- 著者
- Shigeru Saito Seiji Yamazaki Akihiko Takahashi Atsuo Namiki Tomohiro Kawasaki Satoru Otsuji Shigeru Nakamura Yoshisato Shibata for the Disrupt CAD IV Investigators
- 出版者
- The Japanese Circulation Society
- 雑誌
- Circulation Journal (ISSN:13469843)
- 巻号頁・発行日
- vol.85, no.6, pp.826-833, 2021-05-25 (Released:2021-05-25)
- 参考文献数
- 31
- 被引用文献数
- 2 58
Background:Intravascular lithotripsy (IVL) delivers acoustic pressure waves to modify calcium, enhance vessel compliance and optimize stent deployment. The objective of this study was to assess the safety and effectiveness of IVL treatment of de novo stenoses involving severely calcified coronary vessels in a Japanese population.Methods and Results:Disrupt CAD IV (NCT04151628) was a prospective, multicenter study designed for Japanese regulatory approval of coronary IVL (SWM-1234). The primary safety endpoint was freedom from major adverse cardiac events (MACE) at 30 days. The primary effectiveness endpoint was procedural success (residual stenosis <50% by QCA without in-hospital MACE). Noninferiority analyses for the primary endpoints were performed by comparing the CAD IV cohort with a propensity-matched historical IVL control group. Patients (intent-to-treat, n=64) were enrolled from 8 centers in Japan. Severe calcification by core laboratory assessment was present in all lesions, with a calcified length of 49.8±15.5 mm and a calcium angle of 257.9±78.4° by optical coherence tomography. Primary endpoints were achieved with non-inferiority demonstrated for freedom from 30-day MACE (CAD IV: 93.8% vs. Control: 91.2%, P=0.008), and procedural success (CAD IV: 93.8% vs. Control: 91.6%, P=0.007). No perforations, abrupt closures, or slow/no-reflow events occurred at any time during the procedures.Conclusions:Coronary IVL demonstrated high procedural success with low MACE rates in severely calcified lesions in a Japanese population.
- 著者
- Shigeru Saito Seiji Yamazaki Akihiko Takahashi Atsuo Namiki Tomohiro Kawasaki Satoru Otsuji Shigeru Nakamura Yoshisato Shibata
- 出版者
- The Japanese Circulation Society
- 雑誌
- Circulation Reports (ISSN:24340790)
- 巻号頁・発行日
- pp.CR-23-0082, (Released:2023-11-29)
- 参考文献数
- 22
Background: Intravascular lithotripsy (IVL) delivers acoustic pressure waves to modify calcification to enhance vessel compliance and optimize stent deployment. The Disrupt CAD IV study enrolled patients with severe coronary artery calcification. The primary safety (30-day major adverse coronary events [MACE], 6.3%) and effectiveness (procedural success, 93.8%) endpoints were achieved. The present analysis evaluated the 2-year outcomes of the study.Methods and Results: Disrupt CAD IV (NCT04151628) was a prospective, single-arm, multicenter study designed for regulatory approval of the Shockwave Coronary C2IVL system in Japan. Angiographic outcomes were analyzed by an independent core laboratory and adverse events were adjudicated by a Clinical Events Committee. Kaplan-Meier analysis was performed for MACE (composite of cardiac death, MI or target-vessel revascularization [TVR]), target lesion failure (TLF: composite of cardiac death, TV-MI, and target lesion revascularization [TLR]), and stent thrombosis (ST). At 2 years, 62 subjects had completed follow-up. MACE occurred in 12.6% (cardiac death 0.0%, MI 6.3%, TVR 7.9%) and TLF occurred in 7.8% of patients, with both rates driven by non-Q-wave MI events (6.3%). TLR was 3.2%; no ST occurred through 2 years.Conclusions: Treatment with IVL in patients with severely calcified coronary lesions was associated with low rates of MACE, TLR, and ST at 2 years, demonstrating continued durable safety and effectiveness of coronary IVL in a Japanese population.
- 著者
- Yoshiaki Seki Kiyoshi Ohishi Yuki Yokokura Toshiki Sano Yuji Ide Daigo Kuraishi Akihiko Takahashi
- 出版者
- The Institute of Electrical Engineers of Japan
- 雑誌
- IEEJ Journal of Industry Applications (ISSN:21871094)
- 巻号頁・発行日
- vol.6, no.2, pp.73-82, 2017-03-01 (Released:2017-03-01)
- 参考文献数
- 32
- 被引用文献数
- 1 5
In the field of high precision positioning control, the position servo system must be highly robust against disturbance torque. A Permanent Magnet Synchronous Motor (PMSM) has various torque ripple components that degrade control performance. A portion of the torque ripple is caused by the harmonic current. The torque ripple can be suppressed using a highly robust current control system. The remaining torque ripple is defined as the disturbance torque and is compensated for using a Disturbance OBserver (DOB). However, it is very difficult for a DOB to perform the appropriate compensation because it uses a low-pass filter to reduce noise. To obtain highly robust performance, this paper proposes a new position servo system using a disturbance torque hybrid observer and a current control system in the α-β stationary frame. In addition, this paper uses the torque ripple equation instead of a torque ripple table so as to reduce the amount of Digital Signal Processor (DSP) memory. The effectiveness of the proposed position servo system is confirmed using numerical and experimental results.
- 著者
- Noriyuki Tsuchida Taiji Kawahata Eiichiro Ishimaru Akihiko Takahashi Hiroshi Suzuki Takahisa Shobu
- 出版者
- 一般社団法人 日本鉄鋼協会
- 雑誌
- ISIJ International (ISSN:09151559)
- 巻号頁・発行日
- vol.53, no.7, pp.1260-1267, 2013 (Released:2013-08-20)
- 参考文献数
- 27
- 被引用文献数
- 3 26
To investigate the tensile deformation behavior of a lean duplex stainless steel (S32101) from the viewpoints of plastic deformability among phases or grains, we performed static tensile tests, in situ neutron diffraction, and white x-ray diffraction experiments at room temperature. In the static tensile tests, the S32101 steel displayed a larger uniform elongation and a better tensile strength–uniform elongation balance than a commercial SUS329J4L duplex stainless steel. A larger uniform elongation of S32101 is associated with the macroscopic work hardening behavior that a work hardening rate higher than the flow stress can maintain up until high true strains. From the experimental results of synchrotron radiation white x-ray diffraction experiments, the hard phase of S32101 was changed from the ferrite (α) phase to austenite (γ) one during tensile deformation. This led to a larger stress partitioning between the phases at the latter stage of deformation. From the experimental results of in situ neutron diffraction, it was found that the stress partitioning of the γ phase in the S32101 was the largest among the present results. Therefore, the larger work hardening rate of S32101 can be explained by the large stress partitioning of the γ phase, that between γ and α phases and γ volume fraction.
- 著者
- Takashi Kato Akihiko Takahashi Toshihiro Yamada
- 出版者
- 一般社団法人 日本応用数理学会
- 雑誌
- JSIAM Letters (ISSN:18830609)
- 巻号頁・発行日
- vol.5, pp.17-20, 2013 (Released:2013-03-06)
- 参考文献数
- 3
- 被引用文献数
- 2 7
This paper derives a new semi closed-form approximation formula for pricing an up-and-out barrier option under a certain type of stochastic volatility model including SABR model by applying a rigorous asymptotic expansion method developed by Kato, Takahashi and Yamada (2012). We also demonstrate the validity of our approximation method through numerical examples.