Extra Cardio Flashcards
(198 cards)
Where are common places for atherosclerosis to develop?
- circumflex artery
- Left anterior descending
- right coronary arteries
Why is older age a risk factor for atherosclerosis?
As the body ages the risk for atherosclerosis increases and genetic or lifestyle factors cause plaque to gradually build in the arteries
What is claudication?
Claudication is pain caused by too little blood flow to muscles during exercise
Why is tobacco smoking a risk factor for atherosclerosis?
Tobacco leads to endothelium erosion of the arteries, which then means that lipids can get in and speed up the process.
Why is high levels of serum Cholesterol and obesity risk factors for atherosclerosis?
High levels of LDL’S means more will be deposited in the periphery.
Obesity means there is more pericardial fat and thus increase in inflammation.
Why is diabetes a risk factor for atherosclerosis?
Hyperglycaemia damages the endothelium and also magnifies the effect of other risk factors such as raised cholesterol levels, blood pressure, smoking ext.
Why is hypertension risk factor for atherosclerosis?
Mechanical stimulus to endothelial layer, weakens it.
Why is family history a risk factor for atherosclerosis?
It is a polygenic disease and some of the other risk factors also have a genetic part to them.
- ANRIL expression is associated with atherosclerosis risk at chromosome 9p21
- The ACE enzyme gene contains a insertion/deletion polymorphism, the DD genotype of which has been associated with a predisposition to CAD and MI
What are some other risk factors of atherosclerosis?
1) Male gender
2) Sedentary lifestyle
3) Psychosocial factors (type A personality)
4) Over consumption of alcohol
5) High levels of coagulation factor VII
Why is the focal distribution of an atherosclerosis along the artery length?
Changes in flow/turbulence e.g. at a bifurcation cause the artery to alter endothelial cell pattern. Wall thickness is also changed leading to neointima
What is neointima?
A new or thickened layer of arterial intima formed especially on a prosthesis or in atherosclerosis by migration and proliferation of cells from the media.
How can atherosclerosis lead to angina and thrombus formation?
Eventually the plaque will either occlude the vessel lumen resulting in restriction of blood flow (ANGINA).
or the plaque may rupture (THROMBUS FORMATION).
What initiates atherosclerosis formation?
Injury to the endothelium through smoking, cholesterols, BP, bacterial/viral infection… which leads to endothelial dysfunction(the vessel wall becomes sticky).
Once initiated chemoattractants are released from the endothelium at the site of injury to attract leukocytes which then accumulate and migrate into the vessel wall. When chemoattractants released a concentration gradient is produced.
What are the main cytokines involved in atherosclerosis formation?
IL-1 (MAIN) IL-6 IL-8 IFN-GAMMA C-REACTIVE PROTEIN
What other molecules are involved in leukocyte recruitment to the vessel wall?
Selectins, integrins and chemoattractants.
What do the fatty streaks consist of?
Aggregations of lipid-laden macrophages and t-lymphocytes within the intimal layer of the vessel wall.
What are foam cells?
Macrophages that have taken up lots of lipids
Progression of atherosclerosis: what are constituents of intermediate lesions?
- Foam cells.
- Vascular smooth muscle cells.
- T lymphocytes.
- Platelet adhesion and aggregation.
- Extracellular lipid pools.
Progression of atherosclerosis: what are the constituents of fibrous plaques?
The fibrous cap is made of extracellular matrix proteins including collagen (strength) and elastin (flexibility) laid down by smooth muscle cells that overly lipid core and necrotic debris. Maybe calcified.
- Smooth muscle cells.
- Macrophages.
- Foam cells.
- T lymphocytes.
- Plaque is filled with fibrin
Fibrous plaques can impede blood flow and are prone to rupture.
Progression of atherosclerosis: why might plaque rupture occur?
Fibrous plaques are constantly growing and receding. The fibrous cap has to be resorbed and redeposited in order to be maintained. If balance shifted in favour of inflammatory conditions due to increased enzyme activity), the cap becomes weak and the plaque ruptures. Basement membrane, collagen and necrotic tissue exposure as well as haemorrhage of the vessel within the plaque. Thrombus formation and vessel occlusion.
Progression of atherosclerosis: why might plaque erosion occur?
The fibrous cap may be disrupted by collagen leading to thrombosis. The difference to a plaque rupture is that thrombosis is triggered by collagen and not tissue factors. A platelet-rich clot may overlie the luminal surface and there may be a prominent lipid core.
What is restenosis?
Restenosis means that a section of the blocked artery that was opened up with angioplasty or a stent has become narrowed again. This is normally due to the response of the vascular tissue to the injury caused by coronary angioplasty
What are stents made from? why?
Made from stainless steel as they are able to withstand the pressure.
What drugs could be put on the stent? why do we do this?
Sirolimus. It stops the proliferation of smooth muscle cells from the media layer into the plaque.