Lecture 10 - Thrombosis And Embolus Flashcards
What is a thrombus?
Formation of a solid mass of blood WITHIN the circulatory system
What is a clot?
A mass of blood OUTSIDE the vessel wall
Are thrombus and clot interchangeable terms?
NO
THROMBUS = solid mass INSIDE vessel
CLOT = mass of blood OUTSIDE vessel
What is Virchow’s Triad?
The 3 main factors needed for a thrombus to occur
What are the 3 factors of Virchow’s triad that can cause thrombus formation?
Abnormal:
Vessel wall
Blood flow
Blood components
How can the endothelium of blood vessels be damaged?
Atheroma
Inflammation (vasculitis)
Direct injury
Damage to heart (MI, Aortic valve stenosis)
What does Transmural mean?
Spanning the full thickness of the wall
What can cause stasis (slowing) of the blood?
Narrowing of vessels
Immobility
Low blood pressure
What can cause narrowing of blood vessels leading to stasis?
Stenosis
Atherosclerosis
How does immobility lead to stasis?
Skeletal muscle contraction not contributing to squeezing blood to heart
What can cause turbulent blood flow in the heart? (Healthy flow is laminar flow)
Defects in wall and heart valves
Atrial fibrillation
Dead cardiac muscle
What is the technical term for the blood being sticky?
It is in a hypercoagulable state
Who are more at risk of stasis
Smokers
Pregant/postpartum
COVID-19 patients
Why are smokers at risk of hypercoagulable blood?
More factor XII
Why are pregnant women more at risk of hypercoagulable blood?
More fibrinogen
Why are COVID-19 patients more at risk of hypercoagulable blood?
More cytokines
What are the properties of a Arterial Thrombus?
Pale
Granular
Low cell content (mainly platelets and fibrin)
Lines of Zahn
What cause the Iines of Zahn in an Arterial thrombus?
Layering of platelets, fibrin and RBCs
Why are venous thrombi redder than arterial thrombi?
Higher cell content
They are also softer
What is the function of Tissue plasminogen activator?
Converts Plasminogen to plasmin
If somebody has issues with Thrombi, what type of drug can be given?
Recombinant Tissue plasminogen activator
Why does giving streptokinase/recombinant tissue plasminogen activator help deal with a thrombus?
Increases Fibrinolysis and breaks down tthe fibrin dissolving the thrombus
More plasminogen → plasmin
What is the lysis outcome of a thrombus?
When fibrinolysis breaks down the thrombus (must be small) and blood flow restablished
What is propagation outcome of Thrombosis?
Progressive spread of thrombosis through the body
If a Thrombus propagates anterograde what does this mean?
Spreads proximally in the veins