Publications by authors named "Nishiura N"

Background: A small mitral valve area (MVA) is one of the challenging anatomies for transcatheter edge-to-edge repair (TEER) for mitral regurgitation, but the relationship between baseline MVA and clinical outcomes remains unknown. This study aimed to evaluate the association of baseline MVA with procedural and clinical outcomes in patients undergoing TEER with MitraClip from the OCEAN-Mitral registry (Optimized Catheter Valvular Intervention-Mitral).

Methods: A total of 1768 patients undergoing TEER were divided into 3 groups according to baseline MVA: group 1: <4.

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Background: Research on the impact of angiographically detected residual trabeculation after left atrial appendage closure (LAAC) is limited.

Objectives: To investigate the incidence, characteristics, and clinical implications of angiographically detected residual trabeculation after LAAC using the WATCHMAN device.

Methods: We analyzed 1350 consecutive patients with atrial fibrillation undergoing LAAC using the WATCHMAN device from the OCEAN-LAAC registry, which is a prospective ongoing, multicenter Japanese registry.

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Article Synopsis
  • This study examined how left ventricular ejection fraction (LVEF) changes after a specific heart valve repair procedure called transcatheter edge-to-edge valve repair (TEER) in patients with mitral regurgitation (MR).
  • Findings revealed that 32% of patients experienced worsened LVEF after the procedure, linked to increased end-systolic volumes in the heart and certain predictors like higher LVEF and levels of B-type natriuretic peptide.
  • Despite the LVEF worsening, long-term outcomes (like death or hospitalization for heart failure) were similar for both patients with worsened and preserved LVEF, indicating that LVEF change might not significantly impact overall health results post-TEER
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Background: Patients with atrial fibrillation and malignant left atrial appendage (LAA) may benefit from LAA closure (LAAC); however, evidence is limited.

Objective: The purpose of this study was to determine management strategies and clinical outcomes in patients with atrial fibrillation and malignant LAA.

Methods: Malignant LAA was defined as a history of ischemic stroke and/or evidence of LAA thrombus despite continuous oral anticoagulation (OAC) therapy (continuous for ≥3 weeks).

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Article Synopsis
  • This study compares the effectiveness and safety of two devices, WATCHMAN-FLX (WM-FLX) and WATCHMAN-2.5 (WM-2.5), used for closing the left atrial appendage in patients with nonvalvular atrial fibrillation who cannot take long-term anticoagulants.* -
  • An analysis of 199 patients highlighted that WM-FLX had shorter procedure times, fewer complications like cardiac tamponade, and a better success rate for complete device sealing at 45 days compared to WM-2.5.* -
  • Despite these advantages, WM-FLX was associated with a higher incidence of device-related thrombosis (DRT) over one year, particularly in patients with nonpar
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Article Synopsis
  • A study investigated the effectiveness of antithrombotic therapy in preventing complications during and after percutaneous left atrial appendage closure (LAAC) in patients with previous thromboembolic or bleeding events while on oral anticoagulation (OAC) therapy.
  • Results showed that patients who experienced thromboembolic events while on OAC were at a higher risk for device-related thrombosis (DRT) and post-procedural thromboembolic events, while those with bleeding events were more likely to have post-procedural bleeding events.
  • Continuing OAC for 12 months after LAAC reduced the incidence of DRT and thromboembolic events without increasing bleeding risks, suggesting that careful management of patients with
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The MitraClip G4 device has controlled gripper actuation (CGA) system, which allows the anterior and posterior grippers operate separately in transcatheter edge-to-edge repair (TEER). We investigated the indications and outcomes of the use of CGA system during TEER for significant mitral regurgitation (MR). We reviewed 158 patients undergoing TEER with MitraClip G4 from September 2020 to July 2023.

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Background: Clinical outcomes after percutaneous coronary intervention have improved with the use of drug-eluting stents, but data beyond 10 years are limited. The purpose of this study was to evaluate the clinical outcomes of patients undergoing sirolimus-eluting stent implantation with follow-up beyond 10 years and to determine the impact of clinical and angiographic characteristics on long-term prognosis.

Methods and results: The clinical outcomes of 885 patients who had undergone sirolimus-eluting stent implantation at a single institution were retrospectively reviewed.

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An 81-year-old woman who had undergone transcatheter aortic valve implantation 3 months earlier underwent routine follow-up transthoracic echocardiography, which revealed a mobile thrombus adhering to the bioprosthetic valve. This thrombus differed in morphology from transcatheter aortic valve implantation valve thrombi commonly seen in daily practice.

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Contrast media are generally necessary for transcatheter left atrial appendage closure (LAAC), however, it should be avoided in patients with chronic kidney disease (CKD). The objective of this study was to evaluate the safety and feasibility of contrast-free LAAC with WATCHMAN FLX device for patients with CKD. Among 141 patients undergoing LAAC using the WATCHMAN FLX between May 2021 and March 2023, we performed LAAC without contrast media in 10 patients.

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Background: Leaflet tear and perforation are serious complications of transcatheter edge-to-edge repair (TEER) using the MitraClip system for severe mitral regurgitation (MR). However, no optimal bailout strategy has been established.

Case Summary: An 80-year-old woman developed heart failure due to acute ischaemic severe MR after primary percutaneous coronary intervention.

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Background The natural history and optimal interventional timing in patients with isolated severe tricuspid regurgitation (TR) have not been well studied. This study aimed to investigate long-term clinical outcomes and risk factors associated with poor prognosis in patients with isolated severe TR. Methods and Results Consecutive transthoracic echocardiographic examinations in 2877 patients with isolated severe TR were retrospectively reviewed.

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A 34-year-old man with no medical history presented with fever 4 days after receiving the first dose of mRNA-1273 coronavirus disease 2019 (COVID-19) vaccine. He had no prior clinical evidence of severe acute respiratory syndrome coronavirus 2 infection and was negative for serial polymerase chain reaction testing. Ten days after vaccination, he was referred to our hospital because of no response to antibiotics and the emergence of neutropenia, thrombocytopenia, and liver dysfunction.

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The 17-membered polyketide, lankacidin C, exhibits considerable antitumor activity as a microtubule stabilizer by binding to the paclitaxel binding site. Esterification of the C-7/C-13 hydroxyl in lankacidin C was performed with acetyl, cinnamoyl and hydrocinnamoyl groups and their antitumor activity was assessed to improve the cytotoxicity of lankacidins through bioinspired computational design. Compared with the cytotoxicity of parent lankacidin C against the HeLa cell line, 13--cinnamoyl-lankacidin C demonstrated sevenfold higher cytotoxicity.

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We investigated the importance of the δ-lactone ring (C1-C5) in lankacidin C using chemoenzymatic synthesis and computational prediction and assessing biological activity, including antitumor activity. Pyrroloquinoline quinone-dependent dehydrogenase (Orf23) in Streptomyces rochei was used in the chemoenzymatic synthesis of lankacyclinone C, a novel lankacidin C congener lacking the δ-lactone moiety. Orf23 could convert the monocyclic lankacidinol derivatives, lankacyclinol and 2-epi-lankacyclinol, to the C-24 keto compounds, lankacyclinone C and 2-epi-lankacyclinone C, respectively, elucidating the relaxed substrate specificity of Orf23.

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A 23-year-old woman was admitted to our hospital because of rapidly developing lower abdominal pain. Computed tomography revealed ascites, splenomegaly, and a huge mass that occupied the pouch of Douglas and surrounded her uterus. A markedly elevated white blood cell count of 495×10/l and the identification of the BCR-ABL1 fusion gene led to the diagnosis of chronic myeloid leukemia (CML).

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Robustness and plasticity are essential features that allow biological systems to cope with complex and variable environments. In a constant environment, robustness, i.e.

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Platelet function of immune thrombocytopenia (ITP) has been controversial because of methodological problems associated with low platelet counts. In this study, we evaluated platelet function in 21 patients with chronic ITP (cITP) using the recently developed flow cytometry (FCM)-based platelet aggregation assay (FCA) along with a PAC1/CD62P assay. Since ITP platelets are larger than controls, whole platelets (whole gating method) and size-adjusted platelets (size-adjusted method) were analysed in the PAC1/CD62P via FCM.

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Article Synopsis
  • Several mutations, including αIIb(R995W), cause consistent activation of integrin αIIbβ3 in congenital macrothrombocytopenia, with αIIb(R995W) being common in Japanese patients.
  • The study investigated the effects of this mutation on platelet production and function by creating mice with the αIIb(R990W) knock-in mutation.
  • Results showed that these mice had reduced platelet counts, larger platelet size, and impaired platelet production and function, indicating that the mutation leads to macrothrombocytopenia and dysfunction similar to Glanzmann thrombasthenia.
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Essentials Acquired Glanzmann thrombasthenia (aGT) is generally caused by function-blocking antibodies (Abs). We demonstrated a unique aGT case due to marked reduction of αIIbβ3 with anti-αIIbβ3 Abs. The anti-αIIbβ3 Abs of the patient did not inhibit platelet function but reduced surface αIIbβ3.

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Background: Thrombin belongs to the most potent platelet agonists and activates human platelets through GPIbα and two protease activated receptors (PARs), PAR1 and PAR4. However, the details of thrombin receptor system, especially the role of PAR4 on human platelet activation is still not clear.

Objectives: We found a significant difference in PAR4-activating peptide (PAR4-AP)-induced, but not PAR1-AP, platelet aggregation between healthy Japanese subjects.

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A 67-year-old man was admitted with a 1-month history of spontaneous hematoma in his right back and severe anemia. He had suffered from rashes with blisters involving both legs for 10 years, which had shown worsening and extended to his entire body concurrently with the hematoma. APTT was markedly prolonged to 119 seconds, and Factor VIII:C and FVIII inhibitor levels were less than 1% and 153.

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Cancer of unknown primary origin (CUP) which is usually diagnosed based on the histological type of metastatic site has marked heterogeneous characteristics. Sarcomatoid carcinoma defined as CUP has not been reported according to our literature survey. A 59-year-old man presented with enlarged multiple thoracic lymph nodes, huge splenomegaly and nodules in left temporal lobe of the brain.

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We report a 77-year-old Japanese man with idiopathic thrombocytopenic purpura (ITP) which developed into chronic myelogenous leukemia (CML) during treatment with eltrombopag, a thrombopoetin (TPO) receptor agonist, because the disease was refractory to prednisolone. Eltrombopag can induce a good reaction in terms of the platelet count. However, CML in the chronic phase developed in about 19 months in our present case.

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