Title: Venous thromboembolism diagnosis
1Venous thromboembolism Diagnosis These
slides were kindly provided by AstraZeneca
2Venous thromboembolism
DVT
PE
Deep vein insufficiency
Post-thrombotic syndrome
Pulmonary hypertension
Death
Ulcus cruris
Chronic PE
3Deep vein thrombosis
Common femoral vein
Thrombus
Proximal
Knee
Distal
Veins of the leg
4Diagnosis of VTE
Clinical diagnosis often uncertain
Diagnosis should be verified objectively
- DVT ultrasonography, venography
- PE scintigram, spiral CT, angiography
5Clinical probability of VTE
- Can be assessed through prediction rules
- Not accurate enough to rule in or out the disease
- Accurate enough to
- refine interpretation of diagnostic tests
- identify a low-risk group in which the diagnostic
workup may be simplified
6D-dimer
- Specific fibrin degradation product Sign of
activated coagulation and fibrinolysis - High sensitivity for VTE (95-99) Nearly all
with VTE test positive - High negative predictive value (95-99) Normal
D-dimer excludes VTE - Low specificity Positive test does not
differentiate between VTE or other cause, e.g.
infection
7Deep vein thrombosis symptoms and signs are
unreliable
- Redness
- Pain
- Oedema/swelling
- Symptoms may be vague or absent
- Increased circumference
- Pain by palpation along the deep vein truncs
8Diagnosis of DVT - venography
9Diagnosis of DVT - ultrasonography
Reflection echoes are translated toproduce a
visual image on a monitor
Transduceremits sound waves
Receivingcrystal
Transmittingcrystal
Sound waves arereflected off internalstructures
Red blood cells
10Diagnosis of DVT - ultrasonography
- Transducer coated in gel is placed on leg
- Transducer is moved along the deep venous system
11Diagnosis of DVT - ultrasonography
- Transducer coated in gel is placed on leg
- Transducer is moved along the deep venous system
- Transducer emits sound waves
- Sound waves are reflected off internal structures
- Reflection echoes are translated to produce a
visual image on a monitor
Receivingcrystal
Transmittingcrystal
Red blood cells
A Doppler flow study, which uses emitted sound to
detect the direction, velocity and turbulence of
blood flow, is often performed in combination
with compression ultrasonography
12Compression ultrasonography
Artery
Vein
Baseline
Compression
artery
vein
13Compression ultrasonography normal veins
14Doppler ultrasonography normal veins
15Doppler ultrasonography normal veins
16Doppler ultrasonography - DVT
17Compression ultrasonography DVT
18Pulmonary embolism symptoms and signs are
unreliable
Symptoms
Signs
- Cough
- Dyspnea
- Chest pain
- Syncope
- Symptoms may be vague or absent
- Tachycardia
- Hypotension
- Hypo- or hyperventilation
- Low PaO2 normal PaCO2
- Deep vein thrombosis?
19Diagnosis of PE - pulmonary angiography
Complete obstruction of vessel or Filling defect
apparent following injection of contrast medium
Normal lung
Pulmonary embolism
20Diagnosis of PE - pulmonary scintigraphyPerfusion
imaging
Obstructed lungs
Thrombus
ProblemPerfusion abnormalities may be due to
other conditions, e.g. pneumonia
21Diagnosis of PE - pulmonary scintigraphyTwo
types of imaging
Ventilation imaging
Perfusion imaging
Thrombus
ProblemPerfusion abnormalities may be due to
other conditions, e.g. pneumonia
Benefit Eliminates abnormalities due to other
conditions
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23Diagnosis of PE - pulmonary scintigraphy
Perfusion scintigram
Mis-match
Ventilation scintigram
24Diagnosis of PE - Spiral Computed Tomography (CT)
25Diagnosis of PE - Spiral Computed Tomography (CT)