PubMed Health⌕ Search

Biomedical subjects

Toshiya Ohtsuka

Publications and source records attributed to Toshiya Ohtsuka.

At least 19 recordsLinked to original sources
PubMed2005

Sternum lifting technique for thoracoscopic internal thoracic artery harvest.

We employed the Laparolift and Laparofan (Origin Medsystems Inc., CA, USA) and developed a sternum lifting technique to create a sufficient intra-pleural space between the heart and the sternum in which the left internal thoracic artery (ITA) in situ graft could be thoracoscopically mobilized. Between June and December 2004, this technique was applied to 12 consecutive patients (eight men, four women, aged 68.5+/-9.6 years) undergoing minimally invasive coronary artery bypass grafting via a left mini-thoracotomy. The Laparofan, connected to the arm of the lift machine (Laparolift), was introduced through a subxyphoidal entry and opened beneath the sternum. The sternum was elevated by about 5 cm until a sufficient working space was created under the sternum. With left hemipulmonary collapse, the left ITA was thoracoscopically taken down through the axillary ports. There was no procedural conversion to direct harvesting. The mean thoracoscopic harvesting time was 34.5+/-7.7 min. There was no mortality and no instrument-related morbidities. Patency of each ITA graft was angiographically confirmed. In conclusion, despite the limited experience, the present sternum elevation technique using the Laparolift system is a viable method for increasing the intra-pleural working space beneath the sternum during thoracoscopic ITA harvesting.

Aged↗
PubMed2005

VATS thoracic-duct division for aortic surgery-related chylous leakage.

Traumatic chylothorax is a serious morbidity due to aortic surgery. We treated this complication successfully by supradiaphragmatic thoracic-duct division in five adults (three men, two women, aged 61.5+/-19.5 years) and a 3-year-old male infant after an average interval of 4.1+/-1.8 days following initial aortic surgery: graft-replacement of subclavian or descending aortic aneurysm in the adults, and correction of aortic coarctation in the infant. A right thoracoscopic approach was used in the adults and the left thoracotomy was re-used in the infant. Individual exposure and division of the thoracic duct was accomplished using an ultrasonic coagulator. The operating time was 22+/-5.5 min for the thoracoscopy cases, and 70 min for the infant. There was no mortality and no procedure-related morbidity, and chylous leakage ceased immediately in all patients. There was no recurrence of chylothorax during a mean follow-up period of 17+/-9.7 months. Despite our limited experience, we conclude that the present supradiaphragmatic thoracic duct division technique (right thoracoscopy in adults) is safe and perfectly effective, and therefore prompt application of this method is recommendable for treatment of aortic surgery-related traumatic chylo-leakage, particularly in vulnerable elderly or infant patients.

Aortic Aneurysm↗
PubMed2004

Epicardial pulmonary vein isolation with a hook-shaped cryoprobe to treat atrial fibrillation.

PURPOSE: After it was shown that a rapidly firing focus in a pulmonary vein (PV) can cause atrial fibrillation, percutaneous endocardial PV isolation using radiofrequency began to be used as a method of treatment. However, this technique is time consuming. It requires fluoroscopy and contrast media to identify the PV, and cardiac tamponade and PV obstruction are major complications. To overcome these drawbacks, we developed a hook-shaped cryoprobe to enable circumferential ablation of PV orifices epicardially. The aim of this experimental study in dogs was to confirm the efficacy of this method electrophysiologically. DESCRIPTION: Five mongrel dogs (32 PVs) were used. Surrounding tissue was dissected to expose all PVs and their orifices into the left atrium. Each PV was stimulated with an electrode to measure the length of PV which has the same pacing threshold as the left atrium. EVALUATION: The mean distance from the PV orifice to the pacing boundary line was 8.9 +/- 1.3 mm. Encircling cryoablation was performed with a hook-shaped cryoprobe to circumferentially ablate each PV orifice epicardially. CONCLUSIONS: Cryoablation by this method created a bidirectional conduction block in all PVs. All PVs were electrically isolated, and the PV isolation was achieved epicardially without atriotomy. This method should enable less invasive treatment of AF clinically.

Animals↗
PubMed2004

A new needle driver for minientry coronary artery bypass.

PURPOSE: This article describes our clinical experience with a new needle driver (Olympus, Tokyo, Japan), which we have produced to facilitate minithoracotomy or port-access coronary artery anastomosis with the running suture technique. METHODS: The needle driver is 21 cm long, weighs 38 g, and has a grip shaft 1.4 cm in diameter. The device is held like a pencil. A side lever and a revolving disk in the shaft are manipulated with the fingers; a fine needle with a 7-0/8-0 monofilament suture can be grasped/released and driven to penetrate the coronary arterial wall. This device was employed in 10 consecutive patients (8 men, 2 women, 73 +/- 7.5 years old), and off-pump bypass to the left anterior descending artery was achieved using the left internal thoracic artery or vein via a minithoracotomy (4.2 +/- 0.6 cm long). RESULTS: There was no instrument-related injury during each anastomosis. The mean sewing time per anastomosis was 12 minutes (range, 8-18 minutes). Angiography confirmed the patency of the graft in all cases. CONCLUSIONS: Although our experience is limited, we consider the present needle driver to be a viable device for facilitating off-pump, minientry coronary artery anastomosis with the suturing technique.

Anastomosis, Surgical↗
PubMed2003

Beating atrial septal defect closure monitored by epicardial real-time three-dimensional echocardiography without cardiopulmonary bypass.

BACKGROUND: We assessed the feasibility of beating atrial septal defect (ASD) closure monitored by real-time 3D echocardiography (RT3DE). METHODS AND RESULTS: RT3DE was developed with prototype ultrasound equipment consisting of a high-speed 3D rendering unit with a frame rate of 5 to 10 frames/s. We also developed a prototype semiautomatic suture device and suture cutting system. In the experiment, 12 mongrel dogs were anesthetized, and after median sternotomy, the echo probe was applied directly to the surface of the right atrium. Three surgical maneuvers (balloon atrial septectomy, enlargement of the ASD, and ASD closure) were performed through the atrial port inserted into the right atrial appendage. The heart was then excised, and the area of the ASD measured by RT3DE was compared with its area measured directly. The ASD was successfully closed in all experimental animals except the first 2. Examination of the excised heart showed that none of the sutures were loose. The mean area of the ASD was 82.5+/-38.6 mm(2) when measured by RT3DE and 81.6+/-38.2 mm(2) when measured directly, and there was a significant correlation between the areas measured by RT3DE and those measured directly (echo measurements=1.007xdirect measurements+0.337; P<0.0001). A Bland-Altman analysis revealed close agreement between the results obtained by the 2 methods (7.807 mm(2) upper and -6.024 mm(2) lower limit of agreement). CONCLUSIONS: Introduction of RT3DE, a semiautomatic suture device, and a suture cutting system made beating ASD closure without cardiopulmonary bypass possible.

Animals↗
PubMed2003

Early valvular obliteration of cryopreserved aortic valve allograft.

This report describes a 60-year-old male patient who developed early valvular obliteration of a cryopreserved aortic valve allograft with associated severe valvular leakage. The patient had previously undergone two operations for aortic valve insufficiency resulting from infective endocarditis, and prosthetic valve endocarditis: aortic valve replacement with a mechanical prosthesis was done 4 years ago, and two years later aortic root replacement with a cryopreserved allograft was performed. Perforation through the non-coronary cusp of the aortic allograft was found, and valve replacement was achieved using a mechanical prosthesis. The intraoperative findings, histological, immunological, and bacteriological studies of the resected cusps demonstrated negative for infection and rejection, therefore, the valvular perforation might have been caused by an injury or degeneration during management of the homologous graft. The patient showed neither aortic regurgitation on echocardiography nor recurrence of endocarditis 10 months after surgery.

Aortic Valve↗
PubMed2003

Open retroperitoneal irrigation for graft infection after thoracoabdominal aortic aneurysm repair.

A successfully-treated case of graft infection after thoracoabdominal aortic repair is reported. A 61-year-old male underwent graft replacement of a Crawford type IV thoracoabdominal aortic aneurysm and developed graft infection due to methicillin-resistant Staphylococcus aureus. After 35 days' open retroperitoneal irrigation, the culture around the graft turned negative, and omental transposition and skin flap transfer were successfully conducted. The long-term open retroperitoneal irrigation could be conducted without significant complications, and it was very effective in controlling the severe infection.

Aortic Aneurysm, Abdominal↗
PubMed2003

Epicardial pulmonary vein isolation by cryoablation as concomitant cardiac operation to treat nonvalvular atrial fibrillation.

Since Haïssagere and colleagues reported that a rapid firing focus in or close to the pulmonary veins could be the cause of atrial fibrillation, a transcutaneous catheter technique directed at isolating these foci has been developed. How should patients with nonvalvular atrial fibrillation who require cardiac operation be managed? We developed an epicardial technique that uses cryoablation to isolate the left atrial posterior wall and pulmonary veins and used it to treat a patient. Because cryoablation is achieved epicardially, the technique does not require atriotomy and does not prolong aortic cross-clamp time. Isolation of the left atrium was confirmed by electrophyscologic studies, and the patient remains in sinus rhythm 16 months after operation. This concomitant procedure allows treatment of patients with nonvalvular atrial fibrillation.

Aged↗
PubMed2003

Left atrial dissection after double valve replacement.

Left atrial dissection, a rare complication occurring mainly after mitral repair, is reported after double valve replacement in a patient with a connective tissue disease. A 63-year-old woman with systemic sclerosis underwent double valve replacement. Laceration of the tissue between the two mechanical prostheses and dissection of the left atrial wall emerged postoperatively and regurgitation through the dissection caused heart failure, which later improved without surgery. The possible causes of the dissection were thought to be shear forces against the tissue between the two prostheses and tissue fragility due to systemic sclerosis and corticosteroid therapy.

Aortic Valve Stenosis↗
PubMed2003

Needle-guided mini-entry in video-assisted coronary artery bypass.

In minimally invasive coronary artery bypass (MICAB), a video-assisted needle-guided technique was used to make a mini-thoracotomy or an access-port just above the target site in the left anterior descending coronary artery (LAD). After thoracoscopic preparation of the left internal thoracic artery (LITA) and pericardiotomy, a 7-cm, 23-gauge needle was used to examine the skin-point where the needle vertically penetrated the chest wall and thoracoscopically indicated the target site in the LAD. This point was used as the mid-point of the skin incision for a 6-cm thoracotomy (six cases) or a 33-mm access-port (four cases). Consequently, there was no conversion of approach except in the patient with pulmonary dysfunction, and each LITA-LAD anastomosis was completed directly through the mini-entry. There was no mortality and no procedure-related morbidity. Patency of each graft was confirmed within a week after surgery. After a mean follow-up period of 12.5+/-7.8 months, all of the patients except one, who died of stroke 1 year after surgery, are alive with no ischemic events. Although our experience is limited, the present video-assisted needle-guided technique can be a simple method to facilitate appropriate positioning of a mini-entry in MICAB to the LAD with a thoracoscopically prepared LITA graft.

Aged↗
PubMed2002

Long-term treatment with nipradilol, a nitric oxide-releasing beta-adrenergic blocker, enhances postischemic recovery and limits infarct size.

BACKGROUND: This study examines whether the chronic administration of nipradilol, a nitric oxide-releasing beta-adrenergic blocker, decreases ischemia-reperfusion injury. METHODS: Rats were treated with nipradilol (10 mg/kg per day orally) or a vehicle alone for 4 weeks. Isolated rat hearts were assigned to one of five groups (each n = 6): global ischemia groups treated with the vehicle or with nipradilol were subjected to 20 minutes of ischemia; ischemic preconditioning groups treated with the vehicle or with nipradilol were subjected to 3 minutes of ischemic preconditioning; and the L-arginine group treated with the vehicle received 1 mmol/L of L-arginine before global ischemia. Hemodynamic variables and coronary flow were recorded continuously. Nitrites and nitrates levels were measured 60 minutes after reperfusion, and the infarct size was determined. In another series (each n = 6), lipid peroxidation was investigated. RESULTS: In the nipradilol group, significant preservation of the left ventricular pressure and coronary flow, as well as the level of nitrates and nitrites, was observed, compared with the global ischemia group. The infarct size was also significantly reduced in the ischemic preconditioning (23.5%+/-5.47%), L-arginine (25.6%+/-5.59%), and especially the nipradilol (10.7%+/-1.65%) groups. However, in the nipradilol plus ischemic preconditioning group, the protective effects were eliminated. Lipid peroxidation after nipradilol treatment was significantly reduced before and after global ischemia, compared with the global ischemia group. CONCLUSIONS: The chronic administration of nipradilol improves postischemic functional recovery and infarct size, partly by preventing the formation of lipid peroxides. These cardioprotective effects were, however, abolished by ischemic preconditioning.

Adrenergic beta-Antagonists↗
PubMed2002

Ultrasonic evaluation of graft anastomoses during coronary artery bypass grafting without cardiopulmonary bypass.

Performance of the graft-to-coronary anastomosis in coronary artery bypass grafting without cardiopulmonary bypass is more difficult than conventional coronary artery bypass grafting. We report a new method that uses high-frequency epicardial echocardiography to detect technical errors and inadequacies in graft anastomoses. This method improves the operative outcome and enables detection of septal perforator branches and deeply embedded coronary arteries during coronary artery bypass grafting without cardiopulmonary bypass.

Anastomosis, Surgical↗
PubMed2002

Video-assisted limited anterior thoracotomy approach for lingular segmentectomy and left anterior descending coronary artery bypass.

Minimally invasive cardiothoracic combined surgery was performed successfully in an octogenerian with left anterior descending coronary artery disease and concurrent adenocarcinoma in the lingular segment of emphysematous lung. Through a limited anterior 4th intercostal thoracotomy, left anterior descending coronary artery bypass grafting without cardiopulmonary bypass was carried out using the left internal thoracic artery (LITA) and the interposed vein graft, and subsequently lingular segmentectomy was accomplished. Videothoracoscopy via a single port placed at the 5th intercostal space below the left nipple was useful for LITA mobilization, lymph nodes sampling and endo-cutter guidance.

Adenocarcinoma↗
PubMed2002

Videoscopic supradiaphragmatic thoracic duct division using ultrasonic coagulator.

Three consecutive male patients underwent videoscopic supradiaphragmatic thoracic duct division using the Harmonic Scalpel with a hook blade (Ethicon Endo-Surgery, Cincinnati, OH, USA) for treatment of chyle leaks that developed after left upper lobectomy, graft replacement of a descending aortic aneurysm and thyroidectomy with concomitant partial sternal resection. The thoracic duct was exposed and divided using just the Harmonic Scalpel. The operations lasted 40, 20 and 18 min. No mortality, morbidity or recurrence occurred during follow-up periods of 27, 17 and 9 months. The Harmonic Scalpel with a hook blade can facilitate supradiaphragmatic exposure of the thoracic duct.

Aged↗
PubMed2002

A simple distal coronary perfusion technique in off-pump coronary artery bypass.

This communication describes the surgical technique and clinical outcomes of a simple coronary perfusion technique for use during off-pump coronary artery bypass grafting. An intra-coronary shunt tube connected to the graft conduit (saphenous vein or radial artery) with an arterial blood source (ascending aorta or right internal thoracic artery) was inserted distally via a coronary arteriotomy for temporary perfusion of six left anterior descending arteries and two right coronary arteries.

Aged↗