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Case
Report -
A 77-year-old Caucasian woman with worsening dyspnea
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Robert
Wang, MD
A 77-year-old Caucasian woman presented with progressively
worsening dyspnea over the past two days. She and her family
attributed this to possible pneumonia since she had cough
productive of light tan sputum and some "low-grade"
fevers. She had been treated for right lower lobe pneumonia
two months prior to admission as an outpatient. She also
had fluid in her lung that her cardiologist was "drying
out."
She
had hypertension and valvular disease that she could not
elaborate on, but denied history of myocardial infarction
or diabetes mellitus. She denied a smoking history and she
had no other pertinent history.
On
examination she was afebrile, with blood pressure of 150/90mmHg,
pulse of 90 beats/min, respiratory rate of 24/min and oxygen
saturation of 87% on room air. Lung exam demonstrated decreased
breath sounds on the right up to the mid lung-field with
dullness to percussion with the left lung clear to auscultation.
Cardiac exam was significant for a III/VI systolic ejection
murmur at the right sternal border, II/VI systolic murmur
at the apex, and an apical heave. Other than 1+ bilateral
pitting edema of the lower extremities, the exam is otherwise
unremarkable.
An
extended metabolic profile, including electrolytes and liver
enzymes, as well as a complete blood count were normal.
A chest roentgen showed a large, right-sided effusion with
possible infiltrate. EKG was consistent with left ventricular
hypertrophy, with no evidence of ST segment changes. Lateral
decubitus films were requested, and showed that the effusion
freely layered.
A
therapeutic thoracentesis was performed. One liter of fluid
was removed and sent for analysis that demonstrated an LDH
and protein level, both less than half of the serum values,
and a cell count that had few white as well as red blood
cells. The fluid was deemed a transudate, and as that the
patient had neither liver nor renal failure, CHF was assumed
the etiology of her effusion. Once a report of the patient's
most recent echocardiogram was obtained from her cardiologist,
it was clear that the patient had indeed developed left
sided heart failure secondary to critical aortic stenosis
(AS). She had an aortic valve orifice of 0.9 cm2
and mitral regurgitation.
Discussion
There
are two etiologies of aortic stenosis (AS). Congenitally,
there is abnormal formation of the aortic valve during embryologic
development of the heart. The aortic valve normally has
three leaflets, but in cases of abnormal development there
is fusion or hypertrophy of leaflets. The abnormal valves
may have from one to three leaflets, and due to asymmetry,
the orifice is decreased in size. Single leaflet valves
have the greatest amount of stenosis, and patients are usually
symptomatic in infancy. In valves with multiple leaflets,
the turbulent flow of blood through an incongruous orifice
leads to fibrosis, calcification and stenosis.
The
second etiology of AS is a conglomerate of disease process
that result in damage and calcification of the valve, and
therefore lead to acquired AS. These include rheumatic,
calcific, atherosclerotic and senile AS. Rheumatic, calcific
and atherosclerotic AS are self-explanatory; senile AS,
however, is not as straightforward. Analysis of senile AS
valves shows a chronic inflammatory process of the leaflets.
The leaflets are infiltrated by macrophages and T-lymphocytes,
and the inflammatory process results in immobilization and
ultimately calcification of the valve. Infection with Chlamydia
pneumoniae has been proposed as an initiator of the
inflammatory process.
The
natural history of AS is a gradual decrease in size of the
valve orifice, during which, the patient is usually without
symptoms. Once there is severe stenosis or signs of left
sided heart failure, the patient will experience symptoms
of the disease process. The cardinal manifestations of AS
are angina pectoris, syncope, exertional dyspnea, and, ultimately,
heart failure. Angina is a result of the increased oxygen
demand of the hypertrophied myocardium, and may be contributed
to by partial obstruction of the coronary arteries by the
abnormal valve. Syncope and exertional dyspnea are attributed
to fixed cardiac output in the face of vasodilatation.
On
physical examination there is usually a decreased or narrowed
pulse pressure; however early in the disease process there
may be an increased pulse pressure when the stenosis is
mild and associated with aortic regurgitation. Auscultation
of the heart yields a late peaking systolic murmur that
is often confused with a pan-systolic murmur, but is differentiated
by the ending of the AS murmur at S2. The aortic component
of the second heart sound is diminished with calcified leaflets,
but can be snappy in congenital AS. Murmur volume varies
with the severity of the AS and amount of heart failure
involved, and it is important to look for signs of left-sided
heart failure. The murmur is heard best at the right sternal
border, but also radiates to the base of the heart and may
be confused with a mitral regurgitant murmur. An AS murmur
does not radiate to the apex and is limited to the base
of the heart, and therefore may be distinguished by careful
auscultation from MR.
Asymptomatic
AS showed be followed with echocardiograms every two years,
and those with mild obstruction have no exercise restrictions.
Those with severe AS should be followed with echocardiography
every 6 to 12 months and should not participate in vigorous
activities. Digitalis may be used in those with dilation
of the left ventricle or reduced ejection fraction. Diuretics
maybe used in those with fluid accumulation like our patient,
but caution is required for AS is a preload dependent lesion
and hypovolemia can result in a low cardiac output state.
Medical management of AS includes antibiotic prophylaxis.
Surgery
is required when the calculated effective orifice is less
than 0.8 cm2 or 0.5 cm2 /m2
body surface area (BSA), or when the patient is symptomatic.
This is true in adults or children. Children have the benefit
of flexible valves that can be treated with balloon valvuloplasty.
Aortic valve replacement is the treatment of choice in adults.
The
patient presented in the opening case did not wish to have
any surgical intervention. Survival in her case is no greater
than 18 months.
References
- Behrman:
Nelson Textbook of Pediatrics, 16th ed.
- Braunwald:
Heart Disease: A Textbook of Cardiovascular Medicine,
6th ed.
- Carabello,
BA. Aortic Stenosis. N Engl J Med 2002; 346:677-682,
Feb 28, 2002.
- Otto
CM:
Valvular Heart Disease. Philadelphia, WB Saunders, 1999,
p. 203.
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