Ischaemic Heart Disease Flashcards
True or False: Cardiovascular Disease is still the most common cause of death (out of all diseases)
True
Why are rates of CV disease in different areas of the country ?
Due to different levels of social deprivation
Are women and men equal when it comes to CV death ?
No, women have a lower rate of CV death
Identify the main effects of IHD.
1) Chronic coronary insufficiency
- Angina (this is the pain of myocardial ischemia. IHD usually becomes symptomatic only when the luminal cross-sectional area of the affected vessel is reduced by more than 75%, leading to coronary insufficiency)
2) Unstable coronary disease (likely due to clot of plaque)
- Myocardial infarction
- Sudden ischemic coronary death
3) Heart Failure
Contractile impairment in these people is due to irreversible loss of myocardium (previous infarcts) and hypoperfusion of surviving muscle, which leads to chronic ventricular dysfunction
4) Arrhythmia
- Acute ischaemic
- Scar related
State another name of ischaemic heart disease.
Atherolscerotic heart disease
Coronary heart disease
Define endocardium and epicardium coronary arteries.
epicardium = outer surface of the heart endocardium = inner surface of the heart
Why is the difference between endocardium and epicardium relevant in ischemic heart disease ?
Subendocardial (beneath the endocardium or between the endocardium and myocardium) region is water-shed area of perfusion and first to become ischaemic
Identify the main epicardial coronary arteries.
The left and right coronary arteries and their branches
Identify the main imaging techniques used for coronary artery imaging.
- Coronary Angiography
- CT
- MR imaging
Identify the main causes of IHD.
Caused by “Risk Factors”
- Age
- Hypertension
- Hypercholesterolaemia
- Smoking
- Diabetes
- Obesity
- Physical inactivity
Describe the histology of coronary atherosclerosis.
- Intimal fibrous cap
- Central core rich in lipids (necrotic center)
- Patchy and raised white to yellow 0.3-1.5cm
- Fatty streaks: may be elongated streaks (1cm or longer) or fatty dots (< 1 mm)
- Foam cells + T lymphocytes
- Cholesterol crystals in tunica intima
Describe the contents of a fatty streak. What is a fatty streak ?
Foam cells + T lymphocytes
Mature fibro-fatty Atheroma, first grossly visible lesion in the development of atherosclerosis (can be precursor to plaque)
Describe the main stages in the pathology of the formation of atherosclerotic coronary artery disease.
- Fatty Streak
- Chronic endothelial injury / dysfunction
- Lipids and macrophages play a role
- Smooth muscle proliferation
- Formation of a fibro-lipid plaque ((fibrous cap (collagen from vascular smooth muscle cells) + fat (lipid contained in macrophages))
- Injury to the plaque (plaque disruption)
-Plaque rupture
-Plaque erosion
Leads to formation of a thrombus (roof of fibrous cap has become disrupted and contents are thrombogenic)
What is the role of lipids in atherosclerosis ?
Hyperlipidaemia (LDL cholesterol) results in:
– Impairs endothelial function
– Accumulates within intima
– Causes oxidative modification of LDL:
• After oxidation, ingested by macrophages via SCAVANGER receptors = foam cells (hence immobilised)
• Chemotactic for monocytes
• Inhibit the motility of macrophages
• Stimulates release of cytokines
• Cytotoxic to endothelial and smooth muscle cells
What is the role of macrophages in atherosclerosis ?
- Monocytes which have migrated from lumen to tunica intima get activated as macrophages
- Secrete IL1 (Interleukin-1), TNF (Tumor necrosis factor), MCP1 (Monocyte chemotactic protein 1) and growth factors
- Engulf oxidised LDL = foam cells
- Foamy cells accumulate together, start raising lumen of artery (brown yellow line, FATTY STREAK)
What is the role of smooth muscle cells in atherosclerosis ?
Migrate from tunica media to tunica intima where they may act as phagocytes (engulf lipids which come from lumen to tunica intima)
Proliferate
Once die, rutpture and the cholesterol ingested becomes crystalised
Smooth muscle cells in tunica intima start organising, (depositing collagen and ECM ?)
Distinguish between stenosis and occlusion of an artery.
Stenosis is a decrease in blood flow through the artery, occlusion is a complete blockage of blood flow through the artery.
How is total occlusion of left anterior descending artery compensated for by the body ?
Filled by Collaterals from the Right Coronary Artery
Identify the main symptoms of angina.
– Gripping central chest pain
– Radiation to arm and jaw
– Clear and precise relationship to exercise
– Goes off in 2-10 mins after discontinuation of exercise
– Worse after food (because of decreased blood flow to gut). Worse in cold
– No autonomic features
– Flat of hand/fist to describe pain
Is angina a disease ?
No, angina is a symptom
What is the main cause of angina ?
Sub-Endocardial ischaemia (mismatch of blood supply (i.e. coronary blood flow) to demand (i.e. myocardial oxygen consumption)), because of epicardial stenosis
What is the main difference on an ECG with angina ?
ST depression