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Understand how coronary arteries
get blocked.
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It is due
to lipid rich plaque. Process of deposition of such
plaque is known as Athrosclerosis . Indians are prone to
enhanced Atherosclerosis.
It has been due to combined
effect of Nature & Nurture. Nature is responsible one
of the very important risk factor for accelerated
Atheroscleosis is a Factor known as "Lipoprotien 'A'
"; which is genetically acquired.
The Nurture is
contributed by affluence, mechanisation and urbanisation.
Affluence leads to consumption of foods rich in calories
and fat, where as the latter results in lower obligatory
energy expenditure associated with daily living [due to
lack of exercise, sedentary habits]. These life style
changes leads to abdominal obesity, Insulin resistance (insulin is not physiologically active),
High
Serum Triglycerides, boderline high LDL and Low HDL, the
good protective cholesterol.
As coronary arteries gets narrowed, there is less supply of blood to the heart
muscle. Then patients get chest pain while walking. If the
narrowing is abruptly blocked due to bleeding or thrombus
formation, heart attack ensues.
Angiogram is done to know
the blocked areas of coronary artery. In bypass surgery
blocked portion is bypassed by a graft.
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Human coronary
atheroscleroticplaque. The lipid rich core is separated
from the lumen by a fibrous cap
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Coronary atherosclerotic
plaque disruption. The fibrous cap is torn and projects
into the arterial lumen and thrombus is present in the
plaque core
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Reversal
Therapy aims at stabilization of lipid rich plaque, which is the
most important factor to prevent heart attack. Also, in many
cases there is regression of the lesion. So we make a vulnerable
lesion less vulnerable, thin fibrous cap is made thick that
protects against contact with blood.
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Bypass
surgery does not prevent myocardial infarction.
10 year follow up of shows (Muhlabaier et al)
In
bypass group incidence of heart attack-49%
In medically treated group- 41%
Another research worker Wiseman showed
Incidence
of heart attack in bypass group- 40%
Incidence of heart attack in medically treated group- 23%
Even Angioplasty is not successful in reducing heart
attack in comparison with medical therapy. |
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It
is very recently known that heart attack can occur even on those
parts where angiogram does not show significant block. Process of
deposition of lipid plaque is a diffuse process. it can occur
anywhere in the coronary artery. Moreover, it is not the degree
of block but composition of the lipid plaque which is responsible
for total block of the artery, ie. Heart attack. Also some
important endothelial mediated vasomotor abnormalities are many
times responsible. |
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Very
Importantly .....................
It is now established . .. Vigorous cholesterol lowering
by a low fat diet & Statin group of cholesterol
lowering drugs or intensive lifestyle change can stop
further blockage in coronary artery ; even many times
blockage regresses and risk of rupture of vulnerable
plaque markedly becomes less !! So naturally chances of
getting heart attack lessens..... |
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| IMPLICATIONS OF THESE
NEW FINDINGS |
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1.
Only by seeing block in angiogram there is no need of submitting the patient for
Bypass, Stenting or Angioplasty 2.
Bypass is not useless, but it should be done in selected
restricted cases (with 3 vessel disease) with reduced
ejection fraction. Benefits of bypass on survival have
not been convincingly documented in cases with good
ejection fraction.
3.
FOR MAJORITY OF PATIENTS EVEN IN HIGH RISK GROUP MEDICAL
TREATMENT WITH REVERSAL THERAPY
IS ALL THAT IS NEEDED. IT REQUIRES STRONG SUPPORT BY A
KNOWLEDGEABLE PHYSICIAN
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