What are the 3 layers of an artery?
- tunica intima: endothelial cells (exchanging)
- tunica media: smooth muscle cells (constriction/dilation)
- tunica externa: collegen and elastic fibers (support/strength)
What is hyperlipidemia? What who lipids are insoluble in plasma and encapsulated by lipoproteins?
Abnormally high levels of fatty lipids
- Cholesterol and triglycerides
What are dietary lipids absorbed as?
chylomircrons
Name the 5 types of lipoproteins?
- Chylomircrons (2% protein)
- VLDL (55-65 TG, 10 C, 5-10 P)
- LDL (10 TG, 50 C, 25 P)
- IDL
- HDL (5 TG, 20 C, 50 P)
Describe the role of low density lipoprotein receptors in removal of cholesterol from the blood?
- 60% go to the liver receptors and get engulfed
- 40% go to the adrenal cortex and gonads and get engulfed. They have the same cells as the liver and get used as steroid hormones.
What are lipid blood levels raised by?
- Nutrition
- Genetics (lack of LDL receptors?)
- Other diseases
- Medications (beta blockers, estrogen)
- Metabolic disorders
What is atherosclerosis?
Formation of fatty lesions in the intimal lining of the arteries. (Hardening)
What are non-modifiable and modifiable risk factors for atherosclerosis?
NM: increasing age, male/post menopausal women, family hx, genetically modified alterations in lipoprotein and cholesterol metabolism
M: Smoking, obesity, HT, hyperlipidemia, DM
C reactive protein, hyperhomocystimia, increased serum lipoprotein (non traditional risks)
How does tobacco use contribute to atherosclerosis?
- increases blood lipid levels
- damages epithelium
- enhances thrombosis formation
- increases blood thickness
- increases circulating catecholamines
What is the role of inflammation in the development of atherosclerosis and how can it be assessed?
CRP is an acute inflam. phase reactant synthesized in the liver, getting a baseline can predict future complications, High CRP= predict cardiovascular risks
As LDL accumulates in the arterial walls, it signals epithelial cells to latch onto WBC circulating in the blood>the immune cells penetrate the wall and trigger an inflam. response>LDL become “foam cells”>form a fatty streak>growth continues=fibrous capsule>substances released by the foam cells can cause capsule to rupture=blood clot=block flow/heart attack
What are stable and unstable plaques?
Stable: thick fibrous capsules, partially block vessels, don’t tend to from clots/ emboli
unstable: thin fibrous, may rupture causing clots, may completely block artery, clot may break free
What vessels are affected by atherosclerosis? What changes are occurring?
Abdominal aorta, iliac, proximal coronary, thoracic aorta, femoral, popliteal, internal carotid
-narrowing of vessels, production of ischemia, obstruction, thrombosis, larger vessels = weakening wall, thrombosis, medium= ischemia
Explain the types of atherosclerosis. Fatty streak, fibrous plaque, complicated lesion
- form foam cells, thin, flat, yellow, becomes thick and long
- grey-white, lipid, smooth muscle, scare tissue and calcification, thickening of intima, predisposes to thrombus formation= decrease blood flow
- fully developed
What is peripheral artery disease and its risk factors?
Atherosclerosis distal to the aortic arch
-male, >60, smokers, DM
What are the manifestations of PAD?
- intermittent claudication (pain when walking)
- calf pain and numbness
- thinning of skin and s/c tissue
- decreased blood supply (pale, cool, brittle, weak/absent pulses, hair loss, rubor)
- leg colour blanches when elevated
What are complications of PAD? How is it diagnosed?
- ulceration, gangrene, ischemic pain at rest, tissue necrosis
- BP changes in legs, pulse changes, doppler U/S (detects BP and pulses), MRI, spiral CT, contrast angiography, inspection of limbs
What is the treatment of PAD?
- protection of tissues
- walking until pain= increases collateral circulation
- avoid surface injury d/t slow healing
- address cause
- antiplatelet therapy (ASA)
- Statins= vasodilator
- surgery (femoralpopliteal bypass grafting)
- percutaneous transluminal angioplasty and stenting
What is raynaud Phenomenon? State the difference between primary and secondary.
Intense vasospastic disorder of arteries and arterioles (usually fingers, less often toes)
P: symmetrical, without cause, no pain
S: non-sym, other disease/state of vasospasm (frostbite, hot/cold, vibration tools), intense pain, associated with PAD
- Usually women
What are the manifestations and treatment for raynaud phen. ?
- tingling, numbness/aching, throbbing, pallor- cyanosis
- avoidance of triggers, avoidance of vasoconstriction meds, vasodilation meds, sympathectomy (interruption of sympathetic nerve pathways)
- decrease smoking and cold
What is an aneurysm? state the difference between true and false.
Abnormal localized dilation of blood vessel True: bounded by complete vessel wall -Berry (D) Saccular (P), fusiform (O) False: dissection or tear of wall -Dissecting, rupture
What are risk factors for aortic aneurysm? diagnosed?
- atherosclerosis, trauma, infection, age
- ECG, U/S, MRI, CT
What are the manifestations of a aneurysm?
Thoracic (substernal, back, neck pain) -trachea= stridor, cough, dyspnea - laryngeal= hoarseness -esophagus= diff. swallowing - superior vena cava= facial/ neck edema Abd. aortic aneurysm (AAA) -pulsating mass if more than >4 cm - mild - severe abd. and back pain - lower back pain that radiates to legs
Name complications of aneurysms.
- thrombi
- compression (vasculature, nerves)
- ruptures
What is a dissecting aortic aneurysm? And risk factors?
Hemorrhage into vessel wall- longitudinal tearing
-HT, 40-60 men, marfans, pregnancy, congenital defects of aortic valve, aortic coarctation/narrowing, blunt trauma
