B4.021 - Atherosclerosis Flashcards
what is atherosclerosis
lipid laden deposits in the intima of large and medium sized arteries
what is atherosclerosis characterized by
linear growth and quantum progression, spatial predilection
what is critical stenosis
when chronic occlusion significantly limits flow and demand begins to exceed supply
when does critical stenosis occur
usually around 70% occlusion
what preserves luminal diameter as the total circumference expands
outward remodeling
what are cholesterol crystals
crystal like absences from where cholesterol used to be
what is looked at in an angiogram
lumen
what is seen within the plaque here
cholsterol crystals
describe the response to injury hypothesis
Chronic endothelial cell injury leads to accumulation of lipoproteins (LDL) in injured area. Modification of lesional lipoproteins by oxidation leads to adhesion and migration o fblood monocytes into lesion and transformation to foam cells. Platelets adhese and cytokines and growth factors cause migration of smooth muscle cells from media to intima then that produces extracellular matrix
risk factors for atherosclerosis
age
gender
genetic influences
hyperlipidemia
hypertension
smoking
DM
other
what is c reactive protein a marker for
inlammation
why are women less likeyl to get atherosclerosis earlier in life
estrogen is protective
describe the structure of lipoproteins
within the surface: cholesterol, phospholipids
center: cholesteryl esters, triglycerides
what is the highest density lipoprotein
HDL
what are the largest/least dense lipoproteins
chylomicrons
what are the 2 major goals of lipoprotein metabolism
- transport TGs from intestine and liver to sites of utilization
- transport of cholesterol to peripheral tissues for membrane synthesis and steroid hormone production
what is the main lipoprotein that transports TGs from intestine to liver
chylomicrons
what is the main lipoprotein that transports cholesterol from liver to other tisseus
VLDL, LPL
what is the “good cholesterol”
HDL
what does HDL do
reverse cholesterol transort
takes up cholesterol from extrahepatic sources, esterification by LCAT and transport by large HDL particles
how do cells regulate cholesterol content
- synthesis in the SER
- receptor mediated endocytosis of LDL
- efflux of cholesterol from plasma membranes to apo-A1/HDL
- intracellular cholesterol esterification via acetyl-CoA acetyltransferase
clinical assessment of lipids
total cholesterol
TGs
LDL
HDL
what is cholestyramine
bile-acid binding resin
what does ezetimibe do
cholesterol absorption inhibitor
what do statins do
decrease LDL, HMG-CoA inhibitor
who are statins indicated for
those with 10 yr cardiac risk >7.5%
what is fenobritate
fibrate
inhibits PPAR-alpha
what does niacin do
decreases hepatic VLDL secretion
what can niacin cause as a side effect
intense flushing
not being able to take statins is a risk factor for what
Future events
how does aspirin work
inhibits thromboxane A2 by irreversible acetylating COX-1, this attenuates platelet activation
how long does it take for aspirin to get out of your system
1 week bc it irreversibly binds
if you have a life threatening issue youre taking aspirin for when do you stop taking it before surgery
you dont
how is aspirin used for primary prevention of atherosclerosis
prevents events
doses >75 mg/day show clear reduction in mortality and cardiovascular events
what are contraindicatinos for aspirin in pts with atherosclerosis
allergy
bleeding
most common cause of aspirin intolerance
GI upset
what are risk factors for atherosclerosis you can prevent/treat
HTN
Hyperlipidemia: use of statins
smoking cessation
DM and glucose intolerance
lifestyle
how is CRP generated
in response to IL-1/6 pathway
what is a biomarker
something that varies with disease, can be detected specifically and sensitiviely and is relatively cheap to test for
how early can atherosclerosis be seen
2nd decade of life
what is a xanthoma
when foam cells accumulate at site of vascular injury under the epithelium
natural history of atherosclerosis
normal–> fatty streak –> fibrofatty plaque –> advanced/vulnerable plaque –>
- aneurysm/rupture
- occlusion by thrombus
- critical stenosis
sites that have a predispostion to atherosclerosis
thoracic and abdominal aorta
coronary arteries
peripheral arteries
carotid arteries
sites with natural protection form atherosclerosis
internal mammary (thoracic) artery
which artery is used as a bypass conduite
internal mammary (throacic) artery
where do plaques form usually in vessels
areas with low sheer stress
where are aueurysms common
aorta
where are aneurysms rare
coronary
peripheral
carotids
where are plaque ruptures frequent
coronary
where are occlusions common
coronary
peripheral
where are occlusions rare
aorta
where are occlusions uncommon
carotids
where are embolisms uncommon
coronary
where are embolisms common
aorta, peripheral, carotids
where are dissections rare
coronary
peripheral
carotid
who are coronary dissections seen in
nonathero females
where are dissections common
aorta
what is determinant of if a rupture is going to happen in atherosclerosis
thickness of fibrous cap
what is ultrasound and virtual histology used for
visualizing TCFA and how likely a plaque is to burst
what is optical coherence tomography
flush and clear a blood field to visualize fibrous caps in a vessel
which imaging modality is used here
ultrasound and virtual histology
what imaging modality is used here
optical coherence tomography
what is depicted here
TCFA
cholesterol crystals
what type of event does this represent
rupture
what type of event does this depict
erosion
what is virchows triad
3 primary factors contributing to pathogenesis of thrombosis
- injury to epithelium
- alterations in blood flow
- increased coagulability of blood
what does this represent
lines of Zahn
alternating bands of fibrin with WBC and RBCs entrapped
healed thrombi over the years
what can cause this
cholesterol emboli from aorta causing skin necroses
what is this pathopneumonic for
cholestrol emboli from atherosclerosis
note the cholestrol crystals
how does abdominal aortic aneurism present
abdominal mass, pay pulsate
risk of rupture directly related to size of aneurysm
cutoff diameter for intervention in abdominal aortic aneurysm
5 cm
what is this
aortic dissection
Cross section showing lumen compression due to hemoatoma in tunica media
what is this
recanalized coronary artery post bypass
treatment for MI
stent
treatment for pts with persistent angina
Beta blockers
ACEI
calcium channel blockers
optimal medical therapy for chronic treatment of coronary atherosclerosis
aspirin
statins
risk factor modification
