Network


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

Hotspot


Dive into the research topics where Masashi Amano is active.

Publication


Featured researches published by Masashi Amano.


Journal of Atherosclerosis and Thrombosis | 2015

Unexpectedly High Prevalence of Acquired von Willebrand Syndrome in Patients with Severe Aortic Stenosis as Evaluated with a Novel Large Multimer Index

Toshihiro Tamura; Hisanori Horiuchi; Masao Imai; Tomohisa Tada; Hiroki Shiomi; Maiko Kuroda; Shunsuke Nishimura; Yusuke Takahashi; Yusuke Yoshikawa; Akira Tsujimura; Masashi Amano; Yukiko Hayama; Sari Imamura; Naoaki Onishi; Yodo Tamaki; Soichiro Enomoto; Makoto Miyake; Hirokazu Kondo; Kazuaki Kaitani; Chisato Izumi; Takeshi Kimura; Yoshihisa Nakagawa

AIM Severe gastrointestinal bleeding sometimes occurs in patients with aortic stenosis (AS), known as Heydes syndrome. This syndrome is thought to be caused by acquired von Willebrand syndrome and is characterized by reduced large von Willebrand factor (vWF) multimers. However, the relationship between the severity of AS and loss of large vWF multimers is unclear. METHODS We examined 31 consecutive patients with severe AS. Quantitative evaluation for loss of large vWF multimers was performed using the conventional large vWF ratio and novel large vWF multimer index. This novel index was defined as the ratio of large multimers of patients to those of controls. RESULTS Loss of large vWF multimers, defined as the large vWF multimer index <80%, was detected in 21 patients (67.7%). The large vWF multimer ratio and the large vWF multimer index were inversely correlated with the peak aortic gradient (R = -0.58, p=0.0007, and R=-0.64, p<0.0001, respectively). Anemia defined as hemoglobin <9.0 g/dl was observed in 12 patients (38.7%), who were regarded as Heydes syndrome. Aortic valve replacement was performed in 7 of these patients, resulting in the improvement of anemia in all patients from a hemoglobin concentration of 7.5±1.0 g/dl preoperatively to 12.4±1.3 g/dl postoperatively (p<0.0001). CONCLUSIONS Acquired von Willebrand syndrome may be a differential diagnosis in patients with AS with anemia. The prevalence of AS-associated acquired von Willebrand syndrome is higher than anticipated.


Circulation | 2016

Predictors of Rapid Progression and Clinical Outcome of Asymptomatic Severe Aortic Stenosis.

Shunsuke Nishimura; Chisato Izumi; Masataka Nishiga; Masashi Amano; Sari Imamura; Naoaki Onishi; Yodo Tamaki; Soichiro Enomoto; Makoto Miyake; Toshihiro Tamura; Hirokazu Kondo; Kazuaki Kaitani; Yoshihisa Nakagawa

BACKGROUND The optimal timing of aortic valve replacement (AVR) is controversial in patients with asymptomatic severe aortic stenosis (AS) except when very severe. Prediction of progression of severe AS is helpful in deciding on the timing of AVR. The purpose of this study was to clarify the predictors of progression rate and clinical outcomes of severe AS. METHODSANDRESULTS We retrospectively investigated 140 consecutive patients with asymptomatic severe AS (aortic valve area [AVA], 0.75-1.0 cm(2)). First-year progression rate and annual progression rate of AVA and of aortic jet velocity (AV-Vel) were calculated. Cardiac events were examined and the predictors of rapid progression and cardiac events were analyzed. The median follow-up period was 36 months. The median annual progression rate was -0.05 cm(2)/year for AVA and 0.22 m/s/year for AV-Vel. Dyslipidemia, moderate-severe calcification, and first-year AV-Vel progression ≥0.22 m/s/year were independent predictors of cardiac events. Cardiac event-free rate was lower in patients with AV-Vel first-year progression rate ≥0.22 m/s/year than in those with a lower rate. Diabetes and moderate-severe calcification were related to first-year rapid progression. CONCLUSIONS The annual progression rate of severe AS was -0.05 cm(2)/year for AVA and 0.22 m/s/year for AV-Vel. Patients with first-year rapid progression or severely calcified aortic valve should be carefully observed while considering an early operation. (Circ J 2016; 80: 1863-1869).


Internal Medicine | 2016

Multiple Coronary Artery Aneurysms and Thoracic Aortitis Associated with IgG4-related Disease

Shunsuke Nishimura; Masashi Amano; Chisato Izumi; Maiko Kuroda; Yusuke Yoshikawa; Yusuke Takahashi; Sari Imamura; Naoaki Onishi; Yodo Tamaki; Soichiro Enomoto; Makoto Miyake; Toshihiro Tamura; Hirokazu Kondo; Kazuaki Kaitani; Yoshihisa Nakagawa

A 60-year-old man was admitted due to the onset of right coronary artery (RCA) aneurysms. Coronary angiography showed two RCA aneurysms and focal stenosis with limitations in the blood flow. Balloon angioplasty was performed. However, the follow-up coronary angiography showed restenosis, an enlarged proximal aneurysm and a newly formed aneurysm. The serum immunoglobulin G4 level was elevated to 1,350 mg/dL and fluorodeoxyglucose positron emission tomography showed increased uptake in the ascending aorta, so the patient was diagnosed with immunoglobulin G4-related vascular disease. The prevention of further enlargement of the aneurysms and an improvement in the RCA flow were achieved with steroid therapy. Steroid therapy may therefore be effective for immunoglobulin G4-related vascular disease.


Journal of Arrhythmia | 2015

Relationship between plasma dabigatran concentration and activated partial thromboplastin time in Japanese patients with non-valvular atrial fibrillation

Daiki Shimomura; Yoshihisa Nakagawa; Hirokazu Kondo; Toshihiro Tamura; Masashi Amano; Yukiko Hayama; Naoaki Onishi; Yodo Tamaki; Makoto Miyake; Kazuaki Kaitani; Chisato Izumi; Masahiko Hayashida; Aya Fukuda; Fumihiko Nakamura; Seiji Kawano

Activated partial thromboplastin time (aPTT) is recommended for monitoring anticoagulant activity in dabigatran‐treated patients; however, there are limited data in Japanese patients. To clarify the relationship between plasma dabigatran concentration and aPTT, we analyzed plasma dabigatran concentration and aPTT at various time points following administration of oral dabigatran in a Japanese hospital.


International Journal of Cardiology | 2017

Actual management and prognosis of severe isolated tricuspid regurgitation associated with atrial fibrillation without structural heart disease

Yusuke Takahashi; Chisato Izumi; Makoto Miyake; Miyako Imanaka; Maiko Kuroda; Shunsuke Nishimura; Yusuke Yoshikawa; Masashi Amano; Sari Imamura; Naoaki Onishi; Yodo Tamaki; Soichiro Enomoto; Toshihiro Tamura; Hirokazu Kondo; Kazuaki Kaitani; Yoshihisa Nakagawa

BACKGROUND Patients with atrial fibrillation (AF) without structural heart diseases can show severe tricuspid regurgitation (TR), especially among aged people. The aim of this study was to clarify the actual management, prognosis, and prognostic factors for severe isolated TR associated with AF without structural heart diseases. METHODS AND RESULTS We retrospectively investigated actual management in 178 consecutive patients with severe isolated TR associated with AF between 1999 and 2011 in our institution. Prognosis and its predictors were also investigated in 115 patients (68 persistent TR and 47 transient TR) who were followed-up for >1year. During the follow-up period (mean: 5.9years), event free rate from death due to right-sided heart failure (RHF) was 97% at 5years. Persistent TR was associated with higher risk of hospitalization due to RHF than transient TR (log-rank P=0.048) and death due to RHF were all seen in patients with persistent TR who experienced hospitalization due to RHF. Among patients with persistent TR, right ventricular outflow tract dimension >35.3mm, right atrial area >40.3cm2, and tenting height >2.1mm were associated with higher risk of hospitalization due to RHF (adjusted hazard ratio: 3.32, 3.83, and 2.89, respectively; P=0.003, 0.002, and 0.009, respectively). CONCLUSION The prognosis of severe isolated TR associated with AF was good with a focus on cardiac death. However, the incidence of cardiac death increased among patients who experienced hospitalization due to RHF. Larger right ventricular outflow tract dimension, right atrial area and tenting height were predictors of hospitalization due to RHF.


Journal of Clinical Laboratory Analysis | 2016

The Influence of Assay Selection on Prothrombin Time Measured in Patients Treated With Rivaroxaban for Nonvalvular Atrial Fibrillation

Daiki Shimomura; Yoshihisa Nakagawa; Hirokazu Kondo; Toshihiro Tamura; Masashi Amano; Soichiro Enomoto; Naoaki Onishi; Yodo Tamaki; Makoto Miyake; Kazuaki Kaitani; Chisato Izumi; Aya Fukuda; Fumihiko Nakamura; Seiji Kawano

Prothrombin time (PT) can provide a qualitative assessment of the relative intensity of anticoagulation by rivaroxaban. More than ten types of assay are available for the measurement of PT in clinical settings, but it is not yet fully understood whether their interactions with rivaroxaban are uniform or inconsistent.


Journal of Cardiology | 2017

Diagnostic accuracy of the Embolic Risk French Calculator for symptomatic embolism with infective endocarditis among Japanese population

Yusuke Takahashi; Chisato Izumi; Makoto Miyake; Miyako Imanaka; Maiko Kuroda; Shunsuke Nishimura; Yusuke Yoshikawa; Masashi Amano; Sari Imamura; Naoaki Onishi; Yodo Tamaki; Soichiro Enomoto; Toshihiro Tamura; Hirokazu Kondo; Kazuaki Kaitani; Kazuo Yamanaka; Yoshihisa Nakagawa

BACKGROUND Recently, the Embolic Risk French Calculator (ER-Calculator) was designed to predict symptomatic embolism (SE) associated with infective endocarditis (IE), but external validation has not been reported. This study aimed to determine predictors of SE and the diagnostic accuracy of the ER-Calculator in left-sided active IE among a Japanese population. METHODS This retrospective cohort study included 166 consecutive patients with a definite diagnosis of left-sided IE from 1994 to 2015 in our institution. SE during the period after initiation of antibiotic therapy was defined as new SE and embolism during the period before initiation of antibiotic therapy was defined as previous embolism. The primary endpoint was new SE. RESULTS The mean age of patients was 63±17 years. New SE occurred in 23 (14%) patients at a median of 6 days (interquartile range: 2.5-12.5 days) after initiation of antibiotic therapy. The cumulative incidence of new SE at 12 weeks was 18.2%. The 2-week probability by the ER-Calculator as well as previously reported predictors, such as previous embolism, vegetation length (>10mm), and their combination, were associated with a high risk of new SE. By receiver operating characteristic analysis, the area under the curve of the 2-week probability by the ER-Calculator for prediction of new SE was 0.75 and the optimal cut-off value was 8%. A 2-week probability >8% by the ER-Calculator was the most useful predictor of new SE (hazard ratio 3.63, 95% confidence interval 1.50-8.37; p=0.006), which was more remarkable for fatal embolic events (hazard ratio 13.9, 95% confidence interval 3.19-95.4; p=0.004). CONCLUSIONS The ER-Calculator is a useful predictor of new SE. Predictive ability is more remarkable for critical embolic events.


Circulation | 2017

Long-Term Clinical Outcomes and Prognostic Factors After Pericardiectomy for Constrictive Pericarditis in a Japanese Population

Shunsuke Nishimura; Chisato Izumi; Masashi Amano; Sari Imamura; Naoaki Onishi; Yodo Tamaki; Soichiro Enomoto; Makoto Miyake; Toshihiro Tamura; Hirokazu Kondo; Kazuaki Kaitani; Kazuo Yamanaka; Yoshihisa Nakagawa

BACKGROUND Constrictive pericarditis (CP) is characterized by impaired diastolic cardiac function leading to heart failure. Pericardiectomy is considered effective treatment for CP, but data on long-term clinical outcomes after pericardiectomy are limited.Methods and Results:We retrospectively investigated 45 consecutive patients (mean age, 59±14 years) who underwent pericardiectomy for CP. Preoperative clinical factors, parameters of cardiac catheterization, and cardiac events were examined. Cardiac events were defined as hospitalization owing to heart failure or cardiac death.Median follow-up was 5.7 years. CP etiology was idiopathic in 16 patients, post-cardiac surgery (CS) in 21, tuberculosis-related in 4, non-tuberculosis infection-related in 2, infarction-related in 1, and post-radiation in 1. The 5-year event-free survival was 65%. Patients with idiopathic CP and tuberculosis-related CP had favorable outcomes compared with post-CS CP (5-year event-free survival: idiopathic, 80%; tuberculosis, 100%; post-CS, 52%). Higher age (hazard ratio: 2.51), preoperative atrial fibrillation (3.25), advanced New York Heart Association class (3.92), and increased pulmonary artery pressure (1.06) were predictors of cardiac events. Patients with postoperative right-atrial pressure ≥9 mmHg had lower event-free survival than those with right-atrial pressure <9 mmHg (39% vs. 75% at 5 years, P=0.013). CONCLUSIONS Long-term clinical outcomes after pericardiectomy among a Japanese population were related to the underlying etiology and the patients preoperative clinical condition. Postoperative cardiac catheterization may be helpful in the prediction of prognosis after pericardiectomy.


Heart | 2016

Progression of aortic regurgitation after subpulmonic infundibular ventricular septal defect repair

Masashi Amano; Chisato Izumi; Sari Imamura; Naoaki Onishi; Yodo Tamaki; Soichiro Enomoto; Makoto Miyake; Toshihiro Tamura; Hirokazu Kondo; Kazuaki Kaitani; Kazuo Yamanaka; Yoshihisa Nakagawa

Objective In patients with subpulmonic infundibular ventricular septal defect (VSD), postoperative progression of aortic regurgitation (AR) sometimes occurs despite early operation before the development of AR. The present study was aimed to identify the occurrence rate and predictors of late AR progression after VSD repair alone. Methods We retrospectively investigated 91 consecutive patients who underwent subpulmonic infundibular VSD repair alone and were followed up with echocardiography for >3 years postoperatively. The clinical backgrounds and chronological changes in postoperative AR were evaluated. Results The median follow-up period after VSD repair was 13.4 years. Among 91 patients, 7 patients showed postoperative AR progression (AR progression group) and 84 patients did not (No AR progression group). No patient in AR progression group revealed more than moderate AR preoperatively. The incidence of postoperative VSD leakage was significantly higher in AR progression group than No AR progression group (43.0% vs 2.4%, respectively; p<0.01). No significant differences were present in sex, age, preoperative AR severity, VSD diameter or rate of cusp herniation. All patients in AR progression group showed deformity of the right coronary cusp or leaflet, resulting in AR progression. Conclusions Among patients with subpulmonic infundibular VSD, the incidence of late AR progression after VSD repair alone was unexpectedly high (7.7%). Postoperative VSD leakage may be a significant risk factor for late AR progression. Long-term follow-up of postoperative AR is needed even for patients who undergo VSD repair alone.


Journal of Cardiology Cases | 2012

Aortic prosthetic graft infection accompanied with esophagomediastinal fistulas: A case report

Masashi Amano; Teruhisa Azuma; Chisato Izumi; Hisayoshi Hashimoto; Michihito Nonaka; Yoshito Asao; Fusako Kusumi; Ryuuichi Sada; Hiroyasu Ishimaru; Kazuhiro Hatta; Yoshiaki Kori

Prosthetic graft infection is difficult to diagnose early, and hence, is associated with high mortality and morbidity rates. A 63-year-old man who had undergone surgical prosthetic replacement for an inflammatory thoracic aortic aneurysm 10 months previously visited our emergency room, complaining of chills, shivering, frequent vomiting, and back pain. He was diagnosed with severe sepsis, and a blood culture detected Streptococcus anginosus and Prevotella oralis. Repeated contrast-enhanced computed tomography (CT) scans of his chest revealed ectopic gas around the graft, and esophagogastroduodenoscopy revealed esophageal perforations at several sites. We therefore diagnosed him with aortic prosthetic graft infection accompanied with esophagomediastinal fistulas. He received medical treatment and three operations and recovered from the infection. This is a rare case of aortic prosthetic graft infection accompanied with esophagomediastinal fistulas, and we conclude that repeated CT is useful for identifying the primary infection site and invasion route in patients with suspected aortic prosthetic graft infection.

Collaboration


Dive into the Masashi Amano'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
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge