Arterial Thrombosis and Anti-platelet Drugs

Question 1

What is atherosclerosis?

Answer 1

Combination of atheromas (fatty deposits in the artery walls) and sclerosis (the process of hardening or stiffening of the blood vessel walls)

Question 2

Which arteries does atherosclerosis affect?

Answer 2

Medium and large arteries

Question 3

Physiology of atherosclerosis

Answer 3

Caused by chronic inflammation and activation of the immune system in the artery wall

Question 4

Stable atherosclerotic plaques can lead to..

Answer 4

Stable angina (coronary
artery)
Intermittent claudication (leg artery)

Question 5

Unstable atherosclerotic plaques can lead to..

Answer 5

Unstable angina or myocardial infarction (coronary arteries)
Stroke (cerebral arteries)

Question 6

Role of platelets in arterial thrombosis

Answer 6

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

Question 7

Risk factors for arterial thrombosis

Answer 7

Hypertension
Smoking
Hypercholesteraemia
Diabetes mellitus

Question 8

Venous thrombosis vs arterial thrombosis

Answer 8

Question 9

Give examples of anti-platelet drugs

Answer 9

Aspirin
Clopidogrel, prasugrel
Dipyridamole
Abciximab

Question 10

Function of aspirin

Answer 10

Inhibits cyclo-oxygenase which is necessary to produce Thromboxane A2 (a platelet agonist released from granules on activation)

Question 11

Side effects of aspirin

Answer 11

Bleeding
Blocks production of prostaglandins
GI ulceration
Bronchospasm

Question 12

Function of Clopidogrel/ Prasugrel

Answer 12

ADP receptor antagonists which reduce the expression of glycoprotein IIB/IIIA

Question 13

Function of Dipyridamole

Answer 13

Phosphodiesterase III inhibitor - increases production of cAMP which inhibits platelet aggregation

Question 14

Function of abciximab

Answer 14

GP IIb/IIIa inhibitors - inhibit aggregation by preventing fibrinogen from cross linking platelets

Question 15

Answer 15

Question 16

Answer 16

Question 17

Anti-platelet drugs tend to affect platelet function for their..

Answer 17

7-10 day life span

Question 18

Stop anti-platelet agents _____ prior to elective operations

Answer 18

7 days

Question 19

If serious bleeding with anti-bleeding, can reverse with..

Answer 19

Platelet transfusion

Question 20

What can be used in place of aspirin if the patient is allergic?

Answer 20

ADP receptor inhibitors eg clopidogrel

Question 21

Side effects of ADP receptor inhibitors

Answer 21

Increased risk of bleeding
Thrombotic thrombocytopenic purpura

Question 22

Side effects of phosphodiesterase inhibitors

Answer 22

Dizziness
Headaches
Palpitations
GI disturbances

Question 23

T or F: Abciximab is a monoclonal antibody

Answer 23

True

Question 24

What are anti-platelet agents?

Answer 24

Interfere with the first step of hemostasis (plug formation)

Question 25

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

Answer 25

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

Question 26

What are potent platelet activators?

Answer 26

Thromboxane A2, ADP

Question 27

Give examples of thrombolytics

Answer 27

Alteplase
Streptokinase

Question 28

Function of thrombolytics

Answer 28

Convert plasminogen to plasmin which degrades fibrin mesh

Question 29

Primary adverse affect of thrombolytics is..

Answer 29

Bleeding - can use aminocaproic acid or tranexamic acid