Vascular Flashcards
Define a DVT
The formation of a blood clot in the deep veins of a limb, most commonly affecting those of the legs or pelvis.
What are the 3 components of Virchow’s triad?
- Stasis of blood flow
- Endothelial injury
- Hypercoagulability
What is a provoked DVT?
Occurs in the presence of risk factors (inherited or acquired)
What is an unprovoked DVT?
Occurs in the absence of a risk factor.
Are provoked or unprovoked DVTs more common?
Provoked (80%)
What is Virchow’s triad?
3 factors that are critically important in the development of venous thrombosis
Give some acquired risk factors for a DVT
- Surgery
- Malignancy
- Pregnancy
- COCP
- Smoking
- HRT
- Obesity
- Immobilisation >3 days (e.g. post-surgical)
- Long haul flights
- Previous VTE
- Chronic medical conditions (e.g. heart disease, endocrine)
- Increased age
- Acute infections
Which surgeries are particularly risky for DVTs?
Orthopaedic, abdominal and pelvic (risk increased with length of procedure)
Which stage is pregnancy is the biggest risk for DVTs?
Post-partum
What are some inherited risk factors for DVTs?
- First degree relative with a history of VTE
- Thrombophilias
- Antiphospholipid syndrome
- Factor V Leiden
What is Factor V Leiden?
A mutation in human factor V which causes a state of hypercoagulability.
Due to this mutation, protein C (an anticoagulant protein that usually inhibits the pro-clotting activity of factor V) is unable to work.
What is antiphospholipid syndrome?
An autoimmune disease (mostly affects young women). The body makes antiphospholipid antibodies which affect the nomral clotting process, leading to dangerous clotting in arteries and veins.
What is a thrombophilia?
Thrombophilia is a blood disorder that makes the blood in your veins and arteries more likely to clot.
What is the most common inherited form of thrombophilia?
Factor V Leiden
Give some symptoms and signs of a DVT
- Unilateral leg pain and swelling
- Pitting oedema
- Tenderness over deep veins of leg
- Heavy ache in affected area
- Warm skin in area of clot
- Pain may be worse when foot is dorsiflexing
- Asymptomatic
What is the standard diagnostic test for a DVT?
Duplex ultrasound
What test can be used for initial screening in a DVT?
D-dimer
What does a positive d-dimer test mean?
A positive test means the D-dimer level in the body is higher than normal and suggests someone might have blood clots.
What is Well’s score?
The Wells score is a number that reflects your risk of developing deep vein thrombosis
How many points in the Well’s score indicates a likely DVT?
2 points or more
What bloods should be done in the context of a DVT?
- D dimer (urgent)
- FBC
- U&Es
- LFTs
Pathway for investigations in the context of DVT
What is the purpose of a duplex ultrasound?
duplex ultrasound is a test to see how blood moves through your arteries and veins.
Duplex US example with a DVT:
What are the 3 main goals when treating a DVT?
- Prevent clot from getting bigger
- Prevent clot from breaking loose and travelling to lungs
- Reduce chances of another DVT
What is the 1st line pharmacological treatment for anyone with a DVT/PE (as long as no contraindications)?
DOACs e.g. apixaban, rivaroxaban, edoxaban
If DOACs are contraindicated, what is given instead in the context of a DVT/PE?
Warfarin
Which patient population are DOACs contraindicated in?
Patients with severe hepatic disease
What class of drug are enoxaparin, tinzaparin and dalteparin?
LMWH
What type of anticoagulant is given prior to having an USS in a DVT?
LMWH
N.B. LMWH have 2 doses – prophylactic and treatment dost (look at local trust guideline)
What is the target INR on warfarin?
2-3
What is the recommended length of treatment for a provoked 1st VTE (with risk factors)?
3 months
What is the recommended length of treatment for an unprovoked VTE?
Lifelong
What are the 3 main complications a patient can develop following a DVT?
- PE
- Post-thrombotic syndrome
- Bleeding associated with anticoagulation
What % of people with an untreated DVT go on to develop a severe PE?
10%
How does a DVT lead to a PE?
A piece of the blood clot breaks off and travels through the blood and the right side of the heart into the pulmonary arteries, increasing pulmonary arterial pressure
How may a small PE present?
Often asymptomatic
How may a medium size PE present?
- SOB
- Pleuritic chest pain
- SOB
- Tachycardia