Arterial Thrombosis

Question 1

What is an arterial thrombi?

Answer 1

When a thrombus forms within an artery, this is known as an arterial thrombosis

Question 2

What is clot formation typically triggered by?

Answer 2

the rupture of an atherosclerotic plaque, a highly thrombotic event, with platelets rapidly recruited to the site.

Question 3

What slowly increases as the thrombus extends into the arterial lumen?

Answer 3

The fibrin content
Thus, an arterial thrombus is typically platelet-rich, fast growing, and exposed to fast blood flow

Question 4

What do AF- related thrombi closely resemble?

Answer 4

AF-related thrombi are also categorized as arterial clots, but more closely resemble ‘venous-type’ clots, fulfilling Virchow’s triad for thrombogenesis
AF-related thrombi form in low-flow, low-pressure environments, producing slow-growing, fibrin-rich clots

Question 5

What are the risk factors for arterial thrombosis?

Answer 5

Smoking
Obesity
High blood pressure
Increased levels of cholesterol
Diabetes
Increasing age
Family history
Physical inactivity
Increased concentrations of blood coagulation factors
Blood serum lipid abnormalities

Question 6

What can cause plaques to rupture?

Answer 6

Inflammation of arterial lining which exposes tissue factors, triggering clotting mechanisms and platelets

Question 7

What is the platelet mechanism?

Answer 7

Thrombin amplifies recruitment to bind to collagen and vWFo

Activation via expressed glycoprotein receptors on cell surface
GPa2b1 – collagen
GPIba, GPIIb/IIIa (aIIb, B3) – vWF

Activation stimulates COX synthesis and TxA2 release, ADP releaseTxA2

Vasonconstriction

oBinding a thromboxane receptor (GPCR)ADPActivates plateletsoP2Y and P2X receptors
ADP binds to P2Y and P2Y12 receptors
oCalcium and PL-3K promotes transient aggregation and sustained aggregation respectivelyoPL-3K – potentiation of secretion
MLC-KinaseoMLC-P