1
Q
Definition of atherosclerosis
A
- degenerative disease of tunica intima affecting large & medium sized arteries
- characterised by atheromas
2
Q
Risk factors of atherosclerosis (2)
A
- Constitutional/Non Modifiable
- age, M, family Hx, genetics - Modifiable
- hyperlipidemia, HTN, diabetes, cigarette smoking, obesity
3
Q
Pathogenesis of atherosclerosis (4)
A
- Chronic endothelial injury
- due to hyperlipidemia, hemodynamic disturbances etc - Response to injury
- Increased permeability & leakage of lipids - lipoprotein accumulation in vessel wall
- LDL oxidised by free radicals - engulfed by macrophages - forms foam cells + stimulates release of growth factors, cytokines, chemokines
- Enhanced leukocyte adhesion, platelet adhesion
- Monocyte migration into intima - transforms into macrophages & foam cells
- Factors induce smooth muscle recruitment - Smooth muscle proliferation & ECM synthesis - stabilises plaque
- Lipid accumulation (extracellularly & within cells)
4
Q
Effects of atheroma (plaque) (2)
A
- Raised lesion - mechanically obstructs blood flow
2. Weakens underlying media - possible aneurysm formation
5
Q
Progression of atheroma (3)
A
- Fatty Streak
- barely visible, smooth, slightly raised, yellow/white
- contains foamy macrophages - Atheroma - Fibrofatty plaque
- raised lesion, protrudes into vessel lumen
- superficial fibrous cap (collagen, SM) + softer necrotic core (lipids, macrophages etc)
- after SM cell prolif & ECM synth - Advanced/Unstable Plaque
- usually smaller, with large lipid core + thin fibrous cap
- more likely to undergo acute plaque change
- intrinsic factors - more MMP (degrade collagen & ECM), less TIMP
- extrinsic factors - bp, platelet reactivity
6
Q
Consequences of atherosclerosis (3)
A
- Chronic atherosclerotic stenosis
- gradual vessel luminal occlusion - compromises blood flow - ischemic injury - stable angina, chronic IHD, intermittent claudication etc - Acute plaque changes
- rupture/fissure, erosion/ulceration, hemorrhage, thrombosis, embolism - Aneurysm formation
