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Dive into the research topics where Shin-ichi Oki is active.

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Featured researches published by Shin-ichi Oki.


Asaio Journal | 2001

Fourteen year experience with the omnicarbon prosthetic heart valve.

Yoshio Misawa; Katsuo Fuse; Tsutomu Saito; Hiroaki Konishi; Shin-ichi Oki

The Omnicarbon prosthetic valve was implanted in 168 patients (mean age, 53 years); 84 had aortic valve replacement (AVR), 57 had mitral valve replacement (MVR), and 27 had both aortic and mitral valve replacement (DVR). The mean follow-up period was 6.8 years, with a maximum of 13.7 years. Three patients (1.8%) were lost to follow-up. There were 4 (2.4%) early deaths and 26 late deaths. Survival at 10 years was 76% in the AVR and MVR groups, and 85% in the DVR group. Freedom from thromboembolism at 10 years was 94% in the AVR group, 80% in the MVR group, and 92% in the DVR group. Freedom from hemorrhagic complications at 10 years was 86% in the AVR group and 92% in the MVR group. At 10 years, 97% in the AVR group and 96% in the MVR group were free from endocarditis. One patient in the DVR group suffered a paravalvular leak. At 10 years, 97% in the AVR group and 95% in the MVR group had not needed reoperation. Elevation of the postoperative serum lactate dehydrogenase levels were acceptable in the three groups. In conclusion, the Omnicarbon prosthetic valve has shown excellent long-term clinical results.


European Journal of Cardio-Thoracic Surgery | 2003

A repair of funnel chest without sternal dissection in aortic root replacement

Shin-ichi Oki; Yoshio Misawa; Katsuo Fuse

A 46-year-old man with Marfan syndrome was admitted for repair of annuloaortic etasia and funnel chest. Before median sternotomy, seven transverse skin incisions were made for resection of deformed ribs. The convex portions at the costochondral junctions of the right 4 approximately 7th and left 5 approximately 7th ribs were removed. Thereafter, the conventional median sternotomy was safely performed. Aortic root was replaced. After weaning from the cardiopulmonary bypass, the redundant distal end of the sternum was resected, fractured sites of the concave sternum were straightened and secured with wire fixation, and the split sternum was sutured with wires in an ordinary fashion.


Journal of Cardiothoracic Surgery | 2007

Clinical experience with the Bicarbon heart valve prosthesis.

Yoshio Misawa; Tsutomu Saito; Hiroaki Konishi; Shin-ichi Oki; Yuichiro Kaminishi; Yasuhito Sakano; Hideki Morita; Kei Aizawa

BacgroundWe have previously reported mid-term results of a study, which ended in January 2000, on the Bicarbon valve. The study concluded that the valve showed excellent clinical results, associated with a low incidence of valve-related complications. In the present study, the same patients were prospectively followed for an additional 5 years.MethodsForty-four patients had aortic valve replacement (AVR), 48 had mitral valve replacement (MVR), and 13 had both aortic and mitral valve replacement (DVR). The mean age of the 105 patients was 61.2 ± 11.3 years. The mean follow-up was 6.1 ± 1.9 years with a cumulative follow-up of 616 patient-years.ResultsThere were 5 early deaths (4.7%: 4 in the AVR group and 1 in the MVR group) and 21 late deaths (3.4%/patient-year: 5 valve related deaths and 16 valve unrelated deaths). Survival at 8 years was 75.2 ± 7.0% in the AVR group, 76.6 ± 6.2% in the MVR group, and 55.4 ± 16.1% in the DVR group. The linearized incidence of thrombo-embolic complications, hemorrhagic complications, and paravalvular leaks in all patients was 0.65 ± 1.48%, 0.81 ± 1.69%, and 0.16 ± 0.54%/patient-year respectively. No other complications were observed.ConclusionThe Bicarbon prosthetic heart valve has shown excellent long-term clinical results, associated with a low incidence of valve-related complications.


European Journal of Cardio-Thoracic Surgery | 2002

Management of anomalous right coronary arteries encountered during aortic valve surgery

Yoshio Misawa; Tsutomu Saito; Shin-ichi Oki; Katsuo Fuse

We experienced three cases with anomalous right coronary arteries during aortic valve surgery. By rotating a Freestyle bioprosthesis by a subcoronary technique, the anomalous artery was secured in one patient. The anomalous artery was injured during the routine aortotomy incision in another patient; a saphenous vein graft was interposed between the ascending aorta and the separated artery. In the third patient, a subannular prosthetic valve was chosen to avoid obstructing the anomalous orifice.


Journal of Vascular Surgery | 2014

Popliteal artery pseudoaneurysm associated with osteochondroma

Hirotaka Sato; Koji Kawahito; Shin-ichi Oki; Yoshio Misawa

A 15-year-old boy developed pain and swelling in the right popliteal fossa after jumping rope. The pain and swelling exacerbated during the next 2 weeks, and he was admitted to our hospital. On physical examination, a 3-cm bluish pulsatile mass was found in the right popliteal fossa, which was painful on palpitation. Neurologic compromise was not evident, and distal pulses were palpable. Plain radiography revealed an osteochondroma arising from the distal femoral shaft. A computed tomography scan revealed a 3.53.02.5-cm popliteal artery pseudoaneurysm, which was closely associated with the spiky spur that was the most probable cause of the perforation of the popliteal artery (A , B, and Cover). Surgery was performed the next day; the popliteal artery was exposed by an anteromedial approach. A 3-cm false aneurysm cavity was found arising from a defect on the anterolateral aspect of the popliteal artery (C), coinciding with a spike of fibular osteochondroma. After the vascular clamps were applied proximally and distally, the pseudoaneurysm was opened. A 2-mm-diameter hole was found in the anterolateral aspect of the popliteal artery. Aneurysmectomy and reconstruction using reversed great saphenous vein was performed, and the bony spike was excised. The patient made an unremarkable recovery and was discharged after 11 postoperative days.


The Japanese Journal of Thoracic and Cardiovascular Surgery | 2010

Asymptomatic papillary fibroelastoma of the mitral valve

Chihiro Iwashita; Shin-ichi Oki; Tsutomu Saito; Yoshio Misawa

We report an asymptomatic case of a papillary fibroelastoma adherent to the mitral anterior leaflet. Transthoracic echocardiography of an 85-year-old man with chronic atrial fibrillation and no thromboembolic episodes, revealed a cardiac tumor on the mitral valve. Transesophageal echocardiography demonstrated typical findings for a papillary fibroelastoma. The tumor was successfully removed using a shave excision technique. Currently, these tumors are found incidentally in asymptomatic patients by advanced diagnostic modalities.


Asaio Journal | 2004

Twenty-two year experience with the omniscience prosthetic heart valve.

Yoshio Misawa; Masanobu Taguchi; Kei Aizawa; Hideki Takahashi; Yasuhito Sakano; Yuichiro Kaminishi; Shin-ichi Oki; Hiroaki Konishi; Tsutomu Saito; Morito Kato

This study was designed to evaluate the long-term clinical results of the Omniscience tilting disc valve. Omniscience valves were implanted in 51 patients (mean age, 50 ± 10 years); 18 had aortic valve, 24 had mitral valve, and 9 had both aortic and mitral valve replacements. Oral warfarin potassium and dipyridamole were prescribed as our anticoagulant therapy. Preoperatively, 42 patients were in New York Heart Association class III or IV, and 23 of 25 surviving patients were in class I or II after operation. There were 2 (3.9%) early deaths and 23 late deaths (3.5 ± 0.7% per patient-year). Cardiac related mortality including congestive heart failure, sudden death, and thromboembolism, and hemorrhagic complications were seen in 16 patients. Overall survival at 10, 15, and 20 years was 77 ± 6%, 62 ± 7%, and 46 ±7%, respectively. Thromboembolic complications were seen in 5 patients, for a rate of 0.8 ± 0.3% per patient-year; similarly, hemorrhagic complications were also seen in 5 patients. Nonstructural prosthetic valve dysfunction was seen in 4 patients, for a rate of 0.6 ± 0.3% per patient-year, and sudden death was seen in 2, a rate of 0.3 ± 0.2% per patient-year. The Omniscience prosthesis demonstrated excellent postoperative clinical status with low rates of valve related complications.


Asaio Journal | 2001

An unusual complication associated with the Carpentier-Edwards porcine bioprosthesis.

Yoshio Misawa; Shin-ichi Oki; Yasuhiro Tezuka; Katsuo Fuse

Primary tissue failure of bioprosthetic heart valves refers primarily to calcification of the leaflets of the bioprosthesis. A 75 year old patient underwent reoperation 15 years after mitral valve replacement with a Carpentier-Edwards porcine bioprosthesis. The extracted bioprosthetic valve was found to have one prolapsed leaflet and a small amount of calcification on all three leaflets without tear or perforation. The two commissures suspending the prolapsed leaflet were detached, causing mitral valve regurgitation.


Surgery Today | 1996

Anomalous Left Main Coronary Artery Arising from the Pulmonary Artery in an Adult: Treatment by Direct Reimplantation

Tsutomu Saito; Katsuo Fuse; Morito Kato; Shin-ichi Oki

We herein report the case of a 37-year-old woman in whom an anomalous origin of the left coronary artery from the pulmonary artery was surgically corrected. A magnetic resonance angiogram showed the left main coronary artery connecting to the right posterior portion of the pulmonary trunk, and exercise-stressed thallium-201 perfusion scintigrams demonstrated a large reversible anterior defect. She was successfully treated by direct aortic reimplantation of the abnormal left coronary artery. We were able to obtain a sufficient length of the left main trunk by excising the large cuff of pulmonary artery wall surrounding the ostium of the anomalous left coronary artery while transecting the pulmonary artery. Postoperative angiograms demonstrated a widely patent left coronary artery, a decrease in the size of the right coronary artery, and no collaterals, and exercise-stressed thallium-201 perfusion scintigrams demonstrated no remaining ischemic defect at all. Direct aortic reimplantation is an ideal operation but is still limited by the anatomical position of the left coronary artery. In this case, magnetic resonance angiography was an excellent method for deciding the optimum operative procedure for the anomalous left coronary artery. In addition, exercise thallium-201 scintigraphy was found to be useful in recognizing the revascularized effect of the left ventricle.


Journal of Artificial Organs | 2002

Early clinical evaluation of the Cosgrove-Edwards prosthetic heart valve ring

Yoshio Misawa; Tsutomu Saito; Hiroaki Konishi; Shin-ichi Oki; Yuichiro Kaminishi; Kei Aizawa; Hideki Takahashi; Osamu Kamisawa; Morito Kato; Katsuo Fuse

Abstract We discuss the usefulness of the Cosgrove-Edwards ring from our early clinical results from 25 rings in 24 patients who underwent mitral annuloplasty (MAP) or tricuspid annuloplasty (TAP) between June 1999 and December 2000. In the MAP group, the posterior mitral annulus between the anterior and posterior fibrous trigones was reinforced with the prosthetic ring. In the TAP group, the annuli of the anterior and posterior leaflets were splinted with the ring. The prosthetic ring was attached by pledgeted U-sutures. Cardiologists performed echocardiography pre- and postoperatively. Thirteen of the 14 in the MAP group showed mitral valve regurgitation of grade 0 or I. Six of the 11 in the TAP group showed tricuspid regurgitation of grade 0 or I, and 5 patients with regurgitation equal to or greater than grade II who remained in atrial fibrillation postoperatively recovered without further clinical symptoms. No patient has required reoperation during a follow-up period of up to 2 years. Cosgrove-Edwards ring-related complications, such as valve stenosis, ring detachment, and arrhythmia, have been not recognized in these patients. In conclusion, for mitral and tricuspid annuloplasty, the Cosgrove-Edwards prosthetic ring showed excellent early clinical results, particularly in patients maintained in sinus rhythm.

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Yoshio Misawa

Jichi Medical University

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Tsutomu Saito

Jichi Medical University

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Katsuo Fuse

Jichi Medical University

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Kei Aizawa

Jichi Medical University

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Hideki Morita

Jichi Medical University

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Koji Kawahito

Jichi Medical University

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