Acute Coronary Syndrome (ACS) and Acute Myocardial Infarction (AMI)

Question 1

Describe the EPIDEMIOLOGY of Coronary Heart Disease (CHD) in the community:

Answer 1

Presentation:

> 50% Stable Angina
20% Myocardial Infarction (MI)
10% Unstable Angina
10% Sudden Cardiac Death

Question 2

What conditions ENCOMPASS ACS?

Answer 2

1) Unstable Angina (UA)
* Evolving to MI

2) Non ST Elevated MI (NSTEMI)
3) ST Elevated MI (STEMI)

Question 3

Describe the PROGRESSIVE PATHOGENESIS of ACS to AMI:

Answer 3

1) Inflammation Leads to Rupture of Fibrous Plaque
2) Thrombus Formation
3) > Occlusion of Coronary Artery Lumen
4) > Ischaemia and > Need for Blood Supply (O2 to Tissues)

• Leading to MI
  5) Complete Occlusion of Vessel Ensues
  6) Blood Cannot Supply Tissues
  7) Tissue Necroses and Infarcts

Question 4

What is a CARDINAL CLINICAL FEATURE of ACS?

Answer 4

Symptoms Always Occur at Rest

Question 5

What are the NON-MODIFIABLE RISK FACTORS for ACS?

Answer 5

1) Gender
2) Race
3) Age
4) Genetics
5) Family History
6) Previous Angina, Cardiac Events or Interventions

Question 6

What are the MODIFIABLE RISK FACTORS for ACS?

Answer 6

1) Lifestyle, i.e. Diet and Weight; Exercise
2) Smoking
3) Hyperlipidaemia (Cholesterol Control)
4) Hypertension (BP Control)
5) Diabetes Mellitus (Glycaemic Control)

Question 7

What are the CHARACTERISTICS of ACS CHEST PAIN?

Answer 7

Site - Retrosternal
Onset - Sudden
Character - Tight Band/Heaviness/Pressure
Radiation - Jaw and/or Neck; Down Arms
Exacerbating/Alleviating - No Relief with GTN Spray; At Rest; is Ongoing
Severity - > Pain

Question 8

How might a patient with UA or NSTEMI PRESENT?

Answer 8

1) May Look Very Unwell
2) May Look Completely Fine
* Often No Specific Features to Find

Question 9

What are some of the SIGNS of ACS?

Answer 9

1) Distress
2) Diaphoresis
3) Pallor
4) > or < BP
5) > or < Pulse Rate
6) Distended JVP (If HF)
7) 3rd Heart Sound (If HF)
8) Chest Crepitations (If HF)

Question 10

What are some of the SYMPTOMS of ACS?

Answer 10

Can be Asymptomatic

OR

1) Dyspnoea
2) Nausea and Vomiting
3) Palpitations
4) Anxiety
5) Epigastric Pain
6) Chest Pain

< Pain Sensation in Women, Elderly and Diabetics

Question 11

What are the MAIN INVESTIGATIONS for a patient suspected of having ACS?

Answer 11

1) Serial ECGs
2) FBCs - Cardiac Troponin (cTn) and Creatine Kinase-MB (CK-MB)
3) CXR

Question 12

What would be the EXPECTED FINDINGS on ECG from a patient with UA or NSTEMI?

Answer 12

*May be Normal

Commonly:

1) ST-Segment Depression
2) Transient ST Elevation and/or T-Wave Inversion

Question 13

What would be the EXPECTED FINDINGS from CARDIAC TROPONIN in a patient with UA?

Answer 13

No Elevation in Troponin

Question 14

What would be the EXPECTED FINDINGS from CARDIAC TROPONIN in a patient with NSTEMI?

Answer 14

Elevated Troponin

*Not all > in Troponin are Triggered by ACS and Caused by Atherothrombosis

Question 15

What would be the IMMEDIATE TREATMENT for a patient with UA or NSTEMI?

Answer 15

1) ABCDE Approach

• MONA
  2) Morphine
  3) O2 Therapy
  4) Nitrates - GTN
  5) Aspirin (300mg; Chewed)

Question 16

What are the GOALS of PHARMACOTHERAPY for ACS and AMI?

Answer 16

1) > Myocardial O2 Supply
- Coronary Vasodilation
2) < Myocardial O2 Demand
- < HR
- < BP
- < Preload and Contractility

Question 17

What are the LONG-TERM TREATMENTS for UA/NSTEMI according to ACS PROTOCOL?

Answer 17

1) Dual Anti-Platelet Therapy
- Aspirin (< Dose) and Clopidogrel/Ticagrelor
2) Anti-Thrombotic Therapy
- LMWH (Fondaparinux)
3) Statins (i.e. Simvastatin)
4) ACEIs (i.e. Ramipril; particularly if in HF)
5) Analgesia
6) Nitrates (i.e. GTN)
7) Beta-Blockers (i.e. Bisoprolol)

Question 18

In what INSTANCES would you use a DIFFERENT ANTI-PLATELET drug to clopidogrel?

Answer 18

Patients With < CYP2C19 Levels - Resistant to Clopidogrel

*Consider Ticagrelor or Prasugrel as Alternatives

Question 19

What is a COMMON SIDE EFFECT of ASPIRIN use?

Answer 19

GI Bleeds

• Low Doses (75-150mg) should be used for 1 year Post-ACS Event
• Proton Pump Inhibitors (PPIs) could be used In Conjunction to Prevent Bleed; < Efficacy of Anti-Platelet Therapy

Question 20

What TREATMENT would be adopted in “HIGH RISK” patients with UA/NSTEMI instead of medical therapy alone?

Answer 20

Percutaneous Coronary Intervention (PCI) and Stenting

or

Coronary Artery Bypass Grafting (CABG)

Question 21

What are the STRENGTHS and WEAKNESSES of using BETA-BLOCKERS POST-MI?

Answer 21

Strength - Secondary Prevention; < Mortality Rate

Weakness - > Risk of Cardiogenic Shock

Question 22

What are the ADVANTAGES of using ASPIRIN for ACS or in AMI?

Answer 22

> Mortality Rate

< Reinfarction Rate

Question 23

What PROPORTION of the MYOCARDIUM is DAMAGED during NSTEMI?

Answer 23

Subendocardium (Partial Thickness of the Muscle)

Question 24

What PROPORTION of the MYOCARDIUM is DAMAGED during STEMI?

Answer 24

Transmural (Full Thickness of the Muscle)

Question 25

What would be the EXPECTED FINDINGS on ECG from a patient with STEMI?

Answer 25

1) ST-Segment Elevation
2) Pathological Q Waves After 3 Days
3) Hyperacute T Waves

Question 26

Following AMI, what is CRUCIAL FACTOR for patient SURVIVAL?

Answer 26

Time

• Necrosis of Myocardial Tissue Happens in Time-Dependent Manner
• Early Intervention is Key to Preserving Tissue Integrity

Question 27

What is FIRST-LINE TREATMENT for a patient with STEMI?

Answer 27

Primary PCI

Question 28

HOW LONG AFTER the incidence of STEMI MUST REVASCULARISATION occur?

Answer 28

Within 90 Minutes

Question 29

In the event that revascularisation cannot be given in time following STEMI, what is the NEXT COURSE of ACTION?

Answer 29

Thrombolysis Via Tissue Plasminogen Activators (t-PA), i.e. Alteplase

Question 30

What is the MECHANISM of ACTION of THROMBOLYSIS?

Answer 30

1) Serine Proteases Convert Plasminogen to Plasmin

2) Plasmin Lyses the Blood Clot by Breaking Down Fibrinogen and Fibrin Mesh

Question 31

What are some of the CONTRAINDICATIONS for THROMBOLYSIS?

Answer 31

1) Previous Intracranial Haemorrhage
2) Recent Ischaemic Stoke
3) Suspected Aortic Dissection
4) Known Malignant Intracranial Neoplasm
5) Recent Significant Closed Head-Trauma