IHD - Acute Coronary Syndromes (ACS)

Question 1

Define ACS

Answer 1

A subclassification of Ischaemic Heart Disease which consists of: Unstable angina, NSTEMI, STEMI

Question 2

What are the 3 main types of ACS?

Answer 2

• Unstable angina (UA)
  
  • Chest pain without evidence of myocardial necrosis
• Non-ST Elevation Myocardial Infarction(NSTEMI)
• ST Elevation Myocardial Infarction(STEMI)

Question 3

What is the pathophysiology of ACS?

Answer 3

• Rupture of an atherosclerotic plaque results in a thrombus in the coronary artery(ies)
• This occludes the lumen and leads to ischaemia of the myocardium and eventually infarction as the O2 supply cannot meet demand

Question 4

How much of the lumen is occluded in the 3 main types?

Answer 4

• Unstable angina and NSTEMI: thrombus leads to partial occlusion
• STEMI: thrombus leads to complete occlusion

Question 5

What is the difference between STEMI and NSTEMI compared to unstable angina?

Answer 5

STEMI and NSTEMI show evidence of myocardial necrosis, unlike unstable angina

Question 6

What are the signs and symptoms of ACS?

Answer 6

• Crushing/pressure-like chest pain that can radiate to the jaw/left arm
• Typical symptoms due to reduced CO
  
  • Breathlessness
  • Dizziness
  • Weakness
• Bilateral leg oedema may present if congestive heart failure (CHF) develops

Question 7

What are the investigations for ACS?

Answer 7

• ECG
• Biomarkers of myocyte necrosis

Question 8

What does an ECG show for ACS?

Answer 8

differentiates between NSTEMI and STEMI

Question 9

What are biomarkers of myocyte necrosis?

Answer 9

• Troponin T and I
• CK-MB
• Lactate dehydrogenase (outdated due to troponin testing)

Question 10

What are the modifiable risk factors for ACS?

Answer 10

Hypertension
Hyperglycaemia (DM)
Smoking
Alcohol
Hypercholesterolaemia
Obesity/inactivity
Stress

Question 11

What are the non modifiable risk factors for ACS?

Answer 11

Age
Sex (men and post-menopausal women)
Genetic/Family History

Question 12

What are the key differences between the 3 main types of ACS?

Answer 12

• STEMI shows ST segment elevation on ECG
  - NSTEMI and UA show ST
  segment depression
• UA does not have raised troponin, whereas NSTEMI and STEMI do

Question 13

What is the primary prevention of ACS and when is it done?

Answer 13

• Before a Patient has ACS
• Lifestyle advice (e.g. exercise, stop
  smoking, reduce alcohol, fats and salt, eat more fruit & veg)
• QRISK score
  
  • If above 10%, consider statins
    ACE inhibitor if hypertensive

Question 14

What is secondary prevention of ACS and when is it done?

Answer 14

• After a Patient has ACS

ABAS
- Aspirin 75mg, indefinite
+ another antiplatelet(clopidogrel, ticagrelor) for 12 months
- Beta-blocker (e.g. bisoprolol)
- ACE inhibitor
- Statin – atorvastatin 80mg

Question 15

What is the immediate management of ACS (acute presentation)?

Answer 15

MONA(C)
- Morphine IV
- Oxygen if sats low (<95%)
- Nitrates (GTN) (glyceryl trinitrate)
- Aspirin 300mg loading dose
- (C)lopidogrel – for NSTEMI and STEMI

Question 16

What is the treatment for a STEMI within 2 hours?

Answer 16

Primary PCI (Percutaneous Coronary Intervention)
- Balloon angioplasty or stenting

Question 17

What is the treatment for a STEMI NOT within 2 hours?

Answer 17

Thrombolytic therapy
- Promotes plasminogen conversion to plasmin to break down fibrin clots
- First line is Tissue Plasminogen Activator (TPAs)
- Streptokinase is alternative

Question 18

What are contraindications of thrombolytic therapy?

Answer 18

Contraindications include pregnancy, recent surgery, recent stroke, increased bleeding risk, evidence of aortic dissection etc

Question 19

What is the treatment of a NSTEMI?

Answer 19

PCI
- Thrombolytic therapy NOT indicated