Aortic
Dissection
Epidemiology and
Etiology:
- May
arise in aneurismal arteries (but not always)
- Men
- 40-60y
- hypertension
(major risk factor)
- medial
degeneration (cystic medial degeneration) is most common preexisting
histological lesion
- may
be caused by a connection tissue abnormality (ex. Marfan’s)
- idiopathic
- hypertension
- bicuspid
aortic valve
- iatrogenic
- pregnancy
(rarely)
- unusual
in the setting of substantial atherosclerosis or other cause of medial
scarring
Common sites:
- usually
intimal tear occurs within 10cm of aortic valve
- may
dissect proximally or distally
Gross features:
Histologic features:
- dissection
of blood between and along the laminar planes of the media
- medial
degeneration may be a pre-existing lesion:
- elastic
tissue fragmentation
- small
cleftlike spaces separating elastic and fibromuscular elements of the tunica media
- filled
with amorphous extracellular matrix of connective tissue
- resemble
cysts
- absent
inflammation
Immunophenotype:
Marker:
|
Sensitivity:
|
Specificity:
|
|
|
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Molecular features:
Other features:
- often
ruptures causing massive hemorrhage
- other
complications:
- aortic
valve insufficiency
- myocardial
infarction (ostia involvement)
- extension
into great arteries of the neck, obstructing flow
- transverse
myelitis
- renal,
mesenteric, or iliac involvement
- Type
A:
- Involving
the ascending aorta
- More
common
- serious
complications
- Type
B:
- Not
involving the ascending aorta
References: