Thrombosis – Haemostasis in the Wrong Place
Topics we’ll explore include:
Consequences of venous thrombosis and treatments
Thrombosis and the role of platelets and coagulation factors
The role of the endothelium in thrombosis and thrombolysis
The differences between venous and arterial thrombosis
Which components of Virchow's triad contribute to arterial and venous
thrombosis
If you cut your knee and bleed you’ll get haemostasis which is normal
If you start clotting in your artery (e.g. brain)-> thrombosis -> dangerous (as can lead
to infarct).
Blood clots prevent blood loss. Inflammation activates coagulation and coagulation
promotes inflammation so they are linked very closely.
Coagulation is therefore an immunological response (you close up wound to prevent
infection).
In very simple terms, a blood clot consists of only two things, one of which is
fribrinogen and when this is cleaved by thrombin it becomes fibrin.
The other part is platelets which become activated and aggregate together.
Anti-coagulants STOP blood from clotting
“Clot busters” undo a clot
Arterial and Venous Thrombosis
Where clots happen determines what happens to your body.
Arterial thrombosis mostly result from atheroma rupture this ends up blocking
downstream smaller arteries which stop blood flow and can cause an infarction (MI
or stroke) as oxygenated blood cannot reach tissue.
, Venous thrombosis result from stasis or a hypercoagulant state. If you have a clot
blocking flow you will get a back pressure causing oedema. If it dislodges
(embolism), as blood is going back to your heart it will eventually end up moving into
the RV and get stuck in a the pulmonary artery or further smaller arteries in the
lungs.
Platelets and Coagulation:
Platelets and coagulation are activated by the similar things in different ways, this is
where we get the idea of primary and secondary haemostasis.
The activation of platelets and fibrinogen is by tissue damage/inflammation but this
is done in different ways (triggering mechanisms different).
Coagulation and Fibrinolysis:
Fibrinolysis (thrombolysis) is getting rid of the clot, it involves an enzyme plasmin
cleaving fibrin. D-dimers are just fragments of fibrin which tell you a clot has
happened somewhere in the body.
Coagulation is a dynamic process, we are constantly clotting and unclotting
(coagulation and fibrinolysis).
Our natural endothelial cells in blood vessels are trying to prevent clotting.
Underneath the endothelial cells is tissue factor (initiates clotting) and von
Williebrand factor (activates platelets).
Topics we’ll explore include:
Consequences of venous thrombosis and treatments
Thrombosis and the role of platelets and coagulation factors
The role of the endothelium in thrombosis and thrombolysis
The differences between venous and arterial thrombosis
Which components of Virchow's triad contribute to arterial and venous
thrombosis
If you cut your knee and bleed you’ll get haemostasis which is normal
If you start clotting in your artery (e.g. brain)-> thrombosis -> dangerous (as can lead
to infarct).
Blood clots prevent blood loss. Inflammation activates coagulation and coagulation
promotes inflammation so they are linked very closely.
Coagulation is therefore an immunological response (you close up wound to prevent
infection).
In very simple terms, a blood clot consists of only two things, one of which is
fribrinogen and when this is cleaved by thrombin it becomes fibrin.
The other part is platelets which become activated and aggregate together.
Anti-coagulants STOP blood from clotting
“Clot busters” undo a clot
Arterial and Venous Thrombosis
Where clots happen determines what happens to your body.
Arterial thrombosis mostly result from atheroma rupture this ends up blocking
downstream smaller arteries which stop blood flow and can cause an infarction (MI
or stroke) as oxygenated blood cannot reach tissue.
, Venous thrombosis result from stasis or a hypercoagulant state. If you have a clot
blocking flow you will get a back pressure causing oedema. If it dislodges
(embolism), as blood is going back to your heart it will eventually end up moving into
the RV and get stuck in a the pulmonary artery or further smaller arteries in the
lungs.
Platelets and Coagulation:
Platelets and coagulation are activated by the similar things in different ways, this is
where we get the idea of primary and secondary haemostasis.
The activation of platelets and fibrinogen is by tissue damage/inflammation but this
is done in different ways (triggering mechanisms different).
Coagulation and Fibrinolysis:
Fibrinolysis (thrombolysis) is getting rid of the clot, it involves an enzyme plasmin
cleaving fibrin. D-dimers are just fragments of fibrin which tell you a clot has
happened somewhere in the body.
Coagulation is a dynamic process, we are constantly clotting and unclotting
(coagulation and fibrinolysis).
Our natural endothelial cells in blood vessels are trying to prevent clotting.
Underneath the endothelial cells is tissue factor (initiates clotting) and von
Williebrand factor (activates platelets).
