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Arokiasamy was admitted with pulmonary edema
(water lodgment in the lungs) due to severe leak in his mitral
valve. He was stabilized with medications and was subsequently
subjected to cardiac surgery. His mitral valve was replaced with
an artificial valve.
Who needs valve surgery?
 Even with badly damaged valves, many people remain symptom free
with proper medications. If the individual discontinues the
medicines, the symptoms would recur. At times, heart beats can
suddenly become too fast precipitating heart failure. These
patients can be effectively managed with medicines and
potentially return to symptom free status. If the symptoms
persist, valve surgery is recommended. At times, valve surgery
is done in patients with mild symptoms to prevent further damage
to the heart.
If an individual is free of symptoms on medications, what is the
need to have periodical cardiac evaluation?
Medications cannot cure the valve problem. In spite of drugs,
heart might start failing slowly. In the initial stages of
failure, the individual would develop only mild symptoms which
he could ignore. Echocardiography is done periodically to assess
the degree of enlargement of heart, its pumping power and other
complications like increase in the lung pressure. Valve surgery
has to be done once these findings start to appear. If not,
permanent damage occurs in the heart and the individual might
become a high risk surgical candidate or can even become
unsuitable for surgery.
What types of valve surgery are available?
It includes ‘valve repair’ and ‘replacement of valve’. At times
patient’s own valve can be retained by repairing it. This is an
ideal situation but unfortunately only a few are suitable for
valve repair surgery. Valve replacement involves removal of the
damaged valve and replacing it with an artificial valve. There
is no ideal artificial valve that can match the native valve.
Do we have any choices regarding artificial valves?
The artificial valves can be classified into mechanical valves
and biological valves. Mechanical valves are made of metals or
similar tough materials. Biological valves are fashioned from
animal or human tissues. Different valves are available for
mitral and aortic positions.
 There are several types of mechanical valves: ball and cage
type, tilting disc valve or bileaflet valves. These valves are
non-antigenic which means the body does not recognize these as
‘foreign’ and hence there is no fear of rejection. However,
blood clots can form over these unnatural surfaces. These clots
can prevent the valve from functioning properly, at times even
causing sudden death. They can get dislodged and travel to brain
to cause stroke. Or, the clots can get lodged in an arm, leg or
kidney causing a sudden reduction in the blood flow. Hence,
these individuals should receive life long drugs that would
reduce the tendency of the blood to form clots on those
surfaces. These agents that prevent the formation of clots are
called anticoagulants, more commonly known as ‘blood thinners’.
The advantage of these valves is that they are durable and can
potentially last for more than 20 years.
The biological valves are treated valves from cadavers or
fashioned from the pericardium of cows. Blood clots do not form
on these valves and hence long term anticoagulation is not
needed. The disadvantage is that they degenerate gradually and
would need to be replaced in 10-15 years time.
How do we choose the valve if a replacement is needed?
It depends on multiple factors. The following set of patients is
preferably given biological valves:
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Those who cannot take blood thinners for another medical
condition
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Those who are not willing to take or monitor
the therapy
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Older patients, e.g. 60 years or more,
who have higher rate of complications with anticoagulation.
As the average life span thereafter is around 15 years,
majority would not need re-operation.
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Those with a life expectancy less than 10
years
The following patients would preferably receive mechanical
valves:
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Young individuals
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When patient is needed to take oral
anticoagulation for another indication
Arokiasamy was told about the details of different valves. His
heart rhythm was irregular due to the long standing valve
disease (atrial fibrillation). This condition needed blood
thinners for indefinite period. Hence, there was no advantage to
give him a biological valve. He underwent open heart surgery
with a tilting disc valve and had good outcome.
Kannan BRJ
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