Cardiovascular System Flashcards
What is atheroma?
A degenerative condition affecting large and medium sized arteries.
Name the arteries affected by atheroma in the heart, brain, kidney, intestine and limbs?
Coronary, carotid, renal, mesenteric, iliac
How does atheroma develop?
It begins with damage to the endothelium of vessel lumen which allows LDL to enter the intima
What happens when lipids enter the intima?
They are phagocytosed by macrophages and form a fatty streak
What is the effect of oxidised lipids?
These are worse for the cell wall as they oxygen free radicals are particularly damaging
What is lipid plaque?
Small amounts of lipid released by macrophages
How is fibrolipid plaque formed?
Macrophages secrete cytokines which cause myelofibroblasts to secrete collagen- this causes initial damage to elastic lamina and also covers the plaque surface
What are muscle fibres replaced with?
Collagen
What happens the surface of the fibro-lipid plaque?
It ulcerates- ulceration exposes collagen with fibrin-platelet thrombus formation
What is the cause of the thinning of media in atheroma?
Leads to weakness and inelasticity
What are the risk factors for atheroma?
Adverse lipid profile, diabetes, smoking,obesity
What is the role of HDL in protection from atheroma?
It reduces free cholesterol and inhibits LDL oxidation
What is the role of endothelial damage in atheroma?
Activation of atherogenesis
1) release of growth factors
2) oxidative stress
3) exposure of monocyte adhesion molecules
What are the 3 main consequences of atheroma?
1) reduction in size of vessel lumen
2) thrombus formation
3) weakening of vessel walls
Complications of atheroma?
Is hammock heart disease Cerebrovascular disease (stroke) Renal artery stenosis Infarcted bowel Peripheral vascular disease- gangrene
What is an MI
Constriction of blood supply to the heart
What change would you expect in an ecg for MI?
And elevated ST segment
What is creating kinase?
An enzyme released from myocardial and skeletal muscle cells
How soon after an MI would you see raised creatine kinase? And when would it return to normal?
3-6hrs. 3 days
What is troponin?
Calcium binding complex in muscle incorporating T and I
How soon after an MI would you see raised troponin and how long will it remain raised?
3 hours, last 8 days
What is one problem of troponin over CK?
Troponin is expensive to measure
Difference between troponin I and T?
I is specific to cardiac troponin
T may cross react with troponin in other tissues
What would troponin be in a patient with acute coronary syndrome?
Within reference range
What would troponin be in patients with non ST elevation MI
Raised
What is the increased risk of MI or death in patients with non st elevation MI and raised troponin?
2 to 3 fold within 3 months
What is the normal CK range or men and women?
24-170 U/L and 24-194 U/L in men
What is normal troponin level?