[Experience of Mitral Valve Replacement Using a Pulmonary Autograft (Ross II Operation) in an Infant;Report of a Case].

A 24-day-old boy suddenly developed progressive heart failure and was transported to our hospital. Echocardiography showed massive mitral regurgitation due to chordal rupture. Mitral valve repair was performed at 28 days of life, but postoperative valvular function was not satisfactory. A mechanical valve was implanted in the supra-annular position at 37 days of life. Two months after valve replacement, the mechanical valve was suddenly stuck. Emergent redo valve replacement was performed, but the prosthetic valve became stuck again 2 months after the 3rd operation, despite sufficient anti-coagulation therapy. At the 4th operation (6 months after birth), we implanted a pulmonary autograft in the mitral position instead of another mechanical valve in an emergent operation. The right ventricular outflow tract was reconstructed with a valved conduit. A postoperative catheter examination, which was performed 1 year after the Ross II operation, showed mild mitral stenosis with no regurgitation. Previous reports of Ross II operations in infants are rare and long-term results are unknown. However, we advocate that this procedure should be a rescue operation for mitral valve dysfunction in the early period of infants.

[Pulmonary artery sling and single ventricle treated with a simultaneous operation of slide tracheoplasty, left pulmonary artery reimplantation, and bidirectional cavo-pulmonary shunt].

Pulmonary artery sling is frequently combined with tracheal stenosis, and occasionally combined with congenital heart defects. However, there are few reports of successfully treated cases that were combined with single ventricle. In this article, we report a successfully treated case of pulmonary artery sling combined with tracheal stenosis, single ventricle, pulmonary atresia, vascular ring, and bilateral superior vena cava. A male infant was referred to our hospital for central cyanosis, and was diagnosed with single ventricle (tricuspid stenosis, multiple ventricular septal defect, and hypoplastic right ventricle)with pulmonary atresia by echocardiogram. Tracheal stenosis was shown at cardiac catheterization. Pulmonary artery sling and tracheal diverticulum were diagnosed by computed tomography (CT) and magnetic resonance imaging(MRI)examination. Furthermore, the patient was complicated by vascular ring, which consisted of right aortic arch, an aberrant left subclavian artery, and patent ductus arteriosus, and this ductus arteriosus was connected to the left subclavian artery and pulmonary arterial trunk. After 6 months of medical treatment, including continuous infusion of prostaglandin, re-evaluation was performed by cardiac catheterization. We considered that bidirectional cavo-pulmonary shunt was appropriate for the patient since his pulmonary vasculature had matured well. An operation was performed under the use of cardio-pulmonary bypass. Release of vascular ring by division of the ductus, bilateral bidirectional cavo-pulmonary shunt, and a slide tracheoplasty for tracheal stenosis were performed simultaneously. His recovery was uneventful, and he is currently waiting to receive a Fontan-type operation.

Complete but not partial thymectomy in early infancy reduces T-cell-mediated immune response: three-year tracing study after pediatric cardiac surgery.

OBJECTIVE: Thymectomy is often performed to secure an operative field in surgery for congenital heart defects in early infancy. However, how neonatal thymectomy affects the subsequent development of the immune system in humans remains unclear. We monitored patients for 3 years from the time of thymectomy that was performed during cardiac surgery in early infancy. METHODS: For up to 3 years, we monitored the number of circulating lymphocytes and the clinical course of the children who underwent complete (n = 17), partial, and no (n = 15) thymectomy during congenital heart defect surgery performed at less than 3 months of age. The titers of immunoglobulin-G produced in response to vaccinated viruses and phytohemagglutinin responses were also measured. RESULTS: Six months after surgery, the number of T cells, including CD4(+) and CD8(+) subpopulations, decreased in patients with complete but not partial thymectomy. The reduction in T-cell number persisted for 3 years, whereas the number of B cells did not change. In patients with complete thymectomy, the titers of immunoglobulin-G produced in response to vaccinated measles and rubella viruses were reduced, whereas the phytohemagglutinin-induced proliferation of T cells was not impaired. In addition, hospitalization frequency associated with infectious diseases increased in patients with complete but not partial thymectomy. CONCLUSIONS: The results revealed that complete thymectomy in early infancy reduces the number of circulating T cells and T-cell-mediated immune responses for at least 3 years, suggesting that the thymus should be at least partially preserved during surgery in early infancy to maintain protective immunity.

[Experience of 3 successfully treated cases of tracheo-innominate artery fistula and significance of preventive surgery].

Tracheo-innominate artery fistula (TIF) is a rare but fatal complication after tracheostomy. Necessary lifesaving measures include proper ventilation, temporary hemostasis, and surgery. Recently, we successfully managed 3 cases of TIF. Ventilation and temporary hemostasis were secured by a long endotracheal tube and overinflated cuff. Division of the innominate artery, restoration of the tracheal fistula with an autologous pericardial patch or direct closure, and aorto-innominate bypass grafting or extra-anatomical bypass grafting with a polytetrafluoroethylene (PTFE) graft were performed through an emergency median sternotomy. All 3 patients recovered with no problems. After TIF occurs, the patient's condition rapidly worsens, and the risk of bacterial contamination in the operative field may increase. Surgical intervention should be performed for patients with tracheal stenosis who are judged to be at high risk for TIF. This preventive surgery includes bypass grafting to divide the innominate artery and partial resection of the anterior bony thorax(upper sternum, medial part of clavicles, and anterior part of upper ribs if necessary). We believe that this procedure will improve tracheal stenosis and minimize the risk of TIF. Thus far, 10 patients have undergone this operation, and their mid-term results are satisfactory.