Histopathology 2 - CVS disease Flashcards
Describe the pathogenesis of an atheromatous plaque
1) endothelial injury –> LDL accumulation in tunica intima
2) monocyte adhesion to endothelium
3) monocyte migration into intima –> macrophages and foam cells
4) platelet adhesion –> factor release –> smooth muscle cell recruitment, VSMCs make the fibrous cap
5) lipid accumulation
Earliest change seen in atherosclerotic disease
Fatty streak, no flow disturbance, virtually present in everyone >10 years olf
where do atherosclerotic plaques occur?
Areas of disturbed flow e.g. carotids and coronary arteries
Characteristics of a vulnerable atherosclerotic plaque
Thin fibrous cap, lots of foam cells and extracellular lipid, few smooth muscle cells
2 main fates of an atherosclerotic plaque
Rupture or obstruction
What kinda flow through vessels is atherogenic? What kinda flow protects against atherogenesis
Low/oscillatory shear stress/turbulent = atherogenic
High laminar flow = protective
CAUSE OF STABLE ANGINA?
Atheromatous plaque causes 70% occlusion of vessel and demand > supply, this level of occlusion cannot be reversed by vasodilation
What is the main cause of MI?
90% of MI is caused by reduced blood flow due to atherosclerosis
What % of stenosis is needed to cause pain at rest?
90% stenosis
3 main types of angina
Stable, unstable, prinzmetal
Site of atherosclerotic plaques in IHD
First few cm of LAD or LCX
Entire length of rCA
What is angina?
Transient myocyte ischaemia that does not cause necrosis
What can be a cause of stable angina becoming unstable;e
Superimposed thrombus
What is the most common cause of death in post menopausal women?
IHD
At what point does myocardial ischaemia –> myocyte necrosis?>
20-30 mins
2 most commonly affected arteries in MI
LAD, RCA
Does HF always come after and MI?
NO!
Myocyte ischaemia for 60s –> loss of contractility –> HF
Ischaemia takes 20-30 mins to come on therefore you can have HF without histological changes of ischaemia
Histological findings of MI after 4 hours?
Normal histology (Takes around 6 hours for histology to show ischaemia)
CK-MB levels after 4 hours post MI
Normal
Histological findings of MI after 23 hours?
Loss of nuclei, COAGULATIVE necrotic cell death (6-24 hours)
Histological findings of MI after 3 days
Infiltration of neutrophils and then macrophages to clear up debris
Histological findings of MI after 10 days
Granulation, angiogenesis (angioblasts), collagen synthesis (myofibroblasts)
Histological findings 3 weeks post MI
Decellularising scar tissue
Complications of MI (DARTH VADER)
Death, arrhythmias, rupture (papillary muscle), tamponade, heart failure
Valvular disease, aneurysms of ventricle, Dressler’s syndrome, embolism, recurrence
