Bio

Clinical Focus


  • Cardiovascular Surgery
  • Cardiothoracic Surgery

Academic Appointments


Professional Education


  • Fellowship:The University of Tokyo (2004) Japan
  • Residency:Asahi General Hospital (1998) Japan
  • Residency:Toranomon Hospital (1996) Japan
  • Internship:The University of Tokyo (1996) Japan
  • Medical Education:The University of Tokyo (1995) Japan

Publications

Journal Articles


  • Fetal cardiac intervention: Improved results of fetal cardiac bypass in immature fetuses using the TinyPump device. journal of thoracic and cardiovascular surgery Sebastian, V. A., Ferro, G., Kagawa, H., Nasirov, T., Maeda, K., Ferrier, W. T., Takatani, S., Riemer, R. K., Hanley, F. L., Reddy, V. M. 2013; 145 (6): 1460-1464

    Abstract

    Fetal cardiac surgery is a potential innovative treatment for certain congenital heart defects that have significant mortality and morbidity in utero or after birth, but it has been limited by placental dysfunction after fetal cardiac bypass. We have used the TinyPump device for fetal cardiac bypass in sheep fetuses at 90 to 110 days gestation.Ten mixed-breed pregnant ewes were used over a period of 6 months, and 10 fetuses were placed on bypass for 30 minutes. Five fetuses with a mean gestational age of 104 ± 4.5 days and mean weight of 1.4 ± 0.4 kg were placed on bypass using the TinyPump device, and 5 fetuses with a mean gestational age of 119 ± 4.5 days and mean weight of 3.4 ± 0.4 kg were placed on bypass using the roller head pump. The fetuses were monitored for up to 3 hours after bypass or until earlier demise.Progressive respiratory and metabolic acidosis developed in all fetuses. The TinyPump group had a lower gestational age and weight compared with the roller head pump group. However, the rate of postbypass deterioration in the TinyPump group, as measured with blood gases, was noted to be significantly slower compared with the roller head pump group.We demonstrate the feasibility of the TinyPump device for fetal cardiac bypass in a fetal sheep model. The TinyPump group showed improved results compared with the roller head group despite more immature fetuses. The TinyPump device seems to be a promising device for future studies of fetal cardiac bypass in immature fetal sheep and in primates.

    View details for DOI 10.1016/j.jtcvs.2012.08.014

    View details for PubMedID 22944083

  • Intermediate-term outcomes after combined heart-liver transplantation in children with a univentricular heart JOURNAL OF HEART AND LUNG TRANSPLANTATION Hollander, S. A., Reinhartz, O., Maeda, K., Hurwitz, M., Rosenthal, D. N., Bernstein, D. 2013; 32 (3): 368-370

    Abstract

    For patients with end-stage hepatic failure secondary to failing hemodynamics, combined heart-liver transplant (H-LT) remains the only option for long-term survival. We report a series of three pediatric patients who successfully underwent orthotopic H-LT for failed single-ventricle palliation. All three patients are currently living, now two, three, and five years post-transplant, and remain completely free of cardiac cellular allograft rejection despite reduced immunosuppression protocols. One patient, however, did develop acute antibody-mediated rejection in the immediate post-transplant period, suggesting that this protective effect may be less effective in attenuating humoral mechanisms of rejection.

    View details for DOI 10.1016/j.healun.2012.11.023

    View details for Web of Science ID 000315664600014

    View details for PubMedID 23415318

  • Midterm Results of the Modified Ross/Konno Procedure in Neonates and Infants ANNALS OF THORACIC SURGERY Maeda, K., Rizal, R. E., Lavrsen, M., Malhotra, S. P., Akram, S. A., Davies, R., Suleman, S., Reinhartz, O., Murphy, D. J., Hanley, F. L., Reddy, V. M. 2012; 94 (1): 156-163

    Abstract

    The management of congenital aortic stenosis in neonates and infants continues to be a surgical challenge. We have performed the modified Ross-Konno procedure for patients who have severe aortic insufficiency or significant residual stenosis after balloon aortic dilation. The midterm results of this procedure were evaluated in this subset of patients.Between 1994 and 2010, a total of 24 patients younger than 1 year of age underwent the modified Ross-Konno procedure. The diagnoses were aortic stenosis with or without subaortic stenosis (n = 16), Shone's complex (n = 7), and interrupted aortic arch with subaortic stenosis (n = 1). The aortic root was replaced with a pulmonary autograft, and the left ventricular outflow tract (LVOT) was enlarged with a right ventricular infundibular free wall muscular extension harvested with the autograft.Age at operation ranged from 1 to 236 days (median 28 days). The median follow-up period was 81 months (range 1-173 months). There was 1 early death and no late mortality. Overall the 1-, 2-, and 5-year survival rate was 95% ± 4.5%. Freedom from aortic stenosis was 94.7% ± 5.1% at 1, 2, and 5 years. Less than mild aortic insufficiency was 93.3% ± 6.4% at 2 years, and 74.7% ± 12.9% at 5 years. In total, 23 reoperations and reinterventions were performed; 14 were allograft conduit replacements. Two patients required aortic valve plasty. None required valve replacement. The reintervention-free rate was 64.6% ± 10.8% at 2 years and 36.9% ± 11.3% at 5 years.Pulmonary autografts demonstrated good durability with low mortality and morbidity. This study shows that the modified Ross-Konno procedure can be a practical choice in selective cases for complex LVOT stenosis in neonates and infants.

    View details for DOI 10.1016/j.athoracsur.2012.03.007

    View details for Web of Science ID 000305801600033

    View details for PubMedID 22626750

  • Pediatric combined heart-liver transplantation performed en bloc: A single-center experience PEDIATRIC TRANSPLANTATION Hill, A. L., Maeda, K., Bonham, C. A., Concepcion, W. 2012; 16 (4): 392-397

    Abstract

    Pediatric CHLT is rarely performed in transplant centers and even fewer are performed en bloc. In the hands of an experienced surgeon with the appropriate patient selection, CHLT performed en bloc may have several operative and immunologic benefits, thereby resulting in improved outcomes for the transplant recipient. A single-institutional, retrospective review from 1/1/06 to 12/31/10 was conducted. Three pediatric patients with end-stage heart and liver disease who were considered low immunologic risk were included. All were managed by the same surgeon with a herein-described CHLT donor and recipient operation. Data were collected on patient and graft survival, rejection episodes, infectious complications, operative time, intraoperative transfusion requirements, and immunosuppression regimens. One-yr patient and graft survival rates were 100%. No patients experienced antibody-mediated or cell-mediated rejection. No patients had postoperative infections, and all patients were free of opportunistic infections at one-yr post-transplant. All patients were maintained safely on steroid-free immunosuppression. There were no intraoperative complications. In pediatric end-stage heart and liver disease patients with low immunologic risk, it is reasonable to proceed with en bloc CHLT so long as there is an experienced surgeon to perform the case. This offers operative and immunologic advantages to the recipient while maintaining equivalent, if not improved, recipient and graft outcomes.

    View details for DOI 10.1111/j.1399-3046.2012.01695.x

    View details for Web of Science ID 000303998800024

    View details for PubMedID 22583978

  • Use of the Impella 5.0 as a bridge from ECMO to implantation of the HeartMate II left ventricular assist device in a pediatric patient PEDIATRIC TRANSPLANTATION Hollander, S. A., Reinhartz, O., Chin, C., Yeh, J., Maeda, K., Mallidi, H., Bernstein, D., Rosenthal, D. 2012; 16 (2): 205-206
  • Recovery During Mid-Term Mechanical Support of Fontan Circulation in Sheep ASAIO JOURNAL Tsuda, S., Sasaki, T., Maeda, K., Riemer, R. K., Reichenbach, S. H., Reinhartz, O. 2009; 55 (4): 406-411

    Abstract

    Total cavopulmonary connection (CPC) has a significant incidence of late failure due to increased systemic venous pressure and low cardiac output. Mechanical support could prevent failure by correcting hemodynamics. We established a model of inferior CPC using an axial flow pump (Thoratec HeartMate II, Thoratec Corp. Pleasanton, CA) in a group of ten 47-57 kg sheep and assessed hemodynamics and metabolism as a potential chronic treatment option for failed Fontan circulation. After pilot studies (n = 7), three animals underwent pump-supported inferior CPC to assess hemodynamic and metabolic responses. Pump inflow was connected to the inferior vena cava (IVC) and outflow to the main pulmonary artery. The IVC was ligated at the right atrium. Hemodynamic and biochemical parameters were recorded over four days. The first seven animals died from pump-related causes (graft kinking, three; pump thrombosis, one) or other causes (GI bleeding, one; suspected stroke, two). The subsequent three animals were electively euthanized on postoperative day four due to IRB requirements. Over the four day postoperative period, pump flow was 3.43 +/- 0.62 L/min and IVC pressure 4.05 +/- 3.21 mm Hg (mean +/- SD). Lactate levels remained normal. Low pressure and high-volume IVC flow was sustained by mechanical support. We will next attempt chronic pump implantation.

    View details for DOI 10.1097/MAT.0b013e3181a0a570

    View details for Web of Science ID 000267559100016

    View details for PubMedID 19471161

Conference Proceedings


  • Selective Right Ventricular Unloading and Novel Technical Concepts in Ebstein's Anomaly Malhotra, S. P., Petrossian, E., Reddy, V. M., Qiu, M., Maeda, K., Suleman, S., Macdonald, M., Reinhartz, O., Hanley, F. L. ELSEVIER SCIENCE INC. 2009: 1975-1981

    Abstract

    Favorable outcomes in Ebstein's anomaly are predicated on tricuspid valve competence and right ventricular function. Successful valve repair should be aggressively pursued to avoid the morbidity of prosthetic tricuspid valve replacement. We report our experience with valve-sparing intracardiac repair, emphasizing novel concepts and techniques of valve repair supplemented by selective bidirectional Glenn (BDG).Between June 1993 and December 2008, 57 nonneonatal patients underwent Ebstein's anomaly repairs. The median age at operation was 8.1 years. All were symptomatic in New York Heart Association (NYHA) functional class II (n = 38), III (n = 17), or IV (n = 1). Preoperatively, 26 had mild or moderate cyanosis at rest. We used a number of valve reconstructive techniques that differed substantially from those currently described. BDG was performed in 31 patients (55%) who met specific criteria.No early or late deaths occurred. At the initial repair, 3 patients received a prosthetic valve. Four patients required reoperation for severe tricuspid regurgitation. Repeat repairs were successful in 2 patients. At follow-up (range, 3 months to 6 years), all patients were acyanotic and in NYHA class I. Tricuspid regurgitation was mild or less in 49 (86%) and moderate in 6 (11%). Freedom from a prosthesis was 91% (52 of 57).Following a protocol using BDG for ventricular unloading in selected patients with Ebstein's anomaly can achieve a durable valve-sparing repair using the techniques described. Excellent functional midterm outcomes can be obtained with a selective one and a half ventricle approach to Ebstein's anomaly.

    View details for DOI 10.1016/j.athoracsur.2009.07.019

    View details for Web of Science ID 000272029100037

    View details for PubMedID 19932271

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