20. Common CVDs part 2 Flashcards
Risk of stable vs. unstable blockage.
- Stable blockage up to 65% causes a plumbing prob in which you can’t deliver enough blood during exercise
- Unstable blockage of 33-40% can rupture into the lumen of the vessel and trigger a clot –> fatal
Describe the progression of atheromas in blood vessels w/ age.
- Progresses slowly, over decades
- Foam cell –> fatty streak –> intermediate lesions –> atheroma –> fibrous plaque –> complicated lesion rupture of unstable cap
- Once fibrous plaque is reached, not reversible
What is the effect of risk factors in the progression of atheromas?
Risk factors speed up progression
What are foam cells?
Phagocytic white blood cells, usually macrophages, that ingest large volumes of sub-endothelia lipid droplets
List the atherogenic effects of smoking.
- Endothelial damage
- Increased platelet adhesion
- Pro-inflammatory
- Arterial wall hypoxia
- Increased LDL oxidation
- Reduced HDL cholesterol
- Increased blood viscosity
- Impaired endothelial-mediated vasodilation
What % of circulating blood cholesterol does dietary cholesterol contribute?
What are the dietary modulators of plasma cholesterol?
- Increase in dietary saturated (animal) fat
- Increase in excess body fat stores
- Decrease in dietary fiber (esp water soluble)
- Increase in dietary cholesterol
What is the normal value for total cholesterol?
What is the normal value for HDL cholesterol?
> 40 mg/dl
Contrast the structure of LDL and HDL.
- HDL has a large # of lipoproteins and a smaller amount of cholesterol
- LDL is mostly fat and not much protein
What is the single best intervention for raising HDL?
Exercise
What directly lowers HDL?
Smoking
What is LDL mostly controlled by?
Dietary intervention
What is HDL’s role in plaque regression?
Reverse cholesterol transport
What are the beneficial effects of HDL?
- Anti-inflammatory
- Anti-thrombotic (blood clotting)
- Antioxidant
- Anti-apoptotic (cell death)
- Reverse cholesterol transport
List the natural first presentations of coronary artery disease. What % of CAD present this way?
- 15-20% sudden death
- 45-55% myocardial infarction
- 35-40% angina
What does a narrowed lumen result in? Blocked lumen?
- Narrowed lumen –> exertional ischemia
- Blocked lumen –> MI or death
What is angina? Symptoms?
- Subjective experience of ischemia elicited by exercise or emotional stress
- Vague, aching, squeezing, or burning
What is a significant contributor of angina?
Impaired vasodilatory ability
What is the benefit of exposing an atheroma by exercise as opposed to waiting?
- Waiting for resting sx reveals 90% stenoses
- Exercise may reveal atheromas as small as 60-65%
Stable vs. Unstable plaque.
STABLE: -small lipid pool -thick fibrous cap -preserved lumen UNSTABLE: -large lipid pool -thin fibrous cap -many inflammatory cells
Stable vs. Unstable angina/ischemia
STABLE: -lumen narrowed by plaque -inappropriate vasoconstriction UNSTABLE: -plaque rupture -platelet aggregation -thrombus formation -unopposed vasoconstriction
What is acute coronary syndromes?
Sudden, severe alterations in coronary flow leading to unstable angina and may become acute MIs
What causes 90% of acute coronary syndromes?
Rupture of an atherosclerotic plaque, leading to platelet aggregation and formation of a thrombus
