Cardiovascular system and disease II Flashcards
What is Atherosclerosis?
- “hardening of the arteries”
- Is a generic term for thickening and loss of elasticity of arterial walls
What is Atherosclerosis characterised by
- Characterised by intimal lesions which protrude into an obstruct vascular lumens
Where does Atherosclerotic develop?
- Atherosclerotic plaques develop primarily in elastic arteries (e.g. aorta, carotid) and large and medium sized muscular arteries (e.g. coronary arteries)
What is Atherosclerosis associated with
- Associated with increased LDL-cholesterol and reduced HDL-cholesterol
What are the causes of Atherosclerosis
- Causes are still unclear
What are the NON MODIFIABLE risk factors for Atherosclerosis
- Age
- Gender M>F
- Positive family history
- Genetic abnormality (eg ACE gene)
What are the MODIFIABLE risk factors for Atherosclerosis
- Hyperlipidemia
- Hypertension
- Smoking
- Diabetes
- Obesity
- Physical inactivity
What is Atherosclerotic plaques
build up of fats, cholesterol and other substances in and on the artery walls
How does plaques slow blood flow
- The plaques protrude into the vessel lumens and
What does plaque consists of
- The plaque consists of a raised lesion with a soft yellow, grumous core of lipid (mainly cholesterol and cholesterol esters) covered by a white fibrous cap
What are the structure of atherosclerotic plaques
- A superficial FIBROUS CAP - SM cells, relatively dense collagen
- Beneath and to the side of the cap (“shoulder”) - a more cellular area containing macrophages, T cells, SM cells
- NECROTIC CORE (deep to the fibrous cap, containing lipid, debris from dead cells, foam cells, fibrin, variably organised thrombus, and other plasma proteins)
- The CHOLESTEROL, frequently present as crystalline aggregates or “clefts”
- NEOVASCULARISATION at the periphery of the lesions
What are the 3 principal components of Atherosclerosis
- CELLS: SMCs, macrophages and other leukocytes
- EXTRACELLULAR MATRICES: collagen, elastin, proteoglycans
- INTRACELLULAR AND EXTRACELLULAR LIPID
What are the morphology of the lesions of Atherosclerosis
- Earliest aortic atherosclerosis: fatty streaks:
- lipid-filled foamy macrophages
- begin as multiple minute flat yellow spots
- Advanced complicated atherosclerosis in abdominal aorta
- many of the lesions have ruptured
- become thrombosed
Explain Endothelial injury as a key pathological event
- Endothelial injury will do two things:
- increases vascular permeability due to damage endothelium
- any damaged endothelium will express adhesion proteins, in normal conditions they will not be expressed
Explain the key pathogenic events
- Endothelial injury: increase vascular permeability, leukocyte adhesion, and thrombosis
- Accumulation of lipoproteins: (mainly LDL) in the vessel wall
- Monocyte adhesion to the endothelium, followed by migration into the intima and transformation into macrophages and foam cells
- ## Platelet adhesion
describe the consequences of Rupture, ulceration or erosion of the intimal surface
- rupture, ulceration or erosion of the intimal surface -> highly thrombogenic substances -> thrombosis
Describe the consequences of Haemorrhage into a plaque
- Haemorrhage/bleeding into a plaque. Rupture of the fibrous cap -> intra-plaque haemorrhage -> plaque rupture
Describe the consequences of Atheroembolism
- Plaque rupture -> atherosclerotic debris into bloodstream -> microemboli
Describe the consequences of Aneurysm formation
- Atherosclerosis-induced pressure, ischemic atrophy, loss of elastic tissue -> weakness -> aneurysmal dilation and potential rupture
What does the clinical outcome of atherosclerotic depend on
- Size of the involved vessels
- Relative stability of the plaque itself
- Degree of degeneration (underlying arterial wall)
What are the major consequences of atherosclerotic diseases
- Myocardial infraction (heart attack)
- Cerebral infraction (stroke)
- Aortic aneurysms
- Peripheral vascular disease (gangrene of the legs)
What is Ischemic heart disease and what is its cause
- Leading cause of death WORLDWIDE for both men and women
- the cause of myocardial ischemia is reduced blood flow due to obstructive atherosclerotic lesions in the coronary arteries
what are the clinical manifestations of ischemic heart disease
- Angina pectoris
- Myocardial infraction , the most important form of IHD
- Heart failure
- Sudden cardiac death
What is chest pain also known as
- Angina pectoris
What is chest pain/angina pectoris characterised by
- paroxysmal and usually recurrent attacks
- substernal or precordial chest discomfort
- variously described as constricting, squeezing, choking, knifelike
- caused by transient (15 seconds to 15 minutes) myocardial ischemia
What are the 3 overlapping patterns of angina pectoris
1) Stable or typical angina
2) Variant (Prinzmetal, vasospastic) angina
3) Unstable (crescendo) angina
What is heart attack also known as
- Myocardial infraction
What is Myocardial infraction
- also known as heart attack, is the death of cardiac muscle due to prolonged severe ischemia
What is the pathogenesis of Myocardial infraction
- Pathogenesis: Coronary arterial occlusion
What is the causes of coronary arterial occlusion
- Coronary atherosclerosis (90%)
- Vasospasm with or without coronary atherosclerosis
- Emboli from the left atrium in association with atrial fibrillation
- Others
