lecture 3 Flashcards
(30 cards)
What are the two most common types of venous thromboembolism (VTE)?
Deep vein thrombosis (DVT) and pulmonary embolism (PE).
How does a pulmonary embolism (PE) occur?
A blood clot breaks loose (embolises) and travels to the pulmonary circulation, blocking blood flow.
What are the components of Virchow’s Triad, summarising VTE pathophysiology?
Venous stasis, endothelial injury, and hypercoagulability.
What are the long-term complications of VTE?
Post-thrombotic syndrome (PTS) and chronic thromboembolic pulmonary hypertension (CTEPH).
Name three common risk factors for VTE.
Obesity, hospitalisation, and surgery with general anaesthesia lasting >90 minutes.
How does increasing age affect VTE incidence?
The incidence rises significantly, reaching ~1/100 in patients over 80 years old.
What are the classic signs and symptoms of DVT?
Leg pain, swelling, tenderness, discolouration, and pitting oedema.
What are the common symptoms of a pulmonary embolism?
Shortness of breath, chest pain, haemoptysis, tachycardia, and hypotension.
What are some atypical presentations of VTE?
Bilateral leg swelling, asymptomatic clots (e.g., found on cancer staging CT), or VTE at unusual sites (e.g., cerebral veins).
What are the key aims of clinical and laboratory assessment in suspected VTE?
To confirm the presence of VTE, identify the underlying cause, assess contraindications to anticoagulation, and address other clinical considerations.
Which clinical scoring system is commonly used to assess DVT risk?
The two-level DVT Wells score
What is the significance of a Wells score ≥2 for DVT?
It indicates that DVT is likely, warranting further investigation.
What is the initial confirmatory test for DVT diagnosis?
Proximal leg vein ultrasound
When is a D-dimer test useful in suspected DVT?
To rule out DVT in patients with a low Wells score and no other risks.
What are potential causes of elevated D-dimer levels aside from VTE?
Infection, inflammation, malignancy, pregnancy, and recent surgery.
What imaging is used to confirm pulmonary embolism?
CT pulmonary angiography (CTPA) or ventilation-perfusion (V/Q) scan.
How does heparin work as an anticoagulant?
It enhances antithrombin’s inhibition of clotting factors, particularly factor IIa (thrombin) and Xa.
What is the mechanism of action of warfarin?
It inhibits vitamin K epoxide reductase, reducing the synthesis of clotting factors II, VII, IX, and X.
Name two advantages of direct oral anticoagulants (DOACs) over warfarin.
Fixed dosing with no routine monitoring and lower risk of intracranial bleeding.
Why is low molecular weight heparin (LMWH) preferred during pregnancy?
It does not cross the placenta and is safer for the fetus.
How is warfarin’s anticoagulant effect monitored?
Using the international normalised ratio (INR).
What is the standard duration of anticoagulation for provoked VTE?
Three months.
When might indefinite anticoagulation be considered for VTE?
For unprovoked VTE or when persistent significant risk factors (e.g., cancer) are present
What anticoagulants are first-line for VTE treatment?
Direct oral anticoagulants (DOACs), such as rivaroxaban or apixaban.
