Coronary Heart Disease Flashcards
Pathogenesis of CAD
-Atherosclerosis
-Rare
=Aortitis
=Vasculitis
=Autoimmune connective tissue diseases
Describe atherosclerosis
-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
Clinical manifestations of CAD
-Stable angina
-Unstable angina
-MI
HF
-Arrhythmia
-Sudden death
What is stable angina?
Ischaemia due to fixed atheromatous stenosis of one or more coronary arteries
What is unstable angina?
Ischaemia caused by dynamic complete or partial obstruction of a coronary artery due to plaque rupture or erosion with superimposed thrombosis
What causes MI?
-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
Risk factors for atherosclerosis
-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
Primary prevention of CAD
-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
Pathogenesis of Angina
-Coronary atherosclerosis
-Aortic valve disease and hypertrophic cardiomyopathy
-Coronary artery spasm (transient ST elevation)
Characteristic features of angina
- Constricting discomfort in the centre of the chest, or in the neck, shoulders, jaw or arms
- Precipitated by physical exertion
- Relieved by rest (or GTN) within 5 minutes
Classification of angina
-Typical angina : All three features
-Atypical angina : Two features
-Non-anginal chest pain : One or no features
Investigations of angina
-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
Advice to patients with stable angina
-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
Medications for stable angina
-Low-dose 75mg aspirin/ clopidogrel 75mg
-Statin
-GTN
-Beta-blocker
-CCB and long-acting nitrate if needed
Non-pharmacological treatments for angina
-Percutaneous coronary intervention
=dilated balloon, coronary stent
-Coronary artery bypass grafting
=radial and internal mammary arteries, saphenous vein
