index of suspicion is needed to make the Dx
Preferred diagnostic method for PE
CT Angiogram
it may also provide other clues/causes to the patient’s symptoms
VQ scan and venous dopplers are reserved for patients with?
contraindications to CT scan such as renal insufficiency
contraindications to CT angiogram
renal insufficiency
PE diagnosis with renal insufficiency or contraindications to CT scan
VQ scan and venous dopplers
How is d-dimer used for PE?
useful only in patients with low clinical suspicion to rule out
PE Treatment first-line therapies
- low molecular weight heparin
- oral factor Xa inhibitors
- IV unfractionated heparin
Treatment of PE in shock
Thrombolytics (tissue plasminogen activator-TPA) are reserved for patients in shock
TPA for treating PE
Reserved for patients in shock
Warfarin MOA
Vitamin K antagonist
Long-term treatment options for PE
- Warfarin
- Factor Xa inhibitors
- Direct thrombin inhibitors
Direct oral anticoagulant reversibility?
Direct oral anticoagulants are not readily reversible
