Case Report
A 30-week gestational premature male neonate, weighing 1.538 kg,
presented to our Department of Neonatal Pathology for hemodynamic
instability caused by aortic stenosis with severe left ventricular
dysfunction. The mean gradient was 70 mmHg. Intubation and surfactant
administration were required due to respiratory failure with severe
acidosis.
When the infant was 9 days of age, percutaneous balloon aortic
valvuloplasty was performed with an echocardiogram showing moderate
mitral regurgitation and a patent foramen ovale with a left-to-right
shunt. One week later, another echocardiography revealed moderate aortic
stenosis and aortic coarctation (likely initially masked by a patent
ductus arteriosus, PDA). The prostaglandin infusion was started
immediately and after 5 days the patient underwent coartectomy and PDA
ligation via left thoracotomy.
One month after coartectomy, severe hypotension occurred and
administration of epinephrine was required. Weaning of the baby from
mechanical ventilation was not possible due to hemodynamic instability
and an important edematous state worsened the clinical condition.
Echocardiography showed massive mitral regurgitation and severe aortic
steno-insufficiency. The child then developed necrotizing enterocolitis
(stage 2A according to the modified Bell staging criteria for
necrotizing enterocolitis) and triple antibiotic therapy with
ceftazidime, vancomycin, and metronidazole was started. At that point,
echocardiography [video 1] revealed a dilated left ventricle and a
left mega-atrium (17 mm in diameter, z-score = + 3.3) with jet-to-roof
lesions. Massive mitral regurgitation was present due to prolapse of a
posterior hypomobile leaflet and coaptation deficiency. The aortic valve
appeared bicuspid and severely dysplastic with a diameter of 10 mm and 7
mm on the short and long axis, respectively. The pulmonary artery had a
diameter of 8.6 mm (z score = + 1.5). Severe aortic insufficiency with
holosystolic outflow into the abdominal aorta and a median transvalvular
gradient of 34 mmHg was identified on Doppler echocardiography.
After 8 days the patient underwent a Ross procedure with mitral valve
plasty and closure of the patent foramen ovale. The weight at the time
of the operation was 2.100 kg. Cardiopulmonary bypass was established
through a median sternotomy and aorto-bicaval cannulation. After
selective cardioplegia administration, the ascending aorta was opened. A
detached aortic cusp was identified as a result of the previous balloon
dilation. The pulmonary autograft was harvested and then implanted in
the aortic position with a continuous 7-0 polypropylene suture. Coronary
buttons were reimplanted with 8-0 polypropylene suture. After distal
aortic suture, left atriotomy was performed in hypothermic circulatory
arrest (22 ° C nasopharyngeal). The mitral valve leaflets were both
dysplastic with an arch-like subvalvular apparatus. A splitting of the
papillary muscle was performed and closure of a patent foramen ovale was
accomplished. Finally, a 12 mm Contegra Conduit was downsized (with a
bicuspidalization according to the patient’s body surface area) and then
interposed between the right ventricle and the pulmonary artery with a
continuous 7-0 polypropylene suture [figure 1]. Post-operative
transesophageal echocardiogram showed good biventricular function, mild
aortic regurgitation, and mild-to-moderate mitral regurgitation.
The postoperative course was noteworthy for inotropic support and
temporary atrioventricular block. Chest closure was performed on the
2nd postoperative day and the patient was discharged
on the 30th postoperative day. After 11 months the
patient developed endocarditis of the Contegra conduit and subsequent
stenosis with a maximum gradient of 90 mmHg [Video 2]. Antibiotic
treatment and stent placement in the proximal duct were required with
good results and without complications. At the last postoperative
follow-up at 38 months the patient was in optimal clinical conditions
(weight 11.880 kg) and the last echocardiogram showed no dilation of the
left ventricle with normal systolic function (EF> 70%),
mild aortic regurgitation and mild-to-moderate mitral regurgitation
[video 3].