Cardiology - Acute Coronary Syndromes

Question 1

What causes an acute coronary syndrome?

Answer 1

Thrombus from an atherosclerotic plaque blocking a coronary artery

Question 2

Why are anti-platelet medications used in acute coronary syndromes?

Answer 2

Thrombus formation occurs in a fast-flowing artery

Formed mainly from platelets

Question 3

What are 3 main anti-platelet medications?

Answer 3

Aspirin
Clopidogrel
Ticagrelor

Question 4

What is the mechanism of action of aspirin?

Answer 4

Inhibits cyclooxygenase-1 from producing thromboxane A2 from arachidonic acid

Reduces platelet aggregation

Irreversible

Question 5

Why do anti-platelet medications last the lifespan of the platelet?

Answer 5

Platelets have no nuclei

Cannot produce more COX-1

Question 6

What is the mechanism of action of clopidogrel and ticagrelor?

Answer 6

Clopidogrel
Irreversible

Ticagrelor
Reversible

Both prevent binding of ADP to P2Y12 receptors

This inhibits activation of Glycoprotein IIb/IIIa receptors

Less aggregation

Question 7

What are the three types of acute coronary syndrome?

Answer 7

Unstable angina
ST-elevation myocardial infarction (STEMI)
Non-ST-elevation myocardial infarction (NSTEMI)

Question 8

What does the right coronary artery supply?

Answer 8

RA
RV
Inferior LV
Posterior 1/3 inter ventricular septum

Posterior heart

Question 9

What does the left coronary artery become?

Answer 9

Circumflex artery
Left anterior descending artery

Question 10

What does the circumflex artery supply?

Answer 10

Left atrium
Posterior aspect of the left ventricle

Lateral heart

Question 11

What does the left anterior descending supply?

Answer 11

Anterior left ventricle
Anterior 2/3 of the interventricular septum

Question 12

How does acute coronary syndrome present?

Answer 12

Central, constricting chest pain

• Pain radiates to the jaw or arms
• Nausea and vomiting
• Sweating and clamminess
• Feeling of impending doom
• Shortness of breath
• Palpitations

Symptoms continue at rest for more than 15 minutes

Question 13

What is a silent myocardial infarction and who experiences it?

Answer 13

Do not experience typical chest pain during acute coronary syndrome

Diabetics at much higher risk

Question 14

Complete the table

Answer 14

Question 15

What type of acute coronary syndrome is troponin needed for diagnosis?

Answer 15

NSTEMI

Not needed for STEMI as based on presentation and ECG

Question 16

Asides from acute coronary syndromes what else can cause raised troponin?

Answer 16

CKD
Sepsis
Myocarditis
Aortic dissection
PE

Question 17

What additional investigations should be done for suspected or confirmed acute coronary syndromes?

Answer 17

Baseline bloods

CXR
- Pulmonary oedema

Echocardiogram
- Assess functional damage to heart, specifically LV function

Question 18

What is different in investigations between unstable angina and NSTEMI?

Answer 18

Raised troponin in NSTEMI

Both have either:
- Normal ECG
- ST depression or T wave inversion

Question 19

If a patient is pain-free but had pain within 72 hours what should be done?

Answer 19

Referred to hospital for same-day assessment

May have ECG changes

Question 20

How are patient’s with a STEMI managed?

Answer 20

Percutaneous coronary intervention (PCI)
WITHIN 12 hours of symptom onset
Within 2 hours of presenting to the hospital

Thrombolysis
If PCI not available within 2 hours

Question 21

What fibrinolytics are used in thrombolysis?

Answer 21

Streptokinase (can only be used once as antibodies develop against it)

Alteplase

Tenecteplase

Question 22

How do fibrinolytics work?

Answer 22

Converts plasminogen to plasmin which enables degradation of fibrin

Question 23

How should NSTEMI and STEMI be managed?

Answer 23

STEMI
MONA
Morphine
Oxygen
Nitrate (GTN)
Aspirin 300mg

PCI and thrombolysis

NSTEMI
BATMAN
Based on GRACEscore for PCI
Aspirin 300mg
Ticagrelor
Morphine
Anti-thrombin (fondaparinux)
Nitrates

Question 24

What is the GRACE score?

Answer 24

6 month probability of death after NSTEMI

3% or less- Low risk
Over 3%- Medium to high risk

Medium to high risk patients considered for angiography with PCI within 72 hours

Question 25

After initial management what do patients require?

Answer 25

Echocardiogram
- Assess functional damage to heart
- Specifically LV function

Cardiac rehabilitation

Secondary prevention

Question 26

What medication is used for secondary prevention?

Answer 26

Aspirin 75 mg
Atorvastatin 80mg
ACEi (ramipril)
Atenolol (or bisoprolol)
Aldosterone antagonist for heart failure e.g. eplerenone 50mg
Another antiplatelet (ticagrelor or clopidogrel)

Question 27

Why must renal function be monitored in patients taking ACEi and aldosterone antagonists?

Answer 27

Can cause hyperkalaemia

ACEi + ARB carries risk of fatal hyperkalaemia

Question 28

What is Dressler’s syndrome?

Answer 28

2-3 weeks post MI patient will experience pericarditis

Due to localised immune response that causes inflammation in pericardium

Question 29

How does Dressler’s syndrome present / pericarditis?

Answer 29

Pleuritic chest pain
Low-grade fever
Pericardial rub on auscultation
Global ST elevation and T wave inversion
Pericardial effusion with echo
Raised CRP and ESR

Question 30

How do you manage Dressler’s syndrome?

Answer 30

NSAIDs

More severe cases steroids such as prednisolone

Pericardiocentesis if significant effusion

Question 31

What are the different types of MI?

Answer 31

Type 1
- Acute coronary event

Type 2
- Ischaemia secondary to raised demand or reduced supply of oxygen (severe anaemia, tachycardia or hypotension)

Type 3
- Sudden cardiac death or cardiac arrest (ischaemic event)

Type 4
- Associated with procedures such as PCI, stenting and CABG

ACDC

1- A- ACS type MI
2- C- Can’t Cope MI
3- D- Dead by MI
4- C- Caused by us

Question 32

What are some causes of non-cardiac chest pain?

Answer 32

Costochondritis
GORD
PE
Pneumonia
PTX
Psychogenic/psychosomatic