ATHEROMA: MORPHOLOGY AND EFFECTS
ATHEROMA: MORPHOLOGY and
EFFECTS
Brian Angus
Pathology
Department
University of
Newcastle
upon Tyne
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ATHEROMA: MORPHOLOGY AND EFFECTS
ATHEROMA
CONTENTS
INTRODUCTION
DEFINITIONS
MORPHOLOGY
CONSEQUENCES: VASCULAR
CONSEQUENCES: ORGANS
The fibrous
plaque
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ATHEROMA: MORPHOLOGY AND EFFECTS
INTRODUCTION
Atheroma is the single most
important cause of morbidity and
mortality in Western countries.
The most important effects of
atheroma are ischaemic heart
disease, peripheral vascular
disease and cerebrovascular
disease.
The cause of atheroma is not
known, but many risk factors, and
factors which accelerate disease
development have been identified.
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ATHEROMA: MORPHOLOGY AND EFFECTS
DEFINITIONS
Atheroma = Atherosclerosis
Athere
= porridge.
Sclerosis = hardening
Atheroma is manifest as the
development of deposits of
fibrous tissue and lipid on
arterial walls.
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ATHEROMA: MORPHOLOGY AND EFFECTS
DEFINITIONS
Atheroma is the same as
atherosclerosis.
However arteriosclerosis is the
medical term for hardening of
the arteries with advancing age.
The media and intima become
replaced by fibrous tissue
sometimes with calcification.
Arteriosclerosis is not often of
serious consequence.
No picture
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ATHEROMA: MORPHOLOGY AND EFFECTS
THE FATTY STREAK
The fatty streak comprises
a slightly elevated zone on
the arterial wall caused by
accumulation of a small
number of lipid laden
histiocytes, with some free
lipid also (not shown).
They occur in all societies,
even those without a high
prevelance of atheroma,
but are thought to be the
origin of atheroma, as they
occur at the same sites.
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ATHEROMA: MORPHOLOGY AND EFFECTS
THE FATTY STREAK
.
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ATHEROMA: MORPHOLOGY AND EFFECTS
THE FIBROUS PLAQUE
This is the second stage
in development of
atheroma.
Lipid accumulates, free
and in foamy histiocytes.
Smooth muscle cells
migrate from the media
and proliferate.
Fibrosis develops around
the lipid, and forms a cap
over the lesion
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ATHEROMA: MORPHOLOGY AND EFFECTS
THE FIBROUS PLAQUE
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ATHEROMA: MORPHOLOGY AND EFFECTS
THE COMPLICATED PLAQUE
Ulcers and fissures of the
fibrous cap reveal plaque
contents, resulting in
thrombosis.
The plaque may undergo
calcification, visible on Xray.
Inflammation associated
with the plaque destroys
the media which
undergoes fibrosis, and
is weakened.
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ATHEROMA: MORPHOLOGY AND EFFECTS
PLAQUE MORPHOLOGY
Take a closer look at this
picture on the next slide.
Identify the three stages of
development of
atherosclerosis.
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ATHEROMA: MORPHOLOGY AND EFFECTS
PLAQUE MORPHOLOGY
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ATHEROMA: MORPHOLOGY AND EFFECTS
ARTERIES AFFECTED
All arteries down to 1 mm
diameter can be affected.
The brachial arteries are
spared.
The renal arteries are spared
(except in diabetes).
Maximum atheroma occurs at
sites of haemodynamic stress
e.g. bifurcations.
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ATHEROMA: MORPHOLOGY AND EFFECTS
VASCULAR CONSEQUENCES
Atheroma has the following effects on
vessels and the organs/parts served:
LUMENAL NARROWING: ISCHAEMIA
LUMENAL OCCLUSION:
INFARCTION
EMBOLISM :
ISCHAEMIA
AND
INFARCTION
Coronary artery thrombosis
WEAKENED WALL
ANEURYSM
The following slides show each of these in turn.
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ATHEROMA: MORPHOLOGY AND EFFECTS
VASCULAR CONSEQUENCES:
LUMENAL NARROWING
Lumenal narrowing results in
ischaemia if severe enough.
Usually a much greater degree of
narrowing is required to cause
symptoms than in the diagram.
An example is chest pain on
exertion due to narrowing of the
coronary arteries (angina).
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ATHEROMA: MORPHOLOGY AND EFFECTS
VASCULAR CONSEQUENCES
LUMENAL OCCLUSION
Lumenal occlusion is due to
thrombosis.
This will often result in
infarction of the part served. An
example is myocardial
infarction due to thrombosis of
a coronary artery.
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ATHEROMA: MORPHOLOGY AND EFFECTS
VASCULAR EFFECTS:
EMBOLISM
This usually occurs when
non occlusive thrombus
breaks off and travels with
the blood flow until it
occludes a distal vessel. A
clinical example is transient
cerebral ischaemic attacks
due to embolism from
carotid atheroma.
Embolism of lipid rich plaque
contents is rare.
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ATHEROMA: MORPHOLOGY AND EFFECTS
VASCULAR EFFECTS:
ANEURYSM
The commonest site for
aneurysm is the abdominal
aorta, as shown here. The
aorta dilates, becomes
filled with lamellated
thrombus, and eventually
ruptures.
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ATHEROMA: MORPHOLOGY AND EFFECTS
VASCULAR EFFECTS:
ANEURYSM
The patient with a ruptured
aneurysm presents with
severe abdominal or back
pain, and is often shocked
due to blood loss. This is a
surgical emergency, and
grafting is required.
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ATHEROMA: MORPHOLOGY AND EFFECTS
VASCULAR EFFECTS:
ANEURYSM
The patient with a ruptured
aneurysm presents with
severe abdominal or back
pain, and is often shocked
due to blood loss. This is a
surgical emergency, and
grafting is required.
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ATHEROMA: MORPHOLOGY AND EFFECTS
ORGAN CONSEQUENCES
We will now examine the
consequences of narrowing,
occlusion and embolism on
the principal organs affected,
namely the:
HEART
BRAIN
LEGS
GUT
and
KIDNEYS
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ATHEROMA: MORPHOLOGY AND EFFECTS
ORGAN CONSEQUENCES 1
HEART: ANGINA
Narrowing of the
coronary arteries results
in chest pain on exertion
- angina.
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ATHEROMA: MORPHOLOGY AND EFFECTS
ORGAN
CONSEQUENCES 1
HEART:
ANGINA
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ATHEROMA: MORPHOLOGY AND EFFECTS
ORGAN CONSEQUENCES
HEART: INFARCTION
Thrombotic occlusion of
a coronary artery results
in myocardial infarction.
The photograph shows a
10 day old infarct.
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ATHEROMA: MORPHOLOGY AND EFFECTS
HEART: INFARCTION
ddddddddddddddddd
ddddddddddddddddd
ddddd
Myocardial infarct
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ATHEROMA: MORPHOLOGY AND EFFECTS
ORGAN CONSEQUENCES
BRAIN: INFARCTION
Thrombotic occlusion of
a cerebral artery results
in cerebral infarction.
The patient will usually
present with
neurological deficit and
reduced conscious
level; the precise
features depend on the
site and size of the
infarct.
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ATHEROMA: MORPHOLOGY AND EFFECTS
BRAIN: INFARCTION
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ATHEROMA: MORPHOLOGY AND EFFECTS
ORGAN CONSEQUENCES
BRAIN: TRANSIENT ISCHAEMIC ATTACKS
Thrombosis over the carotid
arteries may result in release
of small emboli. These travel
to the brain. The patient
suffers transient neurological
deficit, or loss of
consciousness.
These small emboli usually
lyse without permanent
deficit, but there is always the
risk of this.
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ATHEROMA: MORPHOLOGY AND EFFECTS
ORGAN CONSEQUENCES
LEG: CLAUDICATION
Atheroma of the femoral
artery results in reduced
blood supply to the lower leg.
The patient experiences pain
in the calf on walkingclaudication.
This is relieved by rest and
the patient’s progress is
punctuated by alternate
walking and resting:
intermittent claudication.
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ATHEROMA: MORPHOLOGY AND EFFECTS
ORGAN CONSEQUENCES
LEG: GANGRENE
Thrombosis may develop over an
atheromatous plaque in the
femoral (or other supplying) artery
resulting in infarction of all tissues
served (gangrene).
This can also occur in severe
stenotic atheroma if something
else reduces blood flow, e.g.
development of cardiac failure.
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ATHEROMA: MORPHOLOGY AND EFFECTS
LEG: GANGRENE
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ATHEROMA: MORPHOLOGY AND EFFECTS
ORGAN CONSEQUENCES
GUT: INFARCTION
Thrombosis may develop
over an atheromatous
plaque in one of the
mesenteric arteries
resulting in infarction.
The photograph shows
small bowel infarction.
University of Utah
Small bowel infarction
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ATHEROMA: MORPHOLOGY AND EFFECTS
GUT: INFARCTION
University of Utah
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ATHEROMA: MORPHOLOGY AND EFFECTS
ORGAN CONSEQUENCES
COLON: ISCHAEMIC COLITIS
Lack of blood to the colon
results in ischaemic damage
short of infarction.
The patient has pain and
bloody diarrhoea.
Narrowed inferior
mesenteric artery
to colon
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ATHEROMA: MORPHOLOGY AND EFFECTS
ORGAN CONSEQUENCES
KIDNEY: HYPERTENSION
The renal arteries are usually
spared severe atheroma but
sometimes, especially in
diabetic patients, the origin of
the renal artery is affected. The
kidney gradually becomes
atrophic due to chronic
ischaemia. The underperfused
kidney releases renin resulting
in renal hypertention, with
consequent risk of heart failure
and stroke.
Narrowed origin of
left renal artery.
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ATHEROMA: MORPHOLOGY AND EFFECTS
KIDNEY: Atheroma at origin of renal artery
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ATHEROMA: MORPHOLOGY AND EFFECTS
END OF PRESENTATION
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