Thrombosis + RF Flashcards
what is an arterial thrombosis, causes, RF’s and treatment
atherosclerosis of the vessel wall - - rupture of the plaque then platelet clog
smoking, hypertension, age, diabetes
platelet aggregation and platelet thrombi = vessel occlusion antiplatelet drugs such as aspirin
what is the pathogenesis of venous thrombosis
venous stasis
hypercoaguable states
what are thrombi clots made from
fibrin clots with a lesser role for platelet accumulation and aggregation
what is the treatment of venous thrombosis
anti-coagulation drugs
what is the most common venous thrombus
DVT
which type of DVT can cause sudden death
venous thromboembolism
what are the risk factors of DVT or PE
active cancer, dehydration, surgery, major trauma
obesity
what are the causes of VTE
balance is tipped in the blood between pro-coagulant and anti-coagulant
Virchow triad - stasis, vessel wall injury, hyper coagulability
what are examples of anticoagulant proteins
protein C, S, antithrombin 3, fibrinolytic system
what is the treatment for VTE
injection of LMW heparin or compression stockings - keeps pressure gradient in legs
anti Xa and antithrombin IIa
which drugs is used in VTE which affects Xa but not thrombin and vice vera
fondaparinux = Xa inhibitor
dabigatran = IIa (thrombin) inhibitor
what are the three methods of diagnosis of VTE
exclusive tests - through clinical assessment
wells score / D dimer test
ultrasound scanning - CT or VQ scan
what does the wells score and D dimer test measure for
low wells score means low chance VTE
elevated d dimer = active coagulation process and fibrinolytic system, has broken down
what does a VQ scan do
measure of ventilation perfusion mismatch
what is the management of first time VTE
warfarin
what is thrombophilia
familial or acquired disorder of haematological homeostasis likely to predispose thrombosis
imbalance weighted towards clotting
what are some examples of heritable types of thrombophilia
antithrombin deficiency
protein c/s deficiency (loss of natural anticoagulant)
dysfibrinoganaemia - dysfunctional fibrinogen molecule
what is an examples of acquired thrombophilia
antiphospholipid syndorme
what does antithrombin work against
factor Xa and thrombin
how does protein C affect thrombin
thrombin binds to thrombomodulin which activates protein C - this inhibits F Va and VIIIa
what is the function of protein S
cofactor for the effects of activated protein C
what do protein C / S require before activation
require Vit K for synthesis in the liver
what is the most common acquired polymorphism producing anticoagulant deficiency
factor V leiden
what is factor V leiden polymorphism and mechanism
most common familial thrombophilia
F V leiden is resistant to protein C and can’t be broken down = greater risk of VTE
single point mutation of G to A
what does a mutation in prothrombin 20210A result in
increased prothrombin levels which causes 3x risk of VTE
what is antiphopholipid syndrome
most common acquired thrombophilia
antiphospholipid antibodies with increased risk of thrombosis and recurrent foetal loss
what disease has lupus anticoagulant
antiphospholipid syndrome
what is heparin and the difference in subtype use
IV anticoagulant - activates antithrombin and inactivates FXa and FIIa (thrombin)
unfractional heparin (UFH) - natural form
LMWH - less adverse affects and longer half life
how do you monitor effects of UFH vs LMWH
UFH - APTT
LMWH - FXa assay
what is the risk of using heparin as treatment
heparin induced thrombocytopenia - use protamine sulphate to resolve
