Clinical Aspects Of Thrombosis Flashcards
What is thrombosis?
Inappropriate blood coagulation within a vessel is called thrombosis
What are the two types of thrombosis?
- ) In arterial circulation:
- High pressure system
- Platelet rich - ) In the venous circulation:
- Low pressure system
- Fibrin rich
What are the types of thrombosis in Arterial and Venous thrombosis (2 each)
ARTERIAL:
1.) Myocardial Infarction
2.) Thrombotic Stroke
VENOUS:
1.) Leg deep vein thrombosis (MI)
2.) Pulmonary Embolism (PE)
What type of drugs do we treat thrombosis with?
- Arterial thrombosis - ANTIPLATELET drugs
* Venous thrombosis - ANTICOAGULANT drugs
Describe the formation of arterial thrombosis
• Atherosclerotic plaque
- Initial fatty streak
- Plaque enlargement
- Turbulence due to protrusion in lumen
- Loss of endothelium and collagen exposure
- Platelet activation and adherence
- Fibrin meshwork deposition and red cell entrapment
- More turbulence, more platelet and fibrin deposition
- Thrombus of layers and platelets, fibrin and red cells
What are the risk factors for Arterial Thrombosis?
MAIN: • Family history • Diabetes Mellitus • Hypertension • Hyperlipidaemia • Smoking • Atrial fibrillation for stroke
OTHER:
• Male
• Polycythaemia, gout
• High FVIII
How do we manage Arterial thrombosis
- Stop smoking
- Exercise
- Diet
- Weight Control
• Antithrombotics: primary prevention in patients with atrial fibrillation
What drugs are used to treat arterial thrombosis
Antiplatelets
- Aspirin
- Clopidogrel
How does Aspirin work?
- Inhibits COX1 which inhibits the production of thromboxane
- Inhibition lasts for lifetime of platelet (1 week)
- Risk reduce of non fatal vascular event by 30% and fatal vascular event 15%
How does Clopidogrel work?
- Irreversible ADP mediated platelet inhibition
- Inhibition lasts for lifespan of platelet (1 week)
- Decreases MI risk 18%
- Risk of coronary stent thrombosis/recurrent stroke by 30%
Thrombolysis is another tmt option for AT. What are the indications for this?
- MI
- Stroke within 3 hours
- Life-threatening PE
Drugs used in thrombolysis
- ALTEPLASE
- STREPTOKINASE
- SIDE EFFECT: BLEEDING
What are the invasive procedures for AT
• Percutaneous coronary intervention (cardiac stenting)
- Combined with 3-12 month aspirin and clopidogrel
• REHABILITATION IN ALL CASES:
- Stroke: swallowing, malnutrition, mobilisation
Describe secondary preventative measures for Arterial Thrombosis
- LIFESTYLE: • Exercise • Stop smoking • Diet • Weight control • Safe alcohol use
- BLOOD PRESSURE CONTROL
- CHOLESTROL LOWERING
- DIABETIC CONTROL
- ANTITHROMBOTIC THERAPY IN STROKE ASSOCIATED WITH ATRIAL FIBRILATION
What is atrial fibrillation?
- Irregularly irregular heart rhythm
- 4% > 60yrs 8% > 80yrs
- Left atrial thrombus
- Embolisation leads to stroke
- Impaired cardiac output
• Treatment:
- DC cardioversion
- Heart rate control: Beta blockers, Ca channel blocker, Digoxin, AV junction ablation
- Anticoagulation
How does AF cause stroke?
- ) Blood pools in atria
- ) Blood clot forms
- ) Blood clot breaks off
- ) Blood clot travels to brain and blocks a cerebral artery causing a stroke
What is venous thrombosis?
Most VT starts as Deep Vein Thrombosis (DVT) usually in the leg
What are the two outcomes for DVT
- ) The clot from the leg breaks up and goes to the lungs, leading to a pulmonary embolism.
- This can lead to pulmonary hypertension followed by:
- chronic PE can lead to death. - ) The clot blocks the flow up the leg leading to deep vein insufficiency followed by:
- Post-thrombotic syndrome
- Leg ulcers
What are the three main risk factors for venous thrombosis1
- ) Stasis (poor blood flow)
- ) Vascular damage
- ) Hypercoagulability (contents of blood abnomal)
Name some heritable risk factors for Venous Thrombosis
- Antithrombin deficiency
- Protein C & S deficiency
- Prothrombin mutation 20210 A
Name some acquired risk factors for venous thrombosis
- Age
- Previous vte
- Malignancy
- Pregnancy
- Chemotherapy
- Obesity
- HRT
Nam some mixed risk factors for venous thrombosis
- Raised FVIII
- Raised FIX
- Raised XI
- Raised Fibrinogen
Describe preventative strategies for venous thrombosis
- Adequate hydration
- Early mobilisation
• Mechanical prophylaxis
- All surgical pts at risk of VTE
- Intermittent pneumatic compression
• Chemical prophylaxis prevents 50-70% of VTE:
- Low molecular weight heparin
- Direct oral anticoagulants
What is the risk assessment for Venous thrombosis
- NICE guidelines for adults
- Do not routinely offer pharmacological or mechanical VTE prophylaxis to patients
- All other patient must be risk assessed on admission and reassessed within 24 hours
What are the acute tmt options for VTE
- Anticoagulation
- Thrombolysis
- Thrombectomy
- Inferior vena cava (IVC) filter
What are the long-term tmt options for VTE
- Anticoagulation
* Stockings
What is the duration of the treatment of VTE
- 3 months after a first event
- Provoked events do not need anticoagulation > 3 months
- Distal DVT do not need anticoagulation > 3 months
- Consider long term anticoagulation after 1st unprovoked thrombosis
Venous thrombosis - conclusion
- Multifactorial disease
- Associated with significant mortality/morbidity
- Prevention essential, especially in hospital setting
- Treatment mainly with anticoagulants
- Optimum duration debated
- Associated with increased risk of bleeding
