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Dive into the research topics where Kazuyuki Ishibashi is active.

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Featured researches published by Kazuyuki Ishibashi.


Circulation | 2012

Two Cases of Calcified Amorphous Tumor Mimicking Mitral Valve Vegetation

Mikiko Fujiwara; Hiroyuki Watanabe; Takako Iino; Yusuke Kobukai; Kazuyuki Ishibashi; Hiroshi Yamamoto; Kenji Iino; Fumio Yamamoto; Hiroshi Ito

The term cardiac calcified amorphous tumor (CAT) was coined in 1997 by Reynolds et al,1 who described 11 cases with nonneoplastic cardiac masses characterized by a pedicle and diffuse calcification. Additionally, CAT could originate in any of the 4 chambers. Once the mass is excised, its unique histological features such as the presence of calcified nodules in an amorphous background of fibrin with degeneration and focal inflammation allow an accurate diagnosis of cardiac CAT. However, in cases when CAT has arisen close to the cardiac valves and is mobile, it is not always easy to distinguish between CAT and mitral valve vegetation preoperatively. Here, we report 2 cases of CAT arising from mitral annular calcification (MAC) and propose imaging features that can be used to distinguish CAT from mitral valve vegetation. Case 1. A 58-year-old man with end-stage renal disease secondary to diabetic nephropathy was referred to our hospital. He had been maintained on hemodialysis for the past 4 years. Transthoracic echocardiography revealed 2 cardiac tumors adherent to the posterior MAC (Figure 1A). One was a highly mobile, …


Journal of Vascular Surgery | 2009

In situ replacement with equine pericardial roll grafts for ruptured infected aneurysms of the abdominal aorta

Hiroshi Yamamoto; Fumio Yamamoto; Kazuyuki Ishibashi; Mamika Motokawa

We describe surgical in situ replacement using an equine pericardial roll to treat ruptured infected abdominal aortic aneurysms (AAA) in two patients. A 78-year-old man diagnosed with ruptured infected (Bacteroides fragilis) AAA underwent in situ replacement of the abdominal aorta using a bifurcated equine pericardial roll graft with concomitant omentum flap wrapping. A 50-year-old man diagnosed with ruptured infected (Streptococcus agalactiae) AAA underwent the same procedure, except the graft was straight. Computed tomography of this patient revealed no graft dilation or surrounding fluid accumulation at 48 months after surgery. We therefore suggest that in situ replacement of the abdominal aorta using equine pericardium with concomitant omental flap wrapping may be an option of treating ruptured infected AAAs.


Annals of Vascular Surgery | 2011

Intermediate and Long-Term Outcomes After Treating Symptomatic Persistent Sciatic Artery Using Different Techniques

Hiroshi Yamamoto; Fumio Yamamoto; Kazuyuki Ishibashi; Gembu Yamaura; Keisuke Shiroto; Mamika Motokawa; Fuminobu Tanaka

Persistent sciatic artery (PSA) is a rare congenital vascular malformation. In this article, we have described the case of a 66-year-old woman presenting with a pulsatile mass in the left buttock and bilateral lower limb ischemia, who underwent surgical therapy. Preoperative computed tomography scanning showed a left thrombosed PSA aneurysm (PSAA) with concomitant occlusion of bilateral iliac, bilateral common femoral, and left popliteal arteries. After recanalization of the left common femoral artery occlusion with a systemic heparin treatment, the patient underwent bypass surgery (left femoropopliteal bypass, right iliofemoral bypass) and PSAA exclusion. Postoperative computed tomography scanning 20 months after surgery revealed that the excluded PSAA was thrombosed with no refilling collateral flow, and that the bypass grafts were patent in both legs. In addition to this case report, a literature review of PubMed articles published between 1965 and 2009 that included the treatment and intermediate/long-term management of symptomatic PSAs was conducted. We found 45 articles (67 limbs), of which 24 (29 limbs) described the intermediate/long-term outcomes in patients treated for symptomatic PSA. Regardless of the method of arterial reconstruction or PSAA repair, intermediate/long-term outcomes of different treatments for lower limb ischemia and PSAAs were satisfactory, and the patients were asymptomatic during the follow-up period which ranged from 2 months to 10 years.


The Japanese Journal of Thoracic and Cardiovascular Surgery | 2009

In situ replacement of the thoracic aorta using an equine pericardial roll graft for an aortobronchial fistula due to aortic rupture

Hiroshi Yamamoto; Fumio Yamamoto; Kazuyuki Ishibashi; Yoshifumi Chida; Yoshihiro Minamiya; Hiroshi Nanjo

A 74-year-old woman with massive hemoptysis and shock who had been diagnosed with thoracic aortic rupture underwent in situ replacement of the thoracic aorta using an equine pericardial roll graft. The lower lobe of the left lung was resected because of a massive hematoma and adhesion to the wall of the thoracic aorta. Intraoperative microscopic examination of the resected aortic wall revealed Gram-positive bacteria (α-streptococcus in bacterial cultivation). Histology of the resected aorta revealed abscess formation in the media and adventitia of the aortic wall associated with disruption of the media (dissection). Postoperative computed tomography revealed no fluid collection around the graft 1 month after surgery, and magnetic resonance imaging showed no significant graft dilation 20 months after operation. The equine pericardium can be an option of alternative graft materials for in situ replacement of the thoracic aorta in patients with an aortobronchial fistula due to aortic rupture.


Journal of Vascular Surgery | 2009

Vascular prosthesis rupture caused by contact with rib stump after thoracic aorta replacement

Hiroshi Yamamoto; Fumio Yamamoto; Kazuyuki Ishibashi; Yasuharu Noishiki

A 42-year-old male with Marfan syndrome, who had undergone aortic root and total arch replacement for type-A acute aortic dissection at the age of 40, underwent descending aorta replacement with woven Dacron (Vascutek Ltd., Renfrewshire, Scotland) because of pseudoaneurysm at the site of the distal anastomosis and an enlarged pseudolumen of the dissecting descending aorta. The fourth and eighth ribs were cut at their anterior and posterior sites to allow wide exposure of the entire descending aorta. Postoperative computed tomographic scanning showed that the vascular prosthesis posteriorly contacted the eighth rib stump. On the postoperative day 25, the patient collapsed and developed severe hypotension. Emergency thoracotomy revealed a 6 mm in diameter hole on the posterior side of the vascular prosthesis. One day later, the patient died of cardiac dysfunction resulting from sustained hypotension. Electron microscopic examination of the vascular prosthesis showed that the hole was caused by frayed fabric and disrupted polyester fibers. Our experience warns that a woven polyester vascular prosthesis could rupture within 3 weeks of contacting a rib stump.


Asian Cardiovascular and Thoracic Annals | 2009

Leaflet Suspension and Subvalvular Annuloplasty in Aortic Valve Prolapse

Hiroshi Izumoto; Kohei Kawazoe; Takanori Oka; Kazuyuki Ishibashi; Hiroshi Yamamoto; Fumio Yamamoto

We have utilized the combined techniques of subvalvular annuloplasty and leaflet suspension since 1999 to repair prolapsing aortic valves. We reviewed our short-term results to assess perioperative echocardiographic changes and repair durability. Nineteen patients (15 men and 4 women; mean age, 60.7 years) underwent this operation between July 1999 and June 2002. All were interviewed to establish their latest functional status, reoperation and survival rates. After a mean follow-up of 40.1 months, all patients were alive and in New York Heart Association functional class I. The echocardiographic grade of aortic regurgitation decreased from 3.2 preoperatively to 1.6 at follow-up. Left ventricular end-diastolic dimension shortened significantly from 6.2 to 5.2 cm. Left ventricular end-systolic dimension decreased from 4.1 to 3.3 cm. Annulus size was also significantly less at 2.2 cm from 2.5 cm preoperatively. At 48 months, freedom from reoperation was 88.9% ± 7.4%. The follow-up was 100% complete. Repair of a prolapsing aortic valve with leaflet suspension and subvalvular annuloplasty is a good procedure and the short-term results are satisfying.


Annals of Vascular Surgery | 2011

Long-Term Outcomes of Open Surgical Repair for Ruptured Iliac Artery Aneurysms

Hiroshi Yamamoto; Fumio Yamamoto; Kazuyuki Ishibashi; Ke-Xiang Liu; Gembu Yamaura; Yoshifumi Chida; Mamika Motokawa; Fuminobu Tanaka

BACKGROUND Rupture of an iliac artery aneurysm is rare but could be catastrophic unless it is treated with an appropriate strategy. We reviewed our 10-year institutional experience in treating iliac artery aneurysms to elucidate the effectiveness of open surgical repair strategies for ruptured iliac artery aneurysms in terms of short- and long-term postoperative results. METHODS A total of 26 patients (men/women = 22/4), with a mean age of 72 years, underwent open repair of iliac artery aneurysm with or without rupture (unruptured/ruptured = 15/11) between January 2001 and April 2010. There was no difference in the distribution of aneurysm morphology between the unruptured and ruptured groups, and 20 (76.9%) of the 26 patients had aneurysms involving unilateral or bilateral internal iliac arteries. Long-term event-free survival rates and freedom from secondary intervention were analyzed using the Kaplan-Meier method (follow-up: 55 ± 39 and 40 ± 25 months in the unruptured and ruptured groups, respectively). RESULTS There was no difference in the time of surgery between the two groups (351 ± 118 and 348 ± 152 minutes in the unruptured and ruptured groups, respectively), but the ruptured group showed greater blood loss/min (time of surgery) and transfusion volume than the unruptured group. The early postoperative mortality was 6.7% in the unruptured group and 0% in the ruptured group (p = 0.557). There was no difference in the number of postoperative morbidities between the two groups, but the ruptured group showed significantly greater C-reactive protein, lactate dehydrogenase, and total bilirubin levels than the unruptured group. The cardiovascular event-free survival rate at 5 years was 93.3% and 100.0% in the unruptured and ruptured groups, respectively. The secondary intervention-free rate at 5 years was 100.0% and 90.0% in the unruptured and ruptured groups, respectively. CONCLUSIONS The short- and long-term postoperative mortality rates after open repair for iliac artery aneurysms were satisfactorily low and similar in unruptured and ruptured groups. This suggests that open repair strategies remain as a reliable treatment option to obtain successful postoperative results in patients with rupture of an iliac artery aneurysm.


Heart and Vessels | 2012

A free-floating left atrial thrombus develops intermittent entrapment in the mid-ventricle during diastole

Mikiko Fujiwara; Hiroyuki Watanabe; Yasunori Oguma; Genbu Yamaura; Kazuyuki Ishibashi; Hiroshi Yamamoto; Kiyoshi Nobori; Kenji Iino; Fumio Yamamoto; Hiroshi Ito

Free-floating left atrial thrombi are rare. Here we report a case of a 75-year-old woman with atrial fibrillation who was admitted for treatment of acute myocardial infarction. A free-floating left atrial thrombus was found incidentally on echocardiography. Ten days after percutaneous coronary intervention, the patient had mild faintness with transient hypotension, and it was found that the left atrial thrombus had developed intermittent entrapment in the mid-ventricle during diastole, with abrupt rebound back to the left atrial cavity during systole. Urgent removal of the thrombus was performed successfully. Although the free-floating thrombus had appeared to be spherical, like a ball thrombus, on echocardiography, the excised thrombus was pedunculated. A cut section revealed a laminated thrombus with an onion-skin-like appearance.


The Annals of Thoracic Surgery | 2012

Right Atrial Giant Myxoma Occupying the Right Ventricular Cavity

Teruki Sato; Hiroyuki Watanabe; Megumi Okawa; Takako Iino; Kenji Iino; Kazuyuki Ishibashi; Hiroshi Yamamoto; Fumio Yamamoto; Hiroshi Ito

We report a case of a giant right atrial myxoma mimicking the right ventricular tumor. The 75-year-old patient underwent cardiac surgery, and the tumor was excised along with the stalk. Tricuspid valve annuloplasty was performed before closure of the right atriotomy. The tumor may have caused intraventricular stenosis, hepatic dysfunction, and progressive fatigue as a result of low cardiac output. This case is of special interest because the myxoma was very large compared with those ever reported, and a right atrial myxoma occupying the right ventricular cavity is rare.


Annals of Vascular Surgery | 2010

Repetitive contained rupture of an infected abdominal aortic aneurysm with concomitant vertebral erosion.

Hiroshi Yamamoto; Fumio Yamamoto; Hiroshi Izumoto; Fuminobu Tanaka; Kazuyuki Ishibashi

We describe a rare case of surgical treatment for a repeated contained rupture of an infected abdominal aortic aneurysm (AAA) with concomitant vertebral erosion. A 59-year-old man presented to a nearby hospital with abdominal pain and fever. On admission, computed tomography (CT) scan revealed a contained rupture of AAA, but the patient declined the offer of surgical therapy. Thereafter, the retroperitoneal hematoma gradually reduced in size. The third and fourth lumbar vertebrae were eroded on the CT scan 12 months after the appearance of the first symptom. However, 21 months after the first symptom, he suffered severe lumbago and was diagnosed with recurrence of contained AAA rupture and vertebral body destruction. He underwent debridement of eroded vertebrae and in situ graft replacement of AAA with omentum flap wrapping. Intraoperative microscopic examination of the hematoma revealed gram-positive Streptococcus. His postoperative course was uneventful, and CT 12 months after surgery did not reveal further deterioration of vertebral erosion or fluid accumulation. Repetitive contained AAA rupture may be another entity in contrast to chronic contained AAA rupture. Vertebral erosion could be associated with infection rather than mass effects of the contained hematoma. Surgical treatment is indicated to prevent life-threatening re-rupture and severe spinal instability.

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Fumio Yamamoto

Iwate Medical University

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Keisuke Shiroto

Thomas Jefferson University

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Keisuke Shiroto

Thomas Jefferson University

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Hiroshi Ito

Fukushima Medical University

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