Define atherosclerosis
Formation of focal elevated leisons (in intima of large and medium sized arteries)
atheromas
In coronary arteries atheromatous plaques narrow lumen leading to ischaemia
Can have serious consequences due to myocardial ischaemia
Complicted by thromboembolism
Ateriosclerosis
What are the 4 different developmental stages of an atheroma?
Fatty Streak
Early atheromatous plaque
Fully developed atheromatous plaque
Complicated atheroma
Describe a fatty streak atheroma
Describe early atheromatous plaques
Describe fully developed atheromatous plaques
Describe a complicated atheroma
What are the signs of major hyperlipidaemia
Describe the development of atheromatous plaques
Two step process:
Describe the pathogenesis of atherosclerosis
What are the 2 most common causes of endothelial injury?
Haemodynamic disturbances (turbulent flow) Hypercholesterolaemia
Describe Describe how hypercholesterolaemia can cause injury to the endothelium
describe how endothelial cells are functionally altered in atherosclerosis
Describe advanced plaque formation
What are the consequences of atheroma
Many plaques form over lifetime, many clinically unnoticed
Acute changes in plauqes (complicated atheroma) can have serious consequences
What does stenosis of 50-75% of vessel lumen lead to?
Critical reduction of blood flow in distal arterial bed -> reversible tissue ischaemia
What can very severe stenosis lead to?
Ischaemia - pain at rest
[unstable angina, eg ileal popliteal artery stenosis -> intermittent claudication]
What can longstanding tissue ischaemia lead to?
Atrophy of affected organ eg aterhosclerotic renal artery stenosis -> renal atrophy
What does rupture exposing collagen, lipid and debris to the blood stream do?
these are all highly thrombogenic plaque contents. Leads to the actiation of coagulation cascade and thrombotic occlusion in very short time
What does total occlusion of an artery lead to?
Irreversible iscahemia
embolisation of the distal arterial bed
Ruptured atheromatous abdominal aortic aneurysm
What diameter does an aneurism become at risk of rupture?
5cm