anticoagulants/thrombotics Flashcards
What do anti-platelet drugs do?
decrease aggregation and formation of the platelet clot
What do anti-coagulants do?
interfere with the clotting cascade and thrombin formation
What do thrombolytic agents do?
break down the thrombus by stimulating plasmin
What kind of disease states do antiplatelets work on?
high-velocity disease states affecting arteries
- cerebrovascular disease
- coronary artery disease
- peripheral arterial disease (PAD)
What kind of disease states do anticoagulants work on?
low-velocity disease states affecting veins & the left atrium
- pulmonary embolism (PE)
- atrial fibrillation
- deep vein thrombosis (DVT)
What happens in the first part of primary hemostasis?
formation of a platelet plug
- stimulus to platelets occurs (injury)
- results in platelet adhesion
What happens in the second part of primary hemostasis?
-glycoprotein IIB/IIIa receptors are activated by platelet adhesion
- bind to fibrinogen
- increases platelet aggregation
What happens in secondary hemostasis?
- fibrin (generated by the coagulation cascade)
- forms mesh that is incorporated into & around the platelet plug which strengthens & stabilizes clot
- creates thrombus
What are the two pathways of the coagulation cascade are there and how are they tested in the lab?
intrinsic (contact activated)
- lab test = aPTT
extrinsic (tissue factor pathway)
- lab test = PT/INR
What does the common pathway of the coagulation cascade do?
ends in conversion of fibrinogen into fibrin
What vitamins are needed for proper function of the coagulation cascade & why?
- calcium
- vitamin K = factors II, VII, IX, X are vitamin K dependent
What happens during coagulation?
- local vasoconstriction seals off small injury
- platelet aggregation forms a platelet plug
- hageman factor is activated
- intrinsic & extrinsic pathways clot blood
What does the intrinsic factor do in coagulation?
converts prothrombin to thrombin to seal system (damage inside the vessel)
What does the extrinsic factor do in coagulation?
clots the blood that has leaked out of the vascular system (tissues)
What is hageman factor?
- factor XII floats freely in your bloodstream until it’s needed
- when factor XII comes into contact with the damaged wall of a vein, it activates coagulation factor XI
What causes the release of ADP?
injury to the vessel causing platelet aggregation to the site
What is released when platelets aggregate to an injury site and what do they do?
release ADP & serotonin which help being the platelets together
What is ADP?
a precursor to prostaglandins
What is often all that is needed to stop bleeding?
the platelet plug
What does thromboxane A do?
increases vasoconstriction & platelet aggregation
- produced at site of platelet aggregation
What can increase platelet activity?
disturbances in flow & endothelial damage
- atherosclerosis
vessel injury
- smoking
- elevated lipids
- HTN
- DM
- immune reactions
