PREOPERATIVE DIAGNOSIS: Williams syndrome, supravalvular aortic
stenosis with pulmonary stenosis at the proximal part of the right
pulmonary artery and left pulmonary artery.
POSTOPERATIVE DIAGNOSIS: Williams syndrome, supravalvular aortic
stenosis with pulmonary stenosis at the proximal part of the right
pulmonary artery and left pulmonary artery.
SURGEON:
V. Mohan Reddy, M.D.
ASSISTANT(S):
Anil K Dharmapuram, M.D. and Hanson Quan, P.A.-C.
PROCEDURE PERFORMED:
1.
Patch augmentation of the supravalvular aortic stenosis,
ascending aorta and proximal aortic arch.
2.
Patch-plasty of the confluence of the pulmonary arteries with
bifurcation enlargement.
BRIEF HISTORY AND INDICATIONS: Hayden Sumaoang is a 3-1/2-year-old
child who was diagnosed to have Williams syndrome with supravalvular
aortic stenosis, hypoplastic aortic arch and mild branch pulmonary
stenosis with developmental delay. He has been followed up with
echocardiograms and also a CT angiogram that was performed on 9/1/2004
and repeated on 7/20/2006 at Lucile Packard Children's Hospital. The
follow-up CT angiogram showed the following findings: Aortic arch
hypoplasia with no interval growth in the ascending aorta as compared
to 9/1/2004. Aortic annulus measuring 10 mm, sinuses measuring 13 mm,
that is unchanged from the previous study. The sinotubular junction
measured 4.5 mm, that is unchanged from the previous study. The aortic
arch measured 7 mm against 6 mm previously. The descending aorta
measured 4 mm as against 5 mm previously. More distally, the aorta was
8 mm as against 6 mm previously. There was interval increase in the
size of the aortic arch and descending aorta, as well as the PAs, with
no evidence of coarctation. In conclusion, the CT angiogram impression
was that of aortic arch hypoplasia with no significant interval growth
in the ascending aorta and interval increase in size of the aortic arch
and descending aorta as well as the pulmonary arteries with severe left
ventricular hypertrophy and normal coronary arteries.
The case was discussed in the conference and it was decided to plan for
repair of the supravalvular stenosis and lysis of bifurcation. The
risks and benefits were discussed with the parents and surgery was
planned on this date, that is 9/11/2006.
OPERATIVE PROCEDURE IN DETAIL: After inducing anesthesia and securing
adequate monitoring, the patient was placed in the supine position and
prepared and draped. Meanwhile, an appropriate-sized hemi-pulmonary
artery homograft patch was prepared in anticipation for usage in the
repair. Intraoperative transesophageal echo was performed and that
confirmed the findings. There was no evidence of any VSD
intraoperatively and the evidence of left ventricular hypertrophy.
Left coronary anatomy appeared to be normal.
A midline sternotomy was performed. The thymus was resected and
removed. The pericardium was incised and the heart exposed. The
anatomy was inspected. It was found to be consistent with the
preoperative diagnosis. The ascending aorta was hypoplastic, starting
from just above the annulus at the sinotubular junction and involving
the entire ascending aorta and entire arch and extending onto the
peripheral part of the descending aorta. The ascending appeared
thickened. The bifurcation of the pulmonary arteries appeared narrow.
The pulmonary arteries, on inspection, appeared to be normal from
outside. In the beginning, a dissection was performed to separate the
ascending aorta and the pulmonary arteries. The PDA appeared to be
ligamentous. It was isolated, it was looped with 5-0 Prolene
transfixation suture and tied and clipped at the aortic end. The
pulmonary artery end of the ductus was also sutured with a
transfixation suture and the PDA divided in between the two sutures.
The entire ascending aorta was dissected including the neck vessels and
the arch and the peripheral part of the descending aorta. The
pulmonary arteries were also dissected to expose the bifurcation.
Meanwhile, preparations were made for installation to the
cardiopulmonary bypass. It was decided to perform double aortic
cannulation, that is to cannulate both the innominate and proximal part
of the descending aorta with two separate aortic cannulae. So
pursestrings were placed, one in the base of the innominate artery and
another in the proximal part of the descending aorta. #10 arterial
cannula was used to cannulate the proximal part of the descending aorta
and the innominate separately. Both of these cannulae were connected
to a Y-connector and then connected to the arterial end of the CPB.
The SVC and IVC were cannulated with two angled venous cannulae.
Cardiopulmonary bypass was established and slow cooling was started to
achieve cooling of temperature to 32 degrees centigrade. A vent was
placed in the right pulmonary vein into the LV. A pursestring suture
was placed in the descending aorta just proximal to the innominate
artery for placement of cardioplegia and that was connected to the
cardioplegia system. At the desired temperature, the aorta was cross
clamped just distal to the cardioplegia cannula and proximal to the
innominate cannula to include the aorta and arch. The aortic root was
cooled and cardioplegia infused. Surface cooling was done with ice
cold saline.
After establishment of cardiac asystole, the aortic root cardioplegic
cannula was removed and the cardioplegia cannula incision was enlarged
with a fine scissor. The aorta was incised both proximally and
distally starting from the incision of the cardioplegia cannula.
Proximally, it was incised towards the aortic valve, passing across the
sinotubular junction. At this level, the incision was carried down
both ways into the sinuses of the right coronary artery and beyond the
coronary artery to completely open the aorta that was narrow at this
level of the sinotubular junction. Following this, the coronary
arteries were inspected and found to be normal at the level of the
ostia; however, there was a ridge of tissue above the level of the left
coronary artery ostium that was removed completely. Following this,
both ostia of the coronary artery were inspected and found to be
adequate with no evidence of any obstruction as evaluated by passing of
fine probes of appropriate size. Distally, the incision of the aorta
was continued onto the undersurface of the aortic arch and extended
almost towards the undersurface of the aortic arch. Meanwhile, the
already prepared pulmonary homograft patch was appropriately incised
and shaped into a longitudinal piece with two separate ends at the
proximal ends that would separately fit into both enlarged sinuses of
the NCC and the RCC. The patch was appropriately trimmed to match the
shape of the undersurface of the aortic arch after being sutured.
Augmentation of the entire ascending aorta and arch was performed with
the patch using 5-0 Prolene continuous suture. The suturing was first
started at the bases of the sinuses separately and then continued
distally.
After 25 minutes, the cardioplegia was repeated by infusing cold
crystalloid cardioplegia into both the coronary arteries separately.
Following this the distal augmentation was continued towards the
undersurface of the arch. At this level distally, the incision was
posited towards the arch on the under surface of the aorta to extend to
the proximal part of the aortic arch. To the most distal ends of the
anastomosis, the aortic cross-clamp was replaced with a side-biting Cclamp that was placed to include the base of the neck vessels onto the
undersurface of the aortic arch and well above the aortic cannula that
was placed in the descending aorta. After placing the C-clamp,
adequate exposure was obtained to extend the anastomosis of the
augmentation well onto the undersurface of the aortic arch and the
proximal part of the descending aorta. After completion of the
augmentation of the aorta with this patch, a stab suture incision was
made with a pursestring on the top of the aorta and de-airing was
performed by stopping the vent. Meanwhile, rewarming was started.
After adequate de-airing of the aorta, the aortic cross-clamp, that is
the side-biting clamp, was slowly released and the aortic root
adequately de-aired. After releasing the aortic cross-clamp, the vent
was restored. The heart started beating with normal contraction of the
ventricle. Rewarming was continued to normothermia.
The aortic root vent was snugged. On the beating heart, the
augmentation of the pulmonary artery bifurcation was planned. It was
done as follows. Two stay sutures were placed, one proximal and one
distal at the level of the bifurcation and the MPA was incised
longitudinally. It was extended proximally towards the pulmonary valve
and distally towards the bifurcation. At the level of the bifurcation,
it was noticed that both RPA and LPA origins were narrow due to another
bifurcation. A plasty was performed by cutting onto the bifurcation to
include both the ostia of the RPA and LPA. After initially opening the
bifurcation, suturing was performed into the slightly opened
bifurcation using 7-0 Prolene. The suturing was started at the apex of
the incision, that is towards the opening of both ostia, and posited
upwards, that is toward the bifurcation. By doing so, the entire
bifurcation was adequately enlarged and both origins of the RPA and LPA
appeared adequate and opened up adequately. After enlarging the
bifurcation posteriorly, the anterior part of the MPA was augmented
with separate piece of homograft patch that was appropriately prepared
and then sutured using 6-0 Prolene continuous suture. The entire
augmentation was performed on a beating heart.
At this junction, rewarming was completed. Preparations were made to
wean the patient off cardiopulmonary bypass. At first, the anastomotic
areas were evaluated for bleeding and hemostasis was obtained by
appropriate suturing. The LV vent was stopped and the vent removed.
The heart was gradually weaned off bypass with moderate inotropic
support of 3 mcg of dopamine and 1 mcg of milrinone. To control
hypertension, Nipride was used. The hemodynamics appeared to be stable
with satisfactory saturations. The myocardial contractions appeared to
be normal. The entire ascending aorta and arch filled normally with
good contour. Intraoperative transesophageal echo was performed. It
showed evidence of good repair with no evidence of obstruction at the
level of the aorta and the pulmonary arteries. The LV function
appeared to be normal.
After assuring adequate hemostasis, protamine was administered and
decannulation performed. Hemostasis was checked carefully. The right
pleura was opened and the pleural cavity drained with separate chest
tube. The mediastinum was drained with a #20 chest tube separately.
Two ventricular pacing wires were placed. With adequate hemostasis,
the chest was closed with sternal wires and the subcutaneous layers and
skin were closed appropriately.
The patient was shifted with stable hemodynamics and saturations and
with adequate control of hypertension to the CV ICU.