Shintaro Nemoto

Effect of edaravone, a novel free radical scavenger, supplemented to cardioplegia on myocardial function after cardioplegic arrest: in vitro study of isolated rat heart

Cardioplegic arrest has been the main mechanism of myocardial protection during open-heart surgery; however, it causes myocardial injury during ischemia-reperfusion. Free radical scavengers are widely known to attenuate ischemia-reperfusion injury in various settings. We investigated the effects of edaravone, a novel free radical scavenger that was originally used for cerebral protection, on myocardial function during ischemia-reperfusion after cardioplegic arrest. Rat hearts were excised and perfused using Langendorff apparatus. The hearts were cardioplegically arrested for 90 min using St. Thomas’ Hospital cardioplegic solution (ST solution) at 4°C every 45 min and then reperfused for 20 min. The hearts were divided into 4 groups (n = 13 in each group). In Group ST, the hearts were arrested using the ST solution alone. In Groups L, M, and H, the hearts were arrested using the ST solution supplemented with a low-dose (1 μM), moderate dose (10 μM), and high dose (100 μM) of edaravone, respectively. Left ventricular function (+dp/dtmax) and the levels of the cardiac enzymes released were measured before and after cardioplegic arrest. At the end of the study, the water content and the tissue oxidative stress (8-hydroxy-2′-deoxyguanosine) of the heart were measured. During reperfusion, the edaravone-treated groups showed a greater functional recovery with regard to the +dp/dtmax (P < 0.05). The lactate level was the lowest (P < 0.01) in Group M. The water content of the hearts in the edaravone-treated groups was significantly lower (P < 0.05) than that in Group ST. Oxidative stress was significantly lower (P < 0.01) in the edaravone-treated hearts than in Group ST, and it was the lowest in Group M. The addition of edaravone to the cardioplegic solution ameliorates the impairment in myocardial function by reducing the oxidative stress after cardioplegic arrest. In this study, the maximum improvement in the myocardial function was achieved by addition of a moderate dose (10 μM) of edaravone.

Repair of persistent truncus arteriosus without a conduit: sleeve resection of the pulmonary trunk from the aorta and direct right ventricle-pulmonary artery anastomosis §

OBJECTIVE Establishing a new continuity between the right ventricle and the pulmonary artery is the mainstay of repair for persistent truncus arteriosus. We used the Tran Viet-Neveux technique without a Lecomte maneuver to construct the connection without a conduit. Here, we retrospectively review the mid-term surgical results to examine the effectiveness of this approach. METHODS A cylindrical segment incorporating both pulmonary artery branches was sleeve-resected from the truncal artery. The cylindrical segment was cut in the middle and two truncal arterial flaps were combined to form the posterior floor of the new pulmonary arterial trunk. The edge of the floor was attached directly to the superior margin of an oblique incision made in the left-anterior wall of the right ventricle. A polytetrafluoroethylene monocusp was attached to the lower half margin of the right ventricular incision. A large glutaraldehyde-treated pericardial patch was used to form the anterior hood of the new right ventricular outflow tract. Both great arteries were located in a normal spiral configuration. RESULTS Ten babies (range: 3 days to 9 months of age) underwent this procedure. The Collett-Edwards classification of persistent truncus arteriosus was type I in five cases and type II in five others. There was one hospital death due to severe respiratory distress. During follow-up (36-60 months, median 54 months), only one re-operation was required to enlarge a left branch pulmonary artery stenosis. Follow-up echocardiography showed pulmonary regurgitation (mild two, moderate seven, and severe one) and mild flow acceleration in the left pulmonary artery branch and right ventricle-pulmonary artery connection in one case. CONCLUSION This simple modification for surgical correction of persistent truncus arteriosus may be an effective alternative that overcomes conduit-related problems.

Surgical Treatment of a Mycotic Pseudoaneurysm of the Transverse Arch Using a Rifampicin-Impregnated Dacron Patch in an Infant

We describe a case of successful treatment of mycotic pseudoaneurysm of the transverse aortic arch in a male infant. The aneurysm was resected and the defect was repaired using a patch made from a rifampicin‐impregnated Dacron graft. doi: 10.1111/jocs.12492 (J Card Surg 2015;30:281–283)

Long-term results of aortic valve translocation for mycotic periannular abscess: comparative study of Danielson's original method and our threadless method.

SummaryBetween June, 1983, and October, 1992, we performed Danielson’s original translocation method in four patients (group I) and our translocation method in seven patients (group II), for the treatment of active periannular abscess. There were no perioperative or hospital deaths in either group. The longterm results of these two groups are compared in this report. There were four late deaths (mortality rate 100%) in group I, and three late deaths (mortality rate 43%) in group II. The causes of death were cardiac in six patients and noncardiac in one patient. Vein graft failure occurred in one group I patient (25%) and in two group II patients (28%). Rupture or aortic pseudoaneurysm formation occurred in three group I patients (75%). These findings suggest that our threadless method may be superior to Danielson’s original translocation method. Therefore, with close observation, especially of saphenons vein great (SVG) failure, arterial graft use could be acceptable for translocation.

Development of a simple device enabling percutaneous flow regulation for a small vascular graft for a Blalock–Taussig shunt capable of flow regulation: complete translation of a review article originally published in Pediatric Cardiology and Cardiac Surgery (154–159, 2016: vol. 32)

ObjectivesThe Blalock–Taussig shunt (BTS) operation is a cornerstone as initial palliative surgery for congenital heart disease with severely reduced pulmonary blood flow (PBF). The ideal PBF provided by BTS is crucial for an uneventful postoperative course, since excess PBF results in acute distress of the systemic circulation and insufficient PBF requires another BTS surgery. Therefore, the goal of this study was to develop a simple device to control the shunt graft flow percutaneously using a constrictor balloon connected to a subcutaneous port.MethodsThe device consists of a cylindrical balloon and an anti-bending structure extension connected to the balloon center. A PTFE vascular graft wrapped by the device was connected to a simulated closed circuit to measure the relationship between pressure and blood flow while changing the inner volume of the balloon. In a beagle model of replacement of the right carotid artery, blood flow velocity was measured in the carotid artery after saline injection into the balloon. The blood flow velocity before and after balloon inflation was compared immediately after implantation of the device and at 3 months after implantation.ResultsThe device provided good flow control by inflating and deflating the balloon ex vivo and in vivo for up to 3 months in a canine model with a small graft wrapped with the device.ConclusionsThe simple device developed in this study may enable regulation of PBF through a small vascular graft and help to prevent severe morbidity and mortality in the clinical setting of BTS.

Therapeutic experience with hepatoblastoma associated with trisomy 18

Trisomy 18 is often fatal, but patients with this disease can now have longer survival due to proactive treatment intervention. However, hepatoblastomas may develop in these patients. In this study, we report four cases of hepatoblastoma associated with trisomy 18. All of the patients had congenital heart disease and three had undergone intracardiac surgical repair. Tumor growth was relatively slow in all cases, and there were no problems with chemotherapy tolerability and surgical resection. Three of the patients are currently disease‐free and the fourth is alive with remaining of the tumor. These cases suggest that combined chemotherapy and surgical resection may be an option to treat hepatoblastoma associated with trisomy 18 when cardiac pulmonary function is relatively stable.

In situ tissue regeneration using a warp-knitted fabric in the canine aorta and inferior vena cava†

OBJECTIVES Materials used in paediatric cardiac surgery have drawbacks of deterioration, calcification and pseudointimal proliferation resulting in haemodynamic disturbance. The aim of this study was to investigate whether these drawbacks can be overcome by in situ tissue regeneration using a newly developed synthetic hybrid fabric (SHF). METHODS The SHF is an expandable, warp-knitted fabric composed of a combination of biodegradable [poly-l-lactic acid (PLLA)] and non-biodegradable (polyethylene terephthalate) yarns. The fabric is coated with cross-linked gelatin. Mechanical properties of the SHF were compared with those of 2 commercial products: expanded polytetrafluoroethylene sheet and glutaraldehyde-treated bovine pericardium. An oval-shaped defect created in the canine descending aorta or inferior vena cava was filled with the SHF patch. After 2 weeks and 1, 3, 6 and 12 (or 24 in the inferior vena cava) months, the patch was removed for histological examination and evaluation of the remaining PLLA. RESULTS The SHF exhibited satisfactory tensile and suture retention strength for surgical implantation similar to or better than the 2 commercial products. Tissue regeneration was induced with multilayered smooth muscle cells and collagen fibres on both sides of the patch, along with a mature endothelial layer and tissue connections containing vasa vasorum across the patch in the aorta and inferior vena cava. Inflammatory reactions were minimal, and no calcium deposition occurred. The molecular weight of PLLA was reduced to half at 12 months after implantation. CONCLUSIONS The SHF may solve the drawbacks of the existing products. Further studies of the expandability of the SHF patch after degradation of PLLA are warranted.

Fatal cardiac anomaly of unguarded mitral orifice with asplenia syndrome

We report the case of a newborn baby with an unguarded mitral orifice associated with asplenia syndrome, double-outlet right ventricle, dysplastic tricuspid valve, and pulmonary stenosis. This case was accompanied by severe tricuspid regurgitation and severe right ventricular hypertrophy. The patient had a fatal clinical course due to severe hypoxia and congestive heart failure. Unguarded mitral orifice is a rare disease in which there has been no previous report of lethal clinical course during the neonatal period. Prior reports stated that unguarded mitral orifice was a new constellation of defects and that its etiology and embryology could be classified in the same category because of similar associated malformations of double-outlet right ventricle and pulmonary stenosis or atresia. However, the present case was diagnosed on autopsy as also having asplenia syndrome. Therefore, it is possible that the genetic etiology of unguarded mitral orifice in this case was different from cases of non-heterotaxy. <Learning objective: Unguarded mitral orifice is a rare disease that might be associated with asplenia syndrome and dysplastic tricuspid valve. If unguarded mitral orifice is associated with such defects, the clinical course can be fatal. Therefore, when this diagnosis is recognized, the physician should explain the possibility of neonatal death and plan the treatment of such a case to include grief therapy for the family.>.