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Biomedical subjects

Hitoshi Yaku

Publications and source records attributed to Hitoshi Yaku.

At least 19 recordsLinked to original sources
PubMed2007

Pulmonary arterial reconstruction for pulmonary coarctation in early infancy.

BACKGROUND: Pulmonary atresia with pulmonary coarctation may complicate diminished and unbalanced pulmonary development. The aim of this study is to assess the outcome of pulmonary arterial reconstruction with cardiopulmonary bypass in early infancy for sufficient and balanced pulmonary development. METHODS: We performed a retrospective review of 15 patients with pulmonary coarctation younger than 4 months of age who underwent pulmonary arterial reconstruction between 2001 and 2005. The mean age and weight were 42.2 days and 3.62 kg, respectively. The patient population included 5 biventricular repair candidates and 10 Fontan candidates. To evaluate the pulmonary arterial development, the preoperative and postoperative pulmonary arterial index and minimum diameter of the pulmonary artery were compared. RESULTS: No early or in-hospital deaths occurred, and there was no nonconfluent pulmonary artery development or segmental mal-development after a mean follow-up period of 14.9 months. Immediate pulmonary flow regulation was required in 2 patients because of excessive pulmonary flow. The mean pulmonary arterial index increased significantly from 103 mm2/m2 to 343 mm2/m2, and the mean minimum diameter of the pulmonary artery increased significantly from 2.02 mm to 4.45 mm. Four biventricular repair candidates completed definitive repair, and 2 required surgical reintervention in the pulmonary artery. Six Fontan candidates completed the Glenn procedure, and 1 completed the Fontan procedure. Three required surgical reintervention in the pulmonary artery. Two late deaths occurred after the Glenn procedure because of ventricular dysfunction and respiratory infection. CONCLUSIONS: Pulmonary arterial reconstruction in early infancy provides sufficient and balanced pulmonary arterial development for pulmonary atresia with pulmonary coarctation.

Arterial Occlusive Diseases↗
PubMed2006

Human cardiac stem cells exhibit mesenchymal features and are maintained through Akt/GSK-3beta signaling.

Recent evidence suggested that human cardiac stem cells (hCSCs) may have the clinical application for cardiac repair; however, their characteristics and the regulatory mechanisms of their growth have not been fully investigated. Here, we show the novel property of hCSCs with respect to their origin and tissue distribution in human heart, and demonstrate the signaling pathway that regulates their growth and survival. Telomerase-active hCSCs were predominantly present in the right atrium and outflow tract of the heart (infant > adult) and had a mesenchymal cell-like phenotype. These hCSCs expressed the embryonic stem cell markers and differentiated into cardiomyocytes to support cardiac function when transplanted them into ischemic myocardium. Inhibition of Akt pathway impaired the hCSC proliferation and induced apoptosis, whereas inhibition of glycogen synthase kinase-3 (GSK-3) enhanced their growth and survival. We conclude that hCSCs exhibit mesenchymal features and that Akt/GSK-3beta may be crucial modulators for hCSC maintenance in human heart.

Adult↗
PubMed2006

Atrial septal defect repair through limited lateral thoracotomy in children.

OBJECTIVE: We have developed a surgical method for atrial septal defect repair through a limited right lateral thoracotomy in which the incision line begins 2 cm caudal from the lower angle of the scapula and ends at the midaxial line, thereby improving patient satisfaction with the cosmetic results of treatment. METHODS: We performed a retrospective review of 28 patients who underwent isolated atrial septal defect repair through a limited right lateral thoracotomy between January 2002 and August 2004. The mean age and mean body weight at the time of the operation were 85.8 months (range 9-236 months) and 23.0 kg (range 8.0-56.0 kg), respectively. All repaired defects were the ostium secundum type. RESULTS: There was no operative or late mortality and no late morbidity after a mean follow-up of 26 months (range 12-41 months). Echocardiography showed no residual shunt in any of the patients. The mean length of the skin incision was 7.8 cm (range 5.0-11.0 cm), and almost all the patients had satisfactory cosmetic results. CONCLUSION: The atrial septal defect repair through a limited right lateral thoracotomy in pediatric patients showed satisfactory surgical results and excellent cosmetic results.

Adolescent↗
PubMed2006

Pulmonary artery augmentation using autologous vena cava in right heart bypass operations.

We obtained good results in the right heart bypass operation concomitant with the pulmonary arterial augmentation using the vena cava in 7 patients. We report the techniques used in 2 representative patients. The techniques used were a hemi-Fontan procedure with large superior vena caval patches and a bidirectional cavopulmonary shunt with superior vena caval interposition. These techniques have advantages in that the augmented pulmonary arteries have growth potential and low thrombogenicity because the procedures can be performed without the use of prosthetic materials or xenografts, especially in cases in which it is impossible to use the autologous pericardium.

Cardiopulmonary Bypass↗
PubMed2006

Perioperative amino acid infusion improves recovery and shortens the duration of hospitalization after off-pump coronary artery bypass grafting.

Perioperative amino acid infusion helps maintain core temperature and improves patient outcomes after gynecologic and orthopedic surgery. In the present study we prospectively determined the effect of amino acid infusion on esophageal core temperature and postoperative outcomes during off-pump coronary artery bypass grafting (CABG). One-hundred-eighty consecutive patients undergoing primary elective or urgent off-pump CABG were randomly divided into two groups: the i.v. amino acid infusion group (4 kJ kg(-1) h(-1) starting 2 h before surgery) and the saline infusion group (similar period and volume of saline infusion). The esophageal core temperature at the end of surgery was 35.6 (35.3-35.8) degrees C [mean (95% confidence interval)] in the saline infusion group and 36.1 degrees C (35.9-36.3) degrees C in the amino acid infusion group (P = 0.01). Kaplan-Meier analysis demonstrated that patients given amino acids required a significantly shorter duration of postoperative mechanical ventilation than patients given saline [median (95% confidence interval), 3.0 (2.5-3.9) vs 4.5 (3.8-5.8) h; P = 0.01]. Furthermore, intensive care unit stay [20 (19.5-38.4) vs 44 (21-45) h; P = 0.001] and days until fit for discharge from hospital [10 (9-11) vs 12 (11-13) days; P = 0.004] were significantly shorter in patients given amino acid. Perioperative amino acid infusion in patients undergoing off-pump CABG effectively minimizes intraoperative hypothermia and improves postoperative recovery.

Aged↗
PubMed2006

[Off-pump coronary artery bypass via median sternotomy].

Off-pump coronary artery bypass grafting (off-pump CABG: OPCAB) is a useful technique of coronary revascularization in terms of reduction of operative mortality and morbidity. Because the biggest advantage of OPCAB may be that it can prevent perioperative stroke, we selected patients for OPCAB based on the preoperative evaluation of neck and intracranial vessels. We could totally eliminate intraoperative stroke in patients undergoing OPCAB, although some patients with a severe neck vessel disease developed postoperative stroke/transient ischemic attack in an early postoperative period (the 4th approximately 8th postoperative day) mostly due to thrombosis from the diseased vessel. Therefore, high-risk patients with a severe neck vessel disease should be treated with a more aggressive anticoagulation protocol postoperatively. As for the quality of grafting, the number of graft, the rate of complete revascularization, and early graft patency were comparable between OPCAB and CABG with a cardiopulmonary bypass. The long-term results in terms of freedom from cardiac death and cardiac events were also comparable. We conclude that we could achieve less invasiveness in coronary revascularization by using an OPCAB technique without compromising the quality of grafting.

Aged↗
PubMed2006

Choice of hemodynamic support during coronary artery bypass surgery for prevention of stroke.

The objective of this study was to evaluate a protocol involving cerebrovascular accident (CVA) risk evaluation and choose adequate hemodynamic support that prevents major CVA. For evaluation of CVA risk, we undertook head computed tomography (CT), magnetic resonance imaging (MRI), magnetic resonance angiography (MRA), chest CT, carotid artery Doppler echo, carotid artery MRA, and echo scanning of ascending aorta during surgery. Cerebrovascular specialists did the physical examinations and reading of images. Hemodynamic support (chemical arrest on pump, on-pump beating, or off pump) was chosen according to the result of risk evaluation. We retrospectively studied 92 cases before (group A; 1997 October to 1998 November) and 91 after (group B; 1998 November to 2001 January) starting protocol. We also studied urgent cases (group C; 9 cases; 1997 October to 2001 January) in which we did not use the protocol. When adequate hemodynamic support was chosen, major CVA (modified Rankin scale grades 3, 4, and 5) incidence decreased from 6.6% (six case; group A) to 0% (p < .05; group B). There were three major CVA cases in group C (p < .05 vs. group B), in which the ascending aorta was clamped. Our protocol eliminated major CVA associated with elective coronary surgery. We need simpler evaluation, however, when we undertake urgent surgery.

Aged↗
PubMed2006

[Off-pump CABG].

Explore the source record for details and available documents.

Coronary Artery Bypass, Off-Pump↗
PubMed2005

Early outcome of a randomized comparison of off-pump and on-pump multiple arterial coronary revascularization.

BACKGROUND: Previous randomized comparisons of off-pump and on-pump coronary artery bypass grafting (CABG) have yielded controversial results about the cardiac and neurological events and graft patency. In addition, these randomized studies were composed of CABG with a few arterial grafts. We performed a prospective randomized controlled study to compare off-pump and on-pump CABG with multiple arterial grafts. METHODS AND RESULTS: Between July, 2002, and September, 2004, 167 consecutive unselected patients referred for elective primary CABG were randomly assigned to undergo multiple arterial off-pump CABG (n=81) or on-pump CABG (n=86). The clinical outcomes and S-100 protein, neuron-specific enolase, and maximum creatine kinase-MB levels were compared. Early graft patency was examined within 3 weeks after the operation by angiography. The number of grafts performed per patient (3.5+/-1.0 for off-pump CABG and 3.6+/-0.9 for on-pump CABG) and the number of arterial grafts performed per patient (3.3+/-1.0 for off-pump CABG and 3.4+/-0.9 for on-pump CABG) were similar. Completeness of revascularization (completed grafts/planned grafts) was 98% in both procedures. There were no hospital deaths in either group. The operation time was significantly (P<0.001) shorter in the off-pump group than in the on-pump group (267+/-60 minutes versus 307+/-59 minutes). The incidence of perioperative complications was similar. The frequency of no need for transfusion was higher in the off-pump group than in the on-pump group (80% versus 55%, P<0.001). The S-100 protein levels at the admission into the intensive care unit were significantly (P<0.001) lower in the off-pump group than in the on-pump group (0.20+/-0.11 ng/mL versus 0.34+/-0.22 ng/mL). The neuron-specific enolase levels at the intensive care unit admission were significantly (P<0.001) lower in the off-pump group than in the on-pump group (10.4+/-9.0 ng/mL versus 16.9+/-6.9 ng/mL). Maximum creatine kinase-MB levels were significantly (P=0.046) lower in the off-pump group than in the on-pump group (17.1+/-16.7 IU/L versus 21.5+/-10.6 IU/L). The overall early graft patency rate with or without stenosis was the same (98%) in both groups, but the rate without stenosis was slightly worse in the off-pump group (93%) than in the on-pump group (96%) (P=0.093). The stenosis-free patency rate in the right coronary area was significantly (P=0.028) worse in the off-pump CABG group (90%) than in the on-pump group (99%). CONCLUSIONS: Off-pump CABG with multiple arterial grafts was as safe as the conventional on-pump CABG, with similar completeness of revascularization and early graft patency.

Aged↗
PubMed2005

Differentiation from embryonic stem cells to vascular wall cells under in vitro pulsatile flow loading.

This study evaluated the possibility of differentiation from embryonic stem (ES) cells to vascular wall cells by physical (mechanical) stress loading in vitro. A cell mixture containing Flk1-positive cells (ca. 30%) derived from murine ES cells was added to a compliant microporous tube made of segmented polyurethane. The compliance of the tube was close to that of the human artery [the stiffness parameter (beta) = 57.2 (n = 5, SD < 5%)]. The luminal surface of the tube was fully covered with the cells by preincubation for two days in the presence of vascular endothelial growth factor (VEGF). After 2 days of additional incubation without VEGF under static conditions, layering of the grown cells, mostly smooth muscle actin (SMA)-positive cells, was observed only on the luminal surface of the tube. The cells were flat, polygonal, and randomly oriented. On the other hand, after a 2-day incubation under a weak pulsatile flow simulating the human venous systems [wall shear stress (WSS) from -0.98 to 2.2 dyn/cm(2); circumferential strain (CS) 4.6-9.6 x 10(4) dyn/cm(2)] without VEGF, cells in the superficial layer were regularly oriented in the direction of the pulsatile flow. The oriented cells exhibited endothelial-like appearance, indicating that they were platelet endothelial cell adhesion molecule 1 (PECAM1)-positive. In addition, the cells growing into the interstices in the deeper layer showed smooth muscle-like appearance, indicating that they were SMA-positive. Differentiation to two different cell types and segregation of incorporated ES cells may be simultaneously encouraged by the combination of WSS and CS. It is expected that the monobloc building of hierarchically structured hybrid vascular prostheses composed of several vascular wall cell types is possible by physically synchronized differentiation of ES cells.

Actins↗
PubMed2005

Development of sutureless vascular connecting system for easy implantation of small-caliber artificial grafts.

A novel sutureless vascular connecting system, an assembly with a delivery rod, an introducing sheath, and a connecting device, was developed for easy implantation of small-caliber vascular grafts less than 2 mm in internal diameter. A microporous stainless tube (length 2 mm, external diameter 1.6 mm, wall thickness 65 microm, pore diameter 400 microm, pore-to-pore distance 500 microm) was designed to serve as a connecting device. The feasibility of the system was tested using two types of preliminary animal experiments. One animal model consisted of graft implantation into the rat abdominal aorta (1.5 mm in diameter). The connecting device was inserted into the proximal and distal ends of the aorta through the introducing sheath by pushing the delivery rod with the connecting device placed over it. Subsequently, the aortic segments were inserted into both ends of model grafts made of segmented polyurethane (1.8 mm in internal diameter) and were fixed with banding silk threads from the exterior. The procedure was completed within 20 min without requiring specialized microsurgery techniques. Blood leakage and obstruction did not occur. The second model consisted of an end-to-end anastomosis between rabbit common carotid arteries (2 mm in diameter), which was performed within several minutes of blood flow interruption. Scanning electron microscopy demonstrated that the luminal surface of the device was fully covered with endothelial cells (ECs) after 1 week as a result of transluminal ingrowth of native ECs through the micropores in the device. This endothelialization may prevent early thrombus-induced occlusion. This simple and "easy-to-learn" technique will promote the development of small-caliber arterial grafts, and furthermore, it may have potential for clinical application.

Anastomosis, Surgical↗
PubMed2005

Does off-pump coronary artery bypass grafting beneficially affect renal function?

BACKGROUND: Off-pump coronary artery bypass grafting (CABG) has been reported to beneficially affect renal function, but this remains to be confirmed. The purpose of the present paper was to study the effects of off-pump CABG on renal function and analyse predictors of postoperative renal impairment in patients who received off-pump CABG. METHODS: A total of 451 patients who underwent isolated CABG between January 1999 and August 2003 were retrospectively studied. No patient was receiving dialysis. A total of 300 patients (228 men) underwent off-pump CABG (off-pump group) and 151 patients (104 men) underwent on-pump CABG (on-pump group). Perioperative serum creatinine levels and creatinine ratios (peak postoperative creatinine level/preoperative creatinine level) were compared between the groups. RESULTS: Renal impairment (serum creatinine >1.5 mg/dL) developed postoperatively in 12.7% of the off-pump group and 18.5% of the on-pump group (P = 0.1). The creatinine ratio was significantly lower in the off-pump group (1.2 +/- 0.4) than in the on-pump group (1.4 +/- 0.7, P = 0.003). Logistic regression analysis demonstrated that the strongest predictors of postoperative renal impairment in off-pump CABG were left ventricular dysfunction (odds ratio 10.8) and multivessel grafting (odds ratio 4.3). CONCLUSIONS: Off-pump CABG provides better renal protection than on-pump CABG. However, perioperative renal function should be closely monitored in patients who have left ventricular dysfunction or who undergo multivessel grafting, even when off-pump CABG is performed.

Aged↗