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Biomedical subjects

Takuro Misaki

Publications and source records attributed to Takuro Misaki.

18 recordsLinked to original sources
PubMed2006

Closure of multiple ventricular septal defects by the felt sandwich technique: further analysis of 36 patients.

OBJECTIVES: We previously described a novel technique for closure of trabecular ventricular septal defects by sandwiching the septum with 2 polyester felt patches without requiring left ventriculotomy. We describe the midterm results of this technique and the postoperative cardiac function. METHODS: This is a retrospective study of 36 consecutive patients. The median age and body weight at the time of repair was 15 months (range: 2-115 months) and 7.8 kg (range: 3.9-51.9 kg), respectively. RESULTS: Sixty-three trabecular ventricular septal defects in 36 patients were closed with the felt sandwich technique. In the early postoperative period, 1 patient died of pulmonary hypertensive crisis. There were 2 late deaths. One patient died of pneumonia 6 months after surgery, and another died suddenly of ventricular arrhythmias 2 years after surgery. Three patients required reoperation (closure of major residual ventricular septal defect, cardiac transplantation for dilated cardiomyopathy, and pacemaker implantation for complete atrioventricular block). Postoperative left ventricular fractional shortening in the group with a body surface area less than 0.4 m2 was significantly lower than that in the group with a body surface area of 0.4 m2 or greater (0.22 +/- 0.09 vs 0.31 +/- 0.06, P = .0027). Moreover, there was a strong correlation between postoperative left ventricular ejection fraction and total patch area/body surface area ratio (R = -0.74, P = .0004). CONCLUSION: Multiple trabecular ventricular septal defects can be closed with the felt sandwich technique easily and safely. Although this technique can be used in small infants, the use of numerous felt patches disturbs the movement of ventricular septum, which may cause postoperative cardiac dysfunction.

Body Surface Area↗
PubMed2006

Open heart operation in a child with congenital heart disease and hereditary spherocytosis.

An 18-month-old girl with hereditary spherocytosis underwent closure of the ventricular septal defect, commissurotomy of the pulmonary valve, and patch angioplasty of the pulmonary trunk without previous splenectomy. No serious complications as a result of hemolysis occurred in the perioperative period. Open heart surgery can therefore be safely performed in young children with congenital heart disease and hereditary spherocytosis who have not previously undergone splenectomy.

Female↗
PubMed2005

An echo-contrast agent, Levovist, lowers the ultrasound intensity required to induce apoptosis of human leukemia cells.

To verify the effect of echo-contrast agent (ECA) on apoptosis induced by ultrasound, leukemia cell lines (Jurkat, Molt-4 and U937) were sonicated at intensities previously shown to induce optimal apoptosis with or without Levovist, an ECA. The results showed that loss of viability and apoptosis can be induced in all three cell lines, apoptosis highest with Molt-4, based on viability and DNA fragmentation assay. Such finding was supported by corresponding increase of cells with low mitochondrial membrane potential, high superoxide production, increased intracellular calcium concentration, and phosphorylation of histone H2AX after sonication. Optimal ultrasound condition was 0.3W/cm(2), 1MHz, 10% duty factor pulsed at 100Hz; but in the presence of Levovist, an apparent shift of cell killing induction was observed at 0.2W/cm(2). While these results further confirmed previous findings on ultrasound-induced apoptosis, they also suggest that use of an enhancing factor, such as addition of ECA, may be useful in cancer therapy when a much lower intensity is desired.

Apoptosis↗
PubMed2005

Apoptosis induced by the sonomechanical effects of low intensity pulsed ultrasound in a human leukemia cell line.

To obtain an optimal condition for ultrasound (US)-induced apoptosis that could be useful for cancer therapy, we applied low intensity pulsed US to sonicate U937 cells in vitro. Cells were then incubated at different time intervals before measuring apoptosis. The apoptosis was assessed by DNA fragmentation and phosphatidylserine externalization. The pattern of the decrease in mitochondrial membrane potential was determined by flow cytometry. Optimal apoptosis (70.0+/-13.8%) with minimal lysis was attained with 1 MHz ultrasound 0.3 W/cm2, 10% duty factor at 100 Hz for 1 min) at 12 h after sonication. Lack of US-induced free radical detection and absence of Heme oxygenase-1, an intracellular oxidative stress marker, up-regulation in cells, suggest that sonomechanical, not sonochemical, effects are the main mechanism involved.

Apoptosis↗
PubMed2005

Ischemic changes in evoked spinal cord potentials during profound hypothermic circulatory arrest in thoracic aortic surgery.

PURPOSE: We examined the changes in evoked spinal cord potentials (ESCP) during profound hypothermic circulatory arrest to estimate the safe ischemic time. METHODS: We monitored ESCPs during surgery for descending thoracic or thoracoabdominal aneurysms in five patients. Evoked spinal cord potential recordings were obtained before cooling (baseline), then every few minutes during circulatory arrest, and at the end of the operation. RESULTS: After circulatory arrest, the amplitude of ESCPs decreased with time. We calculated the simple linear regression between the amplitude of ESCPs and the circulatory arrest time by the least-squares method, and found a highly linear relationship between amplitude and arrest time in all five patients. The time until disappearance of ESCPs was estimated as 50.7 +/- 20.4 min (95% level of confidence). CONCLUSION: When an ESCP disappeared, ischemic spinal cord injury had occurred. This demonstrates the potential value of estimating the time of disappearance of ESCPs to prevent ischemic spinal cord injury during descending thoracic aortic surgery.

Aged↗
PubMed2005

Left pulmonary arterioplasty--extended end-to-end anastomosis.

Surgical arterioplasty for left pulmonary branch stenosis often produces unsatisfactory results. We report a new operative approach involving a modification of end-to end anastomosis, providing a widely patent and nonredundant anastomosis.

Anastomosis, Surgical↗
PubMed2005

Surgical repair of coronary sinus orifice atresia.

We report a 10-month-old boy who underwent a bi-directional Glenn procedure and repair of coronary sinus orifice atresia. The left superior vena cava was the only vessel communicating with the coronary sinus in this case. The coronary sinus was allowed to communicate freely with the left atrium by creating a partially unroofed coronary sinus using a left superior vena cava flap.

Coronary Angiography↗
PubMed2004

Complete port-accessed lobectomy by the muscle-sparing method.

We report the case of a 53-year-old woman who underwent complete port-accessed middle lobectomy by a new technique that preserves all muscles, including the extracostal and intercostal muscles. The operation was performed by using only thoracovideoscopy, and the resected lobe was withdrawn in a pouch through a subxiphoid incision through the substernal route. This complete port-accessed lobectomy is a new technique and is thought to be less invasive than video-assisted lobectomy with minithoracotomy.

Female↗
PubMed2004

Cusp extension technique for bicuspid aortic valve in Turner-like stigmata.

A 19-year-old girl with bicuspid aortic valve and Turner-like stigmata underwent a successful repair with a cusp extension technique using fresh autologous pericardium for aortic insufficiency. She also had a simultaneous artificial graft replacement for ascending aortic dilatation. Aortic valve function showed no significant stenosis and slight insufficiency 2 years postoperatively. This technique is recommended to avoid a Ross or Ross/Konno procedure because of its ready availability, simplicity and excellent midterm results.

Adult↗
PubMed2004

Complex atrial reentrant circuits evaluated by entrainment mapping using a multielectrode basket catheter.

Atrial tachycardias after open heart surgery sometimes have complex reentrant circuits. A patient with a dual-loop atrial reentrant circuit occurring after mitral valve replacement was evaluated by entrainment mapping with a basket catheter. The position of the catheter was adjusted to obtain atrial electrograms of the anterior and posterior septal areas, the crista terminalis, the free wall, and the tricuspid annular region. Entrainment mapping identified a dual-loop reentry consisting of one circuit around the tricuspid annulus and another around the septal atriotomy scar. The reentrant circuit around the septal incision was eliminated by ablating the area between the septal incision and the inferior vena cava, and the circuit around the tricuspid annulus was terminated with an additional linear ablation between the tricuspid annulus and the inferior vena cava. Entrainment mapping using a multielectrode basket catheter is very useful for identifying complex atrial reentrant circuits.

Catheter Ablation↗
PubMed2004

Abdominal surgery following coronary artery bypass grafting using an in situ right gastroepiploic artery graft.

OBJECTIVE: The usefulness of the gastroepiploic artery (GEA) as arterial grafts in coronary artery bypass grafting (CABG) has been studied extensively. We report our experience performing abdominal surgery after CABG using in-situ GEA. METHODS: The subjects were eight patients who underwent abdominal surgery after CABG with an in situ GEA graft. The surgical indications were malignant tumors in five patients, an infrarenal abdominal aortic aneurysm in two patients and a diaphragmatic hernia in one patient. The interval from the CABG to the abdominal surgery ranged from 3 to 19 months. RESULTS: Operations included distal gastrectomy in two cases, total gastrectomy in one case, local excision of the stomach in one case, and excision of the transverse colon in one case. Aorto-biiliac artery bypass was performed in two cases, and the diaphragmatic hernia was reconstructed using standard techniques. When the skeletonization method has been used to harvest the GEA, GEA grafts were easily identified during a laparotomy, and the abdominal procedure was performed using routine methods. One patient died of cancer, and the other patients are alive 1 year 2 months to 4 years 5 months after surgery. No patient reported recurrence of angina. CONCLUSION: The risk of abdominal reoperations should be considered when using the in situ right GEA for CABG. We recommend the skeletonization method for GEA harvest to decrease the difficulty during second abdominal operations.

Aged↗
PubMed2004

[Arrhythmias].

The success of the radiofrequency catheter ablation procedure for most types of supraventricular and ventricular tachycardia largely eliminated the role of surgical therapy of arrhythmias. However, there remains a subset of arrhythmia patients in whom urgent surgical treatments are required. In this review we mention recent developments of the urgent surgical treatment for arrhythmias. In cases with complete atrioventricular (AV) block and ventricular fibrillation which associated with sudden death, temporary cardiac pacing and cardiac defibrillation using direct current (DC) cardioversion must be immediately induced and followed by implantation of permanent cardiac pacemaker or implantable cardioverter defibrillator (ICD), if necessary. In addition to usual cardiac pacing therapy, novel pacing therapy has been developed recently for the patients with symptomatic heart failure. Cardiac resynchronization therapy (CRT) using biventricular pacing is an emerging therapy for improvement of cardiac function in patients with heart failure in association with intraventricular conduction delay. To prevent the sudden death in patients with heart failure, biventricular pacing combined with ICD are also implanted and its efficacy are reported. With the exception of the pacing therapy, curative surgical treatments are limited in drug-refractory atrial fibrillation and ventricular fibrillation/tachycardia after myocardial infarction requiring Dor's type operation. In any case surgical treatment must be performed promptly and suitably with lower invasive methods.

Arrhythmias, Cardiac↗
PubMed2004

Recent topics on the surgical treatment for atrial fibrillation.

After the introduction of endocardial radiofrequency catheter, only two arrhythmias, atrial fibrillation and ischemic ventricular tachycardia require surgical procedures. In this review, we describe recent advancements and problems of surgical treatment for atrial fibrillation. On the basis of multiple-circuit re-entry theory, Cox developed the maze operation with the aim of interrupting the re-entry circuit. Although this procedure has become the gold standard technique for the surgical treatment of atrial fibrillation with approximately 90% success rate, several modifications have been made over time. To obtain a more physiological atrial transport function, radial approach technique or bilateral appendage-preserved maze procedures were developed and to simplify surgical procedures, maze operation with cryo-ablation or radiofrequency-ablation were created. Other topics are concerned with surgical target or approach to atrial fibrillation. Ectopic focus theories from pulmonary veins have been widely recognized recently and the surgical isolation of pulmonary veins orifices is performed with various energy sources. In addition to standard cut-and-sew surgical technique, cryoablation, unipolar or bipolar radiofrequency ablation, or microwave ablation were induced with endocardial or epicardial approach for the achievement of less invasive cardiac surgery. As atrial fibrillation leads to frequent mortality, cardiac surgeons have to treat atrial fibrillation with other cardiac disease more frequently to obtain better quality of operative results.

Atrial Fibrillation↗
PubMed2003

Transannular patching for tetralogy of Fallot with an anomalous right coronary artery.

A 7-year-old girl underwent transannular patching under the mobilized anomalous right coronary artery across the right ventricular outflow to treat progressing infundibular stenosis 6 years after total repair of the tetralogy of Fallot. The procedure completely relieved recurrent stenosis. Simultaneous angiography of the coronary artery and right ventricle were useful in precisely evaluating coronary anatomy.

Child↗
PubMed2003

Myocardial ischemic preconditioning during minimally invasive direct coronary artery bypass grafting attenuates ischemia-induced electrophysiological changes in human ventricle.

OBJECTIVE: Ischemic preconditioning (IPC) has been found to protect the myocardium in animal studies. However, clinical studies have been limited and the clinical effects of IPC are still uncertain. The purpose of this study was to assess whether IPC has any protective effect on the human myocardium during minimally invasive CABG (MIDCAB), by means of epicardial electrophysiological testing. METHOD: Forty-five patients with left anterior descending artery disease who underwent a MIDCAB procedure were evaluated. In the present study, the electrical potentials which were not affected by cardio-pulmonary bypass or cardioplegia were measured. The ratio of longitudinal to transverse conduction velocity (phiL /phiT), and QT, JT dispersions were measured using plaque electrodes in the preischemic state, during a 5-minute coronary occlusion, during the subsequent 5-minute reperfusion, during 5- and 10-minute anastomosis periods, and after anastomosis. RESULT: The phiL/phiT was 2.2 +/- 0.2 at baseline. Anisotropy was exaggerated during the 5-minute coronary occlusion (2.6 +/- 0.3). During anastomosis, conduction velocities were decreased, but showed no further deterioration (2.4 +/- 0.3, and 2.4 +/- 0.3, respectively). QT and JT dispersions were improved by reperfusion. CONCLUSION: The effectiveness of IPC during the MIDCAB procedure was confirmed electrophysiologically. Anisotropy and dispersions were minimized after IPC, therefore IPC demonstrated antiarrhythmic protective effects on the human myocardium.

Aged↗
PubMed2002

Long-term usefulness of percutaneous intrapericardial fibrin-glue fixation therapy for oozing type of left ventricular free wall rupture: a case report.

This report describes a long-term survival case of left ventricular free wall rupture treated with percutaneous intrapericardial fibrin-glue fixation therapy. A 82-year-old woman was admitted to the emergency room because of vomiting and syncope diagnosed as acute posterolateral myocardial infarction complicated by cardiac tamponade. After her hemodynamic condition was stabilized by drawing off the bloody pericardial effusion, fibrin-glue was injected into pericardial space with the expectation that the glue would cover the oozing site of the left ventricular epicardium. After this therapy, the patient recovered and did not have any no recurrent cardiac events for 1 year. Serial echocardiographic studies revealed a preserved left ventricular function and no development of left ventricular restriction. This case suggests that percutaneous intrapericardial fibrin-glue fixation therapy is an effective treatment for the oozing type of left ventricular free wall rupture and that there is no risk of left ventricular restriction during long-term follow-up.

Administration, Cutaneous↗
PubMed2002

[Current status of surgery for the treatment of arrhythmia].

The success of the radiofrequency catheter ablation procedure for most types of supraventricular and ventricular tachycardia largely eliminated the role of surgical therapy of arrhythmias. However, there remains a subset of arrhythmia patients in whom the catheter approach has not been successful and types of arrhythmias with high recurrence rates following initially successful catheter ablation procedures where surgery can provide more definitive therapy. On the other hand, collaborations therapy with surgery and catheter procedure has become more important. For example, some of the new treatment strategies are based on the replacement of the surgical incisions of the Maze procedure using intraoperative radiofrequency coagulation thereby preventing functional determined reentrant circuits. It can be expected that intraoperative ablation for arrhythmia will become an important curative treatment strategy.

Arrhythmias, Cardiac↗