Atherosclerosis Flashcards
What does atherosclerosis mean?
Athere= gruel Sclerosis= hardness
What is atheroma?
Fibro fatty plaques
- Intimal fibrous cap
- Central core rich in lipids
What is the clinical significance symptomatic atherosclerosis?
- contributes to 50% of all deaths
- MI, Stroke, aneurysms, peripheral vascular disease
Describe the change in death rate due to atherosclerosis from 1963 to 2000
- 1963 (peak)»_space;>2000
- 50% decreased death rate heart attack
- 70% decreased death rate stroke
- due to:
- Prevention of atherosclerosis
- Improved methods of treatment
- Prevention of recurrences
What are the risk factors of atherosclerosis?
- Age
- Sex
- Genetics
- Hyperlipidaemia
- Hypertension
- Smoking
- Diabetes mellitus
What is involved of the pathogenesis of atherosclerosis?
- Chronic endothelial injury/ dysfunction
- Role of lipids
- Role of macrophages
- Smooth muscle proliferation - tunica media
- Formation of a fibro lipid plaque
- Injury to the plaque - thrombus formation
What is Chronic endothelial injury/ dysfunction caused by?
- Haemodynamic disturbances
- Hypercholesterolemia
- Hypertension
- Smoking
- Toxins
- Viruses
- Immune reaction
What happens during chronic endothelial injury/dysfunction?
- Increased endothelial permeability
- Increased Leukocyte adhesion
- Vascular cell adhesion molecule 1 (VCAM-1)
- Intercellular adhesion molecule 1 (ICAM -1)
- P- selectin
- E- selectin
- Increased Monocyte adhesion
Describe the role of lipids in the pathogenesis of atherosclerosis
- Hyperlipidaemia (LDL cholesterol)
- Impairs endothelial function
- Accumulates within intima
- Causes oxidative modification of LDL:
- Ingested by macrophages via SCAVANGER receptors = foam cells
- Chemotactic for monocytes
- Inhibit the motility of macrophages
- Stimulates release of cytokines
- Cytotoxic to endothelial and smooth muscle cells
Describe the role of macrophages in the pathogenesis of atherosclerosis?
- Engulf oxidised LDL = foam cells
- Secret
- IL1 (Interleukin 1)
- TNF (Tumour necrosis factor)
- MCP1 ( monocyte chemotatic protein 1) and growth factors ( PDGF, FGF TNF)
- Interferon α, TGFβ
- Fatty streak -accumulation of the large number of foam cells tunica intima
Describe the role of smooth muscle proliferation in the pathogenesis of atherosclerosis
Collagen and ECM deposition»_space; Fatty streak»_space; Mature fibro fatty Atheroma
What is atheromatous plaque?
fibro-fatty, fibro-lipid plaque
- Patchy and raised white to yellow 0.3-1.5cm
- Core of lipid
- Fibrous cap
Where does atheromatous plaque appear?
- Abdominal aorta
- Coronary arteries
- Popliteal arteries
- Descending thoracic aorta
- Internal carotid arteries
- Vessels of the circle of Willis
What are the complicated lesions of atheroma?
- Calcification
- Rupture or ulceration
- Haemorrhage
- Thrombosis
- Aneurysmal dilatation
What are fatty streaks?
- Fatty dots < 1 mm
- Elongated streaks 1cm or longer
- Foam cells + T lymphocytes
- In aorta age <1 year
- In coronary artery form in adolescence
- May be precursors of plaque
What are the clinical features of atherosclerosis?
- Only if complications:
- Thrombosis
- Calcification
- Aneurysmal dilatation
- Ischaemic events:
- Heart
- Brain
- Lower extremities
- Other organs
How can atherosclerosis be primarily prevented?
- Stop smoking
- Control hypertension
- Weight reduction
- Lowering total LDL
- Reduce calories intake
How atherosclerosis be secondarily prevented?
- Prevent complication
- Antiplatelet drugs in thrombosis
- Lower blood lipid levels
