Angina

Question 1

What is the definition of angina? [3]

Answer 1

chest pain or discomfort / as a result of reversible myocardial ischaemia / usually due to narrowing of coronary arteries by atherosclerosis

Question 2

What are the features of angina and how is it scored? [6]

Answer 2

1. constricting, heavy discomfort to the chest, jaw, neck, shoulders or arms
2. brought on by exertion
3. relieved by rest or GTN spray

3/3 = typical angina
2/3 = atypical angina
1/3 = non-anginal chest pain

Question 3

What are the different types of angina? [3]

Answer 3

1. stable angina - induced by effort, relieved by rest
2. unstable (crescendo) angina - angina of recent onset, with increasing frequency and severity, occurring on minimal exertion or at rest
3. Prinzmetal (variant) angina - caused by coronary artery spasm

Question 4

What is the aetiology of angina? [6]

Answer 4

1. myocardial ischaemia occurs when there is a mismatch between blood supply and metabolic demand (increased O2 demand but decreased O2 supply)

this is caused by -

2. atheroma/stenosis of coronary arteries - impairing blood flow (most common)
3. anaemia - reduced oxygen carrying capacity of the blood
4. coronary artery spasm
5. valvular disease
6. arrhythmia

Question 5

What are the risk factors of angina? [8]

Answer 5

1. hypercholesterolaemia - cholesterol is major risk factor for CVD (normal cholesterol <5.0mmol/L)
2. smoking - endothelial damage
3. diabetes - hyperglycaemia causes endothelial damage
4. obesity - more pericardial and increase in inflammation
5. hypertension - added pressure on arterial walls
6. family history/genetics
7. age - weaker endothelial walls and more time for plaque to develop
8. sedentary lifestyle

Question 6

What is the pathophysiology of angina? [5]

Answer 6

1. atherosclerosis developing narrowing of coronary arteries leads to ischaemia and pain
2. endothelial dysfunction at injury site and accumulation of lipid and leukocytes
3. lipid-laden macrophages (foam cells) apoptose and release lipid content into lipid core
4. growth factors stimulate proliferation of smooth muscle cells and synthesis of collagen and elastin to form a dense fibrous cap
5. plaque continues to grow and narrow lumen, complicated plaques show calcification and mural thrombus, making them vulnerable to rupture

Question 7

What is the clinical presentation of angina? [4]

Answer 7

1. central chest tightness or heaviness
2. brought on by exertion and relieved by rest or GTN spray
3. pain may radiate to jaw, neck, shoulders or arm
4. dyspnoea, nausea, sweatiness, faintness

Question 8

What could the differential diagnosis of angina be? [5]

Answer 8

1. pericarditis/myocarditis
2. pulmonary embolism
3. chest infection
4. aortic dissection
5. GORD

Question 9

How can angina be diagnosed? [5]

Answer 9

1. 12 lead ECG - often normal, may show ST depression, flat or inverted T waves
2. exercise ECG/stress test - on treadmill to induce ischaemia, monitor ECG
3. CT calcium scoring scan - where there is atherosclerosis Ca2+ lights up white
4. SPECT/myoview scan - radiolabelled tracer lights up in good blood supply, doesn’t light up in areas with little blood supply
5. cardiac catheterisation/CT angiography - invasive procedure taking x-rays pictures of coronary arteries

Question 10

How can modifiable risk factors be treated? [4]

Answer 10

1. stop smoking
2. encourage exercise
3. weight loss
4. statins - lower cholesterol

Question 11

What are the pharmacological treatments of angina? [5]

Answer 11

1. glyceryl trinitrate (GTN) spray
2. aspirin
3. beta-blockers
4. calcium channel blockers
5. ACE inhibitors

Question 12

What are the revascularisation treatments of angina? [2]

Answer 12

1. percutaneous coronary intervention (PCI)

2. coronary artery bypass graft (CABG)

Question 13

What are the affects and side effects of glyceryl trinitrate (GTN) spray? [4]

Answer 13

1. nitrate is a venodilator so dilates systemic veins
2. reduces venous return and so reduces preload
3. reduces the work of the heart and lowers oxygen demand
4. side effects - profuse headaches and lower blood pressure

Question 14

What are the affects and side effects of aspirin? [4]

Answer 14

1. COX inhibitor - irreversibly inactivates COX-1
2. reduces prostaglandin synthesis including thromboxane A2
3. reduced platelet aggregation
4. side effects - gastric ulceration

Question 15

What are the affects and side effects of beta-blockers? [5]

Answer 15

1. act on B1 adrenoreceptors in the heart
2. reduce heart rate (-ve chronotropic) and reduce LV contractility (-ve inotropic)
3. reduce cardiac output so less O2 demand
4. do not give in - asthma, heart block/failure, hypotension, bradyarrhythmias
5. side effects - tiredness, nightmares, bradycardia, erectile dysfunction, hypotension, cold hands and feet

Question 16

What are the affects of calcium channel blockers? [3]

Answer 16

1. primary arterial dilators so dilates systemic arteries
2. decreases blood pressure so reduces afterload
3. reduces work on heart and O2 demand

Question 17

What are the affects of ACE inhibitors? [3]

Answer 17

1. blocks the action of angiotensin-converting enzyme (ACE) so stops the production of angiotensin II
2. less angiotensin II so less vasoconstriction and lower BP and afterload
3. less work on heart and lower O2 demand

Question 18

What is the PCI, it’s pros and cons? [3]

Answer 18

1. percutaneous cutaneous intervention (PCI) involves inflating balloon in coronary artery and inserting stent to maintain wider artery and increase blood flow (coronary angioplasty)
2. pros - less invasive, convenient, repeatable
3. cons - stent thrombosis, restenosis, not good for complex diseases

Question 19

What is CABG, it’s pros and cons? [3]

Answer 19

1. coronary artery bypass graft (CABG) involves using the left internal mammary artery (LIMA) to bypass proximal stenosis in the left anterior descending (LAD) coronary artery
2. pros - good prognosis, deals with complex disease
3. cons - invasive, risk of stroke/bleeding, long recovery, can’t do on the frail