Post on 15-Dec-2015
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ATHEROMA: MORPHOLOGY AND EFFECTS
ATHEROMA: MORPHOLOGY and EFFECTS
Brian Angus
PathologyDepartment
University of Newcastleupon Tyne
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ATHEROMA: MORPHOLOGY AND EFFECTS
CONTENTS
INTRODUCTION
DEFINITIONS
MORPHOLOGY
CONSEQUENCES: VASCULAR
CONSEQUENCES: ORGANSThe fibrous plaque
ATHEROMA
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ATHEROMA: MORPHOLOGY AND EFFECTS
INTRODUCTIONAtheroma 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 X-ray.
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 stresse.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
WEAKENED WALL ANEURYSM
The following slides show each of these in turn.
Coronary artery thrombosis
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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 CONSEQUENCESLUMENAL 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
ORGANCONSEQUENCES 1 HEART: ANGINA
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ATHEROMA: MORPHOLOGY AND EFFECTS
ORGAN CONSEQUENCESHEART: 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
Myocardial infarctddddddddddddddddddddddddddddddddddddddd
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ATHEROMA: MORPHOLOGY AND EFFECTS
ORGAN CONSEQUENCESBRAIN: 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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BRAIN: INFARCTION
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ATHEROMA: MORPHOLOGY AND EFFECTS
ORGAN CONSEQUENCESBRAIN: 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 CONSEQUENCESLEG: CLAUDICATION
Atheroma of the femoral artery results in reduced blood supply to the lower leg.
The patient experiences pain in the calf on walking- claudication.
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 CONSEQUENCESLEG: 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 CONSEQUENCESGUT: 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 CONSEQUENCESCOLON: 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 CONSEQUENCESKIDNEY: 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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