Cardiovascular Disease Flashcards
What is this?
Atherosclerosis
What is atherosclerosis?
An arteriosclerosis characterized by atheromatous deposits in and fibrosis of the inner layer of the arteries.
What is atherosclerosis characterised by?
Atheroscelrosis characterized by intimal lesions.
Atheroma (atheromatous plaques) - that protrude into vessel lumen.
What is this?
Atherosclerosis
What is an atheromatous plaque?
Raised lesion
Soft lipid core
White fibrous cap
What are the main risk factors for atherosclerosis?
Age
Gender
Genetics
Hyperlipidaemia
Hypertension
Smoking
Diabetes Mellitus
How do the number of risk factors affect the risk of getting atherosclerosis?
2 risk factors increase the risk fourfold
3 risk factors increase the risk sevenfold
What is the pathogenesis of atherosclerosis?
Chronic inflammatory and healing response of arterial wall to endothelial injury.
- Endothelial injury
- Lipoprotien accumulation (LDL)
- Monocyte adhesion to endothelium
- Monocyte migration into intima -> macrophages & foam cells
- Platelet adhesion
- Factor release
- Smooth muscle cell recruitment
- Lipid accumulation -> extra & intracellular, macrophages & smooth muscle cells
What is the pathogensis of smooth muscle proliferation?
- Intimal smooth muscle proliferation
- Some from circulating precursors – (have synthetic & proliferative phenotype)
- ECM matrix deposition
- Fatty streak -> mature atheroma & growth
- PDGF, FGF, TGF-alpha implicate
Which infections can predispose to atherosclerosis?
Herpes
CMV
Chlamydia pneumonia
What is this?
Atherosclerosis - smooth muscle proliferation
What is a fatty streak?
Earliest lesion
Lipid filled foamy macrophages
No flow disturbance
In virtually all children >10yrs
Relationship to plaques uncertain
Same sites as plaques
What is an atherosclerotic plaque?
Patchy – local flow disturbances
Only involve portion of wall
Rarely circumferential
Appear eccentric
Composed of – cells, lipid, matrix
What is this?
Atherosclerotic plaque
What are the consequences of atheromas?
Stenosis
Acute plaque changes
What is stenosis?
Critical stenosis – demand > supply
Occurs at ~70% occlusion (or diameter <1mm)
Causes “stable” angina
Can lead to Chronic Ischaemic Heart Disease
Acute plaque rupture can occur
What is this?
Plaque disruption Type 11 eccentric ragged stenosis
What is this?
This is a normal coronary artery with no atherosclerosis and a widely patent lumen that can carry as much blood as the myocardium requires.
What are acute plaque changes which can occur?
Rupture: Exposes prothrombogenic plaque contents
Erosion: Exposes prothrombogenic subendothelial basement membrane
Haemorrhage into plaque: Increase size
What are vulnerable plaques?
Lots foam cells or extracellular lipid
Thin fibrous cap
Few smooth muscle cells
Clusters inflammatory cells
What is the mechanism for a rupture of a vulnerable plaque?
Adrenaline increases blood pressure & causes vasoconstriction.
Increases physical stress on plaque.
Hence emotional stress increases risk of sudden death.
Circadian periodicity to sudden death (6am-noon).
How do vulnerable plaques contribute to plaque growth?
Not all rupture causes occlusion.
Plaque disruption with platelet aggregation & thrombosis probably common.
Important mechanism for plaque growth.
What can vasoconstriction be due to?
Adrenergic agonists
Platelet contents
Reduced endothelial relaxing factors
Mediators from perivascular cells
What is this?
Human coronary atherosclerotic plaque with a yellow core of lipid separated from the lumen by a fibrous cap.
What is ischaemic heart disease?
Leading cause of death worldwide for men and women (7million/year).
Group of conditions resulting from myocardial ischaemia.
Imbalance of supply to demand for oxygenated blood.
Also less nutrients & less waste removal.
Therefore less well tolerated than pure hypoxia.
90% myocardial ischaemia due to reduced blood flow due to atherosclerosis.
Long silent progression prior to symptoms.
What is this?
IHD
What is this?
IHD