Coronary Heart Disease

Question 1

Pathogenesis of CAD

Answer 1

-Atherosclerosis
-Rare
=Aortitis
=Vasculitis
=Autoimmune connective tissue diseases

Question 2

Describe atherosclerosis

Answer 2

-Progressive inflammatory disorder of arterial wall characterised by focal lipid-rich deposits of atheroma
=Clinically silent until large enough to impair tissue perfusion/ ulceration/ disruption of lesion resulting in thrombotic occlusion or distal embolisation of vessel

-Deposits of lipids in vessel wall (sites of altered arterial shear stress like bifurcations and abnormalities of endothelial function)
=Monocytes and inflammatory cells bind to receptors expressed by endothelial cells
=Migrate into intima, take up oxidised LDL by phagocytosis to become foam cells

Question 3

Clinical manifestations of CAD

Answer 3

-Stable angina
-Unstable angina
-MI
HF
-Arrhythmia
-Sudden death

Question 4

What is stable angina?

Answer 4

Ischaemia due to fixed atheromatous stenosis of one or more coronary arteries

Question 5

What is unstable angina?

Answer 5

Ischaemia caused by dynamic complete or partial obstruction of a coronary artery due to plaque rupture or erosion with superimposed thrombosis

Question 6

What causes MI?

Answer 6

-Myocardial necrosis caused by acute occlusion of a coronary artery due to plaque rupture or erosion with superimposed thrombosis
-Supply demand imbalance where blood flow cannot meet the needs of the myocardium. This may be caused by fixed atheromatous obstruction with high myocardial demand for blood

Question 7

Risk factors for atherosclerosis

Answer 7

-Age and sex (sex difference disappears after menopause)
-Genetics (hypertension, hyperlipidaemia, DM, early onset disease)
-Smoking
-Hypertension
-Hypercholesterolaemia
-DM (especially T2)
-Obesity
-Inactivity
-Platelet activation and high plasma fibrinogen concentrations
-Alcohol
-Diet
-Social deprivation

Question 8

Primary prevention of CAD

Answer 8

-Lifestyle changes/ therapeutic interventions

=Do not smoke
=Take regular exercise (minimum 20 minutes, three times a week)
=Maintain an ideal body weight
=Eat a mixed diet rich in fresh fruit and vegetables
=Aim to get no more than 10% energy intake from saturated fat

Question 9

Pathogenesis of Angina

Answer 9

-Coronary atherosclerosis
-Aortic valve disease and hypertrophic cardiomyopathy
-Coronary artery spasm (transient ST elevation)

Question 10

Characteristic features of angina

Answer 10

1. Constricting discomfort in the centre of the chest, or in the neck, shoulders, jaw or arms
2. Precipitated by physical exertion
3. Relieved by rest (or GTN) within 5 minutes

Question 11

Classification of angina

Answer 11

-Typical angina : All three features
-Atypical angina : Two features
-Non-anginal chest pain : One or no features

Question 12

Investigations of angina

Answer 12

-Blood tests, 12-lead ECG, CXR, ECHO
-Exercise ECG?= down-sloping ST segment depression 1mm or more indicative of ischaemia

-CT coronary angiography
-Stress testing

Question 13

Advice to patients with stable angina

Answer 13

-Do not smoke
-Aim for an ideal body weight
-Take regular exercise (exercise up to, but not beyond, the point of chest discomfort is beneficial and may promote collateral vessels)
-Avoid severe unaccustomed exertion, and vigorous exercise after a heavy meal or in very cold weather
-Take sublingual nitrate before undertaking exertion that may induce angina

Question 14

Medications for stable angina

Answer 14

-Low-dose 75mg aspirin/ clopidogrel 75mg
-Statin

-GTN
-Beta-blocker
-CCB and long-acting nitrate if needed

Question 15

Non-pharmacological treatments for angina

Answer 15

-Percutaneous coronary intervention
=dilated balloon, coronary stent

-Coronary artery bypass grafting
=radial and internal mammary arteries, saphenous vein