Atherosclerosis, Thrombosis, Embolism Flashcards
Define ‘thrombosis’
Formation of a mass (thrombus) from the constituents of blood within the vasculature during life
How does a thrombus differ from a clot?
Thrombus must form during life in the body; clots can form when blood is extracted post-mortem
What are the 3 components of Virchow’s triad?
Changes in blood flow
(stasis of blood flow causes MARGINATION of platelets)
Changes in blood coagulability
(protein C and S, antithrombin mutations)
Endothelial damage
Give some examples of hypercoaguable aquired states
Myocardial infarction Immobility Cancer Prosthesis AF Cardiomyopathy Oral contraceptive use
Arterial thrombi are red. True/False?
False
Where do arterial thrombi often lodge?
Coronary, cerebral, femoral circulations
Define ‘embolism’
Detached intravascular solid/liquid/gas mass carried distal to point of origin
Venous emboli commonly infarct peripheral circulation. True/False?
False Very rare (carried to pul circulation, more likely lodge there)
Give examples of factors causing endothelial injury
Smoking Hyperlipidaemia Hypertension Toxins Infection
Give examples of what happens due to endothelial dysfunction
Increased permeability
Macrophage + platelet adhesion and activation
Once macrophages are activated on the endothelial surface, what do they generate?
Oxidative free radicals
Cytokines
What do oxygen free radicals do to LDL?
Ingest and trap it within macrophages, forming foam cells/fatty streaks
D-dimer can both rule out and diagnose DVT. True/False?
False
What is D-dimer?
A breakdown product of fibrin
If D-dimer levels are low, a DVT is unlikely. True/False?
True
If D-dimer levels are high, a DVT is very likely. True/False?
False
D-dimer levels are raised by many things (infection, MI, surgery)
If your D-dimers are elevated, what is the next investigation for diagnosing a DVT?
(Doppler) ultrasound
CT scan if ilieo-femoral veins
If your D-dimers are low and US negative, DVT can be excluded. True/False?
True
If your D-dimers are high but US negative, DVT can be excluded. True/False?
False
Repeat US before completely excluding DVT
What is the mainstay of DVT treatment?
Anticoagulation (LMWH heparin, warfarin/NOACS)
TED compression stockings
Analgesia
Calf muscle exercises
What are the investigations of choice for PE?
D dimer
V/Q scan
CTPA (gold standard)
What is the advantage of a caval filter for acute PE?
Prevents recurrence of PE in short term
What is the drawback of a caval filter?
Increases risk of DVT - patients will require anticoagulation if long-term filter
When is warfarin contraindicated?
Pregnancy
Increased haemorrhage risk (uncontrolled drug abuse, dementia etc.)
What are the risk factors for atheroma?
Smoking, hypertension, hyperlipidaemia, DM, age, sex (males), genetics
What is the pathogenesis of atheroma?
Primary endothelial injury
Accumulation of lipids and macrophages
Formation of foam cells and fatty streak
Increased size of collagen cap
Fibrofatty plaque
Arterial wall weakness and loss of lumen patency
(Can form a collagen cap and platelet plug = THROMBUS)
What are the complications of atheroma?
Stenosis (narrowing of lumen)
Thrombosis
Aneurysm (abnormal dilatation due to weakness in wall)
Dissection (splitting within media by flowing blood)
Embolus
What are the common causes of aneurysm?
Myocytic AV Dissecting Congenital Atherosclerotic Traumatic Syphilitic
What are the common causes of dissection?
Atheroma Hypertension Trauma Coarctation Marfans Pregnancy
What do statins inhibit?
HMG-CoA reductase (reduce LDL formation)
What is metabolic syndrome?
Type 2 DM
Obesity
Hyperlipidaemia
(Predisposes you to atherosclerosis)
What score is used to calculate risk of atherosclerosis?
Assign score
What is the difference between DVT and PE?
DVT: Thrombi in venous valve pockets and sites of stasis
PE: Thromboembolus detach and travel to RHS of heart, blocking vessels in the lung
What score is used to predict the probability of DVT/PE?
Wells score
(0: D dimer)
(1-3: imaging)
What are the challenges of new forms of anticoagulation?
NOACS (e.g. rivaroxaban, epixaban, dabigatron) are irreversible, wherease VKA is
What is the treatment of choice in VTE for active cancer patients?
Fragmin
Compression stockings are the only treatment for…
Post thrombotic syndrome (a venous stasis syndrome occurring after DVT)
When are IVC filters indicated?
When anticoagulation is contraindicated
The two main complications of deep vein thrombosis (DVT) are…
PE
Post thrombotic syndrome
What are the main risk factors for VTE?
HRT Thrombophilia Pregnancy Trauma Surgery Malignancy Immobility Pulmonary hypertension Vasculitis Obesity Previous VTE
What are the two main types of DVT?
Proximal (ileo-femoral)
Distal (popliteal)
In what situation of DVT would thrombolysis be considered?
If it is ilieo-femoral veins affected
What are some common signs of DVT?
Calf warmth, tenderness, swelling, erythema, mild fever, pitting oedema
What are some differentials for DVT?
Bakers cyst
Superficial thrombophlebitis
Calf cellulitis
What are some symptoms associated with PE?
SOB (typically acute) Pleuritic chest pain Haemoptysis Leg pain/ swelling Collapse/dizziness (Pyrexia, tachycardia, hypotension)
