Lecture 6 - Atheroma Flashcards
what is an atheroma?
accumulation of intracellular and extracellular lipid in intima and media of large and medium sized arteries
what is atherosclerosis
thickening and hardening of arterial walls as a consequence of atheroma
what is arteriosclerosis?
thickening of walls of arteries and arterioles, usually as a result of hypertension or diabetes mellitus
what is the macroscopic appearance of a fatty streak?
lipid deposits in intima
yellow, slightly raised
what is the macroscopic appearance of a simple plaque?
raised yellow or white
irregular outline
widely distributed
enlarge and coalesce
what is the macroscopic appearance of a complicated plaque?
thrombosis
haemorrhage into plaque
calcification
aneurysm formation
what are the early microscopic changes in atheroma?
proliferation of smooth muscle cells
accumulation of foam cells
extracellular lipid
what are the later microscopic changes in atheroma?
fibrosis
necrosis
cholesterol clefts
change in number of inflammatory cells
what are the cellular events in atheroma?
endothelial damage –> platelets –> pdgf –> smooth muscle proliferation
proliferation and migration of smooth muscle takes lipid with it
macrophages arrive and phagocytose the fat, becoming foam cells
what are the effects of severe atherosclerosis in a coronary artery?
ischaemic heart disease sudden death mi angina pectoris arrythmias cardiac failure
what is the result of cerebral ischaemia?
transient ischaemic attack
cerebral infarction
multi infarct dementia
what is the result of mesenteric ischaemia?
ischaemic colitis
malabsorption
intestinal infarction
anuerysm due to high pressure, hardening and weakening
what is the result of peripheral vascular disease?
intermittent claudication
leriche syndrome
ischaemic rest pain
gangrene
what are the risk factors for atheroma?
age gender hyperlipidaemia cigarette smoking hypertension diabetes mellitus alcohol infection lack of exercise obesity oral contraceptives stress
why is age a risk factor for atheroma?
slowly progressive throughout adult years
why is gender a risk factor for atheroma?
women protected relatively before menopause
presumed hormonal basis
why is hyperlipidaemia a risk factor for atheroma?
high plasma cholesterol associated with atheroma
ldl most significant
hdl protective
why is cigarette smoking a risk factor for atheroma?
risk factor for ischaemic heart disease
why is hypetension a risk factor for atheroma?
strong link between ischaemic heart disease and high bp
potential endothelial damage by high bp
why is diabetes mellitus a risk factor for atheroma?
doubles ischaemic heart disease risk
associated with high risk of cerebrovascular and peripheral vascular disease
what is the unifying hypothesis of atherogenesis?
endothelial injury due to raised ldl, toxins, hypertension and haemodynamic stress
endothlial injury causes platelet adhesion, pdgf release, smooth muscle cell proliferation and migration, insudation of lipid, ldl oxidation, uptake of lipid, migration of monocytes into intima
stimulated smc produce matrix material
foam cells secrete cytokines causing further smc stimulation and recruitment of other inflammatory cells
how can atheroma be prevented?
stop smoking modify diet treat hypertension treat diabetes lipid lowering drugs
what increases susceptibility to coronary heart disease?
genetic disorders eg familial hypercholesterolaemia
geographical eg less common in mediterranean
ethnicity eg common in asians
what are the risk factors for chd?
smoking gender - more common in men hypertension - increased epithelial damage diabetes - increased ihd risk alcohol infection
