Yuji Miyamoto

Hyogo College of Medicine, Nishinomiya, Hyōgo, Japan

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Publications (142)265.5 Total impact

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    ABSTRACT: Left atrial (LA) dimension can predict atrial fibrillation (AF) recurrence after catheter-based or surgical ablation. Pulmonary vein isolation (PVI) may be a surgical option during aortic valve replacement (AVR) and/or coronary artery bypass grafting (CABG), though consensus regarding patient selection and late outcome is lacking. We studied 160 patients (mean age 70 ± 9 years) with paroxysmal AF who underwent radiofrequency-based PVI during AVR and/or CABG, and were followed up postoperatively for at least 6 months. Mean preoperative LA dimension was 44 ± 7 mm. Serial echocardiography was performed to evaluate left ventricular (LV) and LA dimensions, E/e', estimated systolic pulmonary artery (PA) pressure and degree of valvular regurgitation. Follow-up was completed with a mean duration of 47 ± 25 months. At the latest follow-up, 133 patients (83%) remained in sinus rhythm. Preoperative LA dimension was independently associated with increased risk of AF recurrence at 6 months after surgery [adjusted odds ratio 1.3 per 1-mm increase in LA dimension, 95% confidence interval (CI) 1.1-1.6, P < 0.001]. Receiver-operating characteristic curve analysis demonstrated an optimal cut-off value for preoperative LA dimension of 45 mm to predict sinus rhythm restoration (98% for <45 mm vs 55% for ≥45 mm, P < 0.001). Patients with LA dimension ≥45 mm had a significantly lower 5-year survival rate (62 ± 7 vs 82 ± 7%, P = 0.025) and freedom from adverse events defined as cerebral infarction/haemorrhage, admission for heart failure, catheter ablation and permanent pacemaker implantation (58 ± 7 vs 91 ± 4%, P < 0.001). Multivariate analysis showed that preoperative LA dimension ≥45 mm was independently associated with adverse events (adjusted hazards ratio 2.4, 95% CI 1.2-5.1, P = 0.019). Serial echocardiography demonstrated improvement in LV systolic function irrespective of LA dimension, whereas patients with LA dimension ≥45 mm showed less improvement in LA dimension and systolic PA pressure (interaction effect P < 0.001) and persistent higher E/e' (group effect P < 0.001), along with aggravated tricuspid regurgitation. In patients with paroxysmal AF related to aortic valve disease and/or coronary artery disease, a dilated left atrium (≥45 mm) was associated with inferior AF- and event-free survival after PVI, accompanied by persistent abnormalities in cardiac and haemodynamic function. These findings may assist patient selection for PVI during AVR and/or CABG. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 01/2015; DOI:10.1093/ejcts/ezu532 · 2.81 Impact Factor
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    ABSTRACT: We treated a 57-year-old female patient with an atrial tumor that was widely attached to the atrial septum. The tumor was diagnosed as a cystic tumor of the atrioventricular node (CTAVN). This type of tumor is rare, and its antemortem diagnosis is difficult because it is usually asymptomatic. This tumor may cause sudden death; thus surgical resection is recommended. We performed partial resection instead of total resection to avoid pacemaker implantation. Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
    The Annals of Thoracic Surgery 12/2014; 98(6):2223-6. DOI:10.1016/j.athoracsur.2014.02.061 · 3.63 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate whether edaravone (Radicut(®), Mitsubishi Tanabe Pharma Co., Osaka, Japan) injected at the start of reperfusion can suppress myonephropathic-metabolic syndrome (MNMS). MNMS models were made by clamping the bilateral common femoral arteries for 5 hours. At de-clamping (at the start of reperfusion), they were intra-peritoneal injected with 9.0 mg/kg of edaravone (the edaravone group, n = 5) or an equal volume of saline (the control group, n = 5). At five hours after de-clamping, the lower extremity muscles were stained with hematoxylin & eosin (H&E) to count the viable cells, and periodic acid- Schiff (PAS) to assess the glycogen storage. The lungs were also stained with H&E to expresse the alveolar wall thickness, and naphthol AS-D chloroacetate esterase to label infiltrating active neutrophils. The viable muscle cells in the edaravone group was significantly greater than that of the control group (593 ± 60 vs. 258 ± 31 cells/mm(2), p < 0.01). The PAS-positive area in the edaravone group was also significantly higher than that in the control group (30.1 ± 6.9 vs. 7.3 ± 2.1%, p < 0.001). The alveolar wall thickness in the edaravone group was significantly lower than that in the control group (63.6 ± 5.6 vs. 17.2 ± 5.2%, p < 0.001). The active neutrophil infiltration in the edaravone group was also significantly lower than that in the control group (249 ± 59 vs. 68 ± 8 cells/mm(2), p < 0.001). We conclude that edaravone injected at the start of reperfusion can suppress not only muscle reperfusion injury but also lung damage.
    International Journal of Angiology 09/2014; 23(3):193-6. DOI:10.1055/s-0034-1387825
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    ABSTRACT: Valvular calcification is a prominent feature of aortic valve stenosis (AS), and calcified aortic valves share several features with bone tissue. Hypoxia-inducible factor-2 (HIF-2) is activated by nuclear factor-κB (NF-κB) and plays a critical role in an osteoblastic differentiation. The study aim was to determine whether the NF-κB-HIF-2 pathway is involved in the pathophysiology of calcified aortic valve disease. A total of 50 specimens of aortic valve leaflets obtained from patients who had undergone aortic valve replacement for AS was examined. The aortic valve leaflets from 10 patients with annulo-aortic ectasia (AAE) served as controls. The stenotic valve leaflets were examined using immunohistochemistry to detect NF-κB, HIF-2α, vascular endothelial growth factor (VEGF), vascular endothelial cells, and collagen X. The calcification area was measured and any correlation between the calcification area and NF-κB-HIF-2 pathway was assessed. NF-κB and HIF-2α were expressed in the leaflets from patients with AS, but not in those from AAE controls. Both factors were expressed around massive calcified lesions, and HIF-2α was co-localized with NF-κB. VEGF, neoangiogenesis and collagen X were located in the area where HIF-2α was expressed, and correlated positively with HIF-2α expression. The calcification area correlated positively with collagen X expression. The NF-κB-HIF-2 pathway was expressed in calcified aortic valves and associated with an increased expression of VEGF and collagen X. This signaling pathway may play important roles in the pathophysiology of AS.
    The Journal of heart valve disease 09/2014; 23(5):558-66. · 0.73 Impact Factor
  • 01/2014; 43(3):158-161. DOI:10.4326/jjcvs.43.158
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    ABSTRACT: It is well known that free radicals cause reperfusion injury following leg ischemia. We showed that the free radical scavenger, edaravone (Radicut, Mitsubishi Tanabe Pharma Co., Osaka, Japan), might suppress reperfusion injury in rat. In this study, we used transmission electron microscope (TEM) to investigate how edaravone suppresses reperfusion injury by focusing on glycogen granules in the lower extremity muscles. Male Lewis rats (582 ± 35 g) were intraperitoneally injected with edaravone (3.0 mg/kg, edaravone group, n = 5) or the same dose of saline (control group, n = 5). The rat reperfusion injury models were induced by clamping the bilateral common femoral arteries for 5 hours and then declamping. The muscles were harvested at 5 hours after the start of reperfusion. Under a TEM (JEM-1220, Nippon Denshi Co., Tokyo, Japan), we counted the number of glycogen granules at ×50,000 magnification on each five different fields. The TEM sections from the control group showed a marked loss of glycogen granules and swollen mitochondria. In contrast, the TEM sections from the edaravone group showed numerous glycogen granules and normal mitochondria. The mean density of glycogen granules in the edaravone group was significantly higher than that in the control group (88.5 ± 5.3 vs. 16.4 ± 3.1 particles/µm(2), p < 0.001). Our TEM results confirmed that edaravone suppresses reperfusion injury following leg ischemia by maintaining the glycogen granules in muscles.
    International Journal of Angiology 12/2013; 22(4):267-70. DOI:10.1055/s-0033-1357261
  • Shinya Fukui, Yuji Miyamoto
    Kyobu geka. The Japanese journal of thoracic surgery 12/2013; 66(13):1175-7.
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    ABSTRACT: Various rings are available to achieve more physiologic mitral valve repair from viewpoints of physiologic mitral annular structure or dynamics. We evaluated preoperative and postoperative mitral annular structures and dynamics. Thirty-six patients underwent mitral valve repair for degenerative mitral insufficiency. Carpentier-Edwards Physio II ring (semirigid [Edwards Lifesciences, Irvine, CA]), St. Jude Medical Rigid Saddle Ring (RSR [St. Jude Medical, St. Paul, MN]), and MEMO 3D ring (semirigid [Sorin SpA, Milan, Italy]) were implanted in 13, 12, and 11 patients, respectively. Intraoperative real-time three-dimensional transesophageal echocardiography was performed before and after repair. The postoperative anteroposterior diameter reduction rate from end diastole to end systole was significantly (p < 0.0001) larger in MEMO (9.58% ± 2.91%) than in Physio II (0.98% ± 1.04%) and RSR (1.94% ± 1.95%). There were no significant differences in the commissure-to-commissure diameter reduction rates among the groups: 0.81% ± 1.98% for Physio II, 0.12% ± 0.53% for RSR, and 0.51% ± 1.98% for MEMO. The postoperative end-systolic annular height commissure width ratio was significantly (p < 0.0001) larger in both Physio II (17.9% ± 3.0%) and RSR (18.5% ± 1.6%) than in MEMO (13.6% ± 3.0%). The postoperative annular height commissure width ratio increase rate from end diastole to end systole was significantly larger in MEMO (5.1% ± 2.3%) than in Physio II (0.1% ± 0.6%) and RSR (0.3% ± 0.5%). Physio II and RSR could restore the physiologic three-dimensional annular shape, but the annular motion was diminished. Conversely, MEMO could preserve both the anteroposterior movement and folding dynamics, but no three-dimensional restoration of the mitral annulus was obtained.
    The Annals of thoracic surgery 11/2013; 97(2). DOI:10.1016/j.athoracsur.2013.09.077 · 3.65 Impact Factor
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    ABSTRACT: We treated a 21-year-old man with right ventricular thrombus caused by nephrotic syndrome. The right ventricular thrombus was safely removed and his postoperative course was uneventful. Peri- and postoperative management after surgery for the worsened nephrotic syndrome was relatively unique and difficult, and critical care was essential for saving the patient's life and protecting renal function.
    General Thoracic and Cardiovascular Surgery 10/2013; DOI:10.1007/s11748-013-0314-5
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    ABSTRACT: to evaluate the strategy for open heart surgery after renal transplantation performed in a single institution in Japan.
    Asian cardiovascular & thoracic annals 10/2013; DOI:10.1177/0218492313507784
  • Yuji Miyamoto
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    ABSTRACT: The original elephant trunk technique was developed by Borst in 1983 for the treatment of aortic arch aneurysms. This technique reduced operative risks, but was associated with cumulative mortality rates of 6.9 % for the first stage and 7.5 % for the second stage. Patients also waited a long time between two major surgical procedures. Only 50.4 % of patients underwent the second-stage surgery, and there was a significant interval mortality rate of 10.7 %. With the advent of stent-graft techniques, two different hybrid elephant trunk techniques were developed. One technique is first-stage elephant trunk graft placement followed by second-stage endovascular completion. The conventional elephant trunk graft provides a good landing zone for the stent-graft, and endovascular completion is a useful alternative to conventional second-stage surgery. This method has few major complications, and a postoperative paraplegia rate of 1.1 %. The other technique is the frozen elephant trunk technique. This technique eliminates the need for subsequent endovascular completion, and is particularly useful for the treatment of acute type A dissection because it can achieve a secure seal. However, it is associated with a higher rate of spinal cord ischemia than other methods such as the original elephant trunk technique. The left subclavian artery (LSA) is often lost when performing a hybrid elephant trunk procedure. Revascularization of the LSA should be performed to prevent arm ischemia and neurological complications such as paraplegia or stroke, although the level of evidence for this recommendation is low.
    General Thoracic and Cardiovascular Surgery 08/2013; DOI:10.1007/s11748-013-0299-0
  • International journal of cardiology 01/2013; 168(1). DOI:10.1016/j.ijcard.2012.12.059 · 6.18 Impact Factor
  • 01/2013; 42(2):89-93. DOI:10.4326/jjcvs.42.89
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    ABSTRACT: Open repair is the "gold standard" treatment for abdominal aortic aneurysm (AAA) and although considered safe, this operation is very invasive for high-risk patients with severe aortic valve stenosis (AS) because the left ventricular after-load changes sharply with the clamping and unclamping of the aorta. We prevented the change in left ventricular after-load by establishing a temporary axillo-bilateral femoral arterial shunt, which enabled us to perform open repair of an AAA safely in a patient with severe AS.
    Surgery Today 07/2012; 42(11):1116-8. DOI:10.1007/s00595-012-0263-0 · 1.21 Impact Factor
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    ABSTRACT: Subepicardial aneurysm caused by a left ventricular venting catheter inserted from the right superior pulmonary vein is very rare. Generally, this type of aneurysm is a complication of acute myocardial infarction. We report a 76-year-old woman in whom a left ventricular aneurysm was shown by transthoracic echocardiography 3 years after mitral valve replacement. She underwent left ventricular aneurysmectomy via the 4(th) left intercostal space. The left ventricular aneurysm was separated from the pericardium completely; therefore, this aneurysm was not thought to be pseudoaneurysm. The postoperative course was uneventful and the aneurysm was diagnosed as a subepicardial aneurysm from a histological examination.
    General Thoracic and Cardiovascular Surgery 06/2012; 61(3). DOI:10.1007/s11748-012-0118-z
  • Journal of Vascular Surgery 06/2012; 55(6):79S-80S. DOI:10.1016/j.jvs.2012.03.199 · 2.98 Impact Factor
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    ABSTRACT: We evaluated the performance of Terumo-Triplex (TRP) with a large-diameter vascular graft sealed with non-biodegradable material in 48 patients who underwent total arch replacement under selective cerebral perfusion between 2004 and 2009. TRP grafts were used in 13 patients (T group), Gelseal graft in 15 (G group), Hemashield graft in 10 (H group) and Intergard graft in 10 (I group). The total tube drainage, time to tube removal, graft dilation ratio and inflammation were evaluated postoperatively. Cardiopulmonary bypass and selective cerebral perfusion times did not differ between groups. Two patients died in hospital. The total drain drainage was significantly lower in the T group (956 ± 156 ml) than in the H (2058 ± 403 ml, p = 0.001) or I (5959 ± 1027 ml, p = 0.01) groups. The time to tube removal was significantly lower in T group and G group than H and I group (T: 3.7 ± 0.4, G: 4.1 ± 0.4, H: 8.3 ± 1.6, I: 18.6 ± 3.6 days, T vs. H, I: p = 0.07, 0.0002, G vs. H, I: p = 0.004, <0.0001). The graft dilation ratio was significantly lower in T group than G group (T: 104 ± 4 vs. 130 ± 7 %, p = 0.001). The max C-reactive protein level was significantly lower in T group (16.2 ± 4.5 mg/dl) than in the G group (19.4 ± 3.2 mg/dl, p = 0.047), H (20.4 ± 4.1 mg/dl, p = 0.048), or I (20.5 ± 4.5 mg/dl, p = 0.013) groups. Maximum body temperature was also lower in the T group (38.2 ± 0.5 °C) than in the G (38.7 ± 0.4 °C, p = 0.011), H (38.9 ± 0.6 °C, p = 0.0087), and I (39.3 ± 0.7 °C, p = 0.0005). Thus, TRP graft might attenuate inflammatory response compared to the other sealed grafts for total arch replacement in patients with aortic arch aneurysm or dissection.
    Journal of Artificial Organs 04/2012; 15(3):240-3. DOI:10.1007/s10047-012-0646-4 · 1.39 Impact Factor
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    ABSTRACT: We report a new aortic arch occlusion technique with a balloon for distal aortic arch repair via left thoracotomy using an open proximal method. Distal aortic arch repair via left thoracotomy sometimes causes brain infarction and perioperative myocardial infarction. That is because air or debris enters into coronary arteries and cervical branches and the left ventricle. Occlusion of the aortic arch using a balloon can prevent such perioperative complications.
    General Thoracic and Cardiovascular Surgery 04/2012; 60(4):247-8. DOI:10.1007/s11748-011-0828-7
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    ABSTRACT: Previous studies have examined outcomes in dialysis patients undergoing cardiac surgery. However, only a few studies have solely focused on outcomes after aortic valve replacement (AVR). This study aimed to clarify independent predictors of the long-term survival of dialysis patients with AVR and to determine whether a mechanical valve or bioprosthesis is suitable based on the patient's condition. A total of 38 consecutive dialysis patients who underwent AVR at our institute were reviewed (mean age 69.1 ± 9.4 years). There were 23 bioprostheses and 15 mechanical valve replacements. The operative mortality and the long-term survival were not different between the bioprosthesis and the mechanical valve group (13.0 vs. 13.3%). The significant multivariate predictors for long-term survival were concomitant coronary artery bypass grafting (CABG) and prosthesis size. Valve types and age at operation did not affect long-term survival. Five-year survival of patients with small prosthetic valves and concomitant CABG was 0%. When the patient's quality of life is taken into account, it may be appropriate to use a bioprosthesis in a dialysis patient with a small annulus and concomitant CABG even if the patient is young.
    Journal of Artificial Organs 02/2012; 15(2):162-7. DOI:10.1007/s10047-012-0631-y · 1.39 Impact Factor
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    ABSTRACT: BACKGROUND: The mechanisms are unknown why aortic stenosis (AS) progresses faster in patients with bicuspid aortic valve (BAV) than those with tricuspid aortic valve (TAV). The objective of this study is to examine whether neoangiogenesis, haemorrhage in the aortic valve leaflet (intraleaflet haemorrhage) and macrophage infiltration are involved in the mechanisms of rapid progression of AS with BAV. METHODS: We retrospectively examined specimens of aortic valve leaflets obtained from patients who had undergone aortic valve replacement for AS (AS with BAV: n=22, AS with TAV: n=86). The stenotic valve leaflets were examined by immunohistochemistry to detect vascular endothelial cells, red blood cell remnant and macrophage. We assessed the progression of AS by annualized changes in the aortic valve area (ΔAVA: cm(2)/year) which was evaluated by serial echocardiography with the continuity equation. RESULTS: Neoangiogenesis, intraleaflet haemorrhage and macrophage infiltration were frequently observed in leaflets obtained from AS patients with BAV (neoangiogenesis: 82%, intraleaflet haemorrhage: 91%, macrophage infiltration 91%). These pathological changes were more severe in AS with BAV than TAV, and they were positively correlated with progression of AS in patients with BAV. Multivariated analysis revealed that bicuspid anatomy was the only factor that predicted neoangiogenesis, intraleaflet haemorrhage and macrophage infiltration when patients with BAV and those with TAV were combined. CONCLUSIONS: Neoangiogenesis, intraleaflet haemorrhage and macrophage infiltration are more severe in leaflets from AS with BAV than TAV and associated with rapid progression of AS with BAV. This pathological process may account for rapid progression of AS with BAV.
    International journal of cardiology 02/2012; 167(2). DOI:10.1016/j.ijcard.2012.01.053 · 6.18 Impact Factor

Publication Stats

498 Citations
265.50 Total Impact Points

Institutions

  • 2005–2015
    • Hyogo College of Medicine
      • Department of Cardiovascular Surgery
      Nishinomiya, Hyōgo, Japan
  • 1998–2007
    • Sakurabashi Watanabe Hospital
      Ōsaka, Ōsaka, Japan
  • 2002–2006
    • Osaka City University
      • Department of Cardiovascular Surgery
      Ōsaka, Ōsaka, Japan
  • 2004
    • Osaka University
      • Department of Surgery
      Suika, Ōsaka, Japan
  • 1996
    • Yao Municipal Hospital
      Yaochō, Ōsaka, Japan
  • 1995
    • Texas Heart Institute
      Houston, Texas, United States