Pathophysiology of Atheroma Flashcards
What is the definition of atherosclerosis?
Formation of focal elevated lesions in intima of large and medium sized arteries
What is narrowing of coronary artery lumen known as?
Ischaemia
What does myocardial ischaemia lead to?
Angina
What is a thromboembolism?
An embolism broken off from a thrombus
What is the pathology of atherosclerosis?
- Not atheromatous
- Age related change in muscular arteries
- Smooth muscle hypertrophy
- Reduplication of internal elastic laminae
- Intimal fibrosis
When are the clinical affects of atherosclerosis most apparent?
- Haemorrhage
- Major surgery
- Infection
- Shock
What is an atheroma?
- Fatty streak
- Seen in young children
- Yellow linear elevation of intimal lining
- Contains lipid laden macrophages
- May disappear
- Can progress to early atheromatous plaque
What is an early atheromatous plaque?
- Young adults onwards
- Smooth yellow patches in intima
- Lipid laden macrophages
- Progresses to established plaques
What is a fully developed atheromatous plaque?
- Central lipid core with fibrous cap
- Covered by arterial epithelium
What does the fibrous cap of a fully developed atheromatous plaque provide?
- Made from collagens
- Provides structural strength
What cells reside in the fibrous cap?
- Macrophages
- T lymphocytes
- Mast cells
What is commonly present to do with the immune system in a fully established plaque?
- Thrombogenic soft ring of “foamy” macrophages
What occurs late in plaque development that will show on an angiogram?
Dystrophic calcification
What can be detected if the calcification occurs at branching points or bifurcations?
Turbulent flow
What is a complicated atheroma?
- A fully established atheroma but
- Haemorrhage into the plaque leading to calcification
- Plaque rupture can occur
- Thrombosis
What is the most important risk factor for atheromatous plaque?
- Hypercholesteraemia
What ways can hypercholesteraemia lead to plaque?
- Causes plaque formation + growth
- LDL cholesterol (lack of cell LDL receptors causes LDL to be deposited
What ratio of caucasians are heterozygous for hypercholesteraemia?
1/500
What ratio of caucasians are homozygous for the condition?
1/million
What will the hetorozygous mutation lead to?
- Loss of function cell LDL receptors
- Elevated plasma LDL
What will the homozygous mutation lead to?
- Much higher cholesterol level
- Patients usually die from a coronary heart atheroma in infancy