Atherosclerosis Flashcards
What is the definition of atheroma?
Formation of a focal elevated lesion (plaque) win the intima of large and medium-sized arteries
Describe the general progression of atheroma formation?
- Fatty streak
- Early atheromatous plaque
- Fully developed atheromatous plaque
What structures can rim the intima?
Foamy macrophages
What is the nature of atheroma that leads to occlusion of vessels?
Highly thrombogenic
What is arteriosclerosis?
Non-atheromatous disease - age related loss of compliance of elastic fibres of arteries
What comprises a fatty streak?
Lipid laden macrophages - look like a yellow smear
What are the constituents of a fully atheromatous plaque?
Central lipid core capped with fibrous material and covered by a endothelial layer
What is the physiological change in arteriosclerosis?
Smooth muscle hypertrophy, apparent reduplication of elastic laminae, intimal fibrosis leads to decrease in vessel diameter
What is the general aetiology of atheroma?
Hypercholeterolaemia
What are the typical signs of hyperlipidaemia?
Biochemical evidence - LDL, HDL total cholesterol and TAGs
Corneal arcus
Tendon xanthomata
What is the two step process to developing an atheromatous plaque?
- Endothelial injury
2. Chronic inflammation and healing response of the vascular wall
Risk factors of atheroma are?
Smoking Hypertension Diabetes mellitus Male Elderly
What are some less strong risk factors for developing atheroma?
Obesity
Sedentary lifestyle
Low-Socioeconomic status
Low birthweight
Normal blood flow is described as what?
Laminar
What two abnormal blood flow patterns are there?
Stagnation and turbulence
What can abnormal blood flow precede?
Thromboembolism, atheroma, hyperviscosity, spasm, vasculitis and vascular steal
What is vascular steal?
Reduction in blood flow to tissue as a result of abnormal blood flow
What is Virchow’s Triad?
A set of three conditions for the development of thromboembolism
What does Virchow’s Triad consist of?
- Changes in blood vessel intima
- Changes in blood constituents
- Changes in the pattern of blood flow
What is thrombosis?
The formation of a solid mass from the constituents of blood within the vascular system during life
What is the pathogenesis of thrombosis?
- Endothelial injury
- Stasis or turbulent blood flow
- Hypergoaculability of blood
What do the consequences of thrombosis depend on?
Site, extent and collateral circulation
What are the common clinical outcomes of thrombosis?
DVT, Ischaemic limb and MI
What is embolism?
Movement of abnormal material in the bloodstream and its impaction in a vessel; blocking its lumen
What is an embolus?
Detached intravascular solid, liquid or gaseous mass
Most emboli are dislodged thrombi; what are these known as?
Thromboemoli
List a few types of emboli
Systemic/arterial Venous embolism Fat embolus Gas embolus Air embolus
Tumour, trophoblast, septic material, amniotic fluid, bone marrow, foreign bodies
What is the pathophysiology of SIHD?
Due to a mismatch between the demand for O2 by the myocardium and supply
What causes SIHD?
Reduced blood flow in coronary arteries
Reduced oxygen tension
Pathological increase in O2 demand
What are common, infrequent and rare cases of reduced blood flow in coronary arteries?
Common - Atherosclerosis
Infrequent - Coronary artery spasm
Rare - Coronary inflammation/arthritis
What could cause reduced oxygen tension?
Anaemia
What could cause a pathological increase in O2 demand?
Left ventricular hypertrophy and thyrotoxicosis
What are a few examples of modifiable risk factors for SIHD?
Smoking, diet, hyperlipidaemia, hypertension, diabetes
What are a fe non-modifiable risk factors for SIHD?
Age, sex, genetics
What is the defining clinical presentation of SIHD?
Retro-sternal dull chest pain with potential radiation into the left axilla and neck
What are the five relevant investigations for SIHD?
Blood tests CXR ECG ETT Myocardial perfusion imaging
What would you look for in a full blood test?
Electrolytes, thyroid and liver function, fasting glucose, FBC and lipid profile
What would you look for in an ECG?
Pathological Q-waves - Prior MI
High voltage/lateral ST-depression (strain pattern) - LVH
What would you look for in an ETT?
ST depression strain pattern for positive test
What does myocardial perfusion imaging help distinguish?
Between ischaemia and MI
If it is not possible to get the patient to exercise, how can stress be induced?
Adenosine
What is the role of treatment in the SIHD?
- Halt progression
- Relieve symptoms
- Regression of disease
- Prevent MI