Atheroma, hypertension, cardiovascular risks Flashcards
(27 cards)
What is the aetiology of atheroma?
cigarette smoking, hypertension, hyperlipidaemia, diabetes, age (older), sex (males), genetics
What is the 4 steps in developing atheroma?
1- Primary endothelial injury. (smoking, hypertension, hyperlipidaemia, immune factors, toxins, viruses
2- accumulation of lipids and macrophages (increase LDL, reduced HDL)
3- migration of smooth muscle cells (PDGF, FGF, TGFalpha)
4- increase in size
How does atheromatous plaques progress?
- Fatty streak, fibrofatty plaque, complicated plaque-with thrombus
- loss of luminal patency and arterial wall weakness
What are the three things that will leads to atheromatous narrowing leading to a critical disease?
- only artery supplying an organ tissue
- the artery diameter is small
- overall blood flow is reduced
What is the role of macrophages in the formation of athersclerotic plaque?
macrophages take up oxidised LDL-C
What are the 5 major classes of lipoproteins?
VLDL, IDL, LDL-atherogenic
VLDL and chylomicrons- non atherogenic
What is the endogenous pathway of lipid metabolism?
1-chylomicrons transport triglyceride from gut to the liver,
2-triglyceride/cholesterol/cholesterol ester and other lipoproteins are transported in vldl in the blood stream where VLDL undergoes delipidation with the enzyme lipoprotein lipase
3-
this is an endogenous pathway of lipid metabolism
Exogenous pathway of lipid metabolism?
transport and utilises dietary fat.
dietary fat is broken down in the GI tract into cholesterol, fatty acids and mono-glycerides. these molecules together with bile acds, form water soluble micelles that carry the lipid to absorptive site in duodenum
how do statins work to lower cholesterol levels?
- inhibit HMG coA reductase, the enzyme involved in the rate limiting step in the formation of cholesterol.
- in response- hepatocytes increase LDL receptors uptake of LDL and LDL precursors from the plasma. this increases HDL level.
What are the consequences of high lipid levels?
xanthelasma
tendon xanthomas
eruptive xanthomas
What are the complications of atheroma?
arterial stenosis arterial thrombosis aneurysm dissection emoblism
What is cardiac fibrosis ?
loss of cardiac myocytes
replacement by fibrous tissue
loss of contractility
reduced elasticity and filling
what is an aneurysm?
abnormal and persistent dilatation of an artery due to an weakness in its wall
Complication of an aneurysm ?
rupture 6cm thrombosis emoblism pressure erosion of adjacent structures infection
What is an arterial dissection?
- splitting within the media by flowing blood
- middle age +/- atheroma
- false lumen filled with blood within the media
- sudden collapse and high mortality
What are some associations with aortic dissections?
marfans syndrome trauma pregnancy atheroma hypertension
What are the main sites of infarct for an embolism?
-cerebral infarct
renal infarct-renal failure
lower limb infarct
What blood pressure is expected in hypertension?
> 140/90
Risk factors for hypertension?
cerebral haemorrhage
atheroma
renal failure
sudden cardiac death
primary hypertension due to?
-genetic factors salt intake -protein intake -raas system -sympathetic activity BP=TPR X CO
Secondary hypertension?
underlying disease is implicated such as:
- renal disease
- endocrine disease
- aortic disease
- renal artery stenosis
- drug therapy
give examples of renal causes?
reduced renal blood flow
excess renin release
salt and water overload
Endocrine causes, conns syndrome is?
excess aldosterone
cushing syndrome causes secondary hypertension due to?
excess corticosteroids
