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Biomedical subjects

Koichi Tabayashi

Publications and source records attributed to Koichi Tabayashi.

At least 37 records · Page 2Linked to original sources
PubMed2005

[Influences of cardiopulmonary bypass in elderly patients].

Organ hypofunction by aging exaggerate damages, which are caused by cardiopulmonary bypass. The main cause of organ dysfunction after cardiopulmonary bypass is systemic inflammatory response, which is induced by continuous interaction of blood with unphysiologic surfaces, shear stress to blood cells, and incorporation of abnormal substances. To reduce the postoperative complications after cardiovascular surgery in elderly patients, intensive and careful control of cardiopulmonary bypass and several kinds of anti-inflammatory treatment are important.

Aged↗
PubMed2004

Quality of life in elderly patients following thoracic aortic surgery.

OBJECTIVE: While early outcomes following thoracic aortic surgery are improving, the long-term quality of life in elderly patients following this procedure remains uncharacterized. Thus, the goal of this retrospective study was to investigate quality of life in elderly patients following thoracic aortic surgery in regard to age, urgency of operation, operative procedures, skin incision, selective cerebral perfusion (SCP) time, and cardiopulmonary bypass time. METHODS: One hundred-and-eleven surviving patients that underwent thoracic aortic surgery between 1987 and 1999 were enrolled in this study. The Short Form-36 (SF-36) health questionnaire was administered to all participants. RESULTS: Some measures of quality of life were lower in those patients that underwent the procedure as compared to age- and gender-matched normal population. Quality of life (QOL) of the elderly patients with prolonged SCP time (>120 minutes) was significantly lower in the dimension of role-physical of SF-36. On the other hand, there was no significant difference between the subgroups in terms of urgency of operation, operative procedure, skin incision, and cardiopulmonary bypass time. CONCLUSIONS: Physical and mental quality of life was significantly lower in elderly patients undergoing thoracic aortic surgery. Prolonged SCP time (>120 minutes) was a negative factor for long-term QOL. We advocate discussing the data with patients when obtaining informed consent for this procedure.

Aged↗
PubMed2004

Use of an extracorporeal left ventricular assist system after acute myocardial infarction due to occlusion of the left main coronary artery.

A 35-year-old man presented to our institution one day after the onset of dyspnea. Coronary angiography revealed the occlusion of the left main trunk. The left main coronary artery and the left circumflex artery were recanalized, but he was hypotensive with low cardiac output. Even after he was placed on circulatory support with veno-arterial extracorporeal membrane oxygenation (ECMO), hemodynamic deterioration could not be reversed, and lung edema developed. The decision was made to use Toyobo LVAS. With institution of left ventricular assist system (LVAS), however, the patient's arterial saturation decreased. Peripheral veno-venous (V-V) ECMO was promptly established, and the patient's arterial saturation improved. On postoperative day 3, the patient was successfully weaned from V-V ECMO. He was extubated on postoperative day 28. The patient was recovered without any serious complications. Although echocardiography showed no substantial improvement in left ventricular function, his general condition is doing quite well with the assist of Toyobo LVAS. He is on rehabilitation program and awaiting heart transplantation.

Adult↗
PubMed2004

Another blood supply to Adamkiewicz's artery.

A 76-year-old man underwent endovascular stent-grafting therapy for chronic aortic dissection. The preoperative multi detector row helical computed tomography (CT) revealed that Adamkiewicz's artery originated from the level of thoracic 9 intercostal artery. Intraoperative monitoring of motor evoked potentials showed no reduction of amplitude in the anterior tibialis muscle after deployment retrievable stent-graft. Postoperative CT showed that stent-graft blocked the ostium of intercostal arteries including Adamkiewicz's artery. On the other hand, the distal portion of the Adamkiewicz's artery was clearly enhanced. Our result showed that there is a collateral network supplying to Adamkiewicz's artery.

Aged↗
PubMed2004

MCI-186 reduces oxidative cellular damage and increases DNA repair function in the rabbit spinal cord after transient ischemia.

BACKGROUND: Paraplegia is a serious complication of operations on the thoracic and thoracoabdominal aorta. To investigate the mechanism by which motor neurons are damaged during these operations, we have reported a rabbit model of spinal cord ischemia. We also tested whether a free radical scavenger MCI-186 that is useful for treating ischemic damage in the brain can protect against ischemic spinal cord damage. METHODS: Fifteen minutes of ischemia was induced, then MCI-186 or vehicle was injected intravenously. Cell damage was analyzed by observing the function of the lower limbs and by counting the number of motor neurons. To investigate the mechanism by which MCI-186 prevents ischemic spinal cord damage, we observed the immunoreactivity of 8-hydroxy-2'-deoxyguanosine as an oxidative DNA damage marker and redox effector as a DNA repair marker. RESULTS: In sham control, 8-hydroxy-2'-deoxyguanosine was not observed, and the nuclear expression of redox effector was observed. In vehicle injection group (group I), the nuclear expression of 8-hydroxy-2'-deoxyguanosine was observed at 1 and 2 days after reperfusion. The nuclear expression of redox effector was observed at 8 hours and 1 day, and disappeared at 2 days after transient ischemia. In MCI-186 injection group (group M), the nuclear expression of 8-hydroxy-2'-deoxyguanosine was not observed, and redox effector was observed at 8 hours and 1 and 2 days. CONCLUSIONS: These results suggest that redox effector decreased in motor neurons after transient ischemia and this reduction preceded oxidative DNA damage. MCI-186 works as a radical scavenger and reduced oxidative DNA damage, so redox effector did not disappear. MCI-186 could be a strong candidate for a use as a therapeutic agent in the treatment of ischemic spinal cord injury.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2004

Clinical features and long-term outcome of type A and type B intramural hematoma of the aorta.

OBJECTIVE: Most previous reports on intramural hematoma of the aorta have focused on the initial episode. The purpose of this study was to clarify the long-term outcome of intramural hematoma of the aorta. METHODS: Ninety-four cases of intramural hematoma of the aorta (41 type A and 53 type B) were reviewed. There were 69 male and 25 female patients, and their mean age was 66.7 +/- 8.7 years (range, 46-88 years). RESULTS: Eleven (27%) of the patients with type A hematoma and 1 (2%) of the patients with type B hematoma underwent early surgical intervention. Others were treated medically, and the overall hospital mortality was 7% for patients with type versus 2% for patients with type B intramural hematomas of the aorta (P =.315). Twenty-three patients, 9 (22%) with type A and 14 (26%) with type B intramural hematomas of the aorta, underwent late surgical intervention during the follow-up period, and there were no hospital deaths. A total of 23 patients died during the follow-up period, including 6 of intramural hematoma of the aorta-related deaths (3 in the type A group and 3 in the type B group). The estimated freedom from intramural hematoma of the aorta-related events at 1 and 5 years was 70% +/- 8% and 54% +/- 11% for the type A group versus 73% +/- 6% and 58% +/- 8% for the type B group, respectively (P =.972). After excluding the nonintramural hematoma of the aorta-related deaths, the survival rates at 5 and 10 years were 80% +/- 9% and 80% +/- 9% for the type A group and 91% +/- 8% and 81% +/- 11% for the type B group (P =.211). CONCLUSIONS: Intramural hematoma of the aorta-related events occur equally in both types of intramural hematoma of the aorta. We recommend close follow-up for at least 5 years because most intramural hematoma of the aorta-related events occur during this period.

Aged↗
PubMed2004

Biomechanical study of a poly-L-lactide (PLLA) sternal pin in sternal closure after cardiothoracic surgery.

BACKGROUND: Stainless steel wiring is currently the standard method of median sternotomy closure but it has been reported that sufficient stiffness is not obtained by the method in anterior-posterior and cranial-caudal directions. A bioabsorbable Poly-L-Lactide (PLLA) sternal pin has been developed as an additive material for sternal closure. We biomechanically examined the effectiveness of a PLLA sternal pin in the two directions by using the sternum of a juvenile pig. METHODS: Juvenile pigs 14-17 kg weight were used. After the sternum was extirpated it was cut into two pieces at the midline. In a wire fixation group the pieces were fixed by two stainless wires. In a wire and intrasternal fixation group a hole was drilled into the bone marrow and a PLLA sternal pin for an infant was set into the hole. Then the both sides of the wired sternum were fixed tightly at the testing machine and the shear stress was forced into the one side. The shear stress was forced in anterior-posterior and cranial-caudal directions. RESULTS: In an anterior-posterior direction, the stiffness was 13.84 +/- 1.84 (N/mm) in a wire and intrasternal fixation group and 7.00 +/- 2.71 (N/mm) in a wire fixation group (p = 0.0002). In a cranial-caudal direction it was 10.61 +/- 4.88 (N/mm) and 4.38 +/- 2.12 (N/mm), respectively (p = 0.03). CONCLUSIONS: The use of a PLLA sternal pin as an additive material to steel wiring was effective in preventing the displacement of the sternum in both directions. Our data showed that closure technique using a sternal pin would provide adequate fixation.

Absorbable Implants↗
PubMed2004

Expression of the von Willebrand factor in atrial endocardium is increased in atrial fibrillation depending on the extent of structural remodeling.

BACKGROUND: The incidence of stroke in patients suffering atrial fibrillation (AF) is increased when left atrial enlargement occurs. Recently, the platelet adhesive molecule, von Willebrand factor (vWF), located in the atrial endocardium, has been shown to be increased in patients with a variety of heart diseases compared with patients who have no cardiac problems. METHODS AND RESULTS: We investigated the expression of vWF mRNA and protein in the endocardium as a possible prothrombotic alteration of AF in association with atrial structural remodeling. Atrial appendage specimens were obtained during either heart surgery or at an autopsy from AF patients with and without underlying heart disease. The immunohistochemical and in situ hybridization signals for vWF in the endocardium were well correlated and varied widely among the individual atrial appendages examined. The increased expression of vWF in the endocardium was associated with enlarged left atrial dimensions in mitral valvular disease or increased myocyte diameters in the underlying myocardium. Platelet adhesion/aggregation on the endocardium was always found under the fresh thrombi and was colocalized with strong vWF staining, but not necessarily with fibrinogen and/or fibrin staining. CONCLUSIONS: Endocardial overexpression of vWF may occur during the process of atrial structural remodeling contributing to the thrombotic predilection of AF in association with underlying heart disease.

Adult↗
PubMed2004

Lung biopsy diagnosis of operative indication in secundum atrial septal defect with severe pulmonary vascular disease.

OBJECTIVE: Surgical indication was determined by lung biopsy in 91 patients with secundum atrial septal defect (ASD) and severe pulmonary hypertension > 70 mm Hg of pulmonary arterial peak pressure and/or pulmonary vascular resistance of > 8 U/m(2). METHODS AND RESULTS: Pulmonary vascular disease (PVD) in ASD was classified into four types: (1) Musculoelastosis consisting of longitudinal muscle bundles and elastic fibers; surgery is indicated no matter how severely the peripheral small pulmonary arteries are occluded. Surgery was performed in all of the 20 patients, and the postoperative course was uneventful. (2) Plexogenic pulmonary arteriopathy: surgery is indicated for a PVD index < or = 2.3. Surgery was performed in 25 of the 32 patients. The remaining seven patients for whom surgery was not indicated are under follow-up observation. No deaths have occurred among the 32 patients. (3) Thromboembolism of small pulmonary arteries: Surgery is indicated for all such cases. Surgery was indicated in all of the five patients. (4) Mixed type of plexogenic pulmonary arteriopathy and musculoelastosis: Surgery is indicated if the collateral is not observed. Surgery was performed in 15 of the 25 patients. The remaining 10 patients for whom surgery was not indicated are under follow-up observation. Nine of these 91 patients associated with primary pulmonary hypertension were eliminated from this study. CONCLUSION: No deaths due to PVD occurred among the 82 patients who underwent lung biopsy diagnosis. Lung biopsy diagnosis is concluded to be very effective.

Adult↗
PubMed2004

Warfarin-intractable, intraatrial thrombogenesis in a 52-year-old woman with mitral stenosis and chronic atrial fibrillation.

Thromboembolic events are serious complications of atrial fibrillation (AF). We histologically investigated intraatrial thrombogenesis in a 52-year-old woman with mitral stenosis and chronic AF who had recurrent attacks of cerebral infarction despite continuous warfarin therapy. She underwent cardiac surgery for mitral valve replacement and maze procedure including left atrial thrombectomy. Macroscopic thrombi were found on the endocardium and their surfaces appeared rough and dark red in most areas. Histological examination showed that a single thrombus mass was composed of several tissue layers or blocks on the endocardium. Immunohistochemistry revealed stratum-like accumulations of small platelet aggregate/fibrin clot complexes in the superficial, fresh thrombus layers and multiple neovessel formation in the basal organized tissue layers. This case study suggests that intraatrial thrombi may develop in a stepwise fashion on the endocardium involving platelet aggregate/fibrin clot complex formation.

Adult↗
PubMed2003

Aortic root replacement with a stentless bioprosthesis in a patient with giant cell arteritis.

A 66-year-old woman was diagnosed with severe aortic regurgitation. Blood studies constantly showed positive C-reactive protein. Aortic valve replacement using a mechanical valve was carried out. Four months after the operation, echocardiogram showed aortic regurgitation due to paravalvular leakage. Reoperation was performed using a stentless aortic root bioprosthesis. The pathological specimen from the aortic wall was consistent with giant cell arteritis. The patient was treated with prednisone with dramatic improvement of systemic symptoms.

Aged↗
PubMed2003

Surgical repair for tracheo-innominate artery fistula with a muscle flap.

A 70-year-old woman was quickly diagnosed as having tracheo-innominate artery fistula by three-dimensional computed tomography. Immediate surgical exploration was performed to control the bleeding using a temporary shunt. After the damaged artery was excised, vascular reconstruction was performed to preserve the connection between the proximal and distal ends of the innominate artery with the interposition of a saphenous vein graft. A pedicled sternocleidomastoid muscle flap was successfully used for the tracheal reconstruction.

Aged↗
PubMed2003

Use of cuffed anastomosis in total aortic arch replacement.

The distal aortic anastomosis portion of the total arch surgery remains technically complex especially in cases in which an aortic arch aneurysm extends below level of carina. We present the cuffed anastomosis that overcomes this difficulty. We applied this technique in 49 patients of elective total aortic arch aneurysm repair using selective cerebral perfusion from 1996 to 2001. Hospital mortality was 2%.

Anastomosis, Surgical↗
PubMed2003

MCI-186 prevents spinal cord damage and affects enzyme levels of nitric oxide synthase and Cu/Zn superoxide dismutase after transient ischemia in rabbits.

OBJECTIVE: The mechanism of spinal cord injury is believed to be related to the vulnerability of spinal motor neuron cells against ischemia. We tested whether MCI-186, which is useful for treating ischemic damage in the brain, can protect against ischemic spinal cord damage. METHODS: After induction of ischemia, MCI-186 or vehicle was injected intravenously. Cell damage was analyzed by observing the function of the lower limbs and by counting the number of motor neurons. To investigate the mechanism by which MCI-186 prevents ischemic spinal cord damage, we observed the immunoreactivity of Cu/Zn superoxide dismutase, neuronal nitric oxide synthase, and endothelial nitric oxide synthase. RESULTS: MCI-186 eased the functional deficits and increased the number of motor neurons after ischemia. The induction of neuronal nitric oxide synthase was significantly reduced by the treatment with MCI-186. Furthermore, the increase in the induction of endothelial nitric oxide synthase and Cu/Zn superoxide dismutase was more pronounced. CONCLUSION: These results indicate that MCI-186 may protect motor neurons from ischemic injury by reducing neuronal nitric oxide synthase and increasing endothelial nitric oxide synthase. MCI-186 may be a strong candidate for use as a therapeutic agent in the treatment of ischemic spinal cord injury.

Animals↗
PubMed2003

The possible roles of mineralocorticoid receptor and 11beta-hydroxysteroid dehydrogenase type 2 in cardiac fibrosis in the spontaneously hypertensive rat.

In hypertension, aldosterone has been demonstrated to play a crucial role in cardiac fibrosis, which generally increases cardiac morbidity and death. However, few studies have reported the expression of the mineralocorticoid receptor (MR) and 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) in the heart under hypertensive conditions. Therefore, in this study, spontaneously hypertensive rats (SHR) were examined to elucidate the possible actions of mineralocorticoids via binding to MR. Wister Kyoto Rat (WKY), SHR, stroke-prone SHR (SHRSP), and malignant SHRSP (M-SHRSP) were used. Total RNA was extracted from the left ventricle of these rats, and examined for the expression levels of MR, 11beta-HSD2 and Collagen types 1 and 3 using reverse transcription real-time quantitative polymerase chain reaction employing the Light Cycler Instrument. Blood pressure was significantly different among each group. The mean mRNA levels for MR, 11beta-HSD2 and Collagen types 1 and 3 in M-SHRSP were found to be significantly increased compared to those of WKY, whereas no significant differences in mRNA levels were detected among SHR and SHRSP. Findings from the present study appear to demonstrate that MR and 11beta-HSD2 mRNA significantly rise in the left ventricle of M-SHRSP and increase of these mRNA is one of the cause of cardiac fibrosis.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed2003

Intramural hematoma and dissection involving ascending aorta: the clinical features and prognosis.

OBJECTIVE: The clinical features and remedies of acute aortic intramural hemorrhage (IMH) are well discussed. This study prospectively analyzes the features compared with those of Type A aortic dissection, and evaluate the treatment modalities and the prognosis with Type A IMH managed by our original program, Eighty-six consecutive patients consisted of acute type A IMH (n = 36) and dissection (n = 50) were diagnosed between January 1994 and March 2002. Patients with IMH were older (mean 67 and 60, P = 0.0017), more hypertensive (P = 0.0015), not hyperlipidemic (P = 0.0042) than those with dissection. The incidences of preoperative pericardial effusion and aortic regurgitation were significantly lower in patients with intramural hematoma than with dissection, respectively (8:28 versus 22:28, P = 0.0366, 4:32 versus 22:28, P = 0.0011). METHODS: Urgent operation was performed for the patients of IMH with cardiac tamponade or rupture and all dissections. Uncomplicated patients of the patients with IMH were treated medically. Late surgical conversion was applied for the medical treated case on any condition with persistent pain, progression to type A dissection, ruptured aneurysm, or aneurysmal enlargement (>60 mm). Operative mortality, late cardiovascular event, and long-term survival were evaluated statistically. RESULTS: Ten urgent surgical repairs were performed with type A IMH patients and one patient died postoperatively. The rest 26 patients were treated medically. The mean follow up period was 39 +/- 28 months. Among the 26 patients, seven were converted surgical intervention. Cardiovascular event free curve on the 26 patients (Kaplan-Meier, CI: 95%) was 65.6% (45.9-85.3), 59.1% (37.5-80.6) at 2, 4 years. There were six dissection and six IMH patients death during follow up. Two of IMH patients died from cardiovascular event. The actuarial survival rate (Kaplan-Meier, CI: 95%) was 87.5% (76.0-99.1):87.9% (66.2-97.1), 81.7% (66.2-97.1):87.9% (78.8-97.0) at 2, 4 years (P = 0.8393). CONCLUSIONS: Type A IMH tends to occur in older, more hypertensive and not hyperlipidemic patients, showed lower incidences of preoperative aortic valve regurgitation and pericardial effusion than dissection. Medical treatment alone was not enough to manage all type A IMH patients, and 47.2% (17/36) of the patients needed surgical intervention. Urgent surgical repair was not necessary for all type A IMH patients to achieve favorable surgical outcome with careful follow-up using imaging modality.

Acute Disease↗