Vascular Heart Disease Flashcards
(35 cards)
Describe the intimal response to vascular injury
Intimal thickening
- recruitment of smooth muscle cells to the intima (smooth muscle cells are normally only found in the media)
- smooth muscle cells mitosis
- elaboration of extracellular matrix
the thicker intima may make it more difficult for O2 and nutrients to diffuse therefore it is more prone to ischemic injury
Arteriosclerosis
Hardening of the arteries” (arterial wall thickening and loss of elasticity)
3 types of arteriosclerosis
Atherosclerosis
Monckeberg’s medial calcific sclerosis
Arteriosclerosis - hypertension induced
Atherosclerosis modifiable risk factors
Hyperlipidemia Hypertension Cigarette smoking Diabetes mellitus “Inflammation” (increased C peptide)
Atherosclerosis non-modifiable risk factors
Genetic abnormalities
Family history
Increasing age
Male gender
“Response to injury” hypothesis:
Atherosclerosis is a chronic inflammatory response of the arterial wall to endothelial injury.
Lesion progression involves interaction of lipoproteins, monocyte-derived macrophages, T lymphocytes and the cellular constituents
Atheroma morphology
forms inbetween the subendothelium and internal elastic lamina (intima process)
eccentric
fibrous cap
necrotic center
what are the components of the fibrous cap of an atheroma
smooth muscle cells, macrophages, foam cells, lymphocytes, collagen, elastin, proteoglycans, neovascularization
what are the components of the center of an atheroma
cell debris, cholesterol crystals, foam cells, calcium
how is the media affected by an atheroma
the media begins to shrink and nearly dissapear in some areas due to lack of nutrients (cannot diffuse)
this thinning makes the media very weak, less elastic, and more vulnerable to becoming an aneurysm
what are possible faits of a plaque
Rupture/ulceration/erosion (rupture of a cap leads to thrombus formation) Emboli Hemorrhage Weakening of media – aneurysm formation Calcification, growth, lumen occlusion Thrombosis
what happens when the fibrous cap ruptures
platelets become exposed to the necrotic debris and basement membrane causing activation and formation of a thrombus- which further occludes the vessel and may lead to infarct and necrosis of the down stream organ
what do cholesterol deposits look like histologically
they fall out of the samples and look like open (white) spaces
Atherosclerosis- Complications
myocardial ischemia- angina, infarcts, sudden death
cerebral ischemia- stroke, TIA
Peripheral vascular Dz- claudication, gangrene
aneurysms- rupture
Monckeberg’s Medial Calcific Sclerosis
Calcifium deposits
In the MEDIA
Medium sized muscular arteries
NONobstructive
what are the 2 types of Hypertension Induced Arteriosclerosis
Hyaline arteriolosclerosis
Hyperplastic arteriolosclerosis
Hyaline arteriolosclerosis
Arterioles
Hemodynamic stress- due to long term hypertension which causes fenestrations and plasma proteins are able to leak into wall of the vessel
Plasma protein leakage
Homogeneous pink hyaline thickening (histologically)
Lumenal narrowing
Hyperplastic arteriolosclerosis
- Severe acute blood pressure elevation (200s)
- Onion skin concentric thickening
- Smooth muscle cells with thickened, reduplicated membranes
- Progressive lumenal narrowing
what is an aneurysm
Localized abnormal dilatation of a blood vessel
what is a false aneurysm
looks like the wall is pouching out but there was an injury to the wall of the blood vessel and now blood from the lumen is getting caught by the extravascular / external part of the blood vessel
what leads to aneurysms
Poor intrinsic quality of vascular wall connective tissue
• Marfan Syndrome (defective synthesis fibrillin; loss of elastic tissue)
• Ehlers Danlos (defective type III collagen)
Weakened vascular wall through loss of smooth muscle cells or inappropriate synthesis of extracellular matrix
• Ischemia (Atherosclerosis,HTN, syphillis)
• Histology - Cystic medial degeneration
Altered balance of collagen degradation and synthesis
• Local inflammatory infiltrates
• Destructive proteolytic enzymes (Matrix metalloproteinases)
Cystic Medial Degeneration
*elastin fragmentation
loss of smooth muscle cells
leading to areas resembling “cystic” spaces
weakens the blood vessel
the media normally has a very regular pattern of elastin with smooth muscle in between.
causes of aneurysms
Atherosclerosis HTN Congenital defects Inflammation Infections Vasculitis Trauma
Abdominal Aortic Aneurysm etiology/pathogenesis
- End result of a multifactorial process leading to the destruction of aortic wall connective tissue
- Matrix metalloproteinasis play a key role
