Yoshiki Sawa

Osaka City University, Ōsaka, Ōsaka, Japan

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Publications (692)1895.13 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective In order to prevent postoperative migrations and endoleaks after endovascular aneurysm repair (EVAR), we developed a tissue-engineered vascular graft that integrates with the aortic wall by recruiting the host tissue into the graft scaffold. In this study, we assessed the mechanical properties of the new graft, and evaluated the integration between the graft and the aortic wall histologically and mechanically in canine models. Methods The tissue-engineered vascular graft was woven to be partially degradable with a double-layered fiber (core; polyethylene terephthalate (PET), sheath; polyglycolic acid (PGA)) (PET/PGA graft). The mechanical properties of the graft were assessed in comparison with a thin-walled woven polyester graft (control graft). The stent-grafts, composed of a stainless Z stent (20mm in diameter, 25mm in length) and a PET/ PGA or a control graft (12 mm in diameter, 30 mm in length), (n=5 in each group), were implanted in the descending thoracic aorta of mongrel dogs for 2 months. We assessed the histology of the explants and the degree of adhesion between the graft and the aortic wall. Results The PET/PGA achieved nearly the same mechanical properties as those of the control graft in tensile strength and flexibility, but slightly higher water permeability. At 2 months after implantation, in the PET/PGA group, the PGA component degraded and was replaced by host tissue that contained a mixture of α-smooth muscle actin positive cells and other host cells, and the graft was observed as a unified structure with the aorta. The adhesion strength between the graft and the aortic wall was significantly enhanced in the PET/PGA group. Conclusion The PET/PGA stent-graft demonstrated a histological and mechanical integration with the native aorta. This next-generation stent-graft might reduce the risk of migrations and endoleaks, leading to preferable long term results of EVAR.
    The Journal of Thoracic and Cardiovascular Surgery. 10/2014;
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    ABSTRACT: Moyamoya disease (MMD) is a rare disease characterized by occlusive intracranial arteriopathy with formation of abnormal cerebrovascular collateral networks. Conventional cardiovascular surgical procedures using cardiopulmonary bypass for patients with MMD is challenging because low cerebral perfusion pressure and nonpulsatile (continuous) flow during cardiopulmonary bypass can cause severe cerebral ischemia. We successfully performed transcatheter aortic valve replacement in 3 women with severe aortic valve stenosis complicated with MMD. Transcatheter aortic valve replacement may be useful for patients with severe aortic valve stenosis complicated with severe cerebral ischemia, including MMD.
    The Annals of thoracic surgery. 10/2014; 98(4):1443-1445.
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    ABSTRACT: We report the successful longest biventricular support using dual Jarvik 2000 biventricular assist device (BVAD; Jarvik Heart, Inc., New York, NY, USA) as a bridge to transplant. A 27-year old woman with arrhythmogenic right ventricular cardiomyopathy underwent implantation of two Jarvik 2000s as a left ventricular assist device and right ventricular assist device. Although several BVAD-related complications including haemolysis, hepatic dysfunction, heart failure and pulmonary valve insufficiency developed at a very late stage, she was successfully bridged to heart transplantation after 1245 days of biventricular support, which is the longest in the literature. Despite advances in continuous-flow ventricular assist devices, their long-term use for biventricular support remains limited. We report a successful case of 1245 days of biventricular support with dual Jarvik 2000 axial flow pumps in a patient with a small body surface area.
    Interactive Cardiovascular and Thoracic Surgery 09/2014; · 1.11 Impact Factor
  • Transplantation 09/2014; 98(5):e38-9. · 3.78 Impact Factor
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    ABSTRACT: The development fistulas between the thoracic aorta and the esophagus are highly fatal conditions. We aimed to identify a therapeutic strategy for treating aortoesophageal fistula (AEF) in this study, by investigating all AEF cases presented in this special symposium at the 65th Annual Scientific Meeting of the Japanese Association for Thoracic Surgery.
    General thoracic and cardiovascular surgery. 08/2014;
  • Yoshiki Sawa
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    ABSTRACT: Recently, left ventricular assist devices (LVADs) have become a viable therapeutic approach as a bridge to cardiac transplantation, as well as destination therapy or as part of the bridge to recovery. In Japan, paracorporeal pneumatic devices are the only choice for such therapy, as implantable LVADs are not yet generally available due to device lag, which represents a serious problem in this field. Clinical trials of four different continuous-flow pumps, both axial and centrifugal flow types, were completed at about the same time, and two of those devices, DuraHeart and EVAHEART, have already been approved for use in Japan. Thus, reports of advanced treatment for severe heart failure with these devices are expected. The DuraHeart (Terumo Heart, Ann Arbor, MI, USA) and another device named the HeartWare (HeartWare Inc, Miami Lakes, FL, USA) are so-called third-generation devices, as they have achieved miniaturization and improvements in performance from the use of magnetic levitation. Based on our experiences from both clinical research and experimental use, we herein discuss the DuraHeart and HeartWare devices, with a focus on the clinical outcomes and management strategies. Because of the long waiting period for heart transplantation in Japan, these two devices are considered to have important roles in the near future for the treatment of severe heart failure, and a comprehensive strategy for LVAD therapy including such third-generation implantable devices is expected.
    Surgery Today 08/2014; · 0.96 Impact Factor
  • Nature Reviews Cardiology 08/2014; · 10.40 Impact Factor
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    ABSTRACT: Purpose : To assess the significance of aortic remodeling in the prevention of the late aortic events after thoracic endovascular aortic repair (TEVAR) for aortic dissection. Methods : The study involved 52 patients (41 men; mean age was 59.7±13.3 years) with type B aortic dissections and patent false lumens treated with TEVAR between 2004 and 2011. Of the 52 patients, 18 were treated in the acute phase for rupture (n=1), malperfusion (n=10), aortic diameter over 40 mm at onset (n=3), and rapid enlargement of the false lumen (n=4). In the chronic setting, the indications for TEVAR were rupture (n=1), malperfusion (n=2), aortic diameter >50 mm (n=18), and rapid enlargement of the false lumen (n=13). Aortic remodeling was evaluated at 6 months postoperatively, and risk factors for late aortic events were evaluated in multivariate analysis using aortic remodeling and other pre-, peri-, and postoperative factors. Results : Over a mean 36.0±18.9 months, 19 aortic events were documented: enlargement of the false lumen (n=4), type I endoleak (n=2), and erosion at the stent-graft edges (n=13). Multivariate analysis revealed that failure to achieve aortic remodeling at 6 months postoperatively was the only significant risk factor for late aortic events (hazard ratio 0.20, p=0.037). Patients with aortic remodeling had a higher rate of freedom from aortic events compared with those without aortic remodeling (100% vs. 81.5% at 1 year and 79.3% vs. 48.4% at 3 years, respectively). Conclusion : Aortic remodeling after TEVAR is a significant prognostic factor for better long-term results for type B aortic dissection.
    Journal of endovascular therapy : an official journal of the International Society of Endovascular Specialists. 08/2014; 21(4):517-525.
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    ABSTRACT: In contrast to a pulsatile-flow left ventricular assist device (LVAD), an LVAD off test for evaluation of cardiac recovery with a continuous-flow device is difficult because of intra-circuit backflow from the outflow graft when a device is stopped. We report a case of reliable evaluation of cardiac recovery using balloon occlusion of the outflow graft, followed by successful removal of a continuous-flow EVAHEART LVAD using a minimally invasive approach.
    Journal of artificial organs : the official journal of the Japanese Society for Artificial Organs. 07/2014;
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    ABSTRACT: The aim of this study was to evaluate our clinical experience with the Jarvik 2000 axial flow pump (Jarvik Heart, Inc, New York, NY, USA), a miniature axial flow left ventricular assist device (LVAD). The clinical results of eight patients, who underwent LVAD implantation with the Jarvik 2000 (median age 55.0 years; six men) between 2005 and 2010, including two who participated in a multicenter clinical trial in Japan, were reviewed. Two patients underwent LVAD implantation as destination therapy. Four patients underwent Jarvik 2000 implantation via median sternotomy, while the other four underwent implantation via left thoracotomy. There were no major complications during surgery. Four patients were supported for more than 2 years. The longest support duration was 1,618 days. Six patients successfully bridged to heart transplantation after a median 725 days of support. One patient on destination therapy died of a cerebral infarction. The other patient on destination therapy had had the LVAD for 1,618 days. The overall survival rates at 1, 2, and 3 years were 100, 86, and 86 %, respectively. The median postoperative serum lactate dehydrogenase level was 860.5 U/L at 1 month, 735 U/L at 6 months, and 692 U/L at 1 year. There were no fatal device-related infections. We found that the Jarvik 2000 with pin bearing could support patients with end-stage heart failure with acceptable mortality and morbidity rates. Further evaluations of the prevalence of thromboembolic and hemolytic events in patients with the new conical-bearing Jarvik 2000 are required.
    Journal of artificial organs : the official journal of the Japanese Society for Artificial Organs. 07/2014;
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    ABSTRACT: Surgical site infection (SSI) increases medical costs and prolongs hospitalization; however, there has been no multicenter study examining the socioeconomic effects of SSI after cardiovascular surgery in Japan.
    Surgery Today 06/2014; · 0.96 Impact Factor
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    ABSTRACT: Engineering of three-dimensional (3D) cardiac tissues using decellularized extracellular matrix could be a new technique to create an "organ-like" structure of the heart. To engineer artificial hearts functionally comparable to native hearts, however, much remain to be solved including stable excitation-propagation. To elucidate the points, we examined conduction properties of engineered tissues. We repopulated the decellularized hearts with neonatal rat cardiac cells and then, we observed excitation-propagation of spontaneous beatings using high resolution cameras. We also conducted immunofluorescence staining to examine morphological aspects. Live tissue imaging revealed that GFP-labeled-isolated cardiac cells were migrated into interstitial spaces through extravasation from coronary arteries. Engineered hearts repopulated with Ca(2+)-indicating protein (GCaMP2)-expressing cardiac cells were subjected to optical imaging experiments. Although the engineered hearts generally showed well-organized stable excitation-propagation, the hearts also demonstrated arrhythmogenic propensity such as disorganized propagation. Immunofluorescence study revealed randomly-mixed alignment of cardiomyocytes, endothelial cells and smooth muscle cells. The recellularized hearts also showed disarray of cardiomyocytes and markedly decreased expression of connexin43. In conclusion, we successfully demonstrated that the recellularized hearts showed dynamic excitation-propagation as a "whole organ". Our strategy could provide prerequisite information to construct a 3D-engineered heart, functionally comparable to the native heart.
    Biomaterials 06/2014; · 8.31 Impact Factor
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    ABSTRACT: To confirm the validity of using Gore TAG for degenerative descending thoracic aneurysm repair, we evaluated the mid-term clinical outcomes in our single-center experience.
    General thoracic and cardiovascular surgery. 06/2014;
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    ABSTRACT: The efficacy and safety of transcatheter aortic valve implantation (TAVI) in Asian populations were unknown. The purpose of this study was to compare directly the clinical outcomes of the first Japanese trial and a European single-center experience after TAVI.
    Journal of cardiology. 06/2014;
  • Yoshiki Sawa
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    ABSTRACT: With the improvement in the overall life expectancy, the incidence of aortic stenosis has been increasing. Although aortic valve replacement is a standard therapy, many patients do not undergo surgery for various reasons, including advanced age or the presence of multiple comorbidities. Transcatheter aortic valve implantation (TAVI) has been proposed as a less invasive and equally effective treatment for inoperable or high-risk symptomatic aortic stenosis. Numerous rigorous global clinical trials, as well as a pivotal clinical trial in Japan, have been conducted. In this review, we provide data on the development of TAVI worldwide and discuss the prospects for TAVI in Japan.
    Surgery Today 05/2014; · 0.96 Impact Factor
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    ABSTRACT: This study aimed to clarify the relationship between onset of protein-losing enteropathy (PLE) and Fontan circulation, with special reference to the development of contractility-afterload mismatch. The PLE group comprised 9 patients who experienced PLE after undergoing the Fontan operation, and the control group consisted of 32 patients had did not experienced PLE more than 10 years after the Fontan operation. The study compared the pre- and postoperative values of arterial elastance (Ea), end-systolic elastance (Ees), and contractility-afterload mismatch (Ea/Ees). Furthermore, the variations in the values were examined during the preoperative, postoperative, and midterm postoperative periods in seven PLE patients who underwent cardiac catheterization at the onset of PLE and during the pre- and postintervention periods in three PLE patients who underwent surgical intervention to improve the Fontan circulation after the onset of PLE. Comparison of the values obtained before and after Fontan operations showed that the Ea values increased significantly in the PLE group. However, the pre- and postoperative Ees values did not differ in the two groups. During the postoperative period, Ea/Ees increased significantly, and the Ea and Ea/Ees values increased continuously until the onset of PLE in the PLE group. In the patients who underwent surgical intervention to improve the Fontan circulation after the onset of PLE, the Ea/Ees decreased significantly, and the serum albumin levels improved after the intervention. Contractility-afterload mismatch, mainly caused by the increase in the afterload of the systemic ventricle, may have an important role in the development of PLE after the Fontan operation.
    Pediatric Cardiology 05/2014; · 1.20 Impact Factor
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    ABSTRACT: Quadricuspid aortic valve is a rare congenital abnormality often associated with valve incompetence and requires surgical correction in adulthood. However, using a standard suture technique of aortic valve replacement, postoperative complete atrioventricular block is not uncommon because of the downward displacement of the supranumerary leaflet towards the membranous septum. We describe a suture technique where the sutures on the supranumerary leaflet were passed through the aortic sinusal wall above the valvar hinge. This technique can preclude injury to the conduction system, thereby avoiding atrioventricular block.
    Interactive Cardiovascular and Thoracic Surgery 05/2014; · 1.11 Impact Factor
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    ABSTRACT: Matrix metalloproteinases (MMPs) and a family of tissue inhibitors of metalloproteinases (TIMPs) may contribute to myocardial remodeling in heart failure. TIMPs are the main inhibitors of MMPs and have other MMP-independent functions. Because little is known of the role of TIMPs in the heart, we examined the effects of TIMPs on cardiac fibroblasts (CFs) and cardiomyocytes. In vitro, TIMP-1-4 enhanced smooth muscle actin (SMA) expression in CFs, and TIMP-1 and TIMP-3 enhanced the expression of phosphorylated Smad-3 and phosphorylated transforming growth factor (TGF)-β type 1 receptor in CFs; this effect was inhibited by TGF-β receptor blocker SB-505124. TIMP-1, -3, and -4 also inhibited the FAK, AKT, and ERK pathways that induce cardiac hypertrophy. TIMP-1 and TIMP-2 suppressed apoptosis in cardiomyocytes; in contrast, TIMP-4 induced apoptosis in CFs. TIMP-2 stimulated collagen synthesis. Collagen gels containing TIMP-1 or TIMP-3, which exhibit cardioprotective effects in vitro, were transplanted to the left ventricular anterior wall of a rat heart model of myocardial infarction (MI). Gel-released TIMP-1 and TIMP-3 significantly improved cardiac function and myocardial remodeling and enhanced SMA expression in the infarcted area in ischemic cardiomyopathy model rats. Furthermore, the transplantation of TIMP-1 or TIMP-3 gels inhibited apoptosis in the ischemic myocardium and reduced MMP-2 activity. TIMPs may be an ideal target of cardiac regeneration therapy.
    Tissue Engineering Part A 05/2014; · 4.64 Impact Factor
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    ABSTRACT: Sternal wound infection is a devastating complication of cardiothoracic surgery that carries high postoperative morbidity and mortality rates. We explored whether our current program of extensive bacteriological examination including repeat blood cultures may contribute to the early diagnosis of sternal wound infection.
    Journal of Cardiothoracic Surgery 05/2014; 9(1):80. · 0.90 Impact Factor
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    ABSTRACT: Objective Stent graft-related complications—including endoleaks and graft migration—are partly attributed to insufficient graft attachment to the aortic wall. ONO-1301, a stable synthetic prostacyclin agonist, reportedly reorganizes extracellular matrices, enhancing tissue healing. We hypothesized that ONO-1301-eluting stent grafts may strengthen graft attachment to the aortic wall. Methods Either polylactic acid polymer-conjugated ONO-1301, which releases ONO-1301 into adjacent tissues over 3 months (ONO(+) group), or polylactic acid polymer only (ONO(-) group) was coated onto the stent graft and placed in the descending thoracic aorta of canines weighing 16–20 kg under fluoroscopic guidance. Examinations occurred at 1, 2, or 3 months postoperatively (n = 6 for each time point and group). Results ONO-1301 aortic-wall concentrations were within the effective range even at 3 months. The maximal load for tearing the graft from the aortic wall ex vivo was significantly greater in the ONO(+) group than in the ONO(-) group (117.1±44.4%, 133.9±23.2%, and 119.9±13.5% at 1, 2, and 3 months, respectively; P = 0.0007). Immunohistochemical examination revealed abundant α-smooth muscle actin-positive cells in the neointima in both groups. The fibrotic area between the graft and aortic wall was significantly larger (P < 0.0001), and migrating cells into the graft fabric were significantly greater (P = 0.0003) in the ONO(+) group than in the ONO(-) group. Conclusion In canines, the ONO-1301-eluting stent graft enhanced tissue reorganization and improved the attachment between the graft and aortic wall. This new device may be useful in preventing inadequate graft attachment to the aortic wall.
    Journal of Thoracic and Cardiovascular Surgery 04/2014; · 3.53 Impact Factor

Publication Stats

6k Citations
1,895.13 Total Impact Points


  • 1999–2014
    • Osaka City University
      • • Department of Cardiovascular Surgery
      • • Department of Biochemistry
      Ōsaka, Ōsaka, Japan
  • 1996–2014
    • Osaka University
      • • Division of Cardiovascular Surgery
      • • Department of Biotechnology
      • • Department of Chemical Science and Engineering
      • • Center for Medical Research and Education
      • • Graduate School of Medicine
      • • Division of Cellular and Molecular Biology
      Suika, Ōsaka, Japan
  • 2013
    • Hokkaido University
      • Department of Cardiovascular Surgery
      Sapporo-shi, Hokkaido, Japan
    • Kinki University
      Ōsaka, Ōsaka, Japan
  • 2012–2013
    • Queen Mary, University of London
      Londinium, England, United Kingdom
  • 2009–2012
    • Sakurabashi Watanabe Hospital
      Ōsaka, Ōsaka, Japan
  • 2007–2012
    • Osaka Rosai Hospital
      Ōsaka, Ōsaka, Japan
    • Rinku General Medical Center
      Ōsaka, Ōsaka, Japan
    • Osaka Medical Center and Research Institute for Maternal and Child Health
      Izumi, Ōsaka, Japan
    • Dokkyo Medical University
      • Department of Cardiothoracic Surgery
      Tochigi, Tochigi-ken, Japan
    • University Hospital Medical Information Network
      Edo, Tōkyō, Japan
  • 2011
    • University of Helsinki
      • Institute of Biomedicine
      Helsinki, Province of Southern Finland, Finland
    • Kure Medical Centre
      • Department of Cardiovascular Surgery
      Kure, Hiroshima, Japan
  • 2006–2010
    • Foundation for Biomedical Research and Innovation
      Kōbe, Hyōgo, Japan
  • 2005
    • Osaka Minami Medical Center
      Ōsaka, Ōsaka, Japan
  • 1998–2004
    • National Cerebral and Cardiovascular Center
      • Department of Cardiovascular Medicine
      Ōsaka, Ōsaka, Japan
  • 2000
    • Shirasagi Hospital
      Ōsaka, Ōsaka, Japan