Cardiac 2 Shea Flashcards
Take up the released lipids and cell remnants from dying or injured smooth muscle cells
The role of macrophages in athrogenesis
What 3 things do macrophages secrete? What happens?
- Cytokines
- TNF
- other biologically active substances
Which cause more damage by stimulating collagen production (from fibroblasts), along w/ smooth muscle cells
The repair of the initial arterial lesion involves what?
Scarring due to collagen deposition (leads to hardening or sclerosis)
In atherosclerosis, what is the name of the bulge?
Atheroma
Prototype lesion which bulges into the lumen of the artery
Atheroma
- The central part of an atheroma is soft and consists of what 2 things?
- What is the soft core covered by?
- lipids
- cellular debris
- Covered by fibrous tissue (forms fibrous/surface cap)
What is the “cellular debris” inside the atheroma?
Macrophages (filled w/ LDL, VLDL)
- smooth muscle cells
- macrophages
- foam cells
- lymphocytes
- collagen
- elastin
- proteoglycans
- neovascularization
Fibrous Cap of atheroma
- cell debris
- cholesterol crystals
- foam cells
- calcium
Necrotic center of atheroma
What is the major complication of the atheroma?
Hardening of the vessel from calcification (precipitated by local tissue degeneration)
What causes attraction of Ca salts of an atheroma which can be seen on x-rays as a radiodense material?
Lipids released from dead cells and abnormal celluar matrix
What are the 2 main risk factors of atherosclerosis?
- Age (older people)
-
Sex (affects more men by 2x)
- women have estrogens which have a “protecting effect”
- women after menopause who take HRT will continue to have the protecting effect
What are the 7 other risk factors for atherosclerosis besides 1. old age and 2. male sex?
- Heredity
- Lipid metabolism
- HTN
- Obesity
- DM
- Cigarette smoking
- Stress
A genetic defect of LDL receptors, which does not allow lipoproteins into the liver, causes atherosclerosis at an EARLY AGE, best known cause for familial atherosclerosis.
Familial Hypercholesterolemia
How do you modify a genetic predisposition to atherosclerosis? (familal hypercholesterolemia)
Healthy lifestyle and balanced diet
Risk factor of Atherosclerosis : Lipid Metabolism
Serum Cholesterol Levels exceeding ____ mg/dL increases the risk 5 X as compared to levels less than _____ mg/d: (normal range)
Exceeding 260
Less than 200 (normal)
Blood compressing the intimal cells making them ischemic or stimulating them to release cytokines which promote proliferation of smooth muscle cells.
A possible explanation of HTN causing atherosclerosis
What causes changes to clotting system by damaging platelets, causing aggregation and release of biogenic substances from their cytoplasm (over-activated makes them sticky)
HTN
- Causes a secondary hyperlipidemia
- Tissue fat is in equilibrium w/ circulating lipids
- Increased total body fat leads to hyperlipidemia
- Develop atherosclerosis at earlier age w/ more pronounced lesions compared to other patients
Obesity
- ____ Alters metabolism of basement membranes and damages SMALL blood vessels of the glomerular capillaries and larger renal arterioles
- _____ Accelerates atherosclerosis in larger arteries (coronaries, cerebral, aortic)
- Hyperglycemia alters basement membranes
- Diabetes accelerates atherosclerosis
What is the #1 organ killed from DM?
Kidneys, most people on wait list for kidney transplant are DM patients.
How does cigarette smoking contribute to atherosclerosis?
Not fully understood…, but they do cause vasoconstriction.
How does stress contribute to atherosclerosis?
CONSTANT stress may accelerate/aggravate atherosclerosis
- A very common finding in older men and almost all persons over 50
- Lesions vary from mild –> severe, may be focal or diffuse
Atherosclerosis of the Aorta
- Mildest forms of ___ are found in young or middle aged persons
- These people have fatty streaks, slightly raised fibrotic plaques
Atherosclerosis of Aorta
Atherosclerosis of Aorta
- Do fatty streaks progress to atheromas?
Yes, as it progresses, atheromas form (lipid rich/bulging lesion)
In the final stages of atherosclerosis, this vessel is rigid, calcified tube w/ rough/jagged/ulcerated internal surface covered focally w/ thrombi.
Aorta
Is BP affected by atherosclerosis?
Yes, the aorta cannot expand during systole, so HTN develops. The pressure causes dilatation of the inelastic aorta which leads to formation of aneurysms.
Where do atherosclerotic aneurysms of the aorta occur most commonly?
abdominal aorta, are usually clinically silet and discovered by accident during exam
Are most often fusiform, saccular, or spindle-shaped
Atherosclerotic Aneurysms of Aorta
Small saccular aneurysms at base of brain
Berry Aneurysm
What is the “spindle shaped” aneurysm?
Dissecting aneurysm
String sign is associated w/ what?
AAA, tons of plaque
What is the major danger of any aneurysm?
Rupture and death by exsanguination (jet of blood may dissect through wall of aorta forming a periarterial 2nd lumen = dissecting aneurysm)
Aneurysms can be resected surgically and replaced by an artificial vessel made of Dacron or Gortex material. Which one is better and why?
Gortex, is stretches.
- Most common location is 1 inch above dissesction
- 85% uncontrolled HTN
- 15% Marfans
- Blood goes underneath, separates entire wall w/ half of media on either side of blood
- 100% mortality
Aortic Root Dissection
Reversible, unless calcified
Atheromas
Aortic Dissection can lead to what?
Hemopericardium, which may lead to cardiac tamponade
