Arterial Thrombosis and Anti-platelet Drugs Flashcards
What is atherosclerosis?
Combination of atheromas (fatty deposits in the artery walls) and sclerosis (the process of hardening or stiffening of the blood vessel walls)
Which arteries does atherosclerosis affect?
Medium and large arteries
Physiology of atherosclerosis
Caused by chronic inflammation and activation of the immune system in the artery wall
Stable atherosclerotic plaques can lead to..
Stable angina (coronary
artery)
Intermittent claudication (leg artery)
Unstable atherosclerotic plaques can lead to..
Unstable angina or myocardial infarction (coronary arteries)
Stroke (cerebral arteries)
Role of platelets in arterial thrombosis
Plaque ruptures in the high
pressure environment of arteries. Adheres to exposed endothelium and releases VWF
Platelets become activated and release granules that activate coagulation and recruit
other platelets to developing platelet plug
Platelet aggregation via membrane glycoproteins
Risk factors for arterial thrombosis
Hypertension
Smoking
Hypercholesteraemia
Diabetes mellitus
Venous thrombosis vs arterial thrombosis
Give examples of anti-platelet drugs
Aspirin
Clopidogrel, prasugrel
Dipyridamole
Abciximab
Function of aspirin
Inhibits cyclo-oxygenase which is necessary to produce Thromboxane A2 (a platelet agonist released from granules on activation)
Side effects of aspirin
Bleeding
Blocks production of prostaglandins
GI ulceration
Bronchospasm
Function of Clopidogrel/ Prasugrel
ADP receptor antagonists which reduce the expression of glycoprotein IIB/IIIA
Function of Dipyridamole
Phosphodiesterase III inhibitor - increases production of cAMP which inhibits platelet aggregation
Function of abciximab
GP IIb/IIIa inhibitors - inhibit aggregation by preventing fibrinogen from cross linking platelets
Anti-platelet drugs tend to affect platelet function for their..
7-10 day life span
Stop anti-platelet agents _____ prior to elective operations
7 days
If serious bleeding with anti-bleeding, can reverse with..
Platelet transfusion
What can be used in place of aspirin if the patient is allergic?
ADP receptor inhibitors eg clopidogrel
Side effects of ADP receptor inhibitors
Increased risk of bleeding
Thrombotic thrombocytopenic purpura
Side effects of phosphodiesterase inhibitors
Dizziness
Headaches
Palpitations
GI disturbances
T or F: Abciximab is a monoclonal antibody
True
What are anti-platelet agents?
Interfere with the first step of hemostasis (plug formation)
Aspirin, when used as an antiplatelet in low dose formulations, carries the risk of developing ___________, as well as ___________. Aspirin can also cause ___________ reactions at low doses
Aspirin, when used as an antiplatelet in low dose formulations, carries the risk of developing gastric ulcers, as well as bleeding. Aspirin can also cause allergic reactions at low doses
What are potent platelet activators?
Thromboxane A2, ADP
Give examples of thrombolytics
Alteplase
Streptokinase
Function of thrombolytics
Convert plasminogen to plasmin which degrades fibrin mesh
Primary adverse affect of thrombolytics is..
Bleeding - can use aminocaproic acid or tranexamic acid
