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Arteriosclerosis
What
is Arteriosclerosis?
The term arteriosclerosis is often misused by the lay person;
its correct full name is 'arteriosclerosis obliterans' and, in a strict medical sense, it
defines the formation of plaques of cholesterol, platelets, fibrin, and other substances
on the arterial walls, and leads to progressive degrees of blockage of the arterial
circulation.
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Known causes
The known causes of these plaques include smoking, high
cholesterol levels (diet), high blood pressure as well as hereditary susceptibility (ie.
strong family history of similar disease) and diabetes . If the arteries supplying the
heart is called Coronary Artery Disease (CAD) and may cause 'Angina' (pain in the chest)
and even an heart attack.
There are various possible causes for arteriosclerosis but
by far the most common cause is the deposition of plaques of cholesterol (known as
atherosclerosis), platelets and other substances within the arterial walls. Sometimes the
build-up is very gradual, but in other cases the build-up is suddenly increased as a chunk
of matter breaks off and suddenly blocks the already narrowed opening. In this case, diet
is a primary factor to be considered (see below - Diet & Nutrition).
Causative Factors summarised: - There are several factors
which may influence the build-up of plaque on the arterial walls. These include:-
1. Hereditary factors (ie. a strong family history of heart
attacks)
2. Being male - females are less likely to suffer arteriosclerosis, probably because the
female hormones offer some degree of protection.
3. Cigarette smoking and high blood pressure - both of which are reversible in most cases.
4. High blood cholesterol levels (both total and low density types).
5. Risk increases with age.
6. Certain intense, hostile or time- pressured personality types (so- called type A),
inactive lifestyle, and high cholesterol diets.
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Symptoms
A blockage in the arteries can occur anywhere in the body
although the most common site is the arteries of the legs, either high in their course in
the pelvis, or further down in the calf. Once blockage becomes severe, exertion of the
muscles which receive blood supply from the affected artery causes pain due to
insufficient blood. This is known as intermittent claudication and often causes an aching
pain in the muscle which is relieved by rest and worsened by resumed physical activity. If
pain is present even at rest, the problem is serious and unless treated, could necessitate
amputation of the limb.
In the advanced stages, the limb becomes cold, pale,
discoloured, and sores form on the skin from gangrene to the area involved. Infection may
set in, and ultimately the leg must be amputated to save the life of the patient.
It is unusual for other areas to be affected without the
legs being involved, but those with arteriosclerosis in the leg, have a much higher
incidence of heart disease, stroke, and kidney artery blockage.
Where coronary arteries are affected, this will cause
angina (chest pain) or even heart attack. If the arteries in the brain are affected, this
can lead to a stroke.
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Diagnosis
Apart from the above symptoms, arteriosclerosis has other
typical signs including absent pulses and poor
skin filling from capillaries which are
compressed. Ultrasound tests may further confirm the diagnosis, but anarteriography in
which a dye is injected into the larger arteries and traced with X-rays is the most
reliable test.
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Conventional
Treatment
Typical medical treatment ranges from light exercise (if no
major symptoms are evident) and drug therapy to surgery. Bypass grafts made of synthetic
material is inserted in place of the blocked segments; alternatively, the area involved
may be surgically dilated.
If the blockage is in many smaller vessels instead of one
or a few large vessels, surgery is considered inappropriate but if a single severe
blockage is present, a procedure called "balloon dilatation" is sometimes
advised. In this mode of treatment, a tube is inserted into the artery under x-ray
guidance, and at the area of obstruction a tiny balloon is inflated to relieve the
obstruction.
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Drug Therapy
Medications are often prescribed to control the symptoms
relating to arteriosclerosis. The oldest and most common agents are the nitrates,
derivatives of nitroglycerine. They include nitroglycerine, isosorbide, and similar
agents. Newer forms include long acting oral agents, plus skin patches which release a
small amount through the skin into the bloodstream over a full day. They act by reducing
the burden of blood returning to the heart from the veins and also by dilating the
coronary arteries themselves. Nitrates are considered by many to be the mainstay of
medical therapy for angina, and are used both for treatment of symptoms as well as
prevention of anticipated symptoms. They are considered to be effective for relief and
prevention of angina, and sometimes for limiting the size of a heart attack. However,
there are side effects associated with these drugs including headaches, dizziness,
postural hypotension and tachycardia (1).
The second group of drugs are called "beta
blockers" for their ability to block the activity of the beta receptors of the
nervous system. The beta receptors cause blood pressure elevation, rapid heart rate, and
forceful heart contractions. When these actions are decreased, the heart needs less blood,
and thus angina and even the extent of a heart attack may be reduced. Again, these drugs
have known possible side effects including gastro-intestinal disturbances and incredibly,
heart failure! (2).
The latest group of drugs for coronary disease is called
the calcium channel blockers. Calcium channels refer to the areas of the membranes of
heart and other cells where calcium flows in and out, reacting with other chemicals to
modulate the force and rate of contractions. In the heart, they can reduce the force and
rate of contractions and electrical excitability, thereby having a calming effect on the
heart. These drugs also have known side effects including oedema, liver and kidney damage,
headache, nausea and rashes (3).
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Bypass Surgery
Experts who reviewed bypass surgery over a 15 year period
concluded that, in most cases, the operation has not been shown to save lives. In fact,
they found that, quite the contrary, there is a 15% (or greater) risk of brain damage
following coronary bypass surgery(4).
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Prognosis
If arteriosclerosis is left untreated it can be fatal by
leading to a stroke or heart attack (where the coronary arteries are affected.) Especial
caution is needed if a patient is also diabetic because the disease can progress very
rapidly in diabetic patients.
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The use of Aspirin
Aspirin has been shown to help thin the blood and thereby
reduce pressure on the heart and helping to prevent heart disease, BUT at the same time,
it also increases the likelihood of arterial stroke (5).
Fortunately there are effective alternatives worth
considering. For details of research relating to Arteriosclerosis &
Diet & Lifestyle click here
alternative/complementary therapies click here.
References:
(1) British National Formulary
(2) British National Formulary
(3) British National Formulary
(4) H McIntosh 'The first decade of aortocoronary bypass grafting 1967-77 A review',
Circulation 57 (1978):405 G Kolata 'Consensus on Bypass Surgery-Indications and
Limitations' Lancet 2 (1980):511 'Brain Damage after Open Heart Surgery' Lancet 1
(1982):1161
(5) Clarke JTR et al, 'Increased incidence of epistaxis in adolescents with familial
hypercholesterolemia treated with fish oil' Journal of Paediatrics Jan 1990, 116 (1)
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This page was last updated on 04 December 2006 21:15:01
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