7. Acute Coronary Syndromes Flashcards
percentage of patients who will die after and acute coronary syndrome (ACS)?
38%
What are the three ACS?
- unstable angina
- NSTEMI
- STEMI
ACS are a result of:
> 90% are a result of the disruption of an atheroesclerotic plaque with subsequent platelet aggregation and formation of an intracoronary thrombus.
On what depends the form of ACS presented by the patient?
it depends on the degree of coronary obstruction and the associated isquemia.
A partially occlusive thrombus is a typical cause of:
- Unstable Angina (UA)
2. NSTEMI (non-q wave MI)
What is Antithrombin?
plasma protein.
Irreversibly bonds to thrombin and other clotting factors, inactivating them and facilitating their clearance from the circulation.
A completely obstructive thrombus
STEMI (Q-wave MI)
what are the three most important regulators of coagulation?
- Antithrombin
- Protein C/ Protein S/ Thrombomodulin
- Tissue pathway factor inhibitor (TFPI)
How is the thrombus responsible for the ACS generated?
It is generated by the interactions of :
- the atheroesclerotic plaque
- coronary endothelium
- circulating platelets
- dynamic vasomotor tone of the vessel
What molecule increases the effectiveness of antithrombin by 1000 fold?
Heparan sulfate, en heparin like molecule normally present on the luminal surface of endothelial cells.
What is protein C?
synthesised in the liver, circulates as inactivated form. Inactivates factors Va and VIIIa.
What is protein S?
enhances the inhibitory function of protein C.
What is thrombomodulin?
thrombin binding receptor normally present on endothelial cells. Thrombin bound to thrombomodulin cannot convert fibrinogen into fibrin. Instead the the thrombin-thrombomodulin complex activates protein C.
What is the tissue factor pathway inhibitor?
TFPI is a plasma serine protease inhibitor that is activated by factor Xa. Xa-TFPI inhibits the complex of tissue factor with VIIa that normally triggers extrinsic coagulation pathway.
Therefore, TFPI serves as a negative feedback inhibitor that interferes with coagulation.
What is tissue plasminogen activator?
protein secreted by endothelial cells in response to triggers of clot formation. Promotes formation of active plasmin which in turn enzimatically degrades fibrin clots.
