Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Shuichi Hamasaki is active.

Publication


Featured researches published by Shuichi Hamasaki.


Circulation | 2006

Mechanism of Recurrent/Persistent Ischemic/Functional Mitral Regurgitation in the Chronic Phase After Surgical Annuloplasty Importance of Augmented Posterior Leaflet Tethering

Eiji Kuwahara; Yutaka Otsuji; Yoshifumi Iguro; Tetsuya Ueno; Fang Zhu; Naoko Mizukami; Kayoko Kubota; Kenichi Nakashiki; Toshinori Yuasa; Bo Yu; Takeshi Uemura; Kunitsugu Takasaki; Masaaki Miyata; Shuichi Hamasaki; Akira Kisanuki; Robert A. Levine; Ryuzo Sakata; Chuwa Tei

Background— Surgical annuloplasty can potentially hoist the posterior annulus anteriorly, exaggerate posterior leaflet (PML) tethering, and lead to recurrent ischemic/functional mitral regurgitation (MR). Characteristics of leaflet configurations in late postoperative MR were investigated. Methods and Results— In 30 patients with surgical annuloplasty for ischemic MR and 20 controls, the anterior leaflet (AML) and PML tethering angles relative to the line connecting annuli, posterior and apical displacement of the coaptation and the MR grade were measured by echocardiography before, early after, and late after surgery. Early after surgery, grade of MR and AML tethering generally decreased (P<0.01), whereas PML tethering significantly worsened (P<0.01). Nine of the 30 patients showed recurrent/persistent MR late after surgery. Compared with patients without late MR, those with the MR showed similar reduction in the annular area, significant re-increase in posterior displacement of the coaptation, and progressive worsening in PML tethering (P<0.05) late after surgery in comparison to the early phase. Both preoperative MR and late postoperative MR were significantly correlated with all tethering variables in univariate analysis. Although apical displacement of the coaptation was the primary determinant of preoperative MR (r2=0.60, P<0.0001), increased PML tethering was the primary determinant of late MR (r2=0.75, P<0.0001). Conclusions— Whereas both leaflets tethering is related to preoperative ischemic MR, both leaflets tethering but with predominant contribution from augmented and progressive PML tethering is related to recurrent/persistent ischemic/functional MR late after surgical annuloplasty.


Circulation | 2005

Mechanism of Persistent Ischemic Mitral Regurgitation After Annuloplasty Importance of Augmented Posterior Mitral Leaflet Tethering

Fang Zhu; Yutaka Otsuji; Goichi Yotsumoto; Toshinori Yuasa; Takayuki Ueno; Bo Yu; Chihaya Koriyama; Shuichi Hamasaki; Sadatoshi Biro; Akira Kisanuki; Shinichi Minagoe; Robert A. Levine; Ryuzo Sakata; Chuwa Tei

Background—We hypothesized that surgical annuloplasty for ischemic mitral regurgitation (MR) that displaces the posterior annulus anteriorly can potentially augment posterior leaflet (PML) tethering, leading to persistent MR. Relationships between leaflet configurations and persistent ischemic MR after the annuloplasty were investigated. Methods and Results—In 31 patients with surgical annuloplasty for ischemic MR and 20 controls, posterior and apical displacement of the leaflet coaptation, the anterior leaflet (AML) and PML tethering angles relative to the line connecting annuli, coaptation length (CL), and the MR grade were quantified before and early after surgery in echocardiographic left ventricular long-axis views. Six of the 31 patients showed persistent MR despite annuloplasty. Compared with patients without persistent MR, those with MR showed no improvement in the left ventricular ejection fraction and systolic volume, similar reduction in the annular area, significant increase in posterior displacement of the coaptation (P<0.01), no improvement in AML tethering, greater worsening in PML tethering (P<0.01), and no increase in the CL. All tethering variables were significantly correlated with both preoperative and postoperative MR in univariate analysis, and reduced CL was the primary independent determinant of both preoperative and postoperative MR. Although increased AML tethering was the primary determinant of the preoperative CL (r2=0.46, P<0.0001), increased PML tethering was the primary determinant afterward (r2=0.60, P<0.0001). Conclusion—Although tethering of both leaflets is the major determinant of ischemic MR before surgical annuloplasty, both leaflets tethering but with predominant and augmented PML tethering is related to persistent ischemic MR after the annnuloplasty.


Circulation-cardiovascular Interventions | 2014

Late Adverse Events After Implantation of Sirolimus-Eluting Stent and Bare-Metal Stent Long-Term (5–7 Years) Follow-Up of the Coronary Revascularization Demonstrating Outcome Study-Kyoto Registry Cohort-2

Masahiro Natsuaki; Takeshi Morimoto; Yutaka Furukawa; Yoshihisa Nakagawa; Kazushige Kadota; Kyohei Yamaji; Kenji Ando; Satoshi Shizuta; Hiroki Shiomi; Tomohisa Tada; Junichi Tazaki; Yoshihiro Kato; Mamoru Hayano; Mitsuru Abe; Takashi Tamura; Manabu Shirotani; Shinji Miki; Mitsuo Matsuda; Mamoru Takahashi; Katsuhisa Ishii; Masaru Tanaka; Takeshi Aoyama; Osamu Doi; Ryuichi Hattori; Masayuki Kato; Satoru Suwa; Akinori Takizawa; Yoshiki Takatsu; Eiji Shinoda; Hiroshi Eizawa

Background—Late adverse events such as very late stent thrombosis (VLST) or late target-lesion revascularization (TLR) after first-generation sirolimus-eluting stents (SES) implantation have not been yet fully characterized at long term in comparison with those after bare-metal stent (BMS) implantation. Methods and Results—Among 13 058 consecutive patients undergoing first percutaneous coronary intervention in the Coronary REvascularization Demonstrating Outcome study-Kyoto registry Cohort-2, 5078 patients were treated with SES only, and 5392 patients were treated with BMS only. During 7-year follow-up, VLST and late TLR beyond 1 year after SES implantation occurred constantly and without attenuation at 0.24% per year and at 2.0% per year, respectively. Cumulative 7-year incidence of VLST was significantly higher in the SES group than that in the BMS group (1.43% versus 0.68%, P<0.0001). However, there was no excess of all-cause death beyond 1 year in the SES group as compared with that in the BMS group (20.8% versus 19.6%, P=0.91). Cumulative incidences of late TLR (both overall and clinically driven) were also significantly higher in the SES group than in the BMS group (12.0% versus 4.1%, P<0.0001 and 8.5% versus 2.6%, P<0.0001, respectively), leading to late catch-up of the SES group to the BMS group regarding TLR through the entire 7-year follow-up (18.8% versus 25.2%, and 10.6% versus 10.2%, respectively). Clinical presentation as acute coronary syndrome was more common at the time of late SES TLR compared with early SES TLR (21.2% and 10.0%). Conclusions—Late catch-up phenomenon regarding stent thrombosis and TLR was significantly more pronounced with SES than that with BMS. This limitation should remain the target for improvements of DES technology.


Journal of Cardiology | 2009

Waon therapy improves the prognosis of patients with chronic heart failure

Takashi Kihara; Masaaki Miyata; Tsuyoshi Fukudome; Yoshiyuki Ikeda; Takuro Shinsato; Takuro Kubozono; Shoji Fujita; So Kuwahata; Shuichi Hamasaki; Hiroyuki Torii; Soki Lee; Hitoshi Toda; Chuwa Tei

BACKGROUND We developed a Waon therapy (soothing warm therapy) and have previously reported that repeated Waon therapy improves hemodynamics, peripheral vascular function, arrhythmias, and clinical symptoms in patients with chronic heart failure (CHF). The aim of this study was to investigate the effect of Waon therapy on the prognosis of CHF patients. PATIENTS AND METHODS We studied 129 patients with CHF in NYHA functional class III or IV who were admitted to our hospital between January 1999 and March 2001. In the Waon therapy group, 64 patients were treated with a far infrared-ray dry sauna at 60 degrees C for 15 min and then kept on bed rest with a blanket for 30 min. The patients were treated daily for 5 days during admission, and then at least twice a week after discharge. In the control group, 65 patients, matched for age, gender, and NYHA functional class, were treated with traditional CHF therapy. The follow-up time was scheduled for 5 years. RESULTS Recent, complete follow-up data on each patient were obtained. The overall survival rate was 84.5% (Kaplan-Meier estimate). Twelve patients died in the control group and 8 patients died in the Waon therapy group at 60 months of follow-up. Cardiac events due to heart failure or cardiac death occurred in 68.7% of the control group but only 31.3% of the Waon therapy group (P<0.01) at 60 months of follow-up. CONCLUSION Waon therapy reduced cardiac events in patients with CHF. This therapy is a promising non-pharmacological treatment for CHF.


Circulation | 2003

Noninvasive evaluation of coronary reperfusion by transthoracic Doppler echocardiography in patients with anterior acute Myocardial Infarction before coronary intervention

Souki Lee; Yutaka Otsuji; Shinichi Minagoe; Shuichi Hamasaki; Koichi Toyonaga; Midori Negishi; Masanori Tsurugida; Hitoshi Toda; Chuwa Tei

Background—Transthoracic Doppler echocardiography (TTDE) enables evaluation of distal left anterior descending coronary artery (LAD) flow. The purpose of this study was to test whether TTDE can differentiate coronary reperfusion with Thrombolysis in Myocardial Infarction (TIMI) grade 3 from TIMI grade ≤2 in patients with anterior acute myocardial infarction (AMI). Methods and Results—In 46 consecutive patients with a first anterior AMI in the acute phase before emergent coronary intervention, the presence of antegrade distal LAD flow and its diastolic peak velocity were evaluated by color and pulsed TTDE and compared with TIMI grades by subsequent coronary angiography performed 29±12 minutes later. Nineteen patients had TIMI 0 reperfusion, 4 had TIMI 1, 10 had TIMI 2, and 13 had TIMI 3. Visual antegrade distal LAD flow was present in 22 of the 46 patients. TIMI 2 and 3 reperfusions were both generally visualized by color TTDE. However, peak distal LAD flow velocity by pulsed TTDE was significantly greater in patients with TIMI 3 compared with those with TIMI 2 (40±10 vs 20±6 cm/s, P <0.0001). The diagnosis of TIMI 3 based on diastolic peak distal LAD flow velocity ≥25 cm/s by TTDE had a sensitivity, specificity, and accuracy of 77%, 94%, and 89%, respectively. Conclusion—TTDE enables noninvasive differentiation of TIMI 3 from TIMI ≤2 coronary reperfusion in patients with AMI in the acute phase before emergent coronary intervention.


Journal of Cardiology | 2011

Improvement of autonomic nervous activity by Waon therapy in patients with chronic heart failure

So Kuwahata; Masaaki Miyata; Shoji Fujita; Takuro Kubozono; Takuro Shinsato; Yoshiyuki Ikeda; Shuichi Hamasaki; Tomoyuki Kuwaki; Chuwa Tei

BACKGROUND AND PURPOSE We have reported previously that Waon therapy improves cardiac and vascular function, and prognosis of patients with chronic heart failure (CHF). CHF is characterized by generalized sympathetic activation and parasympathetic withdrawal. The purpose of this study was to evaluate the effect of Waon therapy on autonomic nervous activity in patients with CHF. METHODS AND SUBJECTS Fifty-four patients with CHF, who were receiving conventional therapy for CHF, were divided into Waon therapy and control groups. In the Waon therapy group, 27 patients were treated with medication and Waon therapy. In the control group, 27 patients were treated with only conventional CHF therapy. Cardiac function including cardiac output (CO) and left ventricular ejection fraction (LVEF) was evaluated by echocardiography. The heart rate variability, such as the coefficient of variation of RR intervals (CVRR), the low-frequency (LF) component, high-frequency (HF) component, the LF norm [LF/(LF+HF)], and HF norm [HF/(LF+HF)], were measured at admission and 4 weeks after treatment. RESULTS Echocardiography demonstrated that CO and LVEF significantly increased after 4 weeks in the Waon therapy group, but did not change in the control group. In the Waon therapy group, CVRR, HF, and HF norm significantly increased 4 weeks after Waon therapy. In addition, the LF/HF ratio and LF norm significantly decreased 4 weeks after Waon therapy. In contrast, these parameters remained unchanged in the control group. Moreover, the HF and HF norm were significantly higher, and the LF/HF ratio and LF norm were significantly lower after 4 weeks of Waon therapy group than after 4 weeks of only conventional therapy. CONCLUSIONS Waon therapy improved cardiac function and autonomic nervous activity by increasing parasympathetic and decreasing sympathetic nervous activity in patients with CHF.


Journal of the American College of Cardiology | 1994

Rapid diagnosis of coronary reperfusion by measurement of myoglobin level every 15 min in acute myocardial infarction

Masaaki Miyata; Satoshi Abe; Shinichi Arima; Kunihiro Nomoto; Masamitsu Kawataki; Makoto Ueno; Tsuminori Yamashita; Shuichi Hamasaki; Hitoshi Toda; Minoru Tahara; Yoshihiko Atsuchi; Shoichiro Nakao; Hiromitsu Tanaka

OBJECTIVES The purpose of this study was to examine whether coronary reperfusion can be diagnosed rapidly and accurately by myoglobin measurements. BACKGROUND When intravenous thrombolysis is used for acute myocardial infarction, it is important to determine coronary reperfusion rapidly and noninvasively so that further treatment can be initiated. METHODS We determined myoglobin, creatine kinase (CK) and creatine kinase, MB fraction (CK-MB) isoenzyme levels in 63 patients with acute myocardial infarction with total occlusion of the infarct-related artery that was confirmed by coronary angiography. Myoglobin was measured by turbidimetric latex agglutination, which has an assay time of 10 min. We measured myoglobin, CK and CK-MB every 15 min in 45 patients with and 18 patients without reperfusion. The condition of the infarct-related artery was confirmed every 5 to 8 min by coronary angiography. RESULTS The rate of increase in myoglobin, CK, and CK-MB at 15, 30, 45 and 60 min after treatment and reperfusion was significantly higher in the reperfused than in the nonreperfused group. In the reperfused group, the rate of increase in myoglobin was significantly higher than the corresponding rate of increase in CK and CK-MB at 15, 30 and 45 min after reperfusion. When reperfusion was evaluated on the basis of a cutoff level (myoglobin > or = 2.0, CK > or = 1.8, CK-MB > or = 1.5), the predictive accuracy of myoglobin (95%) was significantly higher than that of CK (68%) and CK-MB (73%) at 15 min after reperfusion. CONCLUSIONS Coronary reperfusion can be rapidly and accurately detected by measurement of the plasma myoglobin every 15 min.


American Heart Journal | 1996

High serum concentration of lipoprotein(a) is a risk factor for restenosis after percutaneous transluminal coronary angioplasty in Japanese patients with single-vessel disease

Masaaki Miyata; Sadatoshi Biro; Shinichi Arima; Shuichi Hamasaki; Hiroshi Kaieda; Shoichiro Nakao; Masamitsu Kawataki; Kunihiro Nomoto; Hiromitsu Tanaka

To determine the relation between the concentration of lipoprotein(a) [Lp(a)] and restenosis after percutaneous transluminal coronary angioplasty (PTCA) in Japan, we studied 80 consecutive patients with single-vessel disease who successfully underwent PTCA. All were evaluated by follow-up angiography a mean of 6.9 months after PTCA and were divided into the restenosis (30 patients) and the non-restenosis (50 patients) groups. The serum Lp(a) concentration of 29 +/- 17 mg/dl in the restenosis group was significantly higher than that of 17 +/- 14 mg/dl in the nonrestenosis group (p < 0.01). Multiple logistic regression analysis for risk factors revealed a significant correlation between restenosis and Lp(a) (p < 0.003). The serum Lp(a) concentration was positively correlated with the coronary artery percent stenosis at the time of follow-up angiography (r = 0.32, p < 0.01). High serum concentration of Lp(a) is therefore a risk factor for restenosis after PTCA in Japan.


Journal of Cardiology | 2010

Waon therapy mobilizes CD34+ cells and improves peripheral arterial disease

Takuro Shinsato; Masaaki Miyata; Takuro Kubozono; Yoshiyuki Ikeda; Shoji Fujita; So Kuwahata; Yuichi Akasaki; Shuichi Hamasaki; Hiroshi Fujiwara; Chuwa Tei

BACKGROUND We previously reported that Waon therapy upregulates endothelial nitric oxide synthase protein, and augments ischemia-induced angiogenesis in mice with hindlimb ischemia, and it improves limb ischemia in patients with peripheral arterial disease (PAD). The aim of this study was to investigate the underlying mechanism of Waon therapy for the treatment of patients with PAD, and to determine whether Waon therapy can mobilize blood-derived progenitor cells. METHODS 21 consecutive PAD patients received standard medications, and were randomly divided into control (n=10) and Waon therapy groups (n=11). The Waon therapy group received Waon therapy daily for 6 weeks. The control group continued conventional therapy for 6 weeks. Leg pain was scored using a visual analogue scale. The ankle-brachial pressure index (ABPI) and the 6-min walking distance were measured at baseline and 6 weeks after therapy. Frequency of circulating CD34+ progenitor cell numbers was measured by quantitative real-time polymerase chain reaction, and the serum nitrate and nitrite levels were also measured at baseline and 6 weeks after therapy. RESULTS The leg pain score, ABPI and the 6-min walking distance improved significantly after 6 weeks in the Waon therapy group, but not in the control group. Frequency of circulating CD34+ cells increased after 6 weeks of Waon therapy [2.0 ± 1.2 (×10(-4)) at baseline to 3.9 ± 1.9 (×10(-4)), p=0.015], while it remained unchanged in the control group [1.8 ± 1.8 (×10(-4)) at baseline to 1.2 ± 0.9 (×10(-4))]. Serum nitrate and nitrite levels increased significantly after Waon therapy (29.6 ± 17.6 to 36.0 ± 17.7 μmol/ml, p<0.05), but not in the control group (34.4 ± 9.4 to 38.3 ± 8.8 μmol/ml). CONCLUSION Waon therapy mobilized circulating endothelial progenitor cells and improved limb ischemia in patients with PAD. Waon therapy is a highly promising therapy for patients with PAD.


Circulation-cardiovascular Interventions | 2012

Incidence and Outcome of Surgical Procedures After Coronary Bare-Metal and Drug-Eluting Stent Implantation A Report From the CREDO-Kyoto PCI/CABG Registry Cohort-2

Akihiro Tokushige; Hiroki Shiomi; Takeshi Morimoto; Yutaka Furukawa; Yoshihisa Nakagawa; Kazushige Kadota; Masashi Iwabuchi; Satoshi Shizuta; Tomohisa Tada; Junichi Tazaki; Yoshihiro Kato; Mamoru Hayano; Mitsuru Abe; Natsuhiko Ehara; Tsukasa Inada; Satoshi Kaburagi; Shuichi Hamasaki; Chuwa Tei; Hitoshi Nakashima; Hisao Ogawa; Ryozo Tatami; Satoru Suwa; Akinori Takizawa; Ryuji Nohara; Hisayoshi Fujiwara; Kazuaki Mitsudo; Masakiyo Nobuyoshi; Toru Kita; Takeshi Kimura

Background— There still remain safety concerns on surgical procedures after coronary drug-eluting stents (DES) implantation, and optimal management of perioperative antiplatelet therapy (APT) has not been yet established. Methods and Results— During 3-year follow-up of 12 207 patients (DES=6802 patients and bare-metal stent [BMS] only=5405 patients) who underwent coronary stent implantation in the CREDO-Kyoto registry cohort-2, surgical procedures were performed in 2398 patients (DES=1295 patients and BMS=1103 patients). Surgical procedures (early surgery in particular) were more frequently performed in the BMS group than in the DES group (4.4% versus 1.9% at 42-day and 23% versus 21% at 3-year, log-rank P=0.0007). Cumulative incidences of death/myocardial infarction (MI)/stent thrombosis (ST) and bleeding at 30 days after surgery were low, without differences between BMS and DES (3.5% versus 2.9%, P=0.4 and 3.2% versus 2.1%, P=0.2, respectively). The adjusted risks of DES use relative to BMS use for death/MI/ST and bleeding were not significant (hazard ratio: 1.63, 95% confidence interval: 0.93 to 2.87, P=0.09 and hazard ratio: 0.6, 95% confidence interval: 0.34 to 1.06, P=0.08, respectively). The risks of perioperative single- and no-APT relative to dual-APT for both death/MI/ST and bleeding were not significant; single-APT as compared with dual-APT tended to be associated with lower risk for death/MI/ST (hazard ratio: 0.4, 95% confidence interval: 0.13 to 1.01, P=0.053). Conclusions— Surgical procedures were commonly performed after coronary stent implantation, and the risk of ischemic and bleeding complications in surgical procedures was low. In patients selected to receive DES or BMS, there were no differences in outcomes. Perioperative administration of dual-APT was not associated with lower risk for ischemic events.

Collaboration


Dive into the Shuichi Hamasaki's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Yutaka Otsuji

University of Occupational and Environmental Health Japan

View shared research outputs
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge