Venous Thromboembolic Disease Flashcards
What is DVT?
Deep vein thrombosis
Formation of thrombi within the lumen of the vessels that make up the deep venous system (sites of stasis)
What is distal DVT?
Vein thrombosis distal to the popliteal pulse
What is proximal DVT?
Vein thrombosis of popliteal or femoral vein
What is PE?
Pulmonary embolism
Thromboemboli detach and travel through the right side of the heart to block vessels in the lungs
What are the three aspects to Virchow’s triad?
- Endothelial injury
- Circulatory stasis
- Hypercoaguable state
What may be causes for endothelial injury?
- Venous disorders
- Venous valvular damage
- Trauma or surgery
- Indwelling catheters
What may be the cause of circulatory stasis?
- LV dysfunction
- Immobility or paralysis
- Venous insufficiency or varicose veins
- Venous obstruction from tumour, obesity or pregancy
What may be the cause of hypercoaguable blood?
- Malignancy
- Pregancy
- Oestrogen therapy
- IBD
- Sepsis
- Thrombophilia
What are the consequences of venous thromboembolism?
- Death (PE)
- Risk of recurrence
- Post thrombotic syndrome
- Chronic thromboembolic pulmonary hypertension
- Reduced quality of life
What are the symptoms of post thrombotic syndrome?
- Pain
- Oedema
- Hyperpigmentation
- Eczema
- Varicose collateral veins
- Venous ulceration
What is chronic thromboembolic pulmonary hypertension?
A serious complication of PE
Dyspnoea and hypoxaemia progressively develop
Right heart failure can occur
The disease is caused by original embolic material being converted to fibrous tissue, which can eventually incorporate itself inot the intima and media of pulmonary arteries and cause occlusion
What are the best investigations for venous thromboembolic disease?
D-dimer - breakdown product of fibrin (so absence rules out a clot)
Ultrasound - Doppler ultrasound can view blood flow
What is a Well’s score?
A scoring system to determine probability of VTE
Which imaging techniques can be used for venousthromboembolic disease?
CT angiography - gold standard
CXR - can show infarct and usually associated pleural effusions
V/Q scan - useful in pregancy due to low radiation dose
Which types of drugs can treat DVT and PE?
- Anticoagulation
- Thrombolysis
- Analgesia
As well as drugs, what else can be used to treat DVT and PE?
- Compression stockings
- IVC filters - can capture emboli
- Screening for underlying cause - cancer, thrombophilia (tendency of blood to clot)
What are the two main drug classes used to treat VTE?
- Vitamin K antagonists (warfarin)
- Non-vitamin K antagonist oral anticoagulants (dabigatran, apixiban)
What are the pros and cons of vitamin K antagonists?
Pros
- Can be used in patients with renal impairment
- Anticoagulation can be reversed with vitamin K
Cons
- Slow onset
- Narrow therapeutic window
- Variability in individual to same doses
- Needs INR (international normalised ratio) a test to determine how long blood takes to clot
What are the pros and cons of Non-vitamin K antagonists?
Pros
- Predictable pharmological profiles
- Absence of major food/drug interactions
- Does not require INR
Cons
- No antidote
- No long-term data
- Not readily available for special circumstances such as a major bleed
NOACs (Non-vitamin K antagonists) which can be used for VTE include what?
- Dabigatran
- Apixiban
- Edoxaban
- Rivaroxiban
Which drugs can be used as an option for the prevention of venous thromboembolism in adults after surgery?
Rivaroxiban, apixiban and dabigatran
Which drug is most suitable for treating a diagnosis of acute DVT in adults or for preventing recurrent DVT/PE?
Rivaroxiban
In special cases involving IV drug users, how should VTE be treated?
Rivaroxiban or dalteparin (LWMH)