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Dive into the research topics where Masanobu Watari is active.

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Featured researches published by Masanobu Watari.


The Annals of Thoracic Surgery | 2001

Efficacy of pulmonary vein isolation for the elimination of chronic atrial fibrillation in cardiac valvular surgery

Taijiro Sueda; Katsuhiko Imai; Osamu Ishii; Kazumasa Orihashi; Masanobu Watari; Kenji Okada

BACKGROUND Haissaguerre and colleagues emphasize the importance of the pulmonary veins as a source of ectopic foci for initiating paroxysmal atrial fibrillation (AF). We hypothesized that ectopic foci from the pulmonary veins could also act as drivers for maintaining chronic AF, and that surgical ablation of the pulmonary vein orifices could terminate chronic AF. METHODS Using a computerized 48-channel mapping system, we performed intraoperative atrial mapping in 12 patients with chronic AF associated with mitral valve disease. Patient age ranged from 24 to 82 years (mean, 60.4 years). AF duration ranged from 3 to 240 months (mean, 92+/-84 months). Simple surgical isolation of the pulmonary vein orifices was performed during the mitral valve operation. RESULTS Regular and repetitive activation was found in the left atria of 9 out of 12 patients, and irregular and chaotic activation was found in both atria of 3 out of 12 patients. Chronic AF in the 9 patients (75%) with regular and repetitive activation of their left atria was successfully treated by a simple surgical isolation of the pulmonary vein orifices. The other 3 patients did not recover sinus rhythm after this procedure. In 1 case of recurrent AF, the patient recovered sinus rhythm during the follow-up period (AF-free rate, 83%). CONCLUSIONS Surgical ablation of the pulmonary vein orifices was effective in the treatment of chronic AF associated with mitral valve disease. Intraoperative mapping may be useful in predicting the efficacy of a single pulmonary vein orifice isolation procedure.


The Annals of Thoracic Surgery | 2001

Clinical analysis of results of a simple left atrial procedure for chronic atrial fibrillation.

Katsuhiko Imai; Taijiro Sueda; Kazumasa Orihashi; Masanobu Watari; Yuichiro Matsuura

BACKGROUND We have performed a simple left atrial procedure for eliminating chronic atrial fibrillation (AF) associated with mitral valve disease. This article analyzes the midterm results of this procedure. METHODS Thirty-two patients were enrolled in this study concomitant with mitral valve operations. Patients were divided into two groups (AF- and AF+). We examined the efficacy of this operation and atrial function for more than 12 months of follow-up. RESULTS In a total of 98.5 patient years of follow-up, AF was absent 3 years after operation in 74%. Of preoperative and intraoperative variables, only long duration o


European Journal of Cardio-Thoracic Surgery | 2001

Endovascular stent-grafting via the aortic arch for distal aortic arch aneurysm : an alternative to endovascular stent-grafting

Kazumasa Orihashi; Taijiro Sueda; Masanobu Watari; Kenji Okada; Osamu Ishii; Yuichiro Matsuura

OBJECTIVE We have experienced transaortic stent-grafting for treating distal arch aneurysm or type B dissection. This paper is to mainly report the surgical aspect of these procedures. METHODS Fifteen patients underwent this surgery, including 12 men and three women ranging from 47 to 83 years. Twelve had aneurysms and three aortic dissection. Concomitant surgery was necessary in seven patients (coronary artery bypass grafting in five, tricuspid annuloplasty in one, and replacement of ascending aorta and/or total arch replacement in three cases). A stent graft (Gianturco Z-stent and Intervascular prosthesis) was loaded in a 30-F sheath catheter. Under circulatory arrest, selective cerebral perfusion was established, and the sheath catheter was inserted through aortotomy into descending aorta and the stent graft was deployed at an appropriate level. The proximal end of graft was sutured to the aorta just distal to the left subclavian artery with inclusion method at the posterior wall. Concomitant surgery was done during cooling or rewarming period. TEE was utilized to visualize every endovascular manipulation to avoid unintended intimal injury or misplacement of graft and to assess the surgical results in the operative theater. RESULTS Aneurysm was successfully excluded except in one patient who had a proximal endoleak and distal endoleak due to underestimation of aortic diameter. There was one operative mortality caused by cerebral infarction, possibly due to debris from femoral arterial cannulation. In the remaining patients, there was no enlargement of residual aneurysm. The excluded aneurysmal sac gradually regressed and disappeared within 2 years in five patients and the thrombosed false lumen completely shrunk within 1 year in two patients. One patient had paraplegia, possibly because the graft was intentionally advanced deeply to cover the thick and fragile atheromatous layer in order to avoid destruction of the atheroma by an expanded graft. CONCLUSIONS Endovascular stent graft via the aortic arch is an acceptable treatment for distal arch aneurysms close to or involving left subclavian artery or type B dissections, especially for those cases requiring other cardiac procedures. It can lead to regression and disappearance of aneurysm or dissection in the mid-term follow-up.


The Annals of Thoracic Surgery | 2000

Endovascular stent-grafting through the aortic arch: an alternative approach for distal arch aortic aneurysm

Taijiro Sueda; Masanobu Watari; Kenji Okada; Kazumasa Orihashi; Yuichiro Matsuura

BACKGROUND Endovascular stent-grafting is an innovative procedure; we have developed a novel approach to treat distal arch aortic aneurysm through a small incision in the aortic arch. METHODS Eight patients with thoracic aortic aneurysms were treated with an endovascular stent-graft that was introduced into the thoracic aorta through a small incision in the aortic arch. Of these patients, 7 had distal arch aortic aneurysms, and 1 had chronic aortic dissection of Stanford type B. Four of these patients had received concomitant coronary artery bypass grafting, and 1 patient had undergone tricuspid valvular annuloplasty. The stent-graft was introduced into the distal arch aorta and descending aorta through a small incision in the aortic arch, under selective cerebral perfusion and hypothermic circulatory arrest. RESULTS The selective cerebral perfusion time ranged from 52 to 86 minutes (mean, 68 minutes) and the operating time from 289 to 422 minutes (mean, 318 minutes). There was no endoluminal leakage into the aneurysm. Seven patients survived and were discharged, but 1 patient suffered a cerebral infarction and died during the follow-up period. CONCLUSIONS Placing an endovascular stent-graft through the aortic arch is an acceptable alternative treatment for distal arch aortic aneurysms.


Surgery Today | 2004

Successful Coil Embolization for Spontaneous Arterial Rupture in Association with Ehlers-Danlos Syndrome Type IV: Report of a Case

Yuji Sugawara; Koji Ban; Katsuhiko Imai; Kenji Okada; Masanobu Watari; Kazumasa Orihashi; Taijiro Sueda; Akira Naitoh

When a patient with Ehlers-Danlos syndrome (EDS) presents with a vascular emergency, performing life-saving surgery can be difficult because of the profound fragility of the arterial tissue. We report the case of a 27-year-old woman with EDS in whom a spontaneous arterial rupture was successfully treated with transcatheter embolization. The patient was brought to our hospital in shock, with left lower abdominal pain. She had been diagnosed with EDS type IV following a colonic rupture 8 years earlier. An emergency angiogram revealed rupture of the left external iliac artery. The active bleeding was managed by transarterial embolization of the ruptured artery using stainless steel coils, which took 30 min to achieve. The patient has not suffered any further vascular complications during the year since this procedure. Transcatheter coil embolization may be a reliable option for treating sudden arterial rupture in patients with this syndrome.


The Annals of Thoracic Surgery | 2001

Pulmonary vein orifice isolation for elimination of chronic atrial fibrillation

Taijiro Sueda; Katsuhiko Imai; Kazumasa Orihashi; Masanobu Watari; Kenji Okada

We present a 61-year-old woman with chronic atrial fibrillation (AF) associated with mitral valve disease. Chronic AF was successfully treated by simple isolation of pulmonary vein orifices concomitant with mitral valve replacemen


The Annals of Thoracic Surgery | 2001

Clinical Implication of Orbital Ultrasound Monitoring During Selective Cerebral Perfusion

Kazumasa Orihashi; Yuichiro Matsuura; Taijiro Sueda; Hiroo Shikata; Masanobu Watari; Kenji Okada

BACKGROUND We evaluated clinical relevance of orbital ultrasound (OUS) monitoring to neurological events in aortic surgery associated with selective cerebral perfusion (SCP). METHODS In 24 consecutive cases, blood flow was monitored at central retinal artery (CRA) and retrobulbar vessels. The threshold perfusion pressure for detecting CRA flow in the color Doppler mode (BPt) was determined in individual eyes. RESULTS The BPt ranged from 25 to 71 mm Hg. Events (infarction, anisocoria, delirium) occurred in 8 cases. Infarction occurred in all 3 cases when retrobulbar flow was severely impaired for 40 minutes or longer, while none of the remaining 21 cases had infarction (p = 0.0005). Among the latter cases, perfusion pressure was below BPt for longer than 100 minutes in all 5 cases with events, and in 5 of 16 cases without events (p = 0.0124). No significant difference was found in age, duration of cardiopulmonary bypass, SCP, and circulatory arrest, and duration of blood pressure below 50 mm Hg. CONCLUSIONS Sustained hypoperfusion detected with OUS monitoring is related to an occurrence of neurological events.


The Annals of Thoracic Surgery | 2001

Cardiac papillary fibroelastoma on the pulmonary valve: a rare cardiac tumor

Kenji Okada; Taijiro Sueda; Kazumasa Orihashi; Masanobu Watari; Yuichiro Matsuura

We report the case of a patient with a rare papillary fibroelastoma on the pulmonary valve visualized before surgical intervention. The tumor was an encapsulated, rounded mass. The gelatinous membrane on the surface tore easily, and multiple fronds appeared. This case emphasizes that when there is an encapsulated mass attached to a valve, the initial excision of valve tissue should be as minimal as possible. To avoid unnecessary injury to the valve, it is simple and practical to confirm that the tumor has the appearance of a sea anemone, thus identifying it as a papillary fibroblastoma, a benign tumor.


The Japanese Journal of Thoracic and Cardiovascular Surgery | 2000

Evaluation of motor- and sensory-evoked potentials for spinal cord monitoring during thoracoabdominal aortic aneurysm surgery

Taijiro Sueda; Kenji Okada; Masanobu Watari; Kazumasa Orihashi; Hiroo Shikata; Yuichiro Matsuura

OBJECTIVE To assess the utility of spinal cord monitorings for prediction of spinal cord ischemia, we investigated the role of both motor evoked potentials and sensory evoked potentials during thoracoabdominal aortic aneurysm surgeries. METHODS We monitored two kinds of sensory evoked potentials; descending evoked spinal cord potentials from the lumbar enlargement after cervical spinal cord stimulation and segmental evoked spinal cord potentials at the lumbar enlargement elicited by peroneal nerve stimulation, and motor evoked potentials from the lumbar enlargement elicited by direct subcranial stimulation in 9 thoracoabdomonal aortic aneurysm surgeries. RESULTS Postoperative paraplegia occurred in one case in which the patients died during the perioperative period. One case showed transient paraparesis, but recovered following rehabilitatation. These cases showed a decrease in the amplitude of descending evoked spinal cord potentials and motor evoked potentials. CONCLUSION The recovery of the amplitude of the motor evoked potentials and the descending evoked spinal cord potentials after declamping correlated with the neurologic outcome.


The Japanese Journal of Thoracic and Cardiovascular Surgery | 2001

Kinetics of pro-inflammatory cytokines release in cardiac surgery with cardiopulmonary bypass.

Shinji Hirai; Taijiro Sueda; Kazumasa Orihashi; Masanobu Watari; Kenji Okada

OBJECTIVE Cytokine induction can occur routinely in cardiac surgery with cardiopulmonary bypass. We have studied the relationships between the kinetics of pro-inflammatory cytokine release and the postoperative organ function. METHODS Ten adult patients (6 men and 4 women) undergoing elective cardiac surgery with cardiopulmonary bypass, at Hiroshima University Hospital were studied. Patients with acute infection, insulin-dependent diabetes, acute or chronic respiratory failure, renal or hepatic failure, acute cardiogenic shock, and emergency patients were not included. The age of the patient ranged from 44 to 78 years (mean 69 +/- 2.0 years). The type of surgical intervention performed was coronary artery bypass grafting in four patients, mitral valve plasty or replacement with modified maze procedure in another five patients, and both procedures in the other one patient. Plasma cytokine levels until 48 hours after aortic declamping were measured in blood samples. The Respiratory Index and the serum levels of choline esterase and creatinine were also measured. The plasma levels of the pro-inflammatory cytokines (interleukin-6 and interleukin-8) were measured. RESULTS The highest interleukin-6 levels were significantly correlated with hepatic dysfunction (r = -0.80, p = 0.006) and with renal dysfunction (r = 0.78, p = 0.009). The highest interleukin-8 levels were significantly correlated with respiratory dysfunction (r = 0.86, p = 0.001). CONCLUSION The highest proinflammatory cytokines levels at 1 hour after aortic declamping were related to damage to postoperative organ functions, involving the lung, kidney and liver.

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Hiroo Shikata

Kanazawa Medical University

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