CBD 2: Chest pain

Question 1

Ischaemic heart disease: risk factors

a) FHx - cutoff
b) others

Answer 1

a) MI in 1st degree relative < 55 years

b) HTN, obesity, high cholesterol, diabetes, ethnicity, smoking, alcohol, stress, cocaine

Question 2

ACS: differentials

Answer 2

Cardiac - angina, pericarditis, aortic dissection
Resp - PE, pneumothorax
GI - GORD, oesophageal spasm
MSK - costochondritis, trauma
Psych - non-cardiac chest pain

Question 3

Chest pain on exertion (angina): pathophysiology

Answer 3

Coronary occlusion, on exertion oxygen demand increases and coronary insufficiency leads to hypoxia

Question 4

Troponins

a) Which one at NGH?
b) Measured when?
c) vs. CK

Answer 4

a) high-sensitivity Troponin T assay
b) 6h after onset of pain
c) More cardio-specific

Question 5

Diagnosis of ACS: need two out of what three things?

Answer 5

• Symptoms consistent with ACS
• ECG changes
• Raised cardiac enzymes

Question 6

ACS: investigations

a) 2 initial
b) Gold standard
c) Other

Answer 6

a) ECG, Troponins
b) CT angiography or invasive angiogram
c) Stress ECG, cardiac MRI, D-dimer

Question 7

ACS: management

a) Initial

Answer 7

a) - Nitrates - GTN
- Morphine (+ metoclopramide) if still in pain
- Aspirin loading dose 300 mg
- Oxygen if SpO2 < 94%
- ECG - if ST elevation - transfer for pPCI

Question 8

ECG changes of MI

a) ST elevation
b) ST depression

Answer 8

a) STEMI:
- anteroseptal (V1-V4),
- lateral (V5, V6, aVL, I),
- right (avR)
- inferior (II, III, avF)

b) Depression in anterior leads? - do posterior ECG to rule out posterior STEMI

Question 9

PCI time window in STEMI:

a) Must be within ___ hours of onset of symptoms
b) Should be within ___ hours of when fibrinolysis could have been given
c) Target ‘door to balloon’ window

Answer 9

a) 12 hours
b) 2 hours
c) 90 mins

Question 10

Indications for PCI

Answer 10

• Acute STEMI
• Acute NSTEMI/Unstable angina (if medium-high risk of subsequent cardiac events)
• Stable angina (if resistant to medical therapy)
• Left main artery disease (responds well to PCI, even if asymptomatic)

Question 11

Contraindications to PCI

Answer 11

• Lack of cardiac surgical support
• Critical left main coronary stenosis without collateral flow from a native vessel or previous bypass graft to the left anterior descending artery
• Coagulopathy/ Hypercoagulable states
• Diffusely diseased vessels without focal stenoses
• Total occlusion / stenosis < 50%

Question 12

PCI: adjuvant treatment

a) If cannot be offered PCI within 90 mins symptoms onset, also need to give…?
b) During/after PCI

Answer 12

a) LMWH

b) - Dual antiplatelet therapy (aspirin/clopidogrel) for 1 month (basic metal stent) or 1 year (drug-eluting stent).
- Then stop clopidogrel and continue aspirin for life.
- Also - BB, ACE and statin

Question 13

Alternative to PCI

a) Main one - 3 drugs that may be used. How they work. Time window?
b) If outside 12 hour window?

Answer 13

a) Thrombolysis - streptokinase, alteplase, reteplase.
tPA - activate plasminogen to produce plasmin and break down clots. Also need to be given within 12 hours symptom onset

b) Aspirin, clopidogrel and an antithrombin agent (heparin, enoxaparin or fondaparinux)

Question 14

PCI: risks

Answer 14

Stent thrombosis

Restenosis