Network


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

Hotspot


Dive into the research topics where Junichiro Nishizawa is active.

Publication


Featured researches published by Junichiro Nishizawa.


The Annals of Thoracic Surgery | 2003

Predictors of residual tricuspid regurgitation after mitral valve surgery.

Katsuhiko Matsuyama; Masahiko Matsumoto; Takaaki Sugita; Junichiro Nishizawa; Yoshiyuki Tokuda; Takehiko Matsuo

BACKGROUND Whether preoperative tricuspid regurgitation (TR) will regress or progress late after surgery is unknown. The aim of this study was to evaluate predictors of significant TR late after mitral valve surgery. METHODS A retrospective analysis was performed on a total of 174 patients who underwent mitral valve surgery without tricuspid valve surgery. Preoperatively, 46 patients (26%) had 2+ TR, and 128 patients (74%) had 1+ or less TR. Postoperative 3+ TR was considered significant TR. Variables were used to evaluate predictors of TR development by univariate or multivariate analysis. RESULTS The mean follow-up was 8.2 years (range 1.0 to 14.5 years) after surgery. There was progressive TR (3+ or more) in 28 patients (16%) during the follow-up period. In univariate analysis, atrial fibrillation, rheumatic etiology, huge left atrium, left ventricular dysfunction, and preoperative 2+ TR were significant risk factors for TR development. Multivariate analysis identified preoperative 2+ TR, atrial fibrillation, and huge left atrium as statistically significant predictors for late TR after surgery. CONCLUSIONS Aggressive repair of accompanying TR should be undertaken at the time of initial surgery in patients with huge left atrium or atrial fibrillation, even if preoperative TR is 2+.


The Annals of Thoracic Surgery | 2004

Surgical treatment of five patients with aortobronchial fistula in the aortic arch

Junichiro Nishizawa; Masahiko Matsumoto; Takaaki Sugita; Katsuhiko Matsuyama; Yoshiyuki Tokuda; Kazunori Yoshida; Takehiko Matsuo

Aortobronchial fistula (ABF) is a rare condition that is almost always fatal in the absence of prompt and proper treatment. However, treatment remains challenging, particularly in the aortic arch. We present six operations for 5 such patients, in which no in-hospital deaths occurred. One patient with mycotic aneurysm died suddenly 10 months postoperatively. Another patient required reoperation 5-months after operation due to additional ABF. No pseudoaneurysms or graft-related complications were observed in the remaining patients. In patients with ABF, performance of operations as soon as possible after onset and minimal dissection of adherent lung tissue appear to improve outcomes.


Surgery Today | 2004

Successful repair of an aortoesophageal fistula caused by a thoracic aortic aneurysm: Report of a case

Yoshiyuki Tokuda; Masahiko Matsumoto; Takaaki Sugita; Junichiro Nishizawa; Katsuhiko Matsuyama; Kazunori Yoshida; Takehiko Matsuo; Masaaki Awane

Aortoesophageal fistula occurring as a complication of a thoracic aortic aneurysm is difficult to repair because of the contaminated surgical field. We report the case of a 67-year-old man in whom an aortoesophageal fistula developed secondary to a dissecting thoracic aortic aneurysm. We performed in situ graft repair of the aneurysm, then covered the site with omentum and resected the esophagus to prevent graft infection. About 5 months later, the esophagus was reconstructed subcutaneously using an ascending colon pedicle. The patient recovered well and has resumed leading a normal life.


The Annals of Thoracic Surgery | 2003

Long-term results of reoperative mitral valve surgery in patients with rheumatic disease

Katsuhiko Matsuyama; Masahiko Matsumoto; Takaaki Sugita; Junichiro Nishizawa; Yujiro Kawansihi; Kyokuu Uehara

BACKGROUND Reoperative (redo) mitral valve surgery is still a continuing challenge to surgeons. The aim of this study was to detect the factors that affect late mortality or morbidity after redo mitral valve surgery in patients with rheumatic disease. METHODS Between May 1983 and February 2003, 92 patients who underwent redo mitral valve surgery for rheumatic disease were enrolled. Risk factors influencing survival or cardiac events were investigated with univariate analysis and a Cox model. RESULTS Operative mortality rate was 4.2%. Kaplan-Meier actuarial analysis demonstrated an 84.7% 5-year, a 69.5% 10-year, and a 65.9% 15-year survival. Multivariate analysis demonstrated that age at surgery and preoperative New York Heart Association (NYHA) class were found to be independent predictors of late deaths, and that higher age, advanced NYHA class, and previous mitral valve replacement were independent predictors of cardiac events. CONCLUSIONS Redo mitral valve surgery can be achieved with low early mortality. However, long-term results of redo mitral surgery are not necessarily satisfactory in patients with preoperative advanced NYHA class or with a previous mechanical heart valve, and especially in 60 years or older age.


The Japanese Journal of Thoracic and Cardiovascular Surgery | 2001

Coronary artery bypass grafting for patients with an atherosclerotic ascending aorta.

Hitoshi Ogino; Yuichi Ueda; Takafumi Tahata; Takaaki Sugita; Junichiro Nishizawa; Katsuhiko Matsuyama; Shinichiro Yoshimura; Tatsuya Yoshioka; Yoshiyuki Tokuda

OBJECTIVES We review the outcome of coronary artery bypass grafting in patients with a severe atherosclerotic ascending aorta. METHODS Subjects were 31 patients averaging 69.4 +/- 6.9 years old studied from 1990 through 1998. Ascending aortic lesions were assessed using epiaortic echo and 2 types of aortic nonclamping techniques applied. In 29 patients operated on in the early years, bypass grafting was conducted on the hypothermic fibrillated heart in 22 and on the beating heart in 7. The remaining 2 underwent off-pump coronary artery bypass grafting more recently. For cases with multivessel disease, we used composite grafting. RESULTS Three patients developed mild stroke and 5 died within 30 days of surgery--4 from multiple emboli (1 accompanied by a stroke) and 1 from perioperative myocardial infarction. One hospital death occurred due to brain damage and multiorgan failure following unexpected rupture of a saphenous vein graft. No cardiac deaths occurred in the late stage of our series. Actuarial survival was 73.0% for 3 years and 68.0% for 5 years. Freedom from cardiac events was favorable in the remaining 25 survivors. CONCLUSIONS Outcome was suboptimal for the risks involved. Recent technical advances, including coronary surgery on the beating heart with or without cardiopulmonary bypass using variable in-situ or free arterial grafts, associated with adequate evaluation of systemic atherosclerosis, should improve this outcome.


Asian Cardiovascular and Thoracic Annals | 2001

Mini-Incision Midline Approach for Infrarenal Abdominal Aortic Aneurysms

Hitoshi Ogino; Masahiko Matsumoto; Takaaki Sugita; Junichiro Nishizawa; Katsuhiko Matsuyama; Tatsuya Yoshioka; Yoshiyuki Tokuda

A small (13.1 ± 1.3 cm) anterior midline incision is described for graft replacement of infrarenal abdominal aortic aneurysms. Stoney vasculature retractors were employed to achieve sufficient exposure. The operative outcome was satisfactory in 33 elective cases.


Circulation | 2002

Anticoagulant Therapy in Japanese Patients With Mechanical Mitral Valves

Katsuhiko Matsuyama; Masahiko Matsumoto; Takaaki Sugita; Junichiro Nishizawa; Kazunori Yoshida; Yoshiyuki Tokuda; Takehiko Matsuo


Annals of Thoracic and Cardiovascular Surgery | 2005

Gastrointestinal complications in patients undergoing coronary artery bypass grafting.

Kazunori Yoshida; Masahiko Matsumoto; Takaaki Sugita; Junichiro Nishizawa; Katsuhiko Matsuyama; Yoshiyuki Tokuda; Takehiko Matsuo


Journal of The American College of Surgeons | 2004

Intravenous leiomyomatosis extending into the right ventricle association with pulmonary metastasis and extensive arteriovenous fistula

Junichiro Nishizawa; Masahiko Matsumoto; Takaaki Sugita; Katsuhiko Matsuyama; Yoshiyuki Tokuda; Kazunori Yoshida; Takehiko Matsuo; Satoshi Okayama; Shinichi Fujimoto; Yoshihiko Saito


Circulation | 2003

Vascular surgery using argatroban in a patient with a history of heparin-induced thrombocytopenia.

Yoshiyuki Tokuda; Masahiko Matsumoto; Takaaki Sugita; Junichiro Nishizawa; Katsuhiko Matsuyama; Kazunori Yoshida; Takehiko Matsuo

Collaboration


Dive into the Junichiro Nishizawa's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Takaaki Sugita

Memorial Hospital of South Bend

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Takehiko Matsuo

Memorial Hospital of South Bend

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge