VTE

Question 1

Where do thrombi form

Answer 1

USually at site of valves

Question 2

How does a Thrombus form

Answer 2

Valves become a site of turbulent flow leading to thrombus formation. Valves can be damaged by trauma, stasis and occlusion

Once formed a thrombus grows by successive adherence of platelets and fibrin

Question 3

Consequences of thrombus formation in a vein

Answer 3

1) lysis and resolution: if small thrombus resolves (fibrinolytic action)
2) Organisation: scar tissue obliterates lumen and blocks it so blood flows through collateral vessels
3) Recanalisation: leads to scar formation and residual thrombus in lumen
4) embolism: fragmentation of thrombus leads causes embolus to travel to vessel

Question 4

Consequences of emboli

Answer 4

1) Often numerous small emboli may not affect patient and cause damage gradually, resulting in idiopathic pulmonary hypertension.
2) Larger emboli may cause shortness of breath and chest pain; patient is likely to seek medical attention and these may require treatment or resolve on their own.
3) Long emboli which lodge at bifurcation of pulmonary vessels leading to acute outcome e.g. death

Question 5

Risk factors for thrombus (Virchow’s triad)

Answer 5

Stasis
Hypercoagulable state
vessel wall injury

Question 6

What increases risk of hyper coagulable state

Answer 6

Oestrogen therapy (hrt, COC)
Pregnancy
Sepsis
Malignancy
Congestive heart disease
Factor V Lieden (thrombophilia)
Antiphospholipid/lupus anticoagulant

Question 7

What increases risk of stasis of blood

Answer 7

Age 
Venous insufficiency or varicose veins 
Obesity 
Immobility 
Continuous travel 
Hospitalisation

Question 8

What increases vessel wall injury

Answer 8

Trauma or surgery

Indwelling venous catheters

Question 9

How to take a history for VTE

Answer 9

HPC
SOCRATES
PMH- prior VTE, inflammatory disease, malignancy, thrombophilia
PSH- recent surgery or hospital admission?
Medications- anything with oestrogen, prior need for anticoagulation
Obstetric history- pregnancy, termination, with in past 6 weeks
family history- and VTE or thrombophilia
Travel history- Travel >3h in past 4 weeks
SH- family, dependents, carers, house, smoking and alcohol,
ICE

Question 10

Presenting complaint of DVT

Answer 10

Unilateral localised pain (throbbing) in one leg 
Oedema of leg 
Calf swelling/oedema 
Tenderness of lower limb 
Skin changes (redness, warmth)
Distension of legs

Question 11

Diagnostic tool for suspected DVT

Answer 11

Wells score

Question 12

What test for suspected DVT

Answer 12

D-dimer

-Measures a degradation product released by lysis of a cross-linked fibrin clot

Question 13

When is d-dimer useful and not useful

Answer 13

D dimer should not be done In those with a high clinical probability of VTE

A negative d-dimer can exclude patients with a low probability of PE

Question 14

When would you request a doppler ultrasound

Answer 14

Wells score > or equal to 2, high clinical suspicion or a low Wells score but positive D-dimer

Question 15

When should d-dimer be used

Answer 15

Useful for excluding patients with a low probability of DVT

Question 16

What is May-Thurner syndrome

Answer 16

Compression of left common iliac vein by the right common iliac artery causes a DvT to form

Question 17

If there is an unprovoked DVT what would you do

Answer 17

CT

Question 18

How to emboli travel from leg to lung

Answer 18

Travel up IVC through the right atrium through the right ventricle and into the pulmonary artery

Question 19

What is a saddle embolism

Consequence of this

Answer 19

A large embolus that straddles the bifurcation of the pulmonary trunk, extending into both the right and left pulmonary arteries

Near-immediate death

Question 20

Presenting complaint of Pulmonary embolism

Answer 20

Dyspnoea or tachypnoea
Pleuritic chest pain 
Signs of Dot 
Cough
Fever
haemoptysis 
Substernal chest pain

Question 21

Diagnostic tools in PE

Answer 21

Wells score for PE (2-tier)

PE rule-out criteria (PERC) where clinical suspicion is low (negative d-dimer <15% chance)

Question 22

What happens if Wells score for PE> 4

Answer 22

Hospital admission for CT pulmonary angiography (CTPA)

If CTPA not immediately available give anticoagulation

Question 23

What happens if wells score for PE<4

Answer 23

D dimer within 4 hours at gP or send to hospital

If no. d dimer available consider interim anticoagulation

D dimer positive: CTPA (CT pulmonary angiography)

D dimer negative: its not a PE

Question 24

If pt can’t receive contrast for CTPA egg, for renal failure of anaphylactic contrast allergy - what to use

Answer 24

V/Q scan used.

• Radioactive isotopes delivered by inhaled gas
• Ventilation (v) shows how well air reaches the lung parenchyma
• Perfusion (q) shows how well blood circulates in the lung parenchyma

Question 25

Can be ECG be used to diagnose PE

Answer 25

no

Question 26

What findings can be seen in PE

Answer 26

Sinus tachycardia
Dominant R wave in lead V1
T wave inversion in leads V1-v4 or right bundle branch block
Classical ECG finding of a deep, slurred S wave in lead I with a Q wave and T wave inversion in III (S1 Q3 T3) is rare in PE- this indicates cor pulmonale

Question 27

What is T wave inversion in leads V1-V4 indicate

Answer 27

Right ventricular strain

Question 28

What is right bundle branch block on ECG indicative of

Answer 28

right ventricular strain

Question 29

Classification of a massive PE

Answer 29

acute PE with sustained hypotension (systolic <90mmHg) or decrease in baseline SBP of 40mmHg or more than 15 mins or persistent bradycardia <40bpm)

Question 30

classification of sub-massive PE

Answer 30

Acute PE without hypotension
Signs of right ventricular (RV) dysfunction or myocardial necrosis including:
-Abnormalities on echocardiography (see notes)
-ECG changes: RV strain, ischemic changes, S1 Q3 T3 pattern
-Elevated troponins

Question 31

Classification of low risk PE

Answer 31

Acute PE without the clinical markers that define massive or sub-massive pulmonary embolism

Question 32

Low risk PE presentation, bbs and ECG

Answer 32

linical presentation: pleuritic chest pain, shortness of breath, clinical signs of DVT (calf swelling) most likely. Could have any other symptom listed on slide 28. Asymptomatic is also important- don’t forget!
Observations: Tachycardia is most common.
ECG: Sinus tachycardia might be the only abnormality. The ECG might be normal.

Question 33

Sub-massive PE presentation, obs and ECG

Answer 33

Clinical presentation: this patient is likely to be feeling very unwell- pleuritic chest pain, shortness of breath, clinical signs of DVT (calf swelling) plus other symptoms.
Observations: Tachycardia most likely. Not significantly hypotensive.
ECG: Changes consistent with right ventricular strain and ischaemic changes due to impaired oxygenation of the heart muscle. S1Q3T3 pattern is possible.

Question 34

Massive PE presentation, obs and ECG

Answer 34

Clinical presentation: clinical presentation of PE with possible signs of DVT. Patient is likely to have symptoms suggestive of haemodynamic compromise (e.g. episode of syncope, loss of consciousness).
Observations: Tachycardia or severe bradycardia. Patient has significant hypotension (systolic <90mmHg or reduced significantly for at least 15 mins).
ECG: same changes as seen in sub-massive PE. May be more likely to have cor-pulmonale.