Pathophysiology of atheroma (part 1) Flashcards
What is the other term for atheroma?
atherosclerosis
What is atherosclerosis?
formation of focal elevated lesion (plaques) in intima of large and medium sized arteries
What is the effect of atheromatous plaques forming in coronary arteries?
ischemia
What can angina cause?
myocardial ischemia
Is arteriosclerosis atheromatous?
it is not!
What is arteriosclerosis?
age-related change in muscular arteries
smooth muscle hypertrophy, apparent reduplication f internal elastic laminae, intimal fibrosis –> decrease vessel diameter
What duplicates in arteriosclerosis?
internal elastic laminae
What does arteriosclerosis cause in the elderly population?
contributes to high frequency of cardiac cerebral, colonic and renal ischemia in elderly
What is the earliest significant lesion of an atheroma called?
fatty streak
How does the fatty streak appear as?
yellow linear elevation of intimal lining
What comprises the fatty streak?
masses of lipid-laden macrophages
What will a fatty streak go on to develop?
atheromatous plaque
Who has a fatty streak?
young children
Can a fatty streak disappear?
yes
After the fatty streak what is next to form?
early atheromatous plaque
What is the structure of a fully developed atheromatous plaque?
central lipid core with fibrous tissue cap, covered by arterial endothelium
What provides the structural strength in the fully developed atheromatous plaque?
collagen
What immune cells are recruited from the arterial endothelium? (reside in the fibrous cap)
inflammatory cell (macrophages, T-lymphocytes, mast cells)
What is the central lipid core rich in?
cellular lipids/debris derived from macrophages (died in plaque)
Why are the macrophages in the lipid core called foamy?
due to uptake of oxidised lipoproteins via specialised membrane bound scavenger receptor
What usually occurs late in plaque development?
dystrophic calcification
Where do atheromatous plaques form ?
at arterial branching points/bifurcations (turbulent flow)
What additional elements does a complicated atheroma have?
features of established atheromatous plaque (lipid-rich core, fibrous cap) plus…
haemorrhage into plaque (calcification)
plaque rupture/fissuring
thrombosis
What does complicated atheroma lead to?
it has clinical consequences
What is the most important risk factor for atheroma?
hypercholesterolaemia
What type of cholesterol is atheroma risk?
LDL
Lack of membrane receptors for LDL
elevated LDL levels
What are signs of major hyperlipidaemia?
primary or acquired
need biochemical evidence: LDL, HDL, total cholesterol, triglycerides
corneal arcus (premature)
tendon xanthomata (knuckles, Achilles)
xanthelasmata
What are risk factors for major hyperlipidaemia?
premature, family history MI/atheroma
smoking
hypertension
diabetes mellitus
male
elderly
acceleration of plaque formation driven by lipids
