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Brom Aoroplasty for Supravalvar Aortic Stenosis
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Patient
Selection |
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Brom’s three-patch aortoplasty
is indicated for the repair of supravalvar aortic stenosis, which
can occur as an isolated defect or as a part of Williams syndrom
[1]. This syndrome is characterized
by supravalvar aortic stenosis, elfin craniofacial features, peripheral
pulmonary artery stenosis, and hypercalcemia. The underlying
cause is a loss of function mutation of the elastin gene on chromosome
7q11.23. These patients will have a systolic cardiac murmur and
two-dimensional echocardiography can establish the diagnosis.
Cardiac catheterization is indicated to evaluate the status of
the coronary arteries and assess the pulmonary arterial tree for
related peripheral stenosis.
Indications for surgery include symptoms of diminished exercise
tolerance, syncope, or angina. Other indications would include
1) systolic ascending aorta gradient greater than 50 mm Hg, 2)
aortic valve insufficiency, or 3) evidence of compromised coronary
artery perfusion. These patients should undergo surgery
at a relatively early age because of the detrimental effect of
the high proximal aortic pressure on the coronary arteries with
the possibility for accelerated atherosclerotic changes.
These patients typically have a thickening of the aortic wall
at the sinotubular junction. This abnormal thickening may
extend into the ascending aorta and even into the aortic arch.
In some patients, this abnormal thickening creates stenosis of
the coronary ostium.
The surgical history of operations for supravalvar aortic stenosis
is shown in Table 1. Dwight McGoon and
John Kirklin [2] from the Mayo Clinic
first reported a one-patch teardrop-type repair of supravalvar
aortic stenosis in 1961. Donald Doty [3]
reported the use of an inverted Y-shaped patch which extended
into two of the aortic valve sinuses in 1977. The technique
described in this monograph is that of A. Gerard Brom, [4]
with three patches placed into the three aortic valve sinuses.
This frequently also requires a patch in the distal ascending
aorta. Most recently, John Myers [5]
described an approach with three incisions into the three coronary
sinuses and corresponding counterincisions into the distal ascending
aorta which then insert into the openings created in the proximal
ascending aorta. This technique has the advantage of not
requiring autologous patch material, but is technically more demanding.
Table 1: Surgical History of Operations
for Supravalvar Aortic Stenosis
| Surgeon |
Technique |
Number of Sinuses
Opened |
Year Reported |
| McGoon |
Single-patch |
1 |
1961 |
| Doty |
Inverted "Y" Patch
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2 |
1977 |
| Brom |
Three-patch |
3 |
1988 |
| Myers |
Three-sinus incision
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3 |
1993 |
An asymptomatic, 5-year-old, 18-kg boy known by genetic testing
to have Williams syndrome on physical examination had a IV/VI
harsh systolic ejection murmur and no diastolic murmur.
Preoperative echocardiogram showed an aortic root dimension of
2 cm and the dimension at the level of stenosis in the ascending
aorta was 8 mm. Peak echocardiogram gradient was 70 mm Hg
with a cardiac catheterization gradient of 50 mm Hg. The
child had no peripheral pulmonary artery stenosis.
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Case Study |
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| Figure 1
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An asymptomatic, 5-year-old, 18-kg boy
known by genetic testing to have Williams syndrome on physical
examination had a IV/VI harsh systolic ejection murmur and no
diastolic murmur. Preoperative echocardiogram showed an
aortic root dimension of 2 cm and the dimension at the level of
stenosis in the ascending aorta was 8 mm. Peak echocardiogram
gradient was 70 mm Hg with a cardiac catheterization gradient
of 50 mm Hg. The child had no peripheral pulmonary artery
stenosis.
Preoperative
transesophageal echocardiogram in long-axis view shows ascending
aorta with aortic valve to the left. The markers indicate the
aoritc root dimension to be 2.0 cm and hte mid portion of the
stenosis to be 0.8 cm.
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| Figure
2: Preoperative cardiac catheterization. |
Figure
3:The "waist" in the ascending aorta is readily
apparent. The "waist" is above coronary orifices. |
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| Figure
4: AP/Lateral ventriculogram. The patien has
no subaortic obstruction.
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Figure
5: Main pulmonary artery injection. There is
no peripheral pulmonary artery stenosis. |
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Operative Steps |
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The operative approach is
through a median sternotomy with the use of cardiopulmonary bypass
and bicaval venous cannulation. The first dose of cold blood cardioplegia
is antegrade; the remaining doses are retrograde.
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Results |
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The results of the three-patch
aortoplasty technique are shown in Table 2.
The report by Stamm and associates from Boston Children’s
Hospital, in particular, compared the results of single-patch,
bifurcated-patch, and three-sinus reconstruction [7].
Results improved greatly after the introduction of the three-sinus
technique, a more symmetric reconstruction of the aortic root.
Residual gradients were lower, hemodynamics were superior, and
there was a reduction in both mortality rate and need for reoperation.
Table 2.
Results of three-sinus incision technique
| Author |
Year |
Number
of Patients |
Median
Age (Years) |
%
Williams Syndrome |
Mortality |
Mean
Residual Gradient |
| Myers
[5] |
1993 |
2
- Brom
4 - Myers |
3.8 |
39 |
0
1 |
12mm
Hg |
| Hazekamp
[6] |
1999 |
13 |
15.8 |
38 |
0 |
10mm
Hg |
| Stamm
[7] |
1999 |
4
- Myers
2 - Brom |
7.4 |
61 |
0
0 |
10mm
Hg |
| Total |
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25 |
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1 |
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Tips and Pitfalls |
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High ascending aortic cannulation
adjacent to the innominate artery for maximum exposure of
the ascending aorta and to allow length for positioning
of the patch in the ascending aorta.
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One dose of antegrade cardioplegia
followed by retrograde cardioplegia.
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Pulmonary homograft or pericardial
patches (tanned in glutaraldehyde) for the “shields”.
These patches should not be too large – this will
lead to aortic insufficiency.
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First coronary sinus incision
in noncoronary sinus to facilitate exposure of the incisions
into the coronary orifice sinuses.
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In most cases, the right coronary
artery sinus should be opened to the left of the coronary
orifice and the left coronary artery sinus to the right
of the coronary orifice. Occasionally one may not have enough
room between a coronary orifice and the aortic valve; in
this case the incision site should be tailored to the situation.
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Ensure similar orifice sizes between
the proximal and distal ascending aorta after patch augmentation
by the use of a sizing dilator.
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Transesophageal
echocardiography to assess completeness of repair, coronary
blood flow postoperatively, wall motion abnormalities, and
adequacy of aortic valve.
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References |
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1. Williams JCP, Barratt-Boyes
BG, Lowe JB. Supravalvular aortic stenosis. Circulation
1961;24:1311-8 .
2. McGoon DC, Mankin HT, Vlad P, Kirklin JW. The surgical
treatment of supravalvular aortic stenosis. J Thorac Cardiovasc
Surg 1961;41:125-33.
3. Doty DB, Polansky DB, Jenson CB. Supravalvular aortic
stenosis. Repair by extended aortoplasty. J
Thorac Cardiovasc Surg 1977;74:362-71.
4. Brom AG. Obstruction of the left ventricular outflow tract.
In Khonsari S, editor. Cardiac surgery: safeguards and pitfalls
in operative technique, 1st ed. Rockville, MD: Aspen Publishers,
1988; p 276-80.
5. Myers JL, Waldhausen JA, Cyran SE, Gleason MM, Weber HS,
Baylen BG. Results of surgical repair of congenital supravalvular
aortic stenosis. J
Thorac Cardiovasc Surg 1993;105:281-7.
6. Hazekamp MP, Kappetein AP, Schoof PH, Ottenkamp J, Witsenburg
M, Huysmans HA, Bogers AJ. Brom’s three-patch technique
for repair of supravalvular aortic stenosis. J
Thorac Cardiovasc Surg 1999;118:252-8.
7. Stamm C, Kreutzer C, Zurakowski D, Nollert G, Friehs I,
Mayer JE, Jonas RA, del Nido PJ. Forty-one years of surgical experience
with congenital supravalvular aortic stenosis. J
Thorac Cardiovasc Surg 1999;118:874-85.
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| The pages comprising Experts'
Techniques: Congenital Cardiac Experts' Techniques were compiled
and edited by Carl
L. Backer M.D. Comments, suggestions, and contributions are
welcome. |
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