lecture 5/tutorial 6/7 - atherosclerosis & ischaemic heart disease Flashcards
What is the most common pathology that causes ischaemic heart disease?
Atherosclerosis of coronary arteries
What are the non-modifiable risk factors for atherosclerosis?
genetic condition, family history, increasing age, male sex
What are the modifiable risk factors for atherosclerosis?
high cholesterol, hypertension, smoking, diabetes, inflammation
Which arteries are affected by athersclerosis?
Elastic arteries & large/medium muscular arteries
Why do veins and small arteries/arterioles not get atherosclerosis?
Because the pressure is too low to cause endothelial damage
What is the key driver of the formation of an atherosclerotic plaque?
Endothelial injury
What are the steps in the pathogenesis of atherosclerosis?
- endothelial cell injury causes low grade inflammation
- increased vascular permeability, recruitment of inflammatory cells
- due to increased permeability, oxidised LDL can accumulate in intima
- cytokines released attracting monocytes which migrate, become macrophages and take up lipids to form foam cells.
- smooth muscle cells proliferates, ECM deposited,T cells recruited
- Fibrous cap forms
What are the structural features of an atherosclerotic plaque?
Fibrous cap,
Necrotic centre
What are some of the complications of atherosclerosis?
Mechanical obstruction of vessel lumen, aneurysm (e.g. AAA), acute plaque change
What is acute plaque change?
When an atherosclerotic plaque has haemorrhage into the plaque from new vessels formed by angiogenesis, resulting in ulceration or rupture of the plaque which causes thrombosis
What are the complications of angiogenesis in the development of an atherosclerotic plaque?
Very thin, weak vessels form in the plaque, and if they rupture they can bleed into the plaque causing acute plaque change
What is the morphological difference between a stable and vulnerable atherosclerotic plaque?
Stable has a thicker fibrous cap with a smaller lipid core and less angiogenesis
What percentage stenosis of an artery is considered ‘critical’?
75% occlusion
What are some of the presentations of iscahemic heart disease?
Angina pectoris (stable/unstable), myocardial infarction, sudden cardiac death, heart failure
What is stable angina?
Chest pain caused by coronary occlusion due to a stable atherosclerotic plaque. Brought on by increased cardiac O2 demand, such as during exercise.
What is unstable angina?
Prolonged chest pain caused by plaque change and thrombus occlusion of coronary vessels. Not relieved by rest.
Why does stable angina come on with exercise and resolve with rest?
Caused by narrowed coronary artery which will limit blood supply during periods of high O2 requirements. However, when resting again, blood supply will be sufficient even with the narrowed artery.
What causes the pain experienced with angina pectoris?
Transient and reversible myocardial ischaemia