Takafumi Hiro
Nihon University
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Featured researches published by Takafumi Hiro.
Journal of the American College of Cardiology | 2008
Yusaku Fukumoto; Takafumi Hiro; Takashi Fujii; Genta Hashimoto; Tatsuhiro Fujimura; Jutaro Yamada; Takayuki Okamura; Masunori Matsuzaki
OBJECTIVES The purpose of the present study was to assess the relationship between shear stress distribution and coronary plaque rupture by means of a new color-mapping program of shear stress with 3-dimensional intravascular ultrasound (IVUS). BACKGROUND Various in-vitro studies have demonstrated that shear stress of the vascular lumen is one of the important determinants of coronary plaque vulnerability. However, the in-vivo relationship between shear stress and plaque rupture is still unclear. METHODS In the present study, 3-dimensional IVUS was used to obtain spatial information on luminal geometry from 20 patients with acute coronary syndrome having a distinct ulcerative lesion. These 3-dimensional contours for each lumen were first reconstructed into mesh polygons, and then analyzed by means of a program for calculating the fluid dynamics. The flow was considered to be a constant laminar one. Then, colorized mappings of the distribution of the streamline, blood pressure, and shear stress were performed. The original luminal contour for each ruptured lesion was obtained by smoothing and extrapolation. RESULTS All patients had a coronary plaque rupture in the proximal or top portion of the plaque hill. In the color mapping, localized elevation of blood pressure and shear stress could be observed on each plaque surface. The shear stress concentration was frequently correlated with the plaque rupture site (kappa = 0.79). CONCLUSIONS Although the absolute value of shear stress is not sufficient to directly provoke mechanical destruction of the fibrous cap, localized high shear stress might be a trigger of fibrous cap rupture.
Circulation-arrhythmia and Electrophysiology | 2012
Koichi Nagashima; Yasuo Okumura; Ichiro Watanabe; Toshiko Nakai; Kimie Ohkubo; Masayoshi Kofune; Hiroaki Mano; Kazumasa Sonoda; Takafumi Hiro; Mizuki Nikaido
Background— Although increased epicardial adipose tissue (EAT) volume is known to be associated with increased prevalence of atrial fibrillation (AF), the exact mechanisms are unclear. Therefore, we investigated whether EAT locations were associated with high dominant frequency (DF) sites or complicated fractionated atrial electrogram sites during AF. Methods and Results— Three-dimensional reconstruction computed tomography images depicting EAT volumes (obtained by 320-detector-row multislice computed tomography) were merged with NavX-based DF and complicated fractionated atrial electrogram maps obtained during AF for 16 patients with paroxysmal AF and for 18 patients with persistent AF. Agreement between locations of the EAT, especially EAT surrounding the left atrium, and of high DF or complicated fractionated atrial electrogram sites was quantified. In addition, serum biomarker levels were determined. EAT surrounding the left atrium volumes was significantly greater in patients with persistent AF than in patients with paroxysmal AF (52.9 cm3 [95% CI, 44.2–61.5] versus 34.8 cm3 [95% CI, 26.6–43.0]; P=0.007). Serum high-sensitivity C-reactive protein and interleukin-6 levels were significantly higher in persistent AF patients than in paroxysmal AF patients (median high-sensitivity C-reactive protein, 969 ng/mL [interquartile range, 307–1678] versus 320 ng/mL [interquartile range, 120–660]; P=0.008; median interleukin-6, 2.4 pg/mL [interquartile range, 1.7–3.2] versus 1.3 [interquartile range, 0.8–2.4] pg/mL; P=0.017). EAT locations were in excellent agreement with high DF sites (&kgr;=0.77 [95% CI, 0.71–0.82]) but in poor agreement with complicated fractionated atrial electrogram sites (&kgr;=0.22 [95% CI, 0.13–0.31]). Conclusions— Increased EAT volume and elevation of inflammatory biomarkers are noted in persistent AF rather than paroxysmal AF patients. High DF sites are located adjacent to EAT sites. Thus, EAT may be involved in the maintenance of AF.
Circulation | 2001
Takafumi Hiro; Takashi Fujii; Kyounori Yasumoto; Takashige Murata; Akihiro Murashige; Masunori Matsuzaki
Background — The thickness of the fibrous cap is a major determinant in the vulnerability of atherosclerotic plaque to rupture. It has been demonstrated that intravascular ultrasound (IVUS) backscatter from fibrous tissue is strongly dependent on the ultrasound beam angle of incidence. This study investigated the feasibility of using a new IVUS color mapping technique representing the angle-dependent echo-intensity variation to determine the thickness of the fibrous cap in atherosclerotic plaque. Methods and Results — Nineteen formalin-fixed noncalcified human atherosclerotic plaques from necropsy were imaged in vitro with a 30-MHz IVUS catheter. The IVUS catheter was moved coaxially relative to the plaque. The images showing maximum and minimum echo intensity of the plaque surface were selected to calculate the angle-dependent echo-intensity variation. A colorized representation of the echo-intensity variation in the plaque was obtained from the 2 IVUS images. A clearly bordered area with large variation in echo intensity was revealed for each plaque surface in the colorized IVUS image. The thickness (x, mm) of this area correlated significantly with that of fibrous cap (y, mm) measured from histologically prepared sections as y =1.05 x −0.01 (r =0.81, P <0.0001). Bland-Altman analysis also supported the reliability of this method (mean difference, 0.00±0.10 mm). Conclusions — This novel technique for color mapping the echo-intensity variation in IVUS provided an accurate representation of the thickness of the fibrous cap in atherosclerotic plaque. This method may be useful in assessing plaque vulnerability to rupture in atherosclerosis.
Cardiovascular Diabetology | 2013
Yoshifumi Fukushima; Hiroyuki Daida; Takeshi Morimoto; Takatoshi Kasai; Katsumi Miyauchi; Sho-ichi Yamagishi; Masayoshi Takeuchi; Takafumi Hiro; Takeshi Kimura; Yoshihisa Nakagawa; Masakazu Yamagishi; Yukio Ozaki; Masunori Matsuzaki
BackgroundThe Japan Assessment of Pitavastatin and Atorvastatin in Acute Coronary Syndrome (JAPAN-ACS) trial demonstrated that early aggressive statin therapy in patients with ACS significantly reduces plaque volume (PV). Advanced glycation end products (AGEs) and the receptors of AGEs (RAGE) may lead to angiopathy in diabetes mellitus (DM) and may affect on the development of coronary PV. The present sub-study of JAPAN-ACS investigates the association between AGEs and RAGE, and PV.MethodsIntravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) was undertaken, followed by the initiation of statin treatment (either 4 mg/day of pitavastatin or 20 mg/day of atorvastatin), in patients with ACS. In the 208 JAPAN-ACS subjects, PV using IVUS in non-culprit segment > 5 mm proximal or distal to the culprit lesion and, serum levels of AGEs and soluble RAGE (sRAGE) were measured at baseline and 8–12 months after PCI.ResultsAt baseline, no differences in the levels of either AGEs or sRAGE were found between patients with DM and those without DM. The levels of AGEs decreased significantly with statin therapy from 8.6 ± 2.2 to 8.0 ± 2.1 U/ml (p < 0.001), whereas the levels of sRAGE did not change. There were no significant correlations between changes in PV and the changes in levels of AGEs as well as sRAGE. However, high baseline AGEs levels were significantly associated with plaque progression (odds ratio, 1.21; 95% confidence interval, 1.01 - 1.48; p = 0.044) even after adjusting for DM in multivariate logistic regression models.ConclusionsHigh baseline AGEs levels were associated with plaque progression in the JAPAN-ACS trial. This relationship was independent of DM. These findings suggest AGEs may be related to long-term glucose control and other oxidative stresses in ACS.Trial registrationNCT00242944
Journal of Atherosclerosis and Thrombosis | 2018
Makoto Kinoshita; Koutaro Yokote; Hidenori Arai; Mami Iida; Yasushi Ishigaki; Shun Ishibashi; Seiji Umemoto; Genshi Egusa; Hirotoshi Ohmura; Tomonori Okamura; Shinji Kihara; Shinji Koba; Isao Saito; Tetsuo Shoji; Hiroyuki Daida; Kazuhisa Tsukamoto; Juno Deguchi; Seitaro Dohi; Kazushige Dobashi; Hirotoshi Hamaguchi; Masumi Hara; Takafumi Hiro; Sadatoshi Biro; Yoshio Fujioka; Chizuko Maruyama; Yoshihiro Miyamoto; Yoshitaka Murakami; Masayuki Yokode; Hiroshi Yoshida; Hiromi Rakugi
Toray Industries, Inc., Tokyo, Japan Department of Diabetes, Metabolism and Endocrinology, Chiba University Graduate School of Medicine, Chiba, Japan National Center for Geriatrics and Gerontology, Aichi, Japan Department of Internal Medicine and Cardiology, Gifu Prefectural General Medical Center, Gifu, Japan Division of Diabetes and Metabolism, Department of Internal Medicine, Iwate Medical University, Iwate, Japan Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan Center for Integrated Medical Research, Hiroshima University Hospital, Hiroshima, Japan Egusa Genshi Clinic, Hiroshima, Japan Department of Cardiovascular Medicine, Juntendo University, Tokyo, Japan Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan Biomedical Informatics, Osaka University, Osaka, Japan Division of Cardiology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan Department of Community Health Systems Nursing, Ehime University Graduate School of Medicine, Ehime, Japan Department of Vascular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan Department of Vascular Surgery, Saitama Medical Center, Saitama, Japan Chief Health Management Department, Mitsui Chemicals Inc., Tokyo, Japan Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan Department of Neurology, Kita-Harima Medical Center, Hyogo, Japan Department of Internal Medicine, Mizonokuchi Hospital, Teikyo University School of Medicine, Kanagawa, Japan Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan Tsukasa Health Care Hospital, Kagoshima, Japan Faculty of Nutrition, Division of Clinical Nutrition, Kobe Gakuin University, Hyogo, Japan Department of Food and Nutrition, Faculty of Human Sciences and Design, Japan Women’s University, Tokyo, Japan 25 Department of Preventive Cardiology, National Cerebral and Cardiovascular Center, Osaka, Japan Department of Medical Statistics, Toho University, Tokyo, Japan Department of Clinical Innovative Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan Department of Laboratory Medicine, Jikei University Kashiwa Hospital, Chiba, Japan Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, Osaka, Japan Department of Obstetrics and Gynecology, Aichi Medical University, Aichi, Japan 31 Department of Community Medicine, Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka, Japan Rinku General Medical Center, Osaka, Japan
Journal of Cardiology | 2011
Tadateru Takayama; Takafumi Hiro
Coronary stents have been used for the treatment of patients with coronary artery disease (CAD), and significantly improved procedural safety and are associated with a lower rate of restenosis compared with balloon angioplasty alone. Drug-eluting stents (DES) have been dominant for the treatment of CAD with efficacy in significantly reducing both restenosis and target lesion revascularization. However, late and very late stent thrombosis have become a major concern in DES-implanted arteries compared with those treated with bare-metal stents (BMS). This review focuses on the feature of DES thrombosis and pathological examination and dual antiplatelet therapy for prevention of stent thrombosis. Currently, the incidence of stent thrombosis associated with first-generation and second-generation DES remains unclear in data from real-world cohort registry studies. Further studies of larger multicenter trials would give us insight into the specific mechanisms of stent thrombosis among different generations of DES.
Journal of Cardiology | 2008
Takayuki Okamura; Takafumi Hiro; Takashi Fujii; Jutaro Yamada; Yusaku Fukumoto; Genta Hashimoto; Tatsuhiro Fujimura; Kyounori Yasumoto; Masunori Matsuzaki
A 73-year-old female underwent percutaneous coronary intervention (PCI) because of stable angina. An elective PCI for the RCA lesion was first performed with deploying sirolimus eluting stents (SES). Three weeks later, PCI was also provided in the residual LAD lesion. Eight months later, she presented with new angina. CAG revealed an in-stent restenosis in the mid LAD and a large eccentric saccular coronary aneurysm (17 mm x 9 mm) at the proximal RCA. Intravascular ultrasound (IVUS) showed absence of stent struts around the orifice of aneurysm, which suggested a fracture of SES stent. The entry of coronary aneurysm was finally sealed with a polytetrafluoroethylene-covered stent. This report documented a rare case of late giant coronary artery aneurysm associated with a fracture of SES.
Cardiovascular Diabetology | 2012
Hiroyuki Daida; Tadateru Takayama; Takafumi Hiro; Masakazu Yamagishi; Satoshi Saito; Tetsu Yamaguchi; Masunori Matsuzaki
BackgroundThe incidence of cardiac events is higher in patients with diabetes than in people without diabetes. The Coronary Atherosclerosis Study Measuring Effects of Rosuvastatin Using Intravascular Ultrasound in Japanese Subjects (COSMOS) demonstrated significant plaque regression in Japanese patients with chronic coronary disease after 76 weeks of rosuvastatin (2.5 mg once daily, up-titrated to a maximum of 20 mg/day to achieve LDL cholesterol <80 mg/dl).MethodsIn this subanalysis of COSMOS, we examined the association between HbA1c and plaque regression in 40 patients with HbA1c ≥6.5% (high group) and 86 patients with HbA1c <6.5% (low group).ResultsIn multivariate analyses, HbA1c and plaque volume at baseline were major determinants of plaque regression. LDL cholesterol decreased by 37% and 39% in the high and low groups, respectively, while HDL cholesterol increased by 16% and 22%, respectively. The reduction in plaque volume was significantly (p = 0.04) greater in the low group (from 71.0 ± 39.9 to 64.7 ± 34.7 mm3) than in the high group (from 74.3 ± 34.2 to 71.4 ± 32.3 mm3). Vessel volume increased in the high group but not in the low group (change from baseline: +4.2% vs −0.8%, p = 0.02). Change in plaque volume was significantly correlated with baseline HbA1c.ConclusionsDespite similar improvements in lipid levels, plaque regression was less pronounced in patients with high HbA1c levels compared with those with low levels. Tight glucose control during statin therapy may enhance plaque regression in patients with stable coronary disease.Trial registrationClinicalTrials.gov, Identifier NCT00329160
Journal of Cardiology | 2013
Tadateru Takayama; Takafumi Hiro; Yasunori Ueda; Junko Honye; Sei Komatsu; Osamu Yamaguchi; Yuxin Li; Junji Yajima; Kenji Takazawa; Shinsuke Nanto; Satoshi Saito; Kazuhisa Kodama
BACKGROUND Diabetes mellitus (DM) is a major risk factor for cardiovascular events. The study purpose was to compare DM and non-DM (nDM) patients in terms of statin-induced change of plaque characteristics using intravascular ultrasound (IVUS) and coronary angioscopy. METHODS Patients with coronary artery disease and hypercholesterolemia who were enrolled to the TWINS were selected and classified into two groups: DM group and nDM group. Eleven DM patients and 28 nDM patients were studied. RESULTS Low-density lipoprotein cholesterol levels decreased significantly to a similar extent at weeks 28 and 80 from baseline in DM and nDM (p<0.001). The mean angioscopic color grades of yellow plaques in DM and nDM were similar at baseline and significantly decreased at week 80 from baseline in both groups, however, the mean change of angioscopic color grade from baseline in DM were not significantly decreased and the mean angioscopic color was significantly higher than that in nDM (1.34 vs. 1.00, p<0.05) at week 28. IVUS showed plaque volume reduction in both groups (p<0.01) except at week 80 in DM group, which was not statistically significant different compared to the baseline. CONCLUSION In DM patients, plaque volume regression by atorvastatin was shown to be attenuated, and its color improvement was significantly delayed. However, the yellowness became comparable between DM and nDM groups at week 80. These results indicate that patients with DM should be treated by intensive lipid-lowering therapy with atorvastatin for at least 80 weeks to stabilize vulnerable plaque.
Circulation | 2002
Takashige Murata; Takafumi Hiro; Takashi Fujii; Kyounori Yasumoto; Akihiro Murashige; Masateru Kohno; Jyutaro Yamada; Toshiro Miura; Masunori Matsuzaki
To establish the relationship between the cross-sectional geometry of the post-deployment stent and the degree of in-stent neointimal hyperplasia (INH), intravascular ultrasound (IVUS) was used to examine cross-sections of the coronary arteries from 23 patients with coronary stents 6 months after implantation. Stent cross-sectional area (Sa) and stent perimeter (Sp) from 200 stent cross-sections, and the stent radius (Sr) and thickness of INH (Id) of 2,880 radial axes, were measured, and the mean degree of roundness (Rd) of stent cross-section was calculated for each stent as Rd=4piSa/Sp2. The degree of deformity (Df) of the stent cross-section was also calculated by comparing it with a hypothetical circle (the area of this hypothetical circle was equal to the Sa): Df=Sr/R, where R is the radius of the hypothetical circle. The area of INH was significantly larger in the Rd<0.87 group (n=84) than in the Rd> or =0.87 group (n=116) (3.83+/-1.26 vs 3.16+/-1.32 mm2, p<0.0005). There were significant differences in the thickness of INH among the 3 groups classified by the value of Df (Df<0.95: n=425, 0.21+/-0.12mm; 0.95< or =Df<1.05: n=2008, 0.29+/-0.15mm; Df> or =1.05: n=447, 0.34+/-0.15mm, overall p<0.0001). These data suggest that in-stent neointimal proliferation is more likely to occur in stented coronary arteries with a more oval than rounded cross-section, and particularly within the more pronounced and curved portion of the oval.