Flashcards in Clinical anticoagulants Deck (47):
Why are platelets important for clotting?
They provide the phospholipid surface
Contain clotting factors
binds collagen, vWF and fibrinogen
What is the structure of serine proteases?
They have a GIa domain which is hydrophobic to bind to the phospholipid surface
what are some serine proteases?
Clotting factors II,VII,FIX,X
in brief how is the fibrin strand produced?
Prothrombin is converted to thrombin by FX.
thrombin can then convert fibrinogen to fibrin.
what are some indications for anticoagulation?
- Valvular heart disease
what factors does the CHAD 2 score take into account?
what factors does HASBLED take into account?
- abdominal, renal or liver dysfunction
- drugs/ alcohol
using the CHAD system who gets anticoagulants?
all men with a score of 1
anyone with a score of 2
why can factor 8 increase after surgery?
its an acute phase reactant
what are absolute contraindications of anticoagulants?
what are relative contraindications of anticoagulation?
Active peptic ulceration
alcohol or drug use
severe liver disease
what is unfractionated heparin?
a linear sulphated polysaccharide consisting of negatively charged glycosaminoglycans with a 1;1 raio of anti X and anti II
what is low molecular weight heparin?
Has differing Anti X and anti II ratio's
produced by depolymerisation of unfractionated heparin
how is heparin produced?f
from bovine lung/ porcine intestine
what is the MOA of heparin?
it binds to anti thrombin causing a conformational change, this increases the inhibiton of FX and thrombin
how is unfractionated heparin cleared?
what is the half life of unfractionated heparin?
how is unfractionated heparin given?
IV or sc
what is the reversal for unfractionated heparin?
how is LMWH cleared?
what is the half life of LMWH?
what is the amount of time before LMWH is peak?
how is LMWH administered?
what is the reversal for LMWH?
minimal reversal can be achieved with protamin
what people need anti Xa monitoring?
what tests will unfractionated heparin effect?
What tests will LMWH effect?
what tests will vitamin K antagonists affect?
what tests will dabigatren affect?
what are the side effects of heparin?
what do you do for heparin induced thrombocytopenia with thrombosis?
stop heparin and given danaparoid or hirudin
how does warfarin work?
Its a vitamin K antagonist
What process does vitamin K interfer with?
gamma carboxylation of GIa domain
what does gamma carboxylation of the GIa domain normally allow?
interaction with the phospholipid of platelet membranes which localises coagulation
how is warfarin initiated in patients with thrombosis?
what is warfarin dose sensitive to?
what test is warfarin monitored with?
For warfarin VTE prophylaxis what INR is ideal?
For people on warfarin due to mechanical heart valves what INR value is ideal?
for people on warfarin due to antiphospholipid syndrome what INR is a good range?
what are the side effects of warfarin?
Bleeding, skin necrosis, birth skeletal abnormalities, increased foetal loss
what does warfarin cause skin necrosis?
Due to a protein C deficiency
what does warfarin cause birth skeletal abnormalities
Lack of gamma carboxylation of bone protein takens place
how do DOAC's work?
targeted inhibition of Xa or thrombin
what tests can be done to monitor dabigatran?
what does a normal TT mean in dabigatran?
It excludes the possibility that there is any circulation