Ischaemic Heart Disease

Question 0

Anti-coagulant drugs

Answer 0

Heparin
Bivalirudin
Fondaparinux

Question 1

Anti platelet therapy drugs

Answer 1

Aspirin
Clopidogrel
Newer - prasugrel/ticagrelor

Question 2

Anti-ischaemic agents

Answer 2

Beta-blockers
Nitrates
Calcium channel blockers

Question 3

Haemostatic plug formation

Answer 3

Platelet aggregation

Coagulation - thrombin&fibrin

Question 4

Platelet action in ACS

Answer 4

Circulating platelets activated by binding to exposed collagen and vWf at site of plaque rupture
Activation of platelets results in release of soluble agonists - TXA2 and ADP
ADP activates surrounding platelets

Question 5

ADP release…

Answer 5

Activates surrounding platelets by binding P2Y12 and P2Y2
Then intracellularmsignallimg activates integrin (GP IIb/IIIa) receptor
Causing sustained platelet aggregation by binding fibrinogen and vWf

Question 6

TXA2

Answer 6

Produced by platelets in response to stimuli (ADP, thrombus, collagen)
Increases platelet aggregation
Vasoconstriction

Question 7

Aspirin:

Answer 7

Irreversible COX inhibitor
So platelets produce less prostanoids, less TXA2
Rapid onset of action

Question 8

Aspirin loading dose in acute MI

Answer 8

300mg
Significant decrease in cardiovascular mortality
Reduction in progression from unstable angina to MI

Question 9

Secondary aspirin prevention MI

Answer 9

75md od

Reduction in cardiovascular events

Question 10

Theinopyridines

Answer 10

Antiplatelet agents
Clopidogrel & prasugrel - inhibit ADP mediated stimulation of P2y12 receptor
So inhibition of platelet activation and aggregation
Prodrugs metabolised by cytochrome p450
Active metabolised irreversibly bind P2y12 receptor
(Clopidogrel limited by metabolisation)
Ticagrelor binds reversibly and doesn’t require activation

Question 11

GP IIb/IIIa receptor

Answer 11

Activation leads to cross linking fibrinogen so platelets aggregate
Inhibitors indicated if a visible thrombus on angioplasty
Eg abciximab

Question 12

Abciximab

Answer 12

Glycoproteins IIb/IIIa receptor antagonist
Platelet aggregation inhibitor
During and after coronary angioplasty
Short half life

Question 13

Heparin

Answer 13

Inhibits coagulation cascade
(Vs anti platelet drugs inhibiting aggregation)
Enhances anti thrombin activity

Question 14

Mechanism of ischaemia

Answer 14

Imbalance between myocardial oxygen supply and demand

Question 15

Haemodynamic changes induced by ischaemia:

Answer 15

Increased LV end-diastolic pressure
Increased diastolic stiffness
Decreased cardiac output
Development of LV wall motion abnormalities

Question 16

Mechanism of anti-ischaemic medications

Answer 16

Decrease demand or increase supply myocardial oxygen
Do not correct underlying cause
Inc. nitrates & beta-blockers

Question 17

Nitrates

Answer 17

Relief of a final symptoms
Decrease demand by venodilatation (high dose arterial vasodilatation)
Improve coronary blood flow - dilate coronary arteries, improve collateral flow, revse CA spasm

Question 18

Nitrate treatment types

Answer 18

Sublingual GTN/tablets - fast acting
IV ISDN infusion if nitrate tolerance (isosorbide dinitrate)
Long acting ISMN - near 100% bio available, bypassing hepatic metabolism

Question 19

Beta-blockers

Answer 19

Reduce ischaemia
Competitive inhibition of b-adrenergic receptors in cardiac tissue
Negative chronotropic and inotropic effects
Decrease myocardial oxygen demand
34% reduction in inhospital mortality

Question 20

Beta- blocker contraindications

Answer 20

Hypersensitivity
Acute heart failure & cardiogenic shock
AV block
Severe asthma or COPD
Late stave PAD or sever raynauds
Untreated phaeocgromocytoma
Metabolic acidosis