著者
Kiyoyuki Chinzei Akinobu Shimizu Kensaku Mori Kanako Harada Hideaki Takeda Makoto Hashizume Mayumi Ishizuka Nobumasa Kato Ryuzo Kawamori Shunei Kyo Kyosuke Nagata Takashi Yamane Ichiro Sakuma Kazuhiko Ohe Mamoru Mitsuishi
出版者
Japanese Society for Medical and Biological Engineering
雑誌
Advanced Biomedical Engineering (ISSN:21875219)
巻号頁・発行日
vol.7, pp.118-123, 2018 (Released:2018-05-24)
参考文献数
3
被引用文献数
30

AI-based medical and healthcare devices and systems have unique characteristics including 1) plasticity causing changes in system performance through learning, and need of creating new concepts about the timing of learning and assignment of responsibilities for risk management; 2) unpredictability of system behavior in response to unknown inputs due to the black box characteristics precluding deductive output prediction; and 3) need of assuring the characteristics of datasets to be used for learning and evaluation. The Subcommittee on Artificial Intelligence and its Applications in Medical Field of the Science Board, the Pharmaceuticals and Medical Devices Agency (PMDA), Tokyo, Japan, examined “new elements specific to AI” not included in conventional technologies, thereby clarifying the characteristics and risks of AI-based technologies. This paper summarizes the characteristics and clinical positioning of AI medical systems and their applications from the viewpoint of regulatory science, and presents the issues related to the characteristics and reliability of data sets in machine learning.
著者
Teruhiko Imamura Koichiro Kinugawa Taro Shiga Naoko Kato Miyoko Endo Toshiro Inaba Hisataka Maki Masaru Hatano Atsushi Yao Yasunobu Hirata Takashi Nishimura Shunei Kyo Minoru Ono Ryozo Nagai
出版者
一般社団法人 インターナショナル・ハート・ジャーナル刊行会
雑誌
International Heart Journal (ISSN:13492365)
巻号頁・発行日
vol.53, no.6, pp.391-393, 2012 (Released:2012-12-18)
参考文献数
16
被引用文献数
7 9

Hypervolemic hyponatremia is often complicated with advanced heart failure together with increased excretion of sodium by diuretics. Tolvaptan, an oral vasopressin-2-receptor antagonist, has been previously reported to improve congestion and correct hyponatremia through increased excretion of free water. However, there is little evidence concerning the administration of tolvaptan in patients with stage D heart failure. We experienced 2 patients with stage D heart failure who received 3.75 mg/day of tolvaptan to correct hyponatremia before ventricular assist device implantation. It may be useful, even for patients with stage D heart failure, to administer a low dose of tolvaptan to treat hyponatremia before ventricular assist device implantation to avoid a drastic alteration in serum sodium concentration perioperatively.
著者
Teruhiko Imamura Koichiro Kinugawa Masaru Hatano Takeo Fujino Toshiro Inaba Hisataka Maki Osamu Kinoshita Kan Nawata Shunei Kyo Minoru Ono Issei Komuro
出版者
日本循環器学会
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
vol.78, no.9, pp.2259-2267, 2014-08-25 (Released:2014-08-25)
参考文献数
28
被引用文献数
17 48

Background:Depressed hemodynamics stimulates arginine vasopressin (AVP) release, but the relationship between plasma AVP levels (P-AVP) and cardiac parameters, especially in patients with stage D heart failure (HF) receiving guideline-directed medical therapy, has not examined.Methods and Results:Data including P-AVP were obtained from 162 in-hospital patients with stage D HF and from 80 patients receiving ventricular assist device (VAD, n=46) or heart transplantation (HTx, n=34) at 3 months after surgery. In the HF group, considerably high P-AVP (5.9±6.1 pg/ml) negatively correlated with serum sodium concentration (S-Na, 135.3±5.8 mEq/L, r=–0.548 [P<0.01]) and cardiac index (CI, 2.2±0.5 L·min–1·m–2, r=–0.458 [P<0.01]). After VAD/HTx treatment, improvement in the CI (2.7±0.5 L·min–1·m–2[P<0.01] vs. HF) was accompanied by normalization of serum sodium concentration (S-Na; 138.2±2.0 mEq/L [P<0.01] vs. HF) and suppressed release of AVP (1.7±3.4 pg/ml [P<0.01] vs. HF). P-AVP positively correlated with only S-Na (r=0.454 [P<0.01]), whereas no correlation was observed with CI after VAD/HTx treatment. P-AVP ≥5.3 pg/ml well predicted poor 2-year survival in HF group (60% [P<0.01] vs. 90%).Conclusions:Low cardiac output stimulates AVP release via a non-osmotic process that results in hyponatremia and poor prognosis in patients with stage D HF. After sufficient recovery of cardiac output by cardiac replacement therapy, AVP release is suppressed and is mainly regulated by serum osmolality. (Circ J 2014; 78: 2259–2267)
著者
Teruhiko Imamura Koichiro Kinugawa Naoko Kato Hironori Muraoka Takeo Fujino Toshiro Inaba Hisataka Maki Osamu Kinoshita Masaru Hatano Shunei Kyo Minoru Ono
出版者
The Japanese Circulation Society
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
vol.78, no.3, pp.625-633, 2014 (Released:2014-02-25)
参考文献数
34
被引用文献数
56 57

Background: The continuous flow (CF) left ventricular assist device (LVAD) has replaced the pulsatile flow (PF) LVAD because of its advantages of better patient survival and higher quality of life. However, “late-onset right ventricular failure (RVF)” after CF LVAD implantation has emerged as an increasing concern, but little is known about the mechanism. Methods and Results: We retrospectively analyzed the 3-month hemodynamic and echocardiographic data from 38 consecutive patients who had received CF LVADs, and from 22 patients who had received PF LVADs. Late-onset RVF was defined as persistent right ventricular stroke work index (RVSWI) <4.0g/m2 at any rotation speed and after saline infusion test at 5 weeks after implantation of CF LVAD. Patients with late-onset RVF had significantly impaired exercise tolerance indicated by shorter 6-min walking distance and lower peak VO2, and worsened tricuspid regurgitation, together with enlargement of the RV under CF LVAD treatment (all P<0.05). Univariable analyses demonstrated that preoperative smaller LV diastolic diameter (LVDd) was the risk factor for late-onset RVF with a cutoff value of 64mm calculated by ROC analysis (area under curve, 0.925). In contrast, there was no correlation between preoperative LVDd and postoperative RVSWI in the PF LVAD group, though their preoperative background was worse than that of the CF group. Conclusions: In the setting of preoperative small LVDd, CF LVAD may cause late-onset RVF by leftward shift of the interventricular septum.  (Circ J 2014; 78: 625–633)
著者
Teruhiko Imamura Koichiro Kinugawa Shun Minatsuki Hironori Muraoka Naoko Kato Toshiro Inaba Hisataka Maki Taro Shiga Masaru Hatano Atsushi Yao Shunei Kyo Issei Komuro
出版者
The Japanese Circulation Society
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
vol.77, no.5, pp.1208-1213, 2013 (Released:2013-04-25)
参考文献数
29
被引用文献数
39 41

Background: Urine osmolality (U-OSM) is valuable to predict response to tolvaptan (TLV) in decompensated heart failure patients, but measurement of U-OSM is not always available on site. Methods and Results: Data were collected from 66 hospitalized patients with decompensated heart failure who had received TLV at 3.75–15mg/day. U-OSM, which was estimated using the following formula: 1.07×{2×[(urine sodium (mEq/L)]+[urine urea nitrogen (mg/dl)]/2.8+[urine creatinine (mg/dl)]×2/3}+16, was well correlated with the actual measurement (r=0.938, P<0.001). Criteria consisting of C1 (estimated baseline U-OSM >358mOsm/L) and C2 (%decrease in estimated U-OSM >24% at 4–6h after the first TLV dose) significantly discriminated responders from non-responders (P<0.05). Conclusions: Response to TLV can be predicted using U-OSM, which can be estimated using urine urea nitrogen, sodium, and creatinine concentration data.  (Circ J 2013; 77: 1208–1213)