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].