Three consequences of pathologic change in blood vessels?
Narrowing and obstructing the lumen, slowly by athrosclerosis or quickly by thrombotic embolus
weakening the vessel wall; can lead to dissection dilation , and rupture
causing thrombosis deposits, have the ability to embolize
Reduplicated vessels
anomalous vessels
interest to surgeons
What is a berry aneurysm
vascular outpouching resulting from congenital vascular wall weakness
Mostly found in cerebral vessels
Abnormal communication between artery and vein?
arteriovenous fistula
can be secondary to trauma, inflammation, or a healed ruptured aneurysm
causes a left to right shunt, leads to increased venous return predisposing to high output heart failure
Arteriosclerosis?
arterial wall thickening and loss of elasticity
Three patterns of arteriosclerosis?
atherosclerosis
arteriolosclerosis, associated with HTN
Monckeberg medial calcific sclerosis; medial calcification to small and medium sized muscular arteries. after age 50. non obstructive and clinically insignificant
What vessels is atherosclerosis usually found?
elastic and large to medium sized vessels
abdominal aorta, coronary arteries, popliteal, descending thoracic aorta, internal carotid, circle of willis
Characteristics of atherosclerosis
elevated intimal based fibrofatty plaques composed of lipids
proliferating smooth muscle
increased extra cellular matrix
Morphology of an atheroma
white yellow intimal based lesion protruding into the vessel
composed of a superficial fibrous cap containing SMC. leukocytes, and dense connective tissue ECM overlying a necrotic zone
necrotic core contains dead cells, lipid, cholesterol, foam cells, proteins
What is a fatty streak?
early lesion composed of intimal lipid laden macrophages and SMCs
no real relationship between fatty streaks and plaques
complicated plaque?
calcified, hemorrhagic, fissured, or ulcerated atheroma
predisposed to local thrombus, cholesterol microemboli, and aneurysmal dilation
Risk factors for developing atherosclerosis, major
age
smoking
hypercholestrol
diabetes
Minor risk factors for atherosclerosis
obesity
sedentary life style
high stress life
type A personality
CRP?
an indicator of systemic inflammation and is correlated with atherosclerosis risk
acute phase reactant synthesized in the liver
downstream of many inflammatory triggers
opsonizes bacteria and activates compliment
withing intimal cells it can activate local endothelial cells and induce a prothrombotic state, increasing leukocyte adhesion
causes of endothelial cell injury that promotes atherosclerosis
hyperlipidemia
hemodynamic disturbances
smoking,
HTN
toxins and infections
EC injury causes?
increased permeability
white blood cell and platelet adhesion
coagulation activation
response to injury hypothesis of athersclerosis
considered to be a chronic inflammatory response to arterial wall injury
Stages of atherosclerosis pathogenesis
EC injury, endothelial dysfunction causes increased permeability, and increased expression of adhesion molecules
blood monocytes and leukocytes adhere
monocytes migrate into intima and become macrophages that ingest lipids to form foam cells
LDL and VLDL enter the vessel wall at site of injury
macrophages oxidize lipoproteins
platelets adhere
PDGF is released which causes SMCs to migrate to the intima
SMCs proliferate in the intima and secretes ECM leading to collagen and proteoglycan accumulation
Lipids accumulate in the SMC and macrophages
inflammation mediates lesion progression, initially foam cell formation is protective by removing lipids but then activated macrophages secrete cytokines that recruit more monocytes and T cells, and produce oxygen radicals that oxidize LDLs. The t cell macrophage cross talk initiates chronic inflammation
Stenosis in the popliteal artery causes?
gangrene in the lower leg
What can cause sudden lumina occlusion
plaque rupture
superficial erosion followed by superimposed thrombus formation
embolism
What is the single most important risk factor in coronary heart disease and cerebral event
hypertension
can also be a leading cause of congestive heart failure, renal failure, and aortic dissection