Thrombosis and risk factors for thrombosis Flashcards
1
Q
Arterial thrombosis
A
- Atherosclerosis of the vessel wall, followed by rupture of atheromatous plaques
- Associated with endothelial injury
- Risk factors: smoking, hypertension, diabetes, obesity
- Treatment: antiplatelet drugs e.g. aspirin
2
Q
Venous thrombosis
A
- Venous stasis – abnormal flow
- Hypercoagulable states – abnormalities cause it to become more clottable
- Thrombi - composed of fibrin clots with a lesser role for platelet accumulation and aggregation
- Treatment: anticoagulant drugs
3
Q
DVT
A
- Most common venous thrombus
- 80% of DVTs are clinically silent
- swelling and pain in the leg; often with dusky cynotic changes, temperature raised
4
Q
VTE (venous thromboembolism)
A
- Piece of clot moves off to the lung – present with sudden death (20% of PE)
5
Q
Risk factors for VTE
A
- Active cancer/treatment
- Age>60
- Dehydration
- Medical comorbidities
- BMI>30
- Surgery, major trauma
6
Q
VTE and coagulant proteins
A
- VTE occurs when the balance of pro-coagulant proteins and anti-coagulants is tipped (Loss of AC’s)
- Anticoagulant proteins = protein C, protein S, anti-thrombin III, fibrinolytic system
7
Q
VTE – prophylaxis
A
- Injection of LMW heparin or compression stockings
- Do not treat if they have risk of bleeding
- Oral anti-coagulants - direct inhibitors = Rivaroxaban, Apixaban.
Dabigatran (following ortha surgery)
8
Q
Low dose LMWH
A
- indirect anticoagulants, most common in hospitals – anti-Xa and anti-thrombin (IIa) activity – e.g. Tinzaparin
9
Q
Diagnosis of VTE
A
- Exclusion tests - clinical assessment + blood tests
- Wells score + D dimer
- Ultrasound scanning
10
Q
Wells score
A
- Combines risk factors, symptoms and signs
- Low Wells score, negative D-dimer test = no PE or VTE
- Intermediate Wells score or positive D-dimer test = further imaging
- Elevated D dimer = coagulation process is active and clot is being broken down
11
Q
Ultrasound scanning
A
- Looking for non-compressibility of vein
- CT pulmonary angiogram (spiral CT) = chest contrast to look at blood vessels: filling defects in PE patient
- VQ (ventilation perfusion) scan = compares radio isotopic imaging of vent and perf - look for mismatch present in VTE
12
Q
Management of VTE
A
- First episode of proximal DVT or PE - treat for 3-6 months, For warfarin target INR = 2.5
- Recurrent VTE on therapeutic anticoagulation - increase target INR to 3.5 for warfarin
13
Q
Thrombophilia
A
- Familial or acquired disorders of the haemostatic mechanisms which are likely to predispose to thrombosis
14
Q
Heritable types of Thrombophilia
A
- Antithrombin deficiency
- Protein C deficiency
- Protein S deficiency
- Activated protein C deficiency/FV Leiden – common genetic polymorphism
- Dysfibrinogenaemia – dysfunctional fibrinogen molecule
- Prothrombin 20210A – gene variant; common polymorphism
15
Q
Acquired thrombophilia
A
- Antiphospholipid syndrome
- Some blood count abnormalities e.g. myeloproliferative disorders
