Koichi Toda

Osaka University, Suika, Ōsaka, Japan

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Publications (75)165.27 Total impact

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    ABSTRACT: We describe the first clinical experiences in Japan with the HeartWare ventricular assist device (HVAD: HeartWare Inc., Miami Lakes, FL, USA) in patients awaiting heart transplantation. Nine patients (6 males, 3 females; mean 33.5 ± 7.8 years; New York Heart Association class III or IV) received the HVAD as a bridge to transplantation between 2011 and 2012. Six had dilated cardiomyopathy, 2 secondary cardiomyopathy, and 1 dilated phase hypertrophic cardiomyopathy. All operations were uneventful, with a mean operation time of 269 ± 77 min and cardiopulmonary bypass time of 121 ± 40 min. One required a temporary right ventricular assist device and was weaned on postoperative day 20, while another required pump exchange due to foreign tissue in the inflow. Mean support duration was 245 ± 162 days (range: 50-535 days) and mean pump blood flow at 1 month postoperatively was 4.8 ± 0.8 l/min. There was no mortality after 30 days, though 1 patient died during support due to cerebral hemorrhage. Presently, the others are waiting for heart transplantation without problems, except 1 who suffered from an active infection. There was no pump mechanical failure in any case. The HeartWare pump enables quick implantation with acceptable morbidity and mortality. Our preliminary results indicate that this left ventricular assist device is safe for circulatory assistance for heart transplant candidates in Japan.
    Journal of Artificial Organs 01/2014; · 1.41 Impact Factor
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    ABSTRACT: Background The EVAHEART left ventricular assist device was approved in 2010 by the Japanese Pharmaceuticals and Medical Devices Agency (PMDA) for bridge to heart transplantation (BTT). However, its effectiveness has not been evaluated since approval. This study evaluated the EVAHEART device in a commercial setting in Japan. Methods Ninety-six consecutive patients enrolled in the Japanese Registry for Mechanically Assisted Circulatory Support (J-MACS) who were listed for transplant or likely to be listed and who received an EVAHEART, were enrolled from 2011 to 2013 at 14 Japanese centres. Patients’ survival rates, adverse events, and quality of life data were obtained from the J-MACS registry. Results Patients’ median age was 43 years (male, 85). The Interagency Registry for Mechanically Assisted Circulatory Support profiles revealed 12 patients in level 1, 45 in level 2, 37 in level 3, and 1 patient in level 4. The mean support duration was 384.7 days, with a cumulative duration of 101.2 years. The Kaplan-Meier survival rate during support was 93.4% at 6 months, 87.4% at 1 year, and 87.4% at 2 years. Seventy-seven patients (80.2%) currently remain on support, 7 received a transplant, and 10 died during support. Major adverse events included driveline infection (14.6%) and neurological events such as ischemic stroke (17.7%), haemorrhage (13.5%), transient ischemic attack (3.1%), pump thrombosis (1%), and haemolysis (1%). There was no gastrointestinal bleeding, right heart failure requiring RVAD, or incidences of pump exchange due to mechanical failure. Conclusions The EVAHEART device provides safe and reliable long-term circulatory support, with an improved survival in commercial settings of BTT in Japan, where the transplant-waiting period is extremely longer. Incidences of GI bleeding, haemolysis, RV failure, device thrombosis, and mechanical failure were extremely rare in patients on EVAHEART devices.
    The Journal of Heart and Lung Transplantation. 01/2014;
  • International journal of cardiology 01/2014; · 7.08 Impact Factor
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    ABSTRACT: Conventional coronary artery bypass grafting (CABG) using cardiopulmonary bypass and cardiac arrest is associated with higher mortality and morbidity rates in acute coronary syndrome (ACS) patients undergoing surgery. Although off-pump CABG (OPCAB) is beneficial for high-risk patients, its efficacy for ACS is unknown, with on-pump beating CABG an adjunctive method. We investigated the effects of OPCAB and on-pump beating CABG for ACS. We evaluated 121 consecutive patients with ACS (91 males, 30 females; mean age 69.5 ± 10.3 years) who underwent CABG since 2000. Seventy-five had unstable angina (UA) and 46 acute myocardial infarction (AMI) [non-ST elevation (NSTEMI): 22, ST elevation (STEMI): 24]. We assessed CABG for acute coronary syndrome under our primary OPCAB strategy, and compared perioperative status between UA and AMI patients. (1) Sixty-five (87 %) with UA underwent OPCAB, 8 on-pump beating CABG, and 2 conventional CABG. Conversion from OPCAB was seen in 4 patients. In-hospital mortality was 1.3 %. (2) All UA patients who had intra-aortic balloon pumping (IABP) underwent OPCAB. No patients with preoperative IABP experienced conversion from OPCAB. (3) In AMI patients, hospital mortality was higher (8.9 %) and the ratios for OPCAB, on-pump beating CABG, and conventional CABG were 39, 57, and 4 %, respectively. Mortality was exclusively seen in patients with STEMI who underwent conventional CABG. OPCAB might have beneficial effects for ACS patients with UA, while IABP was found essential for completing OPCAB. In AMI patients, on-pump beating CABG might be reasonable for avoiding conversion from OPCAB and ischemic perfusion injury.
    General Thoracic and Cardiovascular Surgery 12/2013;
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    ABSTRACT: AimsIn the STICH trial, adding surgical ventricular reconstruction (SVR) to coronary artery bypass grafting (CABG) reduced LV end-systolic volume index (LVESVI) by 19%, as compared with 6% with CABG alone, providing no survival or functional benefits. Herein, we compared the efficacy of restrictive mitral annuloplasty (RMA) alone with that of RMA combined with SVR in patients with functional mitral regurgitation (MR). Methods and resultsOne hundred and six patients with ischaemic cardiomyopathy underwent RMA with (n = 52) or without SVR (n = 54) for functional MR. Pre- and post-operative (1 month) left ventriculography and longitudinal measurements of plasma BNP were performed. Pre-operatively, patients who underwent RMA plus SVR had a larger LVESVI (126 ± 26 vs. 100 ± 24 mL/m2, P < 0.0001). After surgery, RMA plus SVR reduced LVESVI more than RMA alone (43% vs. 22%, P <0.0001), yielding a nearly identical post-operative LVESVI (71 ± 17 vs. 78 ± 26 mL/m2). Survival rate was not different between the groups (4-year survival, 62% vs. 62%, P = 0.99), though among patients with pre-operative LVESVI ranging from 105 to 150 mL/m2, that was higher in the RMA plus SVR group (73% vs. 40%, P = 0.046), accompanied by a larger percentage reduction in plasma BNP from baseline to the latest follow-up examination (63 ± 34% vs. 34 ± 46%, P = 0.012). After propensity score adjustment, patients with LVESVI ranging from 105 to 150 mL/m2 who underwent RMA alone showed a greater association with mortality (hazard ratio 7.5, 95% confidence interval 2.1–27, P = 0.010), as compared with those with LVESVI <105 mL/m2 who underwent RMA alone. ConclusionsRMA plus SVR reduced LVESVI to a greater degree than RMA alone, neutralizing anticipated worse prognosis. Selected patients with functional MR and advanced LV remodelling may benefit by adding SVR to RMA.
    European Journal of Heart Failure 12/2013; · 5.25 Impact Factor
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    ABSTRACT: Accurate noninvasive assessment of right atrial pressure (RAP) is important for volume management in patients with heart failure (HF). Transient elastography is a noninvasive and reliable method to assess liver stiffness (LS). We investigated the value of LS for evaluation of RAP in patients with HF without structural liver disease. We measured LS using transient elastography (Fibroscan) in 31 patients undergoing right-sided cardiac catheterization (test group). The relation between LS and RAP found in the test group was used to derive the best-fit model to predict RAP. The applicability of the model was then tested in a validation group of 49 additional patients. There was an excellent correlation between LS and RAP in the test group (r = 0.95, p <0.0001; RAP = -5.8 + 6.7 × ln [LS]). Natural log transformation (ln) of LS provided the regression equation to predict RAP. When the equation model derived from the test group was applied to the validation group, predicted RAP correlated excellently with actual RAP (r = 0.90, p <0.0001). The receiver operating characteristic curve analyses in the test group showed that LS favorably compared with echocardiography for detecting RAP >10 mm Hg (area under the curve 0.958 vs 0.800, respectively, p = 0.047). In the validation group, LS with a cut-off value of 10.6 kPa for identifying RAP >10 mm Hg had a higher sensitivity and accuracy (p = 0.046 and p = 0.049, respectively) than echocardiography. In conclusion, LS may offer an accurate noninvasive diagnostic method to assess RAP in patients with HF.
    The American journal of cardiology 11/2013; · 3.58 Impact Factor
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    ABSTRACT: Transplantation of cardiomyocytes that are derived from human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs) shows promise in generating new functional myocardium in situ, whereas the survival and functionality of the transplanted cells are critical in considering this therapeutic impact. Cell-sheet method has been used to transplant many functional cells; however, potential ischemia might limit cell survival. The omentum, which is known to have rich vasculature, is expected to be a source of blood supply. We hypothesized that transplantation of hiPS-CM cell sheets combined with an omentum flap may deliver a large number of functional hiPS-CMs with enhanced blood supply. Retrovirally established human iPS cells were treated with Wnt signaling molecules to induce cardiomyogenic differentiation, followed by superparamagnetic iron oxide labeling. Cell sheets were created from the magnetically labeled hiPS-CMs using temperature-responsive dishes and transplanted to porcine hearts with or without the omentum flap (n=8 each). Two months after transplantation, the survival of superparamagnetic iron oxide-labeled hiPS-CMs, assessed by MRI, was significantly greater in mini-pigs with the omentum than in those without it; histologically, vascular density in the transplanted area was significantly greater in mini-pigs with the omentum than in those without it. The transplanted tissues contained abundant cardiac troponin T-positive cells surrounded by vascular-rich structures. The omentum flap enhanced the survival of hiPS-CMs after transplantation via increased angiogenesis, suggesting that this strategy is useful in clinical settings. The combination of hiPS-CMs and the omentum flap may be a promising technique for the development of tissue-engineered vascular-rich new myocardium in vivo.
    Circulation 09/2013; 128(26 Suppl 1):S87-94. · 15.20 Impact Factor
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    ABSTRACT: Transcatheter aortic valve replacement (TAVR) for patients with a bicuspid aortic valve (BAV) is challenging as the extent and location of valve calcification as well as bulky leaflets and an enlarged root may increase the risk of transcatheter heart valve (THV) displacement, distortion, or malfunctioning. We report successful TAVR for an 84-year-old man with a BAV. The THV was implanted closer to the aorta than usual to avoid spreading of the bulky leaflets over the THV outflow. Following implantation, there was trivial paravalvular leakage, with no distortion or malfunction detected.
    Annals of thoracic and cardiovascular surgery : official journal of the Association of Thoracic and Cardiovascular Surgeons of Asia. 08/2013;
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    ABSTRACT: Although postoperative liver dysfunction (LD) following left ventricular assist device (LVAD) implantation is associated with high mortality, outcome is difficult to predict in patients with liver dysfunction. We aimed to clarify factors affecting recovery from LD after VAD implantation. A total of 167 patients underwent LVAD implantation, of whom 101 developed early postoperative LD, defined as maximum total bilirubin (max T-bil) greater than 5.0 mg/dl within 2 weeks. We set two different end-points, unremitting LD, and 90-day mortality. The rates of early mortality (90 days) and recovery from LD were 36 % (36/101) and 72 % (73/101), respectively. Univariate analysis showed that preoperative body weight, preoperative mechanical support, preoperative T-bil and creatinine, left ventricular diastolic dimension, right VAD (RVAD) insertion, cardiopulmonary bypass time, postoperative cardiac index, and postoperative T-bil and central venous pressure (CVP) on postoperative day (POD) 3 (non-recovered vs recovered, 12.4 ± 4.5 vs 9.5 ± 3.6 mmHg) were higher in patients with unremitting LD. Preoperative T-bil, RVAD insertion, and T-bil and CVP on POD 3 (non-survivor vs survivor, 12.4 ± 4.4 vs 9.4 ± 3.6 mmHg) were also higher in non-survivors. Multivariate analysis demonstrated that CVP on POD 3 was predictive of recovery from postoperative LD (OR 0.730, P < 0.05) and 90-day mortality (OR 0.730, P < 0.05). A key outcome factor in patients who developed early postoperative LD after LVAD implantation was postoperative liver congestion with high CVP. To overcome postoperative LD, appropriate management of postoperative CVP level is important.
    Journal of Artificial Organs 08/2013; · 1.41 Impact Factor
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    ABSTRACT: Pump thrombosis is one of the major adverse events associated with the use of a left ventricular assist system (LVAS) in patients with advanced heart failure. We investigated the clinical implication of pump replacement because of thrombus formation. This study included 87 patients who underwent implantation of a Nipro (Toyobo) pulsatile extracorporeal LVAS intended as a bridge to transplantation and were alive more than 3 months after implantation. The pump of this device is translucent, and daily evaluation for signs of thrombus formation was performed. Pump replacement was performed for significant thrombus formation that became visible. Data collection including demographics as well as hematologic values were performed 1 day before (baseline) and 3 months after implantation, and all patients were followed for 2 years or until death. At 3 months after LVAS implantation, 41 patients (47.1%) had undergone pump replacement because of pump thrombus. Baseline body surface area <1.63 m(2) was a significant predictor of pump replacement (hazard ratio [HR] 2.15, P = 0.04). At 3 months after implantation, there was a significantly higher incidence of stroke (P < 0.05) as well as a significantly greater decrease in body weight (F = 4.92, P = 0.03) in patients who underwent pump replacement as compared to those without. The 2-year mortality after implantation was 26.4%. Multivariate Cox regression analysis showed that pump replacement within 3 months after implantation was an independent predictor of mortality (HR 2.50, P = 0.03). In conclusion, pump replacement for thrombus formation may have a strong association with worse outcome. Our results reconfirm the clinical importance of device thrombus in the management of LVAS.
    Artificial Organs 05/2013; · 1.96 Impact Factor
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    ABSTRACT: We report a 76-year-old female with Takayasu arteritis who was found to have multiple coronary arteriovenous fistulas (CAVFs), a pulmonary-to-systemic ratio of 2:1, and aortic valve insufficiency. Aortic valve replacement and ligation of multiple CAVFs with cardiopulmonary bypass were performed under cardioplegic arrest, thus minimizing coronary steal.
    Journal of Cardiac Surgery 04/2013; · 1.35 Impact Factor
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    ABSTRACT: Continuous-flow left ventricular assist devices (LVADs) provide acceptable clinical results, but the long waiting period for heart transplantation leads to diverse complications. LVAD support can cause reverse left ventricular (LV) remodeling that results in the improvement of LV function and allows LVAD removal. We present a case of successful removal of a DuraHeart LVAD because of sufficient recovery of LV function. Before LVAD removal, we conducted an "LVAD weaning test" by decreasing pump speed and performing an additional normal saline infusion test. We consider that the LVAD weaning test can be used in place of the "pulsatile LVAD off test."
    Journal of Artificial Organs 03/2013; · 1.41 Impact Factor
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    ABSTRACT: OBJECTIVES: We previously reported favourable short-term results of our 'trans-septal maze procedure', a novel technique for creating biatrial lesions through a septal-superior approach during mitral valve surgery. Here, we reviewed the mid-term results of this procedure and determined the impact of restored left atrial (LA) contraction on late outcomes. METHODS: We examined clinical data of 50 patients with persistent (n = 7) or long-standing persistent atrial fibrillation (AF) (n = 43) (mean period of rhythm disturbance 77 ± 78 months) who underwent a trans-septal maze procedure concomitant with mitral valve surgery and were followed postoperatively for at least 24 months. The mean preoperative LA dimension was 59 ± 9 mm (40-85 mm). The presence of an A wave in Doppler echocardiography was considered to indicate evidence of LA mechanical contraction. Serial echocardiography was performed to evaluate left ventricular and LA dimensions, degree of valvular regurgitation and estimated systolic pulmonary artery (PA) pressure. Follow-up was completed with a mean duration of 59 ± 17 months (27-92 months). RESULTS: There were no ablation-related complications and 48 patients (96%) were free from AF immediately after the operation. At the latest follow-up, 39 patients (78%) were free from AF, while 28 (56%) presented LA mechanical contraction. Patients who restored LA mechanical contraction were less likely to experience postoperative thromboembolic events (4 vs 23%, P = 0.075), as compared with those who did not restore it. Serial echocardiography showed that patients with restored LA contraction showed improvement in Doppler-derived systolic PA pressure to a greater degree and less incidence of significant tricuspid regurgitation (7 vs 41%, P = 0.006). The Cox proportional hazards models with adjustments for all other covariates revealed LA dimension >60 mm at baseline as an independent risk factor for lack of LA mechanical contraction (adjusted hazards ratio 3.9, 95% confidence interval 1.1-14, P = 0.035). CONCLUSIONS: Our trans-septal maze procedure may be an effective alternative surgical treatment for eliminating AF during mitral valve surgery. In patients with valvular AF, early surgery is warranted to restore sinus rhythm with LA mechanical contraction, before severe LA dilatation occurs. The impact of LA contraction recovery conferred by AF ablation on postoperative haemodynamic improvements and thromboembolic events remains to be determined.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 03/2013; · 2.40 Impact Factor
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    ABSTRACT: Infections associated with left ventricular assist devices (LVADs) constitute an important clinical issue because they are difficult to completely eradicate without removal of the LVAD itself and can sometimes be fatal. We encountered a case of extracorporeal LVAD-related candida infection in a patient who was successfully weaned from LVAD support. Although the patient appeared to have recovered from the infection, the patient was readmitted to our institute due to a relapse of candida infection 9 months after LVAD removal. Although the patient did not demonstrate any systemic sign of infection on admission, computed tomography images clearly showed that the residual apical cuff of the LVAD inflow cannula, which was infected with Candida albicans during the initial admission, resulted in re-infection that involved the chest wall with destruction of the adjacent rib.
    Journal of Artificial Organs 02/2013; · 1.41 Impact Factor
  • Journal of Artificial Organs 02/2013; · 1.41 Impact Factor
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    ABSTRACT: A postoperative pseudoaneurysm is a rare complication that is difficult to diagnose. Computed tomography (CT) revealed a pseudoaneurysm in the ascending aorta of a 68-year-old female 8 days after mitral valve replacement and tricuspid annuloplasty. The defect was simply repaired during emergency surgery without cardiopulmonary bypass (CPB). The early detection of a postoperative pseudoaneurysm is important to avoid a second operation complicated by adhesions. Enhanced CT was useful for early detection in this patient. Pseudoaneurysm of the ascending aorta at the cannulation site can occur soon after surgery, and early recognition might allow simpler surgery without CPB.
    Surgery Today 06/2012; · 0.96 Impact Factor
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    ABSTRACT: Infection during left ventricular assist device (LVAD) support is associated with a high mortality. This study investigated the effect of bloodstream infection on survival of patients with LVAD support and assessed risk factors for survival in LVAD patients with bloodstream infection. Between 1999 and 2010, 109 consecutive patients with end-stage heart failure were supported by an LVAD as a bridge to transplantation. Overall survival was compared between those with and without a bloodstream infection. Risk factors for survival of patients with bloodstream infection were analyzed. A bloodstream infection developed in 65 patients (60%) during 584 ± 389 days of LVAD support. Compared with patients without a bloodstream infection, overall survival was significantly worse in those with bloodstream infection (68% vs 84% at 2 years after LVAD implantation, p = 0.0117). However, of 22 patients bridged to transplantation, none had bloodstream infection recurrence after transplantation, and their 3-year survival rate after transplantation was 100%. Cox multivariate analysis (hazard ratio [95% confidence interval]) identified postoperative right ventricular failure (2.890 [1.238 to 6.757]; p = 0.0141) and bloodstream infection caused by a pathogen other than gram-positive cocci (3.336 [1.390 to 8.006] p = 0.0070) as significant risk factors for death in LVAD patients with a bloodstream infection. Bloodstream infection had a significant effect on survival after LVAD implantation. Our results suggest that urgent cardiac transplantation should be considered for LVAD patients with a bloodstream infection based on the causative organism and right ventricular function.
    The Annals of thoracic surgery 05/2012; 94(5):1387-93. · 3.74 Impact Factor
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    ABSTRACT: As of September 30, 2011, a total of 113 patients with end-stage heart failure had undergone heart transplantation in Japan, and the early and late (10-year) survival rates appeared better than those reported by the registry of the International Society of Heart and Lung Transplantation. Among the risk factors negatively affecting survival, utilization of both left ventricular assist devices (LVADs) and marginal donor hearts were higher among Japanese patients, and among the factors favoring survival, younger adult recipients and fewer cases of ischemic cardiomyopathy were noted in Japanese patients. Although only a few patients have reached a survival period longer than 10 years, none has required retransplantation or died due to cardiac allograft vasculopathy (CAV). CAV may develop later in Japanese heart transplant patients than in those with mixed ethnic transplants. In addition, the survival rate with newer LVADs has improved dramatically recently, and therefore selection criteria for the use of an LVAD or heart transplantation require further investigation depending upon the characteristics of candidates with profound heart failure.
    Nippon Geka Gakkai zasshi 05/2012; 113(3):297-301.
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    ABSTRACT: We treated a 77-year-old woman diagnosed with severe aortic stenosis, who had undergone catheter ablation for paroxysmal supraventricular tachycardia at the age of 62. Although the patient remained in sinus rhythm, she had been receiving Coumadin with a target INR level of 2.0 since that time. Preoperative coronary angiography revealed a coronary-left atrium (LA) fistula, while computed tomography and echocardiography findings did not detect thrombus formation. Intra-operative transesophageal echocardiography revealed a 2-cm solid mass, which unexpectedly appeared during deairing manipulation. Prompt cross-clamping and removal of an LA thrombus with closure of the LA appendage contributed to an uneventful postoperative course. The LA should be explored if a coronary-LA fistula is noted, even in non-mitral cases, especially those with a history of catheter ablation.
    General Thoracic and Cardiovascular Surgery 04/2012; 60(6):394-6.
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    ABSTRACT: Total arch replacement, with a long elephant trunk (ET) anastomosed at the base of the innominate artery using an undersized graft, is performed for a variety of arch aneurysms. We investigated the long-term clinical outcomes of this procedure, as well as its long-term effectiveness for preventing retrograde flow into the aneurysm and further dilation of the descending aorta. We treated 127 consecutive patients with an arch aneurysm, who were divided into two groups according to the diameter of the descending aorta at the Th6-Th8 thoracic vertebral level: 35 mm or less (Single-ET, n = 94) and >35 mm (Staged-ET, n = 33). The graft diameter was undersized by 10-20% of the distal aortic diameter. ET length was determined by preoperative computed tomography (CT) to locate the distal end at Th6-Th8. Thrombosis around the ET and the descending aorta diameter around the distal end of the ET were evaluated using CT. Two patients (1.6%) died within 30 days, while seven (5.5%) died in the hospital, three (2.4%) had a new stroke, three (2.4%) had permanent paraplegia and one (0.8%) had paraparesis. CT demonstrated complete thrombosis of the perigraft space around the ET in 81 patients (86%) in the Single-ET group and 11 (33%) in the Staged-ET group within 1 month after surgery, but not in the remaining 35 patients. Twenty-seven of the 35 patients without complete thrombosis underwent a subsequent second-stage operation. In those, the descending aorta showed no further dilation around the distal end of the ET, while new-onset perigraft perfusion occurred in two patients in the Single-ET group at 14 and 126 months, respectively. Overall survival was 89, 86, 78 and 74% at 1, 3, 5 and 7 years, respectively. Our operative strategy for extensive thoracic aortic aneurysms using a long ET technique yielded satisfactory short- and long-term outcomes.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 04/2012; 42(5):840-8. · 2.40 Impact Factor

Publication Stats

193 Citations
165.27 Total Impact Points


  • 2014
    • Osaka University
      Suika, Ōsaka, Japan
  • 2006–2014
    • Osaka City University
      • Department of Cardiovascular Surgery
      Ōsaka, Ōsaka, Japan
  • 2009–2013
    • National Cerebral and Cardiovascular Center
      • Department of Cardiovascular Medicine
      Ōsaka-shi, Osaka-fu, Japan
  • 2008–2011
    • Osaka Rosai Hospital
      Ōsaka, Ōsaka, Japan
  • 2005–2007
    • Kure Medical Centre
      • Department of Cardiovascular Surgery
      Hirosima, Hiroshima, Japan