1/ Ischaemic Heart Disease Flashcards
What questions need to be asked in a chest pain history?
- its location quality , the relationship with food, breathing and exercise
What are the broad DDx for chest pain?
- cardiac, msk, oesophagitic/hiatus hernia, PE, dissecting aortic aneurysm
What are the cardiac risk factors?
age and male gender FHx diabetes blood pressure hyperlipidaemia smoking BMI and exercise
What are the 5 normal layers if a muscular artery?
intima internal elastic lamina media external elastic lamina adventitia
Describe the appearance of atherosclerosis under microscopy
eccentric intimal expansion made up of connective tissue and lipid causing narrowing of the lumen
–> has a lipid core
Which cells are involved in the initiation and progression of atherosclerosis?
Damaged endothelial cells and activated white cells/macrophages
Describe the two process occurring in endothelial dysfuncton in atherosclerosis
Process A
- there is increased permeability allowing access of molecules through the endothelium
Process B
- endothelial cells show an increased expression of adhesion molecules
- white cells adhere to endothelium
- white cells migrate thought the intima, release cytokines attracting yet more cells and leading to the accumulation of lipid
Describe the endothelial response to injury
- the endothelium is damaged by dyslipidaemia. Particularly oxidised LDL and toxins related to cigarette smoking, also shear stress
- this leads to increased permeability - to lipoproteins, oxidised LDLs, and increased expression of adhesion molecules, leucocytes migrate into the intima and release cytokines, transform into foamy macrophages, smooth muscle cells are recruited
- cytokines self perpetuate the process
- vessels grow into the plaque and a fibrous cap is formed
What is a fatty streak?
- the earliest lesion of atherosclerosis where lipid has accumulated in the intima
What happens to blood vessel size as atherosclerosis increases?
positive remodelling
- early plaque accumulation is associated with compensatory enlargement of vessel size
What is the fibrous cap made of?
collagen
When angina becomes present at rest, what is this called?
What does this mean about the plaque?
Unstable angina
- the plaque is ‘complicated’, disrupted and thrombogenic
Describe the process of unstable angina
- the plaque becomes ulcerated and then ruptures allowing the escape of thrombogenic material
- the fibrous cap becomes thinned - proteolytic enzymes from macrophages mediate this
- new vessels in the unstable plaque can rupture
Which artery has occluded in a posterior infarct?
Which artery has occluded in an anterior infarct?
Which artery has occluded in a lateral infarct?
- right coronary artery
- LAD
- left circumflex artery
Describe the difference in appearance between normal heart muscles and heart muscle after an infarct
- necrotic fibres become vacuolated and eventually lose their nuclei
