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Naoki Washiyama

Publications and source records attributed to Naoki Washiyama.

At least 19 recordsLinked to original sources
PubMed2006

Right aortic arch with aberrant left subclavian artery symptomatic in adulthood.

Congenital malformations of the aortic arch are rarely found in adulthood. We describe three cases of right aortic arch with aberrant left subclavian artery with left-sided ligamentum arteriosum presenting in adulthood as vascular rings with symptoms of tracheal compression. Varying presentation as well as surgical strategy which was individualized according to the pathological anatomy of each case are discussed.

Adult↗
PubMed2006

Aorto-right atrial fistula following acute type A aortic dissection repair.

This report describes a rare case of aorto-right atrial fistula caused by rupture of a huge pseudoaneurysm that developed at the proximal aortic anastomotic site after total aortic arch replacement for acute type A aortic dissection. Preoperative aortography revealed that the fistula communicated with the right heart, but it was intraoperative Doppler transesophageal echocardiography that confirmed its course into the right atrium. Repeat total aortic arch replacement with concomitant direct closure of the fistula was performed successfully. The underlying cause of the pseudoaneurysm was the dehiscence of sutures at the proximal aortic anastomotic site, probably due to gelatin-resorcin-formaldehyde glue.

Acute Disease↗
PubMed2006

Intrathecal injection of bone marrow stromal cells attenuates neurologic injury after spinal cord ischemia.

BACKGROUND: It has been shown that transplantation of bone marrow stromal cells (MSCs) into the ischemic brain improves functional outcome. We sought to investigate whether intrathecal injection of MSCs can attenuate neurologic injury of spinal cord ischemia. METHODS: Rabbit MSCs were expanded in vitro and were pre-labeled with bromodeoxyuridine. Spinal cord ischemia was induced in rabbits by infrarenal aortic occlusion. Group A and control A were subjected to a 20-minute ischemia and the ischemic duration was extended to 30 minutes in group B and control B. Two days before spinal cord ischemia, 1 x 10(8) MSCs were intrathecally injected into groups A and B, whereas vehicle alone was injected into the control groups. Hind-limb motor function was assessed during a 14-day recovery period with Tarlov criteria, and then histologic examination was performed. RESULTS: Marrow stromal cells survived and engrafted into the spinal cord 2 days after transplantation, and more MSCs were found in the lumbar spinal cord (ischemic segment) than in the thoracic spinal cord (nonischemic segment) at 14 days. Compared with their respective control groups, Tarlov scores were significantly higher in both groups A and B (p < 0.05, group A vs control A, at 2, 7, and 14 days; p < 0.05, group B vs control B, at 1, 2, 7, and 14 days, respectively). The number of intact motor neurons was much higher in the two experimental groups (p < 0.01 vs the corresponding control groups, respectively). CONCLUSIONS: Intrathecal injection of MSCs attenuates ischemic injury of spinal cord.

Animals↗
PubMed2006

Total aortic arch replacement in patients with arch vessel anomalies.

BACKGROUND: The presence of anomalous arch vessels has considerable impact on aortic arch reconstruction techniques and cerebral protection methods when the separated graft technique is adopted to perform total arch replacement. We analyzed our experience of total arch replacement in patients with arch vessel anomalies. METHODS: Among the 220 patients undergoing total arch replacement at our institution, 21 patients (9.5%) had various arch vessel anomalies. Common brachiocephalic trunk was found in 8 patients (3.6%); an isolated left vertebral artery in 9 (4.1%); aberrant right subclavian artery in 3 (1.4%); and coexistent common brachiocephalic trunk and isolated left vertebral artery in 1 (0.5%). In 4 of the 9 patients with isolated left vertebral artery, preoperative diagnosis was possible with magnetic resonance angiography or three-dimensional computed tomography. In cases with common brachiocephalic trunk, total arch replacement could be performed with the usual techniques after separating the innominate and left common carotid arteries from each other. The isolated left vertebral artery was anastomosed to the left subclavian artery graft in 7 patients and to the native left subclavian artery in 2. In the aberrant right subclavian artery variety, a distal aortic anastomosis was performed distal to the orifice of this anomalous artery. The aberrant vessel was reconstructed on the right side of the trachea and esophagus. RESULTS: There was no early or in-hospital mortality. No neurologic complication attributable to the arch vessel anomalies was found. CONCLUSIONS: A precise preoperative diagnosis is very important for the selection of an appropriate surgical strategy in patients with arch vessel anomalies. Magnetic resonance angiography and three-dimensional computed tomography may be useful diagnostic tools in these patients.

Aged↗
PubMed2006

Nonviral gene transfer of hepatocyte growth factor attenuates neurologic injury after spinal cord ischemia in rabbits.

OBJECTIVE: Paraplegia caused by spinal cord ischemia remains a serious complication after surgical repair of thoracoabdminal aortic aneurysms. Hepatocyte growth factor is a potent angiogenic and neurotrophic factor. We sought to investigate the neuroprotective effect of gene transfer of hepatocyte growth factor on spinal cord ischemia in rabbits. METHODS: Human hepatocyte growth factor expression plasmid was combined with hemagglutinating virus of Japan envelope vector. Hemagglutinating virus of Japan envelope vector containing the hepatocyte growth factor gene was injected intrathecally into the experimental rabbits, whereas control vector or saline was given to the control animals. Five days later, spinal cord ischemia was induced by means of infrarenal aortic occlusion for 30 minutes. Hind-limb motor function was assessed during a 14-day recovery period with Tarlov criteria. RESULTS: Human hepatocyte growth factor was detected in the cerebrospinal fluid 3 days after gene transfer, and the level peaked on day 5. Compared with the control animals, hepatocyte growth factor gene transfer significantly increased the capillary density in the gray matter and decreased the spinal cord edema. All rabbits pretreated with saline or control vector had hind-limb paraplegia (Tarlov score = 0) 14 days after spinal cord ischemia. However, previous transfection of the hepatocyte growth factor gene remarkably enhanced the Tarlov scores, and 8 of the 9 rabbits showed normal motor function (Tarlov score = 5) after a 14-day recovery period. Histologic examination showed that the intact motor neurons were preserved to a much greater extent in the rabbits transfected with the hepatocyte growth factor gene. CONCLUSION: Gene transfer of hepatocyte growth factor attenuates neurologic injury after spinal cord ischemia.

Animals↗
PubMed2005

Emergency operation for distal aortic arch aneurysm in Behcet's disease.

Arterial complications of Behcet's disease rarely affect the thoracic aorta, and the incidence of aortic arch aneurysm is especially low. We present a patient who developed a rapidly expanding aneurysm of the distal aortic arch after 20 years of treatment of Behcet's disease. Emergency total arch replacement was performed with a favorable outcome. Graft anastomosis to the normal aorta involving all three layers, wrapping of the anastomotic sites with wide felt strips, as well as strict management of systemic inflammation are essential for prevention of late complications associated with graft anastomosis sites.

Adult↗
PubMed2005

NS-7, a novel Na+/Ca2+ channel blocker, prevents neurologic injury after spinal cord ischemia in rabbits.

OBJECTIVE: We investigated the neuroprotective effect of NS-7 (4-[4-fluorophenyl]-2-methyl-6- [5-piperidinopntyloxy] pyrimidine hydrochloride), a novel Na(+)/Ca(2+) channel blocker, on transient spinal cord ischemia in rabbits. METHODS: Spinal cord ischemia was induced in New Zealand white rabbits by means of infrarenal aortic occlusion for 20 minutes. Four experimental groups were enrolled. A sham group (n = 3) underwent the same operation without aortic occlusion. A control group (n = 7) received only saline before occlusion. Group A (n = 8) received NS-7 (1 mg/kg) 15 minutes before ischemia, and group B (n = 8) received NS-7 (1 mg/kg) at the onset of reperfusion. Neurologic function was assessed 24 and 48 hours after the operation with modified Tarlov criteria. Spinal cords were harvested for histopathologic examination and in situ terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL staining). Spinal cord infarction was investigated with 2, 3, 5-triphenyltetrazonlium chloride staining. RESULTS: Tarlov scoring demonstrated marked improvement in both group A and group B compared with the control group at 24 and 48 hours after the operation. Minimal histologic changes were found in lumbar spinal cords of the 2 NS-7-treated groups, whereas severe neuronal necrosis was shown in the control group. TUNEL-positive neurons and the infarct size of lumbar spinal cords were significantly reduced by NS-7 administered both before ischemia and at the onset of reperfusion. No significant difference was noted between group A and group B in terms of spinal cord protection. CONCLUSION: These results indicate that NS-7 protects the spinal cord against ischemic injury by preventing both neuronal necrosis and apoptosis.

Animals↗
PubMed2005

Experimental study on the protective effects of edaravone against ischemic spinal cord injury.

OBJECTIVE: Reactive free radical species are thought to be involved in ischemic spinal cord injury. We investigated the effects of edaravone (Mitsubishi Pharma Co, Tokyo, Japan), a free radical scavenger, on spinal ischemia-reperfusion injury in a rabbit model. We also sought to estimate free radicals in the spinal cord using the microdialysis method. METHODS: Spinal cord ischemia was induced in New Zealand White rabbits. The animals were then divided into 4 groups. In the first experiment, which was carried out in group A (non-edaravone treated) and group B (edaravone treated), we assessed neurologic function and evaluated spinal cord histopathology. In the second experiment, which was performed in group C (non-edaravone treated) and group D (edaravone treated), we sequentially estimated the level of free radical species in the spinal cord with the microdialysis method. RESULTS: In the first experiment group B showed better neurologic function than group A. The number of viable neurons in the spinal cord gray matter was also higher in group B than in group A. The second experiment revealed that the level of free radical species was lower in group D at 75, 90, and 150 minutes after the beginning of reperfusion compared with levels seen in group C. The appearance of free radical species in the latter group was found to have a biphasic pattern, with peaks at 75 and 150 minutes after the beginning of reperfusion. CONCLUSION: Edaravone exerted a significant protective effect on the spinal cord against ischemia-reperfusion injury by suppressing the level of free radical species, which was demonstrated with the microdialysis method.

Animals↗
PubMed2005

Surgery for acute type A aortic dissection: the effect of antegrade selective cerebral perfusion on the early outcome of elderly patients.

BACKGROUND: The aim of this study was to evaluate early results and to determine predictive risk factors associated with an adverse outcome in elderly patients after acute type A aortic dissection repair using antegrade selective cerebral perfusion (ASCP). Adverse outcome was defined as the occurrence of death or permanent neurologic dysfunction. METHODS: From October 1995 to March 2002, 178 patients (group A < 75 years, n = 156, 87.6%; group B > 75 years, n = 22, 12.4%) underwent surgery for acute type A aortic dissection using ASCP and moderate hypothermia. An ascending aorta/hemiarch replacement was performed in 128/178 (71.9%) patients (group A 71.2%, group B 77.3%, p = NS), an ascending aorta and arch replacement in 50/178 (28.1%) patients (group A 28.8%, group B 22.7%, p = NS). Associated procedures were performed in 55/178 (20.9%) patients (group A 31.4%, group B 27.3%, p = NS), the arch vessels were reimplanted using the separated graft technique in 32/50 (64.0%) patients (group A 62.2%, group B 80.0%, p = NS). The mean ASCP time was 59 +/- 27 min. RESULTS: The overall adverse outcome rate was 20.8% (group A 21.2%, group B 18.2%, p = NS). The transient neurologic dysfunction rate was 9.5% (group A 9.5%, group B 5.6%, p = NS). A logistic regression analysis revealed cardiopulmonary bypass time (p = 0.045, odds ratio 1.03/min) to be the only independent predictor of adverse outcome in group A. CONCLUSIONS: During type A aortic dissection repair the implementation of ASCP resulted in an acceptable hospital mortality and neurologic outcome. If ASCP is used, the risk of hospital mortality and postoperative morbidity is similar in patients younger and older than 75 years. Duration of cardiopulmonary bypass still remains an important risk factor for hospital mortality and neurologic outcome in elderly patients.

Acute Disease↗
PubMed2005

Endarterectomy and graft replacement of severely calcified (porcelain) ascending aorta with coronary ostial involvement in a patient requiring aortic valve replacement.

We report a successful aortic valve replacement within an extensively calcified (porcelain) aorta, involving the left coronary artery ostium. Clamping such an aorta can result in embolization, dissection, and mural laceration. A 72-year-old female presented with a severely calcified and stenotic aortic valve with a peak pressure gradient of 101 mmHg. Computed tomography demonstrated extensive calcification of the ascending aorta. Coronary angiogram showed a 50% ostial left coronary artery stenosis. Under deep hypothermic circulatory arrest, the aorta was transected at the proximal arch and distal graft anastomosis was performed. This was followed by endarterectomy of the porcelain ascending aorta and the left coronary ostium. Aortic valve replacement, proximal aortic graft anastomosis, and a coronary artery bypass grafting (CABG) with the left internal thoracic artery (LITA) anastomosed to the left anterior descending artery (LAD) were then performed in a sequential manner.

Aged↗
PubMed2004

Surgical experience of full root replacement with freestyle bioprosthesis: indications, surgical technique, and results.

PURPOSE: We examined the postoperative clinical results and hemodynamic performance of full root replacement using a freestyle stentless bioprosthesis performed in patients with severe aortic stenosis or aortic root disease. METHODS: We performed 17 full root replacements with a stentless bioprosthesis. The mean age of the patients was 73.9 +/- 4.1 years, ranging from 63 to 81, and 35% were male. The operative indications were aortic stenosis (AS) in 9 patients, aortic stenosis with regurgitation (ASR) in 4, and aortic regurgitation due to aortic root dissection or annuloaortic ectasia in 4. RESULTS: The valve size of the freestyle bioprosthesis was 25.1 +/- 2.6 mm, ranging from 21 to 29 mm. There were no early or late mortalities. No postoperative aortic regurgitation was found. In the 13 patients undergoing an operation for AS or ASR, peak pressure gradients were 8.5 +/- 4.2 and 8.4 +/- 5.2 mmHg, and LV mass indices were 159.4 +/- 19.0 and 106.9 +/- 22.6 g/m(2), as determined by echocardiography at 1 and 10 months after operation, respectively. CONCLUSION: Full root replacement with stentless bioprosthesis is a suitable procedure for patients of advanced age with severe AS, aortic root dissection, or annuloaortic ectasia, because of its superior hemodynamics.

Aged↗
PubMed2004

Repair of delayed left ventricular rupture after mitral valve replacement: report of a case.

Rupture of the left ventricle (LV) after mitral valve replacement (MVR) is a devastating complication, associated with high mortality. A 64-year-old woman with a type I delayed LV rupture, which occurred after MVR with a 27-mm St. Jude Medical mitral prosthesis for mitral stenosis, was successfully treated by a combination of intracardiac and extracardiac surgical repair techniques. The extracardiac repair involved approximating the edges of myocardium around the tear with large sutures bolstered by strips of Teflon felt, then covering the epicardial hematoma with another porcine pericardial patch, using gelatin resorcinol formaldehyde glue and collagen sheets. The intracardiac repair involved suturing the edges of an oval piece of porcine pericardium to the endocardium around the laceration. No LV pseudoaneurysm was detected postoperatively on echocardiography or computed tomography scans. The patient is well 2 years after the operation.

Bioprosthesis↗
PubMed2004

Combined operation for myasthenia gravis and coronary artery disease.

A 57-year-old man with ocular myasthenia gravis was admitted to our hospital because of acute respiratory insufficiency associated with myasthenic crisis. He had a history of unstable angina indicated percutaneous coronary artery angioplasty. He was diagnosed with generalized nonthymomatous myasthenia gravis and a triple vessel coronary artery disease. We conducted a simultaneous surgical intervention, including extended thymectomy and coronary artery bypass grafting, using a standard cardiopulmonary bypass via median sternotomy. The patient had already been immunocompromised at surgery for having diabetes, and postoperative long-term steroid therapy. In this rare and special condition, a meticulous overall therapeutic strategy was needed in order to avoid myasthenic crisis and prepare for the worst case scenario of mediastinitis.

Cardiopulmonary Bypass↗
PubMed2004

Separate grafts or en bloc anastomosis for arch vessels reimplantation to the aortic arch.

BACKGROUND: This study compares the results of the separated graft technique and the en bloc technique as a method of arch vessels reimplantation during surgery of the aortic arch and determines the predictive risk factors associated with hospital mortality and adverse neurologic outcome during aortic arch repair. METHODS: Between October 1995 and March 2002, 352 patients (mean age 64.9 +/- 11.3 years; urgent status: 49/352 [13.9%]) underwent surgery of the aortic arch using the separated graft technique (group A: n = 230 [65.3%]) and the en bloc technique (group B: n = 122 [34.7%]) to reimplant the arch vessels. An aortic arch replacement was performed in 32 patients (9.1%), an ascending aorta and arch replacement in 222 patients (53.1%), an aortic arch and descending aorta replacement in 16 patients (4.5%), and a complete replacement of the thoracic aorta in 82 patients (23.3%). Brain protection was achieved by means of antegrade selective cerebral perfusion in all patients. The mean cardiopulmonary bypass time was 204.8 +/- 61.9 minutes (group A: 199.7 +/- 57.0 minutes; group B: 214.5 +/- 69.4 minutes; p = 0.033), the mean myocardial ischemic time was 121.5 +/- 43.2 minutes (group A: 116.7 +/- 38.9 minutes; group B: 130.80 +/- 49.4 minutes; p = 0.003), and the mean antegrade selective cerebral perfusion time was 84.5 +/- 36.4 (group A: separated graft technique 91.3 +/- 36.3 minutes; group B: 70.6 +/- 32.7 minutes; p = 0.000). RESULTS: Overall hospital mortality was 6.8% (group A: 6.5%; group B: 7.4%; p = not significant [NS]). The permanent neurologic dysfunction rate was 3.5% (group A: 4.0%; group B: 2.5%; p = NS). The transient neurologic dysfunction rate was 5.4% (group A: 5.5%; group B: 5.2%, p = NS). Postoperative systemic morbidity was similar in the two groups. A logistic regression analysis revealed preoperative cardiac tamponade (p = 0.011; odds ratio [OR] = 5.9) and cardiopulmonary bypass time (p = 0.010; OR = 1.01/min) to be independent predictors of hospital mortality. None of the analyzed preoperative variables were associated with an increased risk of permanent neurologic dysfunction. Age more than 70 years old (p = 0.029, OR = 5.7), myocardial revascularization (p = 0.001, OR = 2.9), and pump time (p = 0.013, OR = 1.01/min) were indicated as independent predictors of transient neurologic dysfunction by logistic regression. CONCLUSIONS: Antegrade selective cerebral perfusion was confirmed to be a safe method of cerebral protection allowing complex aortic arch operations to be performed with acceptable results in terms of hospital mortality and neurologic outcome. The separated graft technique had no adverse impact on hospital mortality and morbidity.

Adult↗
PubMed2004

Comparison of pH management during antegrade selective cerebral perfusion in canine models with old cerebral infarction.

OBJECTIVE: We sought to examine the influence on the brain, with or without old infarction, of pH management during antegrade selective cerebral perfusion in a canine model. METHODS: A cerebral infarct canine model was created by injecting a cylindrical silicone embolus. Dogs that had obvious neurologic deficits and had survived for 4 weeks or more were included in the model. Deep hypothermia with antegrade selective cerebral perfusion was performed in intact mongrel dogs (alpha-stat: group A, n = 6; pH-stat: group B, n = 6) and mongrel dogs with infarctions (alpha-stat: group C, n = 6; pH-stat: group D, n = 6). Maxillary vein saturation of oxygen, venous-arterial lactate difference, and serum concentrations of malondialdehyde and glutamate were measured and central conduction times and amplitude in somatosensory evoked potentials were assessed during the operation. RESULTS: During the experimental procedure, the maxillary vein saturation of oxygen was significantly less (P <.05), whereas the venous-arterial lactate difference was significantly greater (P <.05) in the cooling phase to 28 degrees C in group C than in the other groups. The pH-stat group showed significantly greater arterial Paco(2) and lower pH than the alpha-stat group during the period between the cooling to 28 degrees C and the rewarming to 28 degrees C (P <.05). Other intraoperative parameters did not show any difference among the groups. In group C the serum concentrations of malondialdehyde and glutamate significantly increased, as did the central conduction time, whereas in both groups C and D the amplitude ratio decreased significantly. CONCLUSIONS: This experiment suggests that pH-stat management during antegrade selective cerebral perfusion provides more effective protection for a brain with old infarction than alpha-stat management.

Animals↗
PubMed2004

Thoracoabdominal aortic replacement for abdominal aortic aneurysm with atypical coarctation of thoracoabdominal aorta following mitral valve plasty.

We successfully treated a case of a 65-year-old female with an abdominal aortic aneurysm coexisting with an atypical coarctation of thoracoabdominal aorta and celiac axis and superior mesenteric artery occlusion. A dilated inferior mesenteric artery was supplying the celiac artery and superior mesenteric artery regions. The patient also had mitral regurgitation. After a mitral valve plasty, we repaired the abdominal aortic aneurysm and the atypical coarctation of the thoracoabdominal aorta using partial extracorporeal circulation, segmental clamping, and a selective perfusion of both the bilateral renal artery and dilated inferior mesenteric artery. The patient had an uneventful hospital course and remains well.

Aged↗