VTE Flashcards

1
Q

Where do thrombi form

A

USually at site of valves

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2
Q

How does a Thrombus form

A

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

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3
Q

Consequences of thrombus formation in a vein

A

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

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4
Q

Consequences of emboli

A

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

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5
Q

Risk factors for thrombus (Virchow’s triad)

A

Stasis
Hypercoagulable state
vessel wall injury

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6
Q

What increases risk of hyper coagulable state

A
Oestrogen therapy (hrt, COC)
Pregnancy
Sepsis
Malignancy
Congestive heart disease
Factor V Lieden (thrombophilia)
Antiphospholipid/lupus anticoagulant
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7
Q

What increases risk of stasis of blood

A
Age 
Venous insufficiency or varicose veins 
Obesity 
Immobility 
Continuous travel 
Hospitalisation
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8
Q

What increases vessel wall injury

A

Trauma or surgery

Indwelling venous catheters

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9
Q

How to take a history for VTE

A

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

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10
Q

Presenting complaint of DVT

A
Unilateral localised pain (throbbing) in one leg 
Oedema of leg 
Calf swelling/oedema 
Tenderness of lower limb 
Skin changes (redness, warmth)
Distension of legs
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11
Q

Diagnostic tool for suspected DVT

A

Wells score

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12
Q

What test for suspected DVT

A

D-dimer

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

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13
Q

When is d-dimer useful and not useful

A

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

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14
Q

When would you request a doppler ultrasound

A

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

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15
Q

When should d-dimer be used

A

Useful for excluding patients with a low probability of DVT

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16
Q

What is May-Thurner syndrome

A

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

17
Q

If there is an unprovoked DVT what would you do

A

CT

18
Q

How to emboli travel from leg to lung

A

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

19
Q

What is a saddle embolism

Consequence of this

A

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

Near-immediate death

20
Q

Presenting complaint of Pulmonary embolism

A
Dyspnoea or tachypnoea
Pleuritic chest pain 
Signs of Dot 
Cough
Fever
haemoptysis 
Substernal chest pain
21
Q

Diagnostic tools in PE

A

Wells score for PE (2-tier)

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

22
Q

What happens if Wells score for PE> 4

A

Hospital admission for CT pulmonary angiography (CTPA)

If CTPA not immediately available give anticoagulation

23
Q

What happens if wells score for PE<4

A

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

24
Q

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

A

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
25
Q

Can be ECG be used to diagnose PE

A

no

26
Q

What findings can be seen in PE

A

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

27
Q

What is T wave inversion in leads V1-V4 indicate

A

Right ventricular strain

28
Q

What is right bundle branch block on ECG indicative of

A

right ventricular strain

29
Q

Classification of a massive PE

A

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

30
Q

classification of sub-massive PE

A

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

31
Q

Classification of low risk PE

A

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

32
Q

Low risk PE presentation, bbs and ECG

A

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.

33
Q

Sub-massive PE presentation, obs and ECG

A

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.

34
Q

Massive PE presentation, obs and ECG

A

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.