Yoshiki Sawa

Osaka City University, Ōsaka, Ōsaka, Japan

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Publications (686)1863.34 Total impact

  • [Show abstract] [Hide abstract]
    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: Background: Transcatheter aortic valve implantation (TAVI) may be a viable solution for inoperable or high-risk patients with aortic stenosis (AS), providing the benefit of valve replacement without the associated risks of surgery. Methods and Results: The prospective, multicenter MDT-2111 Japan Trial evaluated the efficacy and safety of a self-expandable TAV in patients with severe AS. A total of 55 patients were enrolled (October 2011 to October 2012). Mean age was 82.5±5.5 years; 30.9% male, 100% NYHA III/IV, and STS 8.0±4.2%. At 6 months, 91.7% of the iliofemoral patients had met the primary endpoint (an improvement of at least 1 NYHA class and an effective orifice area >1.2cm(2) for iliofemoral patients). For all patients, freedom from all-cause mortality at 6 months was 90.8%. At 30 days, the Kaplan-Meier rate of major vascular complications was 10.9%, the rate of permanent pacemaker implantation was 22.2% and the rate of major stroke was 3.7%. The incidences of paravalvular regurgitation for all implanted patients at 6 months were: 38.3% (none), 25.5% (trace), 31.9% (mild), 4.3% (moderate), and 0.0% (severe). Conclusions: This is the first study to evaluate a self-expandable TAV in a Japanese patient population. The data show successful achievement of the study's primary objective and demonstrate the functional and anatomical effectiveness of the MDT-2111 TAV system.
    Circulation Journal 03/2014; · 3.58 Impact Factor
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    ABSTRACT: The most difficult aspect of chordal replacement during mitral valve repair is to determine the correct length of the new chordae. A simple technique of chordal replacement was developed employing the new mitral leaflet retractor that enables easy adjustment of the length of artificial chordae. For prolapse of the anterior mitral leaflet (AML), the level of the normal opposing posterior leaflet can be used to determine the length of new chordae. We developed a double-headed leaflet retractor with which both mitral leaflets can be retracted simultaneously at the same level. This retractor makes it easy to tie the slippery Gore-Tex sutures for artificial chordae adjusting the length of the new chordae on AML to the level of the opposing normal posterior leaflet. We employed this retractor for the creation of artificial chordae in 55 consecutive patients with degenerative AML prolapse between 2005 and 2013. A ring annuloplasty was concomitantly performed to stabilize the reconstruction. We had no hospital death. Follow-up was 100% complete with a mean follow-up duration of 1181 ± 839 (range 50-2892) days. Reoperation-free survival at 5 years was 98.2%. Freedom from moderate-to-severe mitral regurgitation was 88.0% at 5 years. At follow-up, all non-reoperated survivors were in New York Heart Association Class I or II. We have reported the chordal replacement using the new double-headed mitral leaflet retractor. Our leaflet retractor is a convenient tool representing an easy creation of artificial chordae in mitral valve repair.
    Interactive Cardiovascular and Thoracic Surgery 03/2014; · 1.11 Impact Factor
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    ABSTRACT: Transcatheter aortic valve replacement (TAVR) is suggested to be less invasive and/or equally effective in comparison to conventional aortic valve replacement for high-risk symptomatic aortic stenosis patients. We herein report the initial results of a pivotal clinical trial of TAVR in Japan (the PREVAIL JAPAN). Sixty-four aortic stenosis patients (mean age 84.3 ± 6.1 years) not suitable for surgery were enrolled at three centers in Japan, with a primary composite endpoint of the 6-month post-procedure improvements in the aortic valve area and New York Heart Association (NYHA) functional classification. A transfemoral approach was used in 37 patients and a transapical approach was used in 27. The device success rate was 91.9 %. After 30 days and 6 months, the rates of mortality from any cause were 8.1 and 11.3 %, respectively. At 6 months, symptomatic stroke was found in 3.1 % of the patients, and silent infarction in 7.8 %. The aortic valve area and mean pressure gradient were significantly improved over time with both approaches (p < 0.001). At 6 months, the NYHA functional classification based on a conventional physician's assessment was improved in 87.9 % of the patients. We found results that were equivalent to those in other major TAVR trials, such as an acceptable 30-day survival (91.9 %), suggesting that balloon-expandable TAVR is effective for small Japanese AS patients classified as high-risk or inoperable.
    Surgery Today 03/2014; · 0.96 Impact Factor
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    ABSTRACT: Patients who undergo right ventricular (RV) outflow augmentation inevitably develop RV remodeling due to pulmonary insufficiency-related volume overload (VOL). However, the reversibility of this remodeling is not fully understood. The goal of this study was to establish an animal model of VOL and unloading to characterize the functional and pathological characteristics and reversibility of RV remodeling. VOL-RV was successfully induced by establishing direct RV-pulmonary artery (PA) bypass for 12 weeks in beagle canines. There were no procedure-related mortalities (n = 8). The RV developed typical functional features of VOL-related remodeling, such as a significant increase in end-diastolic/systolic volume and end-systolic pressure and a significant reduction in ejection fraction at 12 weeks, as assessed by three-dimensional echocardiography and cardiac catheterization. The RV developed typical pathological signs of remodeling, microstructural disorganization of cardiomyocytes, and/or structural/functional deterioration of the mitochondria. Volume unloading by division of the RV-PA bypass reversed the increase in the end-systolic/diastolic volume over 4 weeks when compared with a sham operation (n = 4 each). In addition, the bypass division also reversed the pathological changes seen in VOL-RV. VOL-RV that yielded typical functional and pathological features of RV remodeling was reproducibly achieved by direct RV-PA bypass in canines. The RV remodeling due to VOL was functionally and pathologically reversed by volume unloading via the bypass division.
    Surgery Today 02/2014; · 0.96 Impact Factor
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    ABSTRACT: To assess the safety, efficacy and performance of the RELAY NBS PLUS stent-graft in patients with aortic arch pathology. From July 2010 to December 2011, the RELAY NBS PLUS was used to treat 13 patients (eight males; mean age 59.8 years, range 29-78 years) suffering from aortic arch pathology. The distribution of the proximal landing zone was Zone 0 in one case, Zone 1 in three cases and Zone 2 in nine cases. Bypass of the cervical branches was performed in 11 patients. The surgery-related mortality within 30 days and postoperative morbidity were 0 %. Postoperative computed tomography at discharge confirmed 100 % clinical success without any endoleaks. The mean radius of the inner curve in the aortic arch was 16.2 mm (range 5.8-25.7 mm). We detected two bird-beak configurations with a severely angulated aortic arch with a radius of the inner curve <15 mm. At the mid-term follow-up (mean 22.1 months; range 13.8-28.2 months), all patients were alive without aorta- or device-related complications. RELAY NBS PLUS stent-grafts can be safely and effectively implanted with controlled deployment to satisfactorily repair aortic arch pathology, even in the cases considered to present with an unfavorable anatomy for the first generation commercially available stent-graft devices. These encouraging outcomes will need to be confirmed in a larger series with a longer follow-up.
    Surgery Today 02/2014; · 0.96 Impact Factor

Publication Stats

6k Citations
1,863.34 Total Impact Points

Institutions

  • 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
      Ōsaka, Ōsaka, Japan
  • 2000
    • Shirasagi Hospital
      Ōsaka, Ōsaka, Japan