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Dive into the research topics where Ario Yamazato is active.

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Featured researches published by Ario Yamazato.


American Journal of Cardiology | 1986

Detection and evaluation of tricuspid regurgitation using a real-time, two-dimensional, color-coded, Doppler flow imaging system: Comparison with contrast two-dimensional echocardiography and right ventriculography

Yukisono Suzuki; Hirofumi Kambara; Kazunori Kadota; Shunichi Tamaki; Ario Yamazato; Ryuji Nohara; Genta Osakada; Chuichi Kawai

To detect and evaluate regurgitant flow in tricuspid regurgitation (TR) with a newly developed, realtime, 2-dimensional (2-D), color-coded, Doppler flow imaging system (Doppler 2-D echo), 27 patients (18 with suspected TR and 9 normal subjects) were examined and the findings were compared with those obtained using contrast 2-D echocardiography (contrast 2-D echo) and right ventriculography. In 16 of 18 patients with suspected TR, Doppler 2-D echo easily visualized the color-coded regurgitant flow in the right atrium and estimated the severity of TR from the distance of the visible TR jet. On the basis of the QRS synchronized appearance of contrast in the inferior vena cava by the subxiphoid approach or of the negative contrast effect above the tricuspid valve just after the contrast entered the right ventricle with its subsequent back-and-forth movements across the tricuspid valve, Doppler 2-D echo was more sensitive and specific in detecting TR (100% and 100%) than contrast 2-D echo (75% and 82% in the subxiphoid view, 56% and 100% in the 4-chamber view) when the fast Fourier transformation frequency analysis was used as the standard of TR, and it was more sensitive in detecting TR (85%) than contrast 2-D echo (69% in the subxiphoid approach, 46% in the 4-chamber view) when right ventriculography was used as the standard of TR. Additionally, the severity of TR as shown by Doppler 2-D echo correlated fairly well with that shown by right ventriculography. Thus, Doppler 2-D echo is clinically useful for detecting and evaluating TR.


Circulation | 1996

Elevated basic fibroblast growth factor in pericardial fluid of patients with unstable angina

Masatoshi Fujita; Masaki Ikemoto; Masamichi Kishishita; Hideo Otani; Ryuji Nohara; Terumitsu Tanaka; Shunichi Tamaki; Ario Yamazato; Shigetake Sasayama

BACKGROUND Collateral growth is induced by chemical signals from the ischemic myocardium. We hypothesized that angiogenic growth factors are produced by cardiac tissue; they are diffusible, more concentrated in pericardial fluids, and are increased by myocardial ischemia. METHODS AND RESULTS With the use of an enzyme-linked immunosorbent assay, we measured the concentrations of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) in pericardial fluids of 12 patients with unstable angina (group 1) and of 8 patients with nonischemic heart diseases (group 2). The levels of protein in pericardial fluids were quite comparable between the two groups (34 +/- 2 versus 32 +/- 4 mg/mL). The concentration of bFGF in pericardial fluids in group 1 was 2036 +/- 357 pg/mL, significantly (P < .001) higher than the 289 +/- 72 pg/mL in group 2. The amount of bFGF per milligram of protein was also significantly (P < .05) higher in group 1 than in group 2 (67 +/- 15 versus 12 +/- 4 pg/mg). The concentration of VEGF in pericandial fluids tended to be higher in group 1, but the difference was statistically insignificant (39 +/- 7 versus 22 +/- 6 pg/mL). The amount of VEGF per milligram of protein was 1.2 +/- 0.3 pg/mg in group 1, similar to the 0.8 +/- 0.4 pg/mg in group 2. CONCLUSIONS This finding provides new evidence that bFGF plays an important role in mediating collateral growth in humans.


The Journal of Thoracic and Cardiovascular Surgery | 1997

Transluminal endovascular branched graft placement for a pseudoaneurysm: Reconstruction of the descending thoracic aorta including the celiac axis

Kanji Inoue; Tomoyuki Iwase; Mitsuru Sato; Yuki Yoshida; Katsuya Ueno; Shunich Tamaki; Ario Yamazato

We I have previously reported a successful transluminal endovascular placement of a branched graft that had a sidearm extending into the left subclavian artery for repair of type B aortic dissection. The sidearm was properly positioned by catching and pulling back the free end of a detachable wire attached to its end by means of a gooseneck snare wire, which was percutaneously inserted through the left brachial artery. However, it is impossible to place sidearm grafts into the celiac axis and renal arteries in a similar manner. In this article, we describe a new method of inserting a sidearm into the celiac axis and report successful transluminal endovascular repair of a pseudoaneurysm with the use of the branched graft. A 73-year-old man with severe chronic renal failure requiring hemodialysis had previously undergone surgical repair of an aneurysm of the descending thoracic aorta. However, a pseudoaneurysm of the descending thoracic aorta resulting from dehiscence of the suture line at the proximal and distal anastomoses after composite graft surgery had continued to dilate, reaching 80 mm in diameter. Although surgical treatment was attempted, the effort was given up because of marked adhesions caused by a previous thoracotomy. He was admitted to our hospital for endovascular treatment of the pseudoaneurysm. The structure of the Inoue endovascular graft was previously described in detail. 2 The graft was constructed from a Dacron polyester fabric cylinder and the surface was supported by multiple rings of extra-flexible nickel titanium wire. The patient gave informed consent in conformance with the protocols approved by the institutional review board of Takeda Hospital. Endovascular grafting with the straight graft was performed on June 28, 1995. Although the proximal communication was completely obliterated after the procedure, the distal communication persisted because the distal orifice of the pseudoaneurysm was in close proximity to the celiac axis. Although transluminal embolization was


Journal of the American College of Cardiology | 1998

Marked Elevation of Brain Natriuretic Peptide Levels in Pericardial Fluid Is Closely Associated With Left Ventricular Dysfunction

Terumitsu Tanaka; Koji Hasegawa; Masatoshi Fujita; Shunichi Tamaki; Ario Yamazato; Yasuki Kihara; Ryuji Nohara; Shigetake Sasayama

OBJECTIVES The purpose of this study was to investigate whether atrial and brain natriuretic peptides (ANP and BNP, respectively) represent autocrine/paracrine factors and are accumulated in pericardial fluid. BACKGROUND ANP and BNP, systemic hormones produced by the heart, have elevated circulating levels in patients with heart failure. Recent evidence suggests that the heart itself is one of the target organs for these peptides. METHODS With an immunoreactive radiometric assay, we measured the concentrations of these peptides in plasma and pericardial fluid simultaneously in 28 patients during coronary artery bypass graft surgery. RESULTS The pericardial levels of BNP were markedly elevated in patients with impaired left ventricular function. We investigated the correlation of ANP and BNP levels in plasma or pericardial fluid with left ventricular hemodynamic variables. None of the hemodynamic variables correlated with ANP levels in plasma or pericardial fluid. Both plasma and pericardial fluid levels of BNP were significantly related to left ventricular end-diastolic and systolic volume indexes (LVEDVI and LVESVI, respectively). In addition, BNP pericardial fluid levels had closer relations with LVEDVI (r = 0.679, p < 0.0001) and LVESVI (r = 0.686, p < 0.0001) than did BNP plasma levels (LVEDVI: r = 0.567, p = 0.0017; LVESVI: r = 0.607, p = 0.0010). BNP levels in pericardial fluid but not in plasma correlated with left ventricular end-diastolic pressure (r = 0.495, p = 0.0074). CONCLUSIONS BNP levels in pericardial fluid served as more sensitive and accurate indicators of left ventricular dysfunction than did BNP levels in plasma. Thus, BNP may be secreted from the heart into the pericardial space in response to left ventricular dysfunction, and it may have a pathophysiologic role in heart failure as an autocrine/paracrine factor.


The Annals of Thoracic Surgery | 1997

Clinical Application of Transluminal Endovascular Graft Placement for Aortic Aneurysms

Kanji Inoue; Tomoyuki Iwase; Mitsuru Sato; Mt Yuki Yoshida; Terumitsu Tanaka; Yasunobu Kubota; Shunichi Tamaki; Koji Hasegawa; Ario Yamazato

BACKGROUND In recent years, transluminal endovascular graft placement techniques have been developed for the treatment of aortic aneurysms. We report our initial clinical experience with endovascular graft placement using a graft developed in our laboratory. METHODS The procedure was performed in 20 patients with a diagnosed aortic aneurysm. The graft is constructed from a Dacron cylinder, and the surface of the graft is supported with multiple rings of extraflexible wire. After the compactly folded graft is delivered through the sheath to the predetermined target point, the graft is deployed and then pressed against the vessel by balloon inflation. Straight graft insertion was attempted in 10 patients, bifurcated graft insertion in 8, and branched graft insertion in 2. RESULTS Graft placement was successful in 19 of the patients and unsuccessful in 1. There were no cases of graft migration, aneurysm rupture, or graft destruction during a mean follow-up period of 9 months. CONCLUSIONS Initial clinical results demonstrated the efficacy and safety of endovascular graft placement using this graft.


Circulation | 2006

Multislice Computed Tomography Accurately Quantifies Left Atrial Size and Function After the MAZE Procedure

Kazuo Yamanaka; Masatoshi Fujita; Kazuhiko Doi; Hiroshi Tsuneyoshi; Ario Yamazato; Katsuya Ueno; Eiwa Zen; Masashi Komeda

Background— Although the MAZE procedure allows for the recovery of sinus rhythm and left atrial (LA) mechanical function in the great majority of patients with chronic atrial fibrillation (AF), the effects of MAZE on the precise LA geometry and wall motion remain to be elucidated. We hypothesized that LA size and mechanical function in patients with chronic AF and mitral valvular disease are well restored after MAZE. Methods and Results— We studied 14 patients (MAZE group: mean±SD age, 63.9±8.6 years; 8 men and 6 women) who underwent MAZE for chronic AF and mitral valve surgery and 10 patients with sinus rhythm (coronary artery bypass graft [CABG] group: age, 70.0±7.9 years; 5 men and 5 women) who underwent CABG at Takeda Hospital between February 2002 and September 2005. MAZE was conducted by the endocardial application of radiofrequency ablation with a temperature-controlled multipolar radiofrequency catheter. LA volume and booster function were quantitatively evaluated by multislice computed tomography at 17.9±10.0 months (MAZE group) and 15.3±13.6 months (CABG group) postoperatively. All patients with MAZE were free of AF and other atrial arrhythmias during the follow-up period. In the CABG group, LA maximal and minimal volumes and ejection fraction were 109±12 mL, 82±11 mL, and 26±10%, respectively. In the MAZE group, LA maximal volume was 139±17 mL (P=0.187 versus CABG), and LA minimal volume was 121±16 mL (P=0.082 versus CABG), with an ejection fraction of 15±7% (P=0.004 versus CABG). In both groups, all parts of the LA wall contracted toward the geometric center of the LA. The extent of wall motion was significantly worse in the MAZE group compared with the CABG group. In both groups, LA booster function was inversely correlated with LA maximal volume. Conclusions— MAZE with radiofrequency ablation is safe and effective for the restoration of sinus rhythm in patients with chronic AF and mitral valve disease. However, chronic AF associated with mitral valve disease deteriorates LA mechanical function diffusely throughout the LA wall. Further studies with the use of multislice computed tomography are needed to sequentially evaluate LA function after MAZE in patients with and without mitral valve surgery.


American Journal of Cardiology | 1985

Detection of intracardiac shunt flow in atrial septal defect using a real-time two-dimensional color-coded doppler flow imaging system and comparison with contrast two-dimensional echocardiography

Yukisono Suzuki; Hirofumi Kambara; Kazunori Kadota; Shunichi Tamaki; Ario Yamazato; Ryuji Nohara; Genta Osakada; Chuichi Kawai; Shigeru Kubo; Takanori Karaguchi

To evaluate the noninvasive detection of shunt flow using a newly developed real-time 2-dimensional color-coded Doppler flow imaging system (D-2DE), 20 patients were examined, including 10 with secundum atrial septal defect (ASD) and 10 control subjects. These results were compared with contrast 2-dimensional echocardiography (C-2DE). Doppler 2DE displayed the blood flow toward the transducer as red and the blood flow away from the transducer as blue in 8 shades, each shade adding green according to the degree of variance in Doppler frequency. In the patients with ASD, D-2DE clearly visualized left-to-right shunt flow in 7 of 10 patients. In 5 of these 7 patients, C-2DE showed a negative contrast effect in the same area of the right atrium. Thus, D-2DE increased the sensitivity over C-2DE for detecting left-to-right shunt flow (from 50% to 70%). However, the specificity was slightly less in D-2DE (90%) than C-2DE (100%). Doppler 2DE could not visualize right-to-left shunt flow in all patients with ASD, though C-2DE showed a positive contrast effect in the left-sided heart in 9 of 10 patients with ASD. Thus, D-2DE is clinically useful for detecting left-to-right shunt flow in patients with ASD.


Heart and Vessels | 2000

Myocardial ischemia enhances the expression of acidic fibroblast growth factor in human pericardial fluid.

Atsushi Iwakura; Masuo Fujita; Masaki Ikemoto; Koji Hasegawa; Ryuji Nohara; Shigetake Sasayama; Shoichi Miyamoto; Ario Yamazato; Keiichi Tambara; Masashi Komeda

Abstract Acidic fibroblast growth factor (FGF) is a potent mitogen that can induce angiogenesis in vivo. We have recently reported a marked increase of basic FGF in the pericardial fluid of patients with severe coronary stenosis and an increase in vascular endothelial growth factor (VEGF) in the pericardial fluid of patients with severe myocardial ischemia. The purpose of this study was to evaluate whether acidic FGF levels in the pericardial fluid are associated with severe myocardial ischemia. Immediately after incision of the pericardium in 48 patients during open-heart surgery, 3–5 ml of pericardial fluid was obtained. Concentrations of basic FGF and VEGF in the pericardial fluid were measured using an enzyme-linked immunosorbent assay (ELISA). The ELISA system for human acidic FGF was newly developed using a rabbit antibovine acidic FGF antibody. The patients were divided into three groups (group A: 13 patients undergoing emergency coronary artery bypass grafting (CABG) for unstable angina; group B: 17 patients undergoing elective CABG for stable angina; group C: 18 patients undergoing nonischemic open-heart surgery). The VEGF level in the pericardial fluid in group A was 68 ± 59 pg/ml, which was significantly higher than 33 ± 9 pg/ml in group B and 31 ± 20 pg/ml in group C (P < 0.05). The concentrations of basic FGF in the pericardial fluid in groups A and B were 722 ± 601 and 773 ± 763 pg/ml, respectively, significantly higher than 263 ± 349 pg/ml in group C. The pericardial acidic FGF level in group A was 4 291 ± 2 336 pg/ml, which was also significantly higher than 2 386 ± 1 048 pg/ml in group B and 2 589 ± 990 pg/ml in group C (P < 0.05). The acidic FGF level correlated well with the level of VEGF (r = 0.61, P < 0.0001). It is concluded that the level of acidic FGF in pericardial fluid is associated with severe myocardial ischemia. This result indicates that the release of acidic FGF from the myocardial tissue into pericardial fluid is closely related to severe myocardial ischemia.


Angiogenesis | 1998

Marked elevation of vascular endothelial growth factor and basic fibroblast growth factor in pericardial fluid of patients with angina pectoris.

Masatoshi Fujita; Masaki Ikemoto; Terumitsu Tanaka; Shunichi Tamaki; Ario Yamazato; Tatsuya Sawamura; Koji Hasegawa; Yasuki Kihara; Ryuji Nohara; Shigetake Sasayama

Although we reported that basic fibroblast growth factor (bFGF) levels in pericardial fluid of patients with unstable angina are apparently increased, it was unclear whether vascular endothelial growth factor (VEGF) is also increased in patients with myocardial ischemia. Using an enzyme-linked immunosorbent assay, we measured the concentrations of VEGF and bFGF in pericardial fluid of 51 patients with open heart surgery. Patients were divided into group A (n=10) with class III unstable angina (Braunwalds classification), group B (n=24) with class I or II unstable angina or stable angina and group C (n=17) with non-ischemic heart disease. The VEGF level in pericardial fluid in group A was 83±7 pg/ml, being significantly (p<0.001) higher than the 27±3 pg/ml in group B and the 28±5 pg/ml in group C. The concentrations of bFGF in pericardial fluid in groups A and B were 1461±579 and 1224±161 pg/ml, respectively, significantly (p<0.05) higher than the 292±97 pg/ml in group C. The level of VEGF in pericardial fluid was increased only in patients with severe rest angina within 2 days before emergency coronary artery bypass graft surgery (CABG), while bFGF was increased in all patients undergoing CABG for coronary artery disease. Thus VEGF and bFGF may play important roles in mediating collateral growth in humans.


Pediatric Cardiology | 1986

Aortopulmonary window, aortic origin of the right pulmonary artery, and interrupted aortic arch: Detection by two-dimensional and color Doppler echocardiography in an infant

Doris A. Mendoza; Tadashi Ueda; Kenya Nishioka; Yoshihumi Yokota; Haruki Mikawa; Shinichi Nomoto; Ario Yamazato; Fukumasu H; Toshihiko Ban

Aortopulmonary (AP) window [6, 10] aortic origin of the right pulmonary artery (RPA) [10], and interruption of the aortic arch [3) are each uncommon malformations . Their coexistence provides a complex that is a rare diagnostic challenge . We here report on an infant who had a combination of all these cardiovascular defects, presenting With cyanosis and congestive heart failure . The use of two-dimensional echocardiography (2DE) in the detection of AP window has been previously described (5, 9, 11] as has been that of anomalous origin of the RPA from the ascending aorta [4, 5, 11]. In our case 2DE detected both the AP window and the aortic origin of the RPA . We also describe the clinical value of the new two-dimensional color Doppler echocardiography (2D color Doppler), as developed by Omoto and associates [7], for the noninvasive visualization of shunting across the aortopulmonary window, in lieu of cineangiography .

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Shunichi Tamaki

Takeda Pharmaceutical Company

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Tomoyuki Iwase

Takeda Pharmaceutical Company

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Kazuo Yamanaka

Takeda Pharmaceutical Company

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