Atheroma formation Flashcards
what are the types of risk factors for atherosclerosis?
unmodifiable
modifiable
unmodifiable risk factors for atherosclerosis
ageing
genetics
ethnicity
gender
effect of genetics on atherosclerosis risk
fibrinogen clotting factor disorders
lipid disorders
unlikely to be a single gene disorders although family history is strong predictor
effect of ethnicity on atherosclerosis risk
asians are at greater risk of heart disease and african and caribbeans have a higher risk of hypertension
effect of gender on atherosclerosis risk
men more at risk than women as oestrogen acts as protective factor until menopause then equal risk
modifiable risk factors for atherosclerosis
smoking alcohol diabetes hypertension obesity raised cholesterol physical inactivity metabolic syndrome - abdominal girth hyperglycaemia
pathogenesis of atherosclerosis
- endothelial dysfunction
- LDL accumulation and oxidation in walls of arteries which damages endothelium
- macrophages - foam cells when they phagocytose LDL and T cells recruited
- inflammation
- cell death
- cell recruitment
- smooth muscle cell proliferation - repair and remodelling
- collagen deposition
- formation of fibrin plug
- fibrin plug weakens so more likely to cause plaque rupture
- plaque rupture causes subendothelium to be exposed
- activates platelets and coagulation cascade causing thrombus formation
- fibrin clot can cause occlusion of artery
- calcification of arteries - more likely to rupture
- narrowing of arteries
what is the end result of atherosclerosis formation?
occlusion of arteries causing: MI Stroke Critical leg ischaemia Cardiovascular death
what is the tunica intima?
innermost layer of artery,
where LDL is deposited in artery
what are the different types of angina?
stable
unstable
how to treat stable angina?
GTN spray
aspirin
beta blocker/ calcium channel blocker
long acting nitrates
what does GTN spray do?
dilates arteries
where is LDL deposited?
tunica intima
what does aspirin do?
prevents platelet aggregation
what happens in stable angina?
there is not complete occlusion of artery/ not rupture, just narrowing.
how to treat coronary thrombosis/ STEMI?
aspirin - 300mg loading dose
P2Y12 inhibitor - 600mg clopidogrel
unfractionated heparin in cath lab
PCI
what is PCI?
percutaneous coronary intervention
what is a pack year?
1 pack year = 20 cigarettes a day for a year, 20 in a pack
what is T wave inversion a sign of?
myocardial ischaemia - NSTEMI
difference between treating NSTEMI and unstable angina?
there is no difference
how to detect an MI?
troponin T and I most sensitive
what does creatinine kinase MB show?
re-infarction
symptoms and signs of unstable plaque but without complete occlusion
chest pain intermittently but at rest
reduced exercise tolerance
associated ECG changes - T wave inversion
how to treat NSTEMI
aspirin - 300mg loading dose P2Y12 inhibitor - clopidogrel 600mg unfractionated heparin (IV) in cath lab anticoagulant - low molecular weight heparin until PCI PCI ASAP but not emergency
what is the difference between NSTEMI, STEMI, coronary thrombosis and unstable angina?
NSTEMI and STEMI - presentation of ECG
coronary thrombosis and unstable angina = how much occlusion there is
how to treat unstable angina?
aspirin - 300mg loading dose P2Y12 inhibitor - clopidogrel 600mg unfractionated heparin (IV) in cath lab anticoagulant - low molecular weight heparin until PCI PCI ASAP but not emergency
antiplatelet agents
glycoprotein IIb/IIIa inhibitors
e.g. aciximab
tirofiban
eptifibatide
what do glycoprotein IIb/IIIa inhibitors do?
block integrin receptor for fibrinogen and block final platelet aggregation pathway by inhibiting fibrinogen bridges
when are glycoprotein IIb/IIIa inhibitors used?
used if patient is going for PCI - just beforehand
how can we regress or stabilise coronary plaques?
reduce vulnerability of plaque
risk factor management
risk factor management
lower cholesterol with statins
control BP
quit smoking
other lifestyle factors - exercise, alcohol
reduce vulnerability of blood to thrombosis
how to reduce the vulnerability of blood to thrombosis?
antithrombotic drugs - aspirin for life
clopidogrel or similar for 1 year following the event
need to compare bleeding risks for other agents used
Post NSTEMI/ STEMI treatment
statins - atorvastatin antiplatelet - clopidogrel beta blocker - bisoprolol ACE inhibitor - ramipril remember GI protection as these drugs cause GI bleeding - lansoprazole
what do statins do after STEMI/ NSTEMI?
stabilise plaque
what do antiplatelets do after STEMI/ NSTEMI?
maintain stent patency
coronary stent
drug eluting stents
prevent proliferation of epithelium and reduce risk of restenosis but increases risk of stent thrombosis which is why anti-platelets are needed
stent thrombosis
iatrogenic acute coronary syndrome
all stented coronaries are vulnerable
how to prevent stent thrombosis?
good technique
anti-platelet drugs
90 times more likely if anti-platelets stopped early
