Obara, Hideaki

写真a

Affiliation

School of Medicine, Department of Surgery (General and Gastroenterological Surgery) ( Shinanomachi )

Position

Associate Professor

Related Websites

External Links
Scopus Paper Info  
Paper Count: 203 Citation Count: 2756 h-index: 26

Click to view the Scopus page. The data was downloaded from Scopus API in April 14, 2026, via http://api.elsevier.com and http://www.scopus.com .

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Other Affiliation 【 Display / hide 】

  • 医学部, 臓器移植センター　センター長（兼任）

  • 医学部, 大血管浸潤腫瘍治療センター　センター長（兼任）

  • 医学部, 感染制御部　副部長

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Career 【 Display / hide 】

  • 2016.08
    -
    Present

    Keio University School of Medicine, Department of Surgery, 准教授

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Academic Background 【 Display / hide 】

  • 1993.03

    Keio University School of Medicine

    University, Graduated

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Academic Degrees 【 Display / hide 】

  • MD, PhD, Keio University, National Institution for Academic Degrees and University Evaluation, 2001.07

    Overexpression of truncated IkappaBalpha induces TNF-alpha-dependent apoptosis in human vascular smooth muscle cells.

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Research Areas 【 Display / hide 】

  • Life Science / General surgery and pediatric surgery (血管外科、移植免疫、再生医療、ロボット手術)

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Research Keywords 【 Display / hide 】

  • 血管再生、ロボット手術、移植免疫

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Research Themes 【 Display / hide 】

  • 血管外科領域におけるロボット手術導入、難治性潰瘍に対する再生医療の治験、超高難度手術の開発と推進、光超音波による新規診断法確立と臨床応用推進, 

    2011.01
    -
    Present

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Papers 【 Display / hide 】

  • An operator assistance control system for skill enhancement and safety assurance in cascade tank systems

    Ishida, R; Inoue, M; Ishihara, S; Obara, H

    SICE JOURNAL OF CONTROL MEASUREMENT AND SYSTEM INTEGRATION 19 ( 1 )  2026.12

    ISSN  1882-4889

  • Early Clinical Results From the Japanese Prospective Multicenter Study to Evaluate Zenith Alpha Abdominal Stent Graft for Abdominal Aortic Aneurysm (JUSTICE) Registry Demonstrate Acceptable Limb Patency at 12 Months

    Fujimura N., Ichihashi S., Shibata T., Matsumura H., Watanabe M., Morikage N., Kurimoto Y., Banno H., Uchiyama H., Obara H.

    Journal of Endovascular Therapy 33 ( 1 ) 227 - 235 2026.02

    ISSN  15266028

    　View Summary

    Purpose: Recent reports of the Zenith Alpha abdominal endovascular graft (Zenith Alpha AAA, Cook, Inc., Bloomington, Indiana) have demonstrated an unexpectedly high incidence of limb graft occlusion (LGO). The purpose of this study was to prospectively evaluate the performance of the Zenith AAA in Japan, with a specific focus on LGO. Materials and methods: All endovascular aneurysm repairs (EVARs) for abdominal aortic aneurysms performed using the Zenith Alpha AAA from July 2020 to October 2021 in 23 Japanese hospitals were prospectively evaluated. All computed tomographic images were analyzed in the core laboratory. Late complications were defined as any aneurysm-related events occurring >30 days after EVAR, including aneurysm sac enlargement of >5 mm and any reinterventions performed. Endoleaks without sac enlargement or reintervention were excluded as late complications. Results: During the study period, 147 EVARs were performed using the Zenith Alpha AAA. The mean patient age was 76.5±7.7 years, 84.4% of patients were male, and the mean aneurysm diameter was 52.4±9.2 mm. Instruction-for-use violations were observed in 76 patients (51.7%), primarily associated with a severely angulated proximal neck (>60°). There were six intraoperative complications and 62 additional intraoperative treatments reported, most of which involved preemptive coil embolization of the inferior mesenteric artery (37 cases). Technical success, defined as the absence of type 1 or 3 endoleaks on final angiography, was achieved in 99.3% of patients. At 12 months, there was only one case of type 1/3 endoleak (0.8%) and one aneurysm sac enlargement exceeding 5 mm (0.8%); however, a high incidence of type 2 endoleaks was observed in 35.2% of patients, and aneurysm sac regression exceeding 5 mm was achieved in 30.1% of patients. Nine late complications were observed, and the rate of freedom from late complications at 12 months was 93.5%, encompassing four LGOs and one limb graft stenosis (3.4%). Conclusions: In contrast to recent reports, our Japanese multicenter prospective study demonstrated satisfactory early clinical results, including an acceptable LGO rate, for the low-profile Zenith Alpha AAA. Long-term follow-ups will be performed to confirm the persistence of these outcomes. Clinical Impact: This study prospectively evaluated the performance of 147 Zenith Alpha AAAs used for endovascular aneurysm repair with core-lab adjudication focusing especially on limb graft occlusion (LGO). At 12 months, aneurysm sac regression exceeding 5 mm was achieved in 30.1% of patients, and there was only one type 1/3 endoleak, one aneurysm sac enlargement (>5 mm), and nine late complications including five LGOs (3.4%), resulting in rate of freedom from late complications at 93.5%. Satisfactory early clinical results, including an acceptable rate of LGO can be achieved, particularly with cautious usage of the Zenith Alpha Spiral-Z Endovascular Leg.” 5mm), and nine late complications including five LGOs (3.4%), resulting in rate of freedom from late complications at 93.5%. Satisfactory early clinical results, including an acceptable rate of LGO can be achieved, particularly with cautious usage of the Zenith Alpha Spiral-Z Endovascular Leg.

  • Validation of novel scoring systems for acute decompensated cirrhosis identifies PBC as an independent poor prognostic factor: a single-center Japanese cohort study

    Nakadai Y., Ojiro K., Kasuga R., Chu P.S., Ueno M., Tabuchi T., Taniki N., Usui S., Hasegawa Y., Abe Y., Kitago M., Obara H., Kanai T., Nakamoto N.

    Journal of Gastroenterology 61 ( 1 ) 85 - 95 2026.01

    ISSN  09441174

    　View Summary

    Background: The Model for End-Stage Liver Disease 3.0 (MELD 3.0) was developed in the United States to improve prioritization for liver transplantation (LT); however, its utility in Japanese patients with liver cirrhosis (LC) and acute decompensation (AD) remains invalidated. Methods: We retrospectively analyzed 312 patients with LC and first-time AD admitted to our institution between 2012 and 2022. Prognostic accuracy of MELD 3.0 was evaluated at 90 and 180 days after admission by comparison with other predictive models. Prognoses according to cirrhosis etiology and contributing factors were also examined. Results: MELD 3.0 demonstrated superior prognostic accuracy at day 180 (C-index: 0.770) compared to the original MELD and MELD Na, although its C-index up to day 90 was comparable to that of MELD and MELD Na. A cut-off value of MELD 3.0 > 20.5 predicted LT or liver-related death at day 180. Patients with primary biliary cholangitis (PBC) had poorer outcomes than non-PBC cases through 180 days and remained an independent risk factor in the Cox proportional hazards model incorporating MELD 3.0. A progressive increase in both MELD 3.0 and total bilirubin from day 0 to day 90 after AD was observed specifically in the PBC group, which may have been associated with the poor prognosis at day 180. Conclusions: MELD 3.0 was effective in predicting 180-day outcomes in Japanese patients with LC and AD. Progressive bilirubin elevation in PBC may be associated with poor prognosis. These findings suggest that early consideration of LT is warranted in patients with PBC.

  • Retroperitoneal Abdominal Aortic Repair With the da Vinci Single Port System: A Porcine Model Feasibility Study

    Takayama, T; Stein, H; Obara, H; Kudo, T; Preuss, M; Berndt, R; Debus, SE; Komiya, T; Kaneta, H; Thaveau, F

    EJVES VASCULAR FORUM 65   25 - 31 2026

    ISSN  2666-688X

  • Open surgical conversion after endovascular aneurysm repair in Japan: Indications and outcomes from a multicenter study (JAST-CONVERT)

    Morisaki K., Sano M., Miyake K., Kikuchi S., Shirasu T., Shibata T., Fukushima S., Takeuchi Y., Fujimura N., Matsubara Y., Orimoto Y., Natsume K., Omori M., Obara H., Azuma N.

    Journal of Vascular Surgery  2026

    ISSN  07415214

    　View Summary

    Objective: This study aimed to evaluate indications and outcomes of open surgical conversion (OSC) after endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm using a multicenter registry in Japan. Methods: Thirteen vascular centers retrospectively reviewed patients who underwent OSC after prior EVAR between 2006 and 2024. Baseline characteristics, indications, procedural details, and outcomes were analyzed. The primary end point was 30-day mortality. Secondary end points were overall survival, aneurysm-related mortality, and freedom from retreatment. Results: A total of 208 patients (85.6% males; median age, 78 years) were included. The median abdominal aortic aneurysm diameter was 62 mm. The median interval from initial EVAR to OSC was 5.2 years. Indications for OSC were type II endoleak with sac enlargement (47.1%), type I endoleak (23.1%), type V endoleak with sac enlargement (13.0%), infection (10.1%), and type III endoleak (9.6%). The most frequently used stent graft was the Excluder, followed by Endurant and Zenith. Complete stent graft removal was performed in 41 patients, partial removal in 51, and 116 underwent OSC with stent graft preservation. Thirty-eight patients (18.3%) presented with rupture and 48 (23.1%) underwent urgent OSC. The 30-day mortality rate was 4.3% in the overall cohort, 2.4% in nonruptured cases, and 13.2% in ruptured cases. Rupture was a risk factor for 30-day mortality (hazard ratio, 5.93; 95% confidence interval, 1.59-22.1; P = .008). At 10 years, overall survival and aneurysm-related mortality were 58.4% and 14.8%, respectively, and freedom from retreatment rate was 87.5% at 10 years. Conclusions: Type II endoleak was the leading common indication for OSC after EVAR in this multicenter retrospective study in Japan. Rupture at OSC markedly increased 30-day mortality, even in patients with type II endoleak. Further studies are needed to refine elective indications for OSC to prevent aneurysmal rupture and avoid treatment delay.

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Papers, etc., Registered in KOARA 【 Display / hide 】

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Reviews, Commentaries, etc. 【 Display / hide 】

  • Foundational basic animal experiments paved the way for the clinical development of uterus transplantation

    Kisu I., Mihara M., Hara H., Kato Y., Matoba Y., Yamada Y., Matsubara K., Obara H., Suganuma N., Banno K.

    Reproductive Medicine and Biology 24 ( 1 ) e12656 2025.01

    ISSN  14455781

    　View Summary

    Uterus transplantation (UTx) has emerged as a revolutionary treatment for absolute uterine factor infertility, made possible by extensive preclinical research. Animal studies have played a pivotal role in advancing UTx to clinical practice. We highlight Japan's contribution, including non-human primate research and regulatory progress, leading to its anticipated clinical implementation. The expansion of UTx in the Asia-Oceania region underscores its global impact. Further refinements in surgical techniques, optimization of immunosuppressive regimens, and establishment of clear patient eligibility criteria will be crucial for ensuring the long-term success and sustainability of UTx programs worldwide. This letter acknowledges the Swedish team's foundational efforts in establishing UTx as a viable reproductive technology.

  • Early Dynamics of MELD Scores Predict Corticosteroid Responsiveness to Severe Acute-Onset Autoimmune Hepatitis

    Noguchi F., Chu P.s., Yoshida A., Taniki N., Morikawa R., Hasegawa Y., Yamataka K., Hoshi H., Kasuga R., Tabuchi T., Ebinuma H., Shinoda M., Obara H., Kitagawa Y., Kanai T., Nakamoto N.

    Clinical Gastroenterology and Hepatology 20 ( 11 ) 2641 - 2643.e3 2022.11

    ISSN  15423565

  • Author response to: Nationwide study of surgery for primary infected abdominal aortic and common iliac artery aneurysms

    Hosaka A., Kumamaru H., Takahashi A., Azuma N., Obara H., Miyata T., Obitsu Y., Zempo N., Miyata H., Komori K.

    British Journal of Surgery 109 ( 2 ) E44 - E44 2022.02

    ISSN  00071323

  • Correction to: Current management strategies for visceral artery aneurysms: an overview (Surgery Today, (2020), 50, 1, (38-49), 10.1007/s00595-019-01898-3)

    Obara H., Kentaro M., Inoue M., Kitagawa Y.

    Surgery Today (Surgery Today)  50 ( 3 )  2020.03

    ISSN  09411291

    　View Summary

    The article Current management strategies for visceral artery aneurysms: an overview, written by Hideaki Obara, Matsubara Kentaro, Masanori Inoue and Yuko Kitagawa, was originally published Online First without Open Access. After publication in volume 50, issue 1, pages 38–49 the author decided to opt for Open Choice and to make the article an Open Access publication. Therefore, the copyright of the article has been changed to © The Author(s) 2020 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License (https :// creat iveco mmons .org/licen ses/by/4.0/), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The original article has been corrected.

  • Emerging problems in uterus transplantation

    Kisu I., Kato Y., Obara H., Matsubara K., Matoba Y., Banno K., Aoki D.

    BJOG: An International Journal of Obstetrics and Gynaecology (BJOG: An International Journal of Obstetrics and Gynaecology)  125 ( 11 ) 1352 - 1356 2018.10

    ISSN  14700328

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

  • 光超音波イメージング画像に対する探索的AI技術を用いた新たな下肢虚血診断法の開発

    2025.04
    -
    2028.03

    Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

    　View Summary

    本研究の対象疾患は包括的高度慢性下肢虚血(以下CLTI)である。本邦で0.2mmまでの微細血管を無侵襲で描出できる新たなモダリティとして、光超音波イメージングが開発された。本研究の目的は、潰瘍局所の微細血管を血行再建前後で光超音波イメージングで評価し、治癒が得られる潰瘍と治癒が得られない潰瘍の間にどのような血管構造の差異があるのかを人工知能(AI)技術を用い見いだし、血行再建後の潰瘍治癒予測モデルを作成することである。潰瘍治癒が期待できなければ、早期再介入や切断をおこなうなどの臨床判断を可能にすることで治療期間を短縮でき、患者負担の軽減および医療資源の大幅な節約につながると考えている。

  • Development of Innovative Revascularization Techniques Using Target tissue oxyygen saturation as an indicator and obtaning evidence

    2024.04
    -
    2027.03

    Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), No Setting

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    多数箇所病変を有する包括的高度慢性下肢虚血肢（CLTI）患者に対して、中枢側病変から血管内治療を行い、標的とする部位のrSO2値をモニターしながら潰瘍治癒が見込まれる値をカットオフ値として、それを超える値を得た場合には末梢の動脈病変にはそれ以上治療を加えないという血管内治療戦略“標的組織酸素飽和度を指標としたCLTI患者に対する血管内治療(TOE)”の是非を調査するため、多施設無作為化非盲検（標準治療対照）並行群間比較試験 (RCT)を計画し、スタートさせる。
    末梢動脈疾患（PAD）の重症病態である包括的高度慢性下肢虚血（CLTI）では潰瘍、壊死などを引き起こし、最悪の場合下肢切断に至る。これを防ぐための血行再建として血管内治療（EVT）が用いられる。EVT の効果を評価する従来の方法には足首上腕指数（ABI）、皮膚灌流圧（SPP）、経皮酸素圧（TcPO2）があるが、いずれも術中モニターには適さない。我々は近赤外分光法（NIRS）技術による術中の四肢血流評価に注目し、組織内の酸素化ヘモグロビンと脱酸素化ヘモグロビンの濃度を測定し、局所組織酸素飽和度（rSO2）を計算して重症度指標となることを示してきた。
    多数箇所病変を有する包括的高度慢性下肢虚血肢（CLTI）患者に対して、中枢側病変（腸骨動脈や大腿動脈病変）から血管内治療を行い、標的とする部位のrSO2値(%)をモニターしながら潰瘍治癒が見込まれる値はいくつかのカットオフ値の探索を目的として症例検討を重ねた。ラザフォードグレード5 または6 の患者を対象とし、潰瘍治癒の目安としては、術後１年間の外来でのfollow-upの結果から、術中のEVTにより上昇したrSO2値と術後3,6,12ヶ月後の潰瘍治癒、救肢率の結果をretrospectiveに検討し、EVTにより上昇した術中rSO2値と術後のfollow-upでの潰瘍治癒についての検討から救肢の指標となる術中rSO2値のcut-off値の探索を行った。その結果、1 年以内の創傷治癒に対する術前のrSO2のカットオフ値は44%（感度: 66.7%、特異度: 78.9%）でEVT 中のrSO2 のカットオフ値は47%（感度: 86.7%、特異度: 73.7%）であった。このことより、EVT術中のrSO2 値が47%以上となれば、その後1 年以内に創傷治癒する可能性が高いと考えられた。
    血管内治療時の目標とするオキシメータが示す組織酸素飽和度については、カットオフ値が示さレ、今後の治療症例のメルクマールとすることが可能となったが、多数箇所病変を有する包括的高度慢性下肢虚血肢の症例数の集まりが悪く、研究に遅れを招いている。
    研究対象である多数箇所病変を有する包括的高度慢性下肢虚血肢の症例数の増加を検討するが、同時に目標とする組織酸素飽和度のカットオフ値設定については、包括的高度慢性下肢虚血肢だけではなく、他の虚血性疾患、例えば急性動脈閉塞肢や、糖尿病性壊疽など疾患の範囲を拡大させることも検討している。

  • Adipose-derived mesenchymal stem/stromal cell line (ASCL) sheets attenuate intimal hyperplasia

    2022.04
    -
    2025.03

    Grants-in-Aid for Scientific Research, Matsubara Kentaro, Grant-in-Aid for Scientific Research (C), No Setting

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    A rat adipose-derived mesenchymal stem/stromal cell line (ASCL) was established and confirmed to satisfy the criteria for defining mesenchymal stem cells. Monolayer cell sheets of rat ASCL were prepared using temperature-responsive culture dishes and further improvements were made to ensure more reliable sheet detachment. After evaluation the timing of intimal hyperplasia in a rat model of abdominal aortic injury, evaluation at 2 weeks post procedure was selected. In the experiment of rat ASCL monolayer sheets transplantation from the adventitia of abdominal aorta, the sheets tends to attenuate intimal hyperplasia compare to control group.

  • Evaluation of Adipose-derived Mesenchymal Stem/stromal Cell Line (ASCL) therapy for hepatic ischemia/reperfusion injury and application to liver transplantation

    2020.04
    -
    2023.03

    MEXT,JSPS, Grant-in-Aid for Scientific Research, OBARA Hideaki, Grant-in-Aid for Scientific Research (C), Principal investigator

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    In the rat liver ischemia-reperfusion injury model, control (saline), ASCs, and ASCLs were injected into the spleen 24 h before the start of ischemia, respectively. The survival rate of 120 min ischemia was significantly increased in the ASCL or ASCs pre-treatment group compared to the untreated control group. AST/ALT levels after 60 min ischemia were significantly lower in the ASCL group than in the control group at 3 hours after the reperfusion. ASCL may inhibit ischemia-reperfusion injury by expressing anti-inflammatory cytokines in vivo.

  • Development of drug eluting bioresorbable stents with antiplatelet effect and protection against hepatic ischemia and reperfusion injury: application to liver transplantation

    2015.04
    -
    2018.03

    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

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Courses Taught 【 Display / hide 】

  • LECTURE SERIES, SURGERY

    2026

  • CLINICAL CLERKSHIP IN GENERAL AND GASTROINTESTINAL SURGERY

    2026

  • PATHOPHYSIOLOGICAL ISSUES IN ACUTE CARE

    2026

  • PATHOPHYSIOLOGICAL ISSUES IN ACUTE CARE

    2025

  • LECTURE SERIES, SURGERY

    2025

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