Shigeteru Oka

Surgery for mitral valve disease in the pediatric age group

OBJECTIVES We reviewed a 20-year experience with the surgical treatment of mitral valve disease in the pediatric age group at our institution with 2 objectives: to clarify the long-term results over the last 2 decades and to evaluate the recent advances in mitral valve operation in children. METHODS Since December 1978, 56 patients have undergone a total of 36 mitral valve repairs and 30 mitral valve replacements. Associated cardiac anomalies were present in 46 patients (82%), and concurrent repair of associated lesions was performed in 37 patients (66%). The age of the patients ranged from 3 months to 15 years (mean, 3.6 years) at mitral valve repair, and ranged from 2 months to 16 years (mean, 5.7 years) at mitral valve replacement. Mean follow-up period was 92.0 months (range, 1-235 months). RESULTS There were 2 hospital deaths and 2 late deaths in patients who underwent mitral valve repair. Reoperation was performed in 4 patients. Three of these patients underwent mitral valve replacement because of residual mitral incompetence. No hospital deaths occurred in patients who underwent mitral valve replacement. Two late deaths occurred after mitral valve replacement. Six patients had a total of 10 episodes of prosthetic valve thrombosis. Thrombolytic therapy with urokinase was successful in all episodes without serious complications. Five patients required reoperations 49 to 141 months (mean, 78.4 months) after the initial valve replacement for relative prosthetic valve obstruction as the result of somatic growth. A valve 2 or 3 sizes larger than the original prostheses was inserted without death. Actuarial survival and freedom from cardiac events at 10 years after the operation were 87.2% and 72.7% in children who underwent mitral valve repair, and 90.3% and 67.3% for those children who underwent mitral valve replacement. CONCLUSIONS The current risk of mitral valve operation in the pediatric age group is low, and the long-term results are satisfactory, irrespective of severe deformation of the mitral valve apparatus and associated complex cardiac anomalies.

Pulmonary atresia with intact ventricular septum: strategy based on right ventricular morphology.

OBJECTIVES Management strategy for pulmonary atresia with intact ventricular septum is controversial. We treated patients with this anomaly according to a management protocol based on our quantitative assessment of right ventricular morphology (index of right ventricular development and right ventricle-tricuspid valve index). In the present study, we reviewed a 20-year experience of the surgical treatment at our institution to define guidelines for selecting the appropriate type of surgical procedure. METHODS Between April 1981 and June 2002, 45 consecutive patients with pulmonary atresia with intact ventricular septum underwent surgical treatment. Open transpulmonary valvotomy was performed in 27 patients and Blalock-Taussig shunt in 18 patients as the initial palliative procedure. Three patients who underwent a successful transpulmonary valvotomy alone in the neonatal period required no further operation. Definitive repair was performed in 32 patients. Biventricular repair was performed on 19 patients, one and a half ventricular repair in 3, and Fontan-type operation in 10. RESULTS There were 1 early and 2 late deaths before the definitive operation in patients who underwent transpulmonary valvotomy. Two patients who had coronary artery interruption died 3 months and 13 years after the initial Blalock-Taussig shunt. There were 1 early and 2 late deaths after the definitive operation. Actuarial survival, including noncardiac death, was 91.1% at 5 years after the initial procedure and 81.5% at 10 years. CONCLUSIONS We treated patients with pulmonary atresia with intact ventricular septum according to a management protocol based on our quantitative assessment of right ventricular morphology with good results.

Risk factors influencing early and late mortality after total cavopulmonary connection

OBJECTIVE Among the later modifications of the Fontan type procedure, a significant alteration was introduced by de Leval and associates when they described the total cavopulmonary connection (TCPC). Although current results of TCPC have encouraged us to extend this procedure to high risk patients, risk factors influencing surgical outcome after TCPC have not been evaluated. We review our experiences with TCPC to identify which risk factors may have had a considerable impact on the outcome of patients undergoing TCPC and to clarify selection criteria of high-risk Fontan candidates for TCPC. PATIENTS AND METHODS We retrospectively reviewed the medical and surgical records of all 76 patients who underwent TCPC between July 1988 and August 2000. A cross-sectional review of these patients was undertaken. RESULTS There were eight early deaths and four late deaths. In a Fishers exact test, the following variables were associated with an increased early mortality after TCPC: systemic ventricular morphology (right ventricle), ejection fraction of the systemic ventricle less than 60%, and prolonged cardiopulmonary bypass time (240 min or longer). The log-rank test demonstrated that heterotaxy syndrome, moderate to severe atrioventricular valve regurgitation, prolonged cardiopulmonary bypass time (240 min or longer), and prolonged aortic cross clamp time (70 min or longer) were associated with late mortality after TCPC. Six deaths occurred in eight (75%) patients who had six or more risk factors, whereas six deaths (9%) occurred in those who had five or fewer. CONCLUSIONS Patients with complex cardiac anomalies who have six or more risk factors should be excluded from TCPC candidates.

Repair of atrial septal defect through a right posterolateral thoracotomy: A cosmetic approach for female patients

BACKGROUND Because the operation for atrial septal defect is considered a low-risk procedure, the cosmetic result has become an important issue. Principally for cosmetic reasons, anterolateral thoracotomy is frequently used for closure of atrial septal defect in young female patients. However, in anterolateral thoracotomy, the skin incision frequently crosses the future breast line, which may cause breast and pectoral muscle maldevelopment. METHODS We review the long-term results of a consecutive series of 126 patients in whom the atrial septal defect was closed through a right posterolateral thoracotomy. The mean age at operation was 7.1 years (range, 1 to 15 years), and the mean body weight was 23.9 kg (range, 6.9 to 56 kg). Defects repaired included 121 ostium secundum (central type), 3 sinus venosus, and 2 ostium secundum without inferior margin. RESULTS The average cardiopulmonary bypass time was 65 minutes (range, 37 to 130 minutes), with an average fibrillation time of 41 minutes (range, 23 to 70 minutes). There was no operative or late mortality. A majority of patients were pleased with their cosmetic results. There were no other late complications. CONCLUSIONS Atrial septal defect can be safely repaired through a right posterolateral thoracotomy approach. This approach offers the benefit of a total absence of scarring and cosmetic disfigurement of the anterior chest wall.

Cardioprotective effects and the mechanisms of terminal warm blood cardioplegia in pediatric cardiac surgery

OBJECTIVES Terminal warm blood cardioplegia has been shown to enhance myocardial protection in adult patients. However, the cardioprotective effects and the mechanisms of terminal warm blood cardioplegia in pediatric heart surgery were still unknown. METHODS One hundred three consecutive patients were prospectively randomized to one of two groups. In the control group (n = 52), myocardial protection was achieved with intermittent hyperkalemic cold blood cardioplegia and topical cardiac cooling. In the terminal warm blood cardioplegia group (n = 51), this was supplemented with terminal warm blood cardioplegia before the aorta was declamped. Arterial and coronary sinus blood samples were analyzed to determine myocardial energy metabolism and tissue injury. RESULTS There were no significant differences between the two groups in age (5.5 +/- 0.6 years in the control group vs 5.6 +/- 0.5 years in the terminal warm blood cardioplegia group), body weight (17.2 +/- 1.4 kg in the control group vs 19.8 +/- 1.7 kg in the terminal warm blood cardioplegia group), percentage of cyanotic heart diseases (50% in the control group vs 51% in the terminal warm blood cardioplegia group), number of patients who required right ventriculotomy (33% in the control group vs 39% in the terminal warm blood cardioplegia group), cardiopulmonary bypass time (194 +/- 12.1 minutes in the control group vs 177 +/- 8.6 minutes in the terminal warm blood cardioplegia group), aortic crossclamp time (83.3 +/- 5.9 minutes in the control group vs 82.3 +/- 5 minutes in the terminal warm blood cardioplegia group), lowest rectal temperature (27.4 +/- 0.3 degrees C in the control group vs 28.1 +/- 0.3 degrees C in the terminal warm blood cardioplegia group), and myocardial temperature (9.6 +/- 0.6 degrees C in the control group vs 9.6 +/- 0.7 degrees C in the terminal warm blood cardioplegia group). Spontaneous defibrillation occurred after reperfusion in 80% in the terminal warm blood cardioplegia group, which was significantly (P <.05) higher than the control group (62%). The lactate extraction rate at 60 minutes of reperfusion was significantly (P <.05) higher in the terminal warm blood cardioplegia group (9.0 +/- 2.8%) than the control group (-3.3 +/- 2.4%). The postreperfusion values of cardiac troponin T (7.4 +/- 0.6 ng/mL vs 11.2 +/- 1.0 ng/mL at 6 hours; 4.6 +/- 0.6 ng/mL vs 9.3 +/- 1.6 ng/mL at 18 hours) and heart-type fatty acid binding protein (137 +/- 28 ng/mL vs 240 +/- 30 ng/mL at 2 hours; 88 +/- 19 ng/mL vs 162 +/- 26 ng/mL at 3 hours) were significantly (P <.05 vs the control group) lower in the terminal warm blood cardioplegia group. CONCLUSION Terminal warm blood cardioplegia enhances myocardial protection in pediatric cardiac surgery by an improvement in aerobic energy metabolism and a reduction of myocardial injury or necrosis.

Inhaled Nitric Oxide Therapy After Fontan-Type Operations

PurposeInhaled nitric oxide (NO) therapy is a newly developed strategy designed to reduce pulmonary vascular resistance after the Fontan-type operation. We reviewed our experience to evaluate its efficacy and true indications.MethodsWe retrospectively examined 47 children who received inhaled NO therapy after the Fontan-type operation between August 1996 and December 2002. The maximal dose of NO ranged from 5 to 30 ppm (median 10 ppm), and the duration of inhaled NO therapy ranged from 5 h to 52 days (median 2 days).ResultsInhaled NO significantly decreased the central venous pressure (CVP), from 16.2 ± 2.2 to 14.6 ± 2.2 mmHg (P < 0.0001), and the transpulmonary pressure gradient between the CVP and left atrial pressure, from 9.9 ± 2.9 to 8.4 ± 2.7 mmHg (P < 0.0001). It also increased the systolic systemic arterial pressure from 71.9 ± 15.2 to 76.8 ± 14.5 mmHg (P < 0.05). In 26 patients with additional fenestration, inhaled NO led to a significant improvement in SaO2 from 90.1% ± 9.6% to 93.3% ± 7.9% (P < 0.01). However, patients with a CVP <15 mmHg or a transpulmonary pressure gradient <8 mmHg, or both, after the Fontan-type operation, showed no significant changes in hemodynamics during inhaled NO therapy.ConclusionsWe propose that a CVP ≥15 mmHg or a transpulmonary pressure gradient ≥8 mmHg, or both, after Fontan-type operations are appropriate indications for inhaled NO therapy.

Effects of Modified Ultrafiltration on Coagulation Factors in Pediatric Cardiac Surgery

AbstractPurpose. Modified ultrafiltration (MUF) after cardiopulmonary bypass (CPB) in children has been reported to reduce the need for postoperative blood transfusion and minimize postoperative blood loss. This study was undertaken to quantify the effects of MUF on coagulation factors in pediatric patients. Methods. Seven children scheduled to undergo open-heart surgery for congenital heart defects were studied. CPB cir-cuits were primed with crystalloid solutions and no blood transfusions were performed. Hematocrit, platelet count, total plasma proteins, albumin, fibrinogen, prothrombin, factor VII, factor IX, and factor X were measured preoperatively, at the termination of cardiopulmonary bypass, and at the end of modified ultrafiltration. Results. MUF was associated with significant (P < 0.05) increases in hematocrit (17.6% ± 1.6% to 21.6% ± 2.4%), platelet count 11.1 ± 2.5 to 12.8 ± 2.4 × 104/mm3), total plasma proteins (2.7 ± 0.3 to 3.4 ± 0.4 g/dl), and albumin (1.6 ± 0.2 to 2.1 ± 0.2 g/dl). Fibrinogen, prothrombin, and factor VII also increased significantly (P < 0.05) during MUF, but factor IX and factor X did not change. Conclusion. We conclude that MUF attenuates the dilutional coagulopathy that occurs during CPB in children. There were slight improvements in the coagulation factors when MUF was employed.

Vascular endothelial growth factor in children with congenital heart disease

BACKGROUND Children with cyanotic congenital heart disease may experience the development of abnormal vessels that become a source of significant morbidity. Abnormal vessel proliferation in these children may take several forms, including systemic-to-pulmonary collateral arteries, systemic-to-pulmonary venous collaterals, systemic venous collateral channels after bidirectional cavopulmonary anastomosis, and pulmonary arteriovenous malformations. However, no entity responsible for these abnormalities has been identified yet. This study determined whether children with cyanotic congenital heart disease have elevated serum levels of vascular endothelial growth factor (VEGF) and whether elevated VEGF correlated with these abnormal vessels. METHODS Mean systemic room air oxygen saturation (SpO2), blood cell counts (RBC), and serum VEGF levels were measured preoperatively. Samples were obtained from 61 children with acyanotic heart disease (group N) and 102 children with cyanotic heart disease (group C) before cardiac surgery. Postoperative catheterization was performed 1-month after the operation to evaluate the abnormal vessels in group C. RESULTS The VEGF level was significantly elevated in group C (355.0 +/- 287.1 pg/mL) compared with group N (203.0 +/- 221.6 pg/mL; p < 0.001). VEGF levels in patients with a single ventricle associated with asplenia syndrome (n = 7) in group C were significantly elevated (711.9 +/- 443.5 pg/mL) compared with other patients. There was no significant correlation between VEGF level and SpO2 or RBC. Abnormal vessels were diagnosed in 19.6% (20/102) patients in group C. There was no difference in VEGF levels between the patients with abnormal vessels (336.8 +/- 182.5 pg/mL) and the patients without abnormal vessels (359.1 +/- 306.8 pg/mL). CONCLUSIONS Children with cyanotic heart disease have elevated systemic levels of VEGF, especially in those patients with a single ventricle associated with asplenia syndrome. There was no significant relationship in VEGF levels between the patients with abnormal vessels and without these vessels.

Simultaneous repair of pectus excavatum and congenital heart disease over the past 30 years

OBJECTIVE Pectus excavatum may be present in patient requiring operations for cardiac defects. The study was undertaken in order to assess our simultaneous repairs of pectus excavatum and congenital heart disease over past 30 years. METHODS Between 1970 and 2000, 12 patients underwent simultaneous repair of pectus excavatum and congenital heart disease. Six of 12 patients had ventricular septal defects as cardiac malformations (subgroup A). Operative technique, after the intracardiac procedure using cardiopulmonary bypass, consists of total subperichondrial resection of deformed costal cartilages, transection of deformed portion of the sternum in 2-3 points, and fixation of the sternum in elevated position using two Kirschner wires and a bridge external traction. Postoperative catheterization was performed in five of 12 patients (subgroup B). We evaluated the operative data, the improvement of pectus deformity and right ventricular performance retrospectively. The operative data in subgroup A were compared with those in recent random patients with ventricular septal defects only or with pectus excavatum only (control groups). RESULTS There was no operative death and non-serious complications were seen in nine patients (atelectasis in six, superficial wound infection in two, chylothorax in one). Pectus deformities improved with the drop of vertebral index postoperatively. The mean total operative time and postoperative drainage in subgroup A were 128.4% and 123.7%, respectively of those in the ventricular septal defect control group. The mean perioperative bleeding in subgroup A was more than the sum of those in control groups. Right ventricular end-diastolic (RVEDVI), end-systolic (RVESVI), stroke (RVSVI) volume indices and ejection fraction (RVEF) in subgroup B tended to increase after surgery. In particular, there were significant increases of RVEDVI (35%, P<0.05) and RVSVI (77%, P<0.01). CONCLUSION Simultaneous cardiac and pectus repairs were performed successfully without serious complications. Moreover, simultaneous repair resulted in an improvement of right ventricular performance with significant increases of RVEDVI and RVSVI.

Clinical and pathological features of accessory valve tissue

BACKGROUND Accessory valve tissue is a rare congenital cardiac malformation causing a variety of clinical features. We describe our experience with the surgical treatment of accessory valve tissue to clarify clinical and pathological features of this anomaly. METHODS Between December 1990 and February 1999, 11 children underwent resection of accessory valve tissue together with repair of coexisting intracardiac malformations. Eight patients had accessory tricuspid valve, while 3 had accessory mitral valve tissue. Associated intracardiac malformations included tetralogy of Fallot in 6 patients, transposition of the great arteries in 3, coarctation complex in 1, and ventricular septal defect in 1. RESULTS Accessory valve tissue was completely resected in all but 1 patient with accessory mitral valve and transposition of the great arteries. As total resection of the accessory valve tissue through the pulmonary artery was unsuccessful, partial resection and bidirectional Glenn shunt operation was performed instead of arterial switch operation in this patient. CONCLUSIONS The clinical signs and symptoms of accessory valve tissue vary according to its location and coexisting cardiac malformations. Congenital heart surgeons should be familiar with the clinical and pathological features of accessory valve tissue, so as not to overlook it during operation.