CVS lll Flashcards
Epi of Moenckberg Arteriosclerosis
: >50 yrs
loc of Moenckberg arterioscleoris
calcification of media, of small and
medium-sized muscular arterie
*no arterial flow obstruction
Macro-/Microscopic picture:
* Stiff, calcific “pipe-stem” arteries
* Ring-like calcifications in the media
Are the features of what type of Plaque?
Moenckeberg arteriosclerosis (Medial Calcific Sclerosis)
Etiology of Calciphylaxis (Vascualar calcinosis)
–> severe form of the media calcification
–> Association with renal failure & hyper-parathyroidism
patho of Calciphylaxis
1) Elevation of acute phase reactants
2) Marked giant-cell reaction in proximal arteries
3) Extension of calcification into distal vessels
4) Intima fibrosis→ Vessel’s obstruction → Ischaemia symptoms or progressive ischaemic gangrene
5) Frequently, vascular micro-thrombi
6) Occasionally, subcutaneous calcium deposits with panniculitis (inflammation of subcutaneous adipose tissue) and fat necrosis
The 2 forms of Arteriosclerosis
1) Hyaline Arteriosclerosis
2) Hyperplastic Arteriosclerosis
Atiology/association of arteriosclerosis
*Hyaline thickening or proliferative changes of
small arteries and arterioles (e.g. Kidneys)
*Associated w/ –> Hypertension or Diabetes Mellitus
patho of Hyaline arteriosclerosis
- Hyaline thickening of arteriolar walls →
- → Narrowing of the arteriolar lumen →
- → Ischaemia
Histopathological features:
- Tubular atrophy, Interstitial fibrosis,
Glomerular alterations (mild hyalinosis to
sclerosis of glomeruli) and peri-glomerular
fibrosis
- Accumulation of pink, amorphous,
homogeneous material in the wall of small
arteries and arterioles
* “Benign nephrosclerosis” –> Long-standing
Hypertension
Are the features of what type of plaque?
Hyaline arteriosclerosis
Histopathological features:
- Concentric, laminated, “onion-skin”
thickening of the arteriolar walls –> narrowed lumen
- accompanied by necrotising arteriolitis
(intramural deposition of fibrinoid material
in arterioles with vascular necrosis and
inflammation) in malignant hypertension
* Malignant hypertension –> “Malignant
nephrosclerosis”
Are the features of what type of palque?
Hyperplastic plaque
Risk factors of Atherosclerosis
1) Age
2) Gender ( M > F) [increased
incidence in post-menopausal women]
3) Cigarette smoking
4) Hypertension
5) Diabetes Mellitus (Peripheral vascular occlusive
disease → Gangrene of the lower extremities)
6) Obesity, “type A” personality, hyper-uricaemia, hyper-homocysteinaemia
7) Hyper-cholesterolaemia
Atheroscleorsis: the formation of fibrous plaque or atheromas within the intima of the arteries.
At which anatomical site do these atheromas form?
1) Proximal portions of coronary arteries
2) Larger branches of carotid arteries
3) Circle of Willis
4) Large vessels of lower extremities
5) Renal and mesenteric arteries
Atherosclerosis are characterised by the formation of ?
Fatty streaks (Accumulation ofOxidised LDL within macrophages and SMCs, underneath the enothelial cells)
Macroscopic features of Fatty streaks?
Yellow elevations on the
internal surface of the vessel wall
patho of Atherosclerotic plaque
1) Death of foamy macrophages → Release of
intra-cytoplasmic lipid → Formation of lipid
debris
2) Proliferation of smooth muscle cells and
secretion of collagen + ECM proteins
→ Development of a fibrous cap over the
core (composed of oxidised lipid and inflammatory cells)
*fibrous cap –> bodies attempt to repaire the injured vessele wall by scaring
*Core –> plaque (oxidised LDL)
The 3 Hallmarks of Chronic inflammation
-
Persistent injury (endothelial damage from
aforementioned risk factors) -
On-going inflammation (macrophages and
lymphocytes) -
Repair with scarring (formation of a fibrous
cap)
Plaque stability depends on the —————- and ————— in the fibrous cap
1) No. of SM
*smooth muscles –> Protective effect
2) Inflammaotry cells
*have Destablising effect
Plaque stability depends on the numbers of smooth muscle and inflammatory cells in the fibrous cap. Explain
1) Inflammatory cells have destabilising effect,
since:
* Produce MMPs → Digestion of fibrous cap
* Induce smooth muscle cells’ apoptosis
2) Smooth muscle cells have protective effect,
since:
* Produce fibrous cap → Plaque stabilisation
* Produce TIMPs → Inhibition of MMPs’ action
Stable plaques vs Unstable plaques
1) Stable plaques:
- Few inflammatory cells but Many smooth muscle cells
* Thick fibrous cap –> Resistant to rupture
* Slow growth → Gradual Stenosis of the lumen
2) Unstable “vulnerable” plaques:
* Inflammatory cells > Smooth muscle cells
* Thin fibrous cap → Acute rupture →
Thrombosis and/or Embolism
Atherosclerosis Complications related to plaques
1) Myocardial infarction (MI)
2) Ischaemic stroke
3) Rupture of aneurysm –> thrombous formation –> Embolisation
4) Stable Angina
Virchow’s Triade
1. Endothelial Injury
a. Atherosclerosis
b. Vasculitis
c. Trauma
2.Abnormal blood flow:
a. Turbulence
b. Stasis
3.Hypercoagulability:
a. Too many blood cells
b. Coagulation factor defects
Types of Aneurysm
1) Atherosclerotic
2) Aneurysms due to cystic medial necrosis
3) Berry aneurysms
4) Syphilitic (luetic) aneurysm
5) Dissecting aneurysm
6) Arterio-venous fistula
loc of Atherosclerotic aneurysm
Abdominal aorta
Epi of Atherosclerotic Aneurysm
Men and smokers
patho of Atherosclerotic aneuryms
1) Excess ECM degradation by the inflammatory
infiltrates in atherosclerotic arteries and the
destructive proteolytic enzymes at these sites
Impairment of the diffusion of nutrients and
wastes between vascular lumen and wall
* Direct compression on the media
* → Degeneration and necrosis → Wall
thinning
CM of Cystic medial Degeneration
Proximal aortic aneurysm → Aortic dissection
and rupture; Aortic incompetence; Mitral valve
prolapse; Peripheral artery aneurysms
loc of cystic medial degeneration
aortic root
- loss of elastic laminae
- loss of smooth muscle cells, with replacement by pools of proteoglycan matrix
Are the histopatho of what type of aneurysm?
Cystic medial degeneration
loc of Berry Aneurysm
Vessels of Willis’ circle
patho of Berry Aneurysm
: Development at sites of congenital
medial weakness (bifurcation of cerebral arteries)