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Path + CR: Atherosclerosis (i) (Atheroma (risk factors (DM (hypertension…
Path + CR: Atherosclerosis (i)
highest BP in arts
followed by arterioles, capills, venules + veins
elastic muscular, small lumen
vasc endothelial cells
semi permeable membrane (maintains blood-tissue interface, alters leakage)
modulate vasc tone, blood flow + immune/inflamm reactions
modify lipoproteins in art wall
Atheroma
fibrolipid plaque deposited on arts
low in vegetarians
if it builds-up vessel wall hardens + lumen narrows (chronic inflamm in response to endothelial injury)
= atherosclerosis
consequences
infarct (complete occlusion)
ischaemia (e.g. bowel ischaemia in a mesenteric occlusion)
emboli (of thrombus/chol/platelet)
aneurysm (dilation that could lead to rupture/dissection)
peripheral vasc disease
death
most common cause of ischaemia + infarction
pathogenesis
chronic endothelial injury due to
hyperlipidaemia
failure to clear LDLs (deliver chol to peripheral tissues)
HDLs mobilise chol + transport it to liver to excrete it in bile
due to high lipid dietary intake commonly
hypertension
smoking
1+ packs/day for several yrs increases death rate from IHD by 200%
toxins
viruses
haemodynamic factors
homocysteine (common AA in meat)
accumulation of LDL in wall
early stages = fatty streaks
monocytes + leucocytes arrive in intima + transform to macrophages to engulf lipids
factors from macrophages + platelets cause migration of smooth muscle cells from media to intima (towards lumen)
smooth muscle prolifs + stims fibroblasts to lay down collagen, which protrudes into lumen + can eventually lead to an occlusion
risk factors
age
risk increases with each decade
gender
increased risk in males, until menopause
genetic abnormalities
usually polygenic
post-menopausal oestrogen deficiency
type A personality (stress)
DM
hyplipidaemia (hypercholestraemia
hypertension
both sys + dias important
MI incidence doubles
100-fold increase in atherosclerosis-induced gangrene of lower extremities
high unsaturated fat intake
obesity
physical inactivity
smoking
alcohol
chlamydia pneumoniae
Distribution
abdominal aorta (esp around ostia of major branches - more turbulence)
coronary arts
left coronary art = critical spot, occlusion = Widow-Maker's disease
popliteal arts
descending thoracic aorta
int carotid + arts of circle of Willis
can be widespread (systemic embolisation)
management
stop smoking
control hypertension + DM
lose weight (diet + excercise)
statins (control hyperlipidaemia, plaque rupture + platelet aggregation)
causes of aortitis
giant cell arteritis
other arteritis
RA
syphilis
arteriolosclerosis
narrowing of small arterioles due to hypertension
Troponins
enzymes in cardiac muscle cells
when necrosis occurs they're released into bloodstream