Coarctation of the Aorta

HISTORY
19-year-old man.
CHIEF COMPLAINT: The patient is asymptomatic, and is referred for the
evaluation of hypertension.
PRESENT ILLNESS: Hypertension was noted at the time of a preinduction
physical for the military. The patient cannot recall any previous blood pressure
determinations. A heart murmur had been noted in early childhood and was
thought to be innocent.
Question:
What etiologies of hypertension should be considered in
this patient?
33-1
Answer:
Essential hypertension, because it accounts for 90% or more of
all cases, must lead the list. However, the combination of hypertension and
murmur in a young man is consistent with a diagnosis of coarctation of the
aorta. Renal parenchymal and vascular disease are considerations; adrenal
cortical and medullary tumors are far less likely.
PHYSICAL SIGNS
a. GENERAL APPEARANCE - Normal 19-year-old man.
b. VENOUS PULSE - The CVP is estimated to be 4 cm H2O.
ECG
JUGULAR
VENOUS
PULSE
Question:
What is your interpretation of the venous pulse?
33-2
Answer:
The venous pulse is normal in mean pressure and wave form.
c. ARTERIAL PULSE - (BP = 170/100 mm Hg both arms)
ECG
CAROTID
S1
S2
APEX 200 CPS
FEMORAL
Question:
What is your interpretation of the arterial pulses?
33-3
Answer:
The carotid pulses are normal to slightly enhanced in upstroke.
The femoral pulse is diminished and also delayed in onset compared to the
carotid. The lower extremity blood pressure in this patient is 120/80 mm Hg,
i.e., significantly lower than the upper extremities, whereas normally it is
somewhat higher. These findings are all consistent with typical coarctation of
the aorta near the origin of the left subclavian artery.
d. PRECORDIAL MOVEMENT
ECG
0.1 sec
APEXCARDIOGRAM
Question:
How do you interpret the precordial movement at the apex?
33-4
Answer:
There is a non-displaced sustained systolic impulse consistent
with left ventricular hypertrophy. The small “a” wave preceding the systolic
impulse is not palpable.
e. CARDIAC AUSCULATION
UPPER RIGHT
STERNAL EDGE
200 CPS
S1
A2
ECG
Question:
How do you interpret the acoustic events at the upper right
sternal edge?
33-5
Answer:
There is an ejection sound (arrow), a short crescendodecrescendo systolic murmur, and a diastolic decrescendo murmur. These
findings suggest that the patient has a bicuspid aortic valve that is minimally
stenosed and regurgitant. A bicuspid aortic valve is found in over 50% of
patients with coarctation of the aorta. The diastolic murmur is heard only at the
upper right sternal edge in this patient, although it is commonly best heard at
the mid-left sternal edge. The fact that the systolic murmur occurs during early
ejection when the flow is rapid suggests that, if there is obstruction at the valve
level, it is mild. The loud aortic second sound likely reflects the augmented
aortic root pressure. The ejection sound also can be heard at the apex.
Proceed
33-6
e. CARDIAC AUSCULTATION (continued)
MID LEFT
STERNAL EDGE
S1
S2
Questions:
1. How do you interpret the acoustic events at the mid-left sternal edge?
2. In coarctation of the aorta, where else may murmurs be heard other than in
the four classic acoustic areas?
33-7
Answers:
1.
There is a crescendo-decrescendo systolic murmur which may be due to
a coarctation per se and may also be heard at the apex.
2.
A murmur may be heard over the posterior thorax and may help to localize
the area of obstruction. In mild coarctation, the murmur is relatively short.
As the degree of obstruction increases, the murmur gets longer and may
extend into diastole. Widespread murmurs from collateral vessels may
also be heard over the intercostals, internal mammaries, and in the
subclavicular areas in some patients.
f.
PULMONARY AUSCULTATION
Question:
How do you interpret the acoustic events in the pulmonary lung
fields?
Proceed
33-8
Answer:
In all lung fields, there are normal vesicular breath sounds.
ELECTROCARDIOGRAM
I
II
III
aVR
aVL
aVF
V1
V2
V3
V4
V5
V6
1/2 STANDARD
Question:
How do you interpret the ECG?
33-9
Answer:
The ECG shows voltage criteria for left ventricular hypertrophy.
CHEST X RAY
I
2
3
Questions:
1. How do you interpret the patient’s chest X ray?
2. Based on the history, physical examination, ECG and X ray, what is your
initial diagnostic impression and plan to further evaluate this patient?
33-10
Answers:
1. The chest X rays are of specific diagnostic value. There is a “3 sign” of
coarctation. The figure “3” is formed by the shadows of:
1. The transverse aortic arch and left subclavian artery.
2. The coarctation site.
3. The post-stenotic dilation of the descending aorta.
Note also the slightly dilated ascending aorta (broken arrow)
and early rib notching (arrows).
2. The history, physical examination, ECG and chest X rays taken together are
diagnostic of coarctation of the aorta with an associated congenital bicuspid
valve. Because the natural history of uncorrected coarctation usually
results in death by the age of 40, and because the lesion is surgically
correctable, further study is indicated as follows.
33-11
LABORATORY - ECHOCARDIOGRAM
TWO-DIMENSIONAL SUPRASTERNAL AORTIC ARCH
LCC
LS
TAo
LCC
LS
TAo
DAo
=
=
=
=
left common carotid
left subclavian
transverse aorta
descending aorta
DAo
Question:
How do you interpret this study?
33-12
Answer:
Two-dimensional echocardiography of the aortic arch shows the
coarctation site (arrow).
A continuous wave Doppler study predicts a systolic gradient of approximately
50 mm Hg.
In adult patients, transthoracic echocardiography may not adequately image an
aortic coarctation. In such patients, magnetic resonance imaging should be
performed. If unavailable, cardiac catheterization with angiography is an
alternative. This patient’s angiographic study follows.
33-13
LABORATORY - AORTIC ROOT ANGIOGRAM - LAO
Left
Common
Carotid
Left
Subclavian
Innominate
Artery
Questions:
1. How do you interpret this
angiogram?
2. How would you treat this
patient?
Left Anterior Oblique
33-14
Answer:
1. The angiogram shows coarctation of the aorta distal to the left subclavian
(white arrow). Aortic regurgitation is not seen in this systolic frame.
2.
Relief of the obstruction is required to treat this patient’s hypertension and
prevent its complications. This can be accomplished by surgery or by
interventional catheterization. Such catheterization includes dilation of the
obstruction and, in some cases, placement of a stent to maintain adequate
aortic diameter at the coarctation site.
Therapeutic intervention ideally should be accomplished in early childhood.
If treatment is delayed, patients may remain hypertensive despite
successful relief of the obstruction.
Proceed
33-15
The patient underwent surgery for correction of coarctation of the aorta. The
pre-operative brachial blood pressures were 170/100 mm Hg. Post-operatively,
they were 130/90 mm Hg. The aortic regurgitation was felt to be trivial and was
not approached. The patient has done well with no medication except for
infective endocarditis prophylaxis.
Proceed for Summary
33-16
SUMMARY
Coarcation of the aorta is a congenital anomaly affecting males in two-thirds of
cases. In 95% of cases, the coarctation site is just distal to the left subclavian
artery near the ligamentum arteriosum. A bicuspid aortic valve occurs in over
50% of patients and aortic regurgitation may be heard in 15% of these patients.
The second most frequent associated lesion is patent ductus arteriosus.
Unless very severe, coarctation does not cause symptoms until adult age, and
even then is commonly diagnosed only by finding hypertension or an abnormal
chest X ray.
Patients are at risk for infective endocarditis. Rarely,
cerebrovascular accidents may occur in children with coarctation.
The typical gross pathology follows.
33-17
PATHOLOGY
INNOMINATE
ARTERY
LEFT COMMON
CAROTID ARTERY
ASCENDING
AORTA
LEFT SUBCLAVIAN
ARTERY
COARCTATION
PULMONARY
ARTERY
LIGAMENTUM
ARTERIOSUM
Proceed for Case Review
33-18
To Review This Case of
Coarctation of the Aorta:
The HISTORY is typical, in that patients are usually asymptomatic
through their teens (and rarely so after the age of 30). A history of hypertension
and murmur, as in our patient, is usual.
PHYSICAL SIGNS
a. The GENERAL APPEARANCE is normal. Females with Turner’s
syndrome (XO chromosome abnormality), who have a distinctive
appearance, demonstrate an increased incidence of coarctation.
Proceed
33-19
The GENERAL APPEARANCE in Turner’s syndrome:
Note the webbed neck, small chin and epicanthal folds.
Proceed
33-20
b. The JUGULAR VENOUS PULSE is normal in mean venous pressure
and wave form.
c. The ARTERIAL PULSES and pressures are diagnostic of coarctation
beyond the left subclavian. The carotid pulses are brisk, and the femorals
small and delayed. There is a significant decrease in lower extremity blood
pressure with hypertension proximally.
d. PRECORDIAL MOVEMENTS reveal a sustained apical systolic impulse
reflecting the afterloaded hypertrophied left ventricle.
33-21
e. CARDIAC AUSCULTATION reveals findings of the coarctation as well
as the patient’s associated bicuspid aortic valve. In many patients, localized
murmurs over the area of coarctation are best heard in the posterior midthorax. The bicuspid valve is minimally stenosed and regurgitant, and
accounts for the ejection sound well heard at the upper right sternal edge
and apex, as well as for the short systolic and diastolic murmurs at the right
sternal edge. Murmurs due to collaterals may be heard in some patients.
f. PULMONARY AUSCULTATION reveals normal vesicular breath sounds
in all lung fields.
33-22
The ELECTROCARDIOGRAM shows left ventricular hypertrophy.
The CHEST X RAYS are diagnostic with rib notching, a “3 sign” and
moderate dilation of the aortic root.
LABORATORY
study with echocardiography and aortic root
angiography shows the anatomy with coarctation distal to the left subclavian.
TREATMENT
is relief of the obstruction, as the patient’s hypertension is
significant and is having an effect on his circulation, even though he is
asymptomatic at this time. The bicuspid valve was not replaced, as the degree
of hemodynamic problem related to it was minimal, especially with the
coarctation corrected. Endocarditis prophylaxis is indicated.
33-23