Anti-Platelet Drugs Flashcards
what are anti-platelets used for
arterial atherosclerotic events
what causes arterial thrombosis
high pressure system
atherosclerosis (formation of cholesterol plaque which rupture and exposes collagen. platelets attracted to collagen forming a plug around the plaque blocking the lumen of the vessel)
platelet rich thrombus
treatment of arterial thrombosis
aspirin and other anti-platelets
modify risk factors
what is atherosclerosis
damage to endothelium
recruitment of ‘foamy’ macrophages rich in cholesterol
forms cholesterol plaque
what does a stable atherosclerotic plaque cause
stable angina
intermittent claudication
(stable is hyalinised and calcified)
what do unstable atherosclerotic plaques cause
unable angina
MI
Stroke
what is unstable angina
plaque ruptures
platelets are recruited and cause an acute thrombus to form
this occludes the vessel
what is the role of platelets in atherosclerosis
plaques only form in high pressure environments
plaque ruptures due to the high pressure
platelets then adhere to the plaque as it exposes damaged epithelium
platelets become activated and release granules that activate coagulation and recruit other platelets to form platelet plug
platelets aggregate via membrane glycoproteins
this forms an acute thrombosis - vessel occlusion
risk factors for arterial thrombosis
hypertension
- damage to endothelium
- platelet activation
smoking
- endothelial damage (toxins directly damage and also increase BP causing damage)
- platelet activation
high cholesterol
-accumulated in plaques
diabetes mellitus
- endothelium damage (from high glucose)
- platelet activation
- more cholesterol
prevention of arterial thrombosis
stop smoking treat hypertension treat diabetes lower cholesterol anti-platelet drugs
how are platelets formed
in the bone marrow by ‘budding’ off from the megakaryocytes
structure of platelets
small enucleate discs with a mean lifespan of 7-10 days
what chemicals are secreted by platelets to increase aggregation
thromboxane A2
ADP
what allows platelets to attach to each other
glycoproteins
fibrinogen
how does aspirin work as an anti-platelet
inhibits cyclo-oxygenase which is necessary to produce thromboxane A2 (a platelet agonist released from granules on activation