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Biomedical subjects

Yutaka Kotsuka

Publications and source records attributed to Yutaka Kotsuka.

27 records · Page 2Linked to original sources
PubMed2002

Biologic glue-molded "bio-mini-paddle" electrode used for atrial and ventricular pacing and defibrillation.

Atrial and ventricular dysrhythmias developing after cardiac operation further reduce cardiac output, posing a serious problem for postoperative management. We have developed a "bio-mini-paddle" electrode designed to be attached directly to the myocardium for atrial or ventricular defibrillation and pacing for intraoperative and postoperative cardiac management. We use fibrin glue for the paddle, which is biodegradable. The characteristics of this unique paddle were examined using mongrel dogs.

Animals↗
PubMed2002

Open stent-grafting for aortic arch aneurysm is associated with increased risk of paraplegia.

BACKGROUND: Open surgery using the endovascular stent-graft is a novel technique that lessens the invasiveness of surgery for the aortic arch. However, the outcome of this procedure remains uncertain. METHODS: Between November 1996 and July 2000, a total of 19 patients underwent open surgery using an endovascular stent-graft for thoracic aortic aneurysms. There were 15 men (78.9%) and 4 women (21.1%). Patient age ranged from 29 to 82 years (mean 69.3 years, median 74 years). Atherosclerotic thoracic aortic aneurysms were present in 17 patients (89.4%) and aortic dissection in 2 patients (10.5%). RESULTS: Two patients (10.5%) died in the hospital and 4 patients (21.1%) presented with paraplegia postoperatively. Among the 4 patients with postoperative paraplegia, 1 case was complicated with intraoperative aortic dissection. The other 3 patients with paraplegia had spinal cord ischemic time of more than 60 minutes and intraoperative body weight gain of more than 4 kg. Of these 3 patients, hemodynamic instability after cardiopulmonary bypass was observed in 1 patient and cholesterin embolus in the anterior spinal artery was found at autopsy in another. On univariate analysis, age greater than 75 years was the only risk factor associated with paraplegia (p < 0.05). Autopsy findings for the 2 patients showed that the Adamkiewicz arteries were not blocked by the stent-graft in either patient. CONCLUSIONS: Intraoperative aortic dissection, embolization of the intercostal arteries, long ischemic time of the spinal cord, and excessive weight gain during operation may have been associated with the high incidence of paraplegia after open surgery using the endovascular stent-graft.

Adult↗
PubMed2002

Short-term result of aortic valve replacement with cryopreserved homograft valve in the University of Tokyo Tissue Bank.

The short-term results after aortic root replacement with 11 cryopreserved aortic homografts was examined. Since 1998, the University of Tokyo Tissue Bank has supplied 11 aortic homograft valves. Nine of the recipients were male, and the average age was 51.2 years. Nine out of 11 patients had suffered from a serious condition of native or prosthetic valve infectious endocarditis. All of the patients underwent aortic root replacement, and the blood type between the patient and the homograft was matched in 8 of the patients. Only 1 patient died (9.1%) in the short-term due to sepsis. The preoperative degree of aortic valve regurgitation in all of the cases was third or fourth while the regurgitation disappeared after the operation in all of them. Thinking of the serious condition of our cases preoperatively, the 9.1% operative mortality was quite acceptable. Long-term follow-up is necessary to estimate the quality of the homografts.

Adolescent↗
PubMed2002

Cerebral metabolism of nitric oxide during retrograde cerebral perfusion.

The aim of this study was to determine whether alpha- or pH-stat protects the brain during deep hypothermic retrograde cerebral perfusion. Fifteen anesthetized dogs on cardiopulmonary bypass were cooled to 18 degrees C under alpha-stat and underwent retrograde cerebral perfusion for 90 minutes under alpha-stat or pH-stat, or underwent antegrade cardiopulmonary bypass under alpha-stat as the control. Cerebral blood flow of the cortex was monitored and serial analyses of blood gases and total nitric oxide oxidation products made. Cerebral blood flow and cerebral metabolic rate for oxygen were significantly higher and plasma levels of nitric oxide oxidation products in the outflow from the brain were significantly lower in retrograde cerebral perfusion under pH-stat than under alpha-stat. This study shows that reduced levels of nitric oxide oxidation products may protect against neuronal damage induced by nitric oxide and that increased cerebral blood flow under pH-stat may lead to a reduction of nitric oxide oxidation products. Under retrograde cerebral perfusion, pH-stat is thus better than alpha-stat for protecting the brain.

Animals↗
PubMed2002

Surgical treatment of malignant tumors of the right heart.

Seven patients with malignant cardiac tumors were treated surgically in the Department of Cardiothoracic Surgery of the University of Tokyo between 1981 and 2000. Their treatments and outcomes are summarized and discussed. The ages of the patients ranged from 21 to 70 years old (mean: 49.5+/-15) and there were three males and four females. The histopathological diagnoses were hepatocellular carcinoma (HCC), spindle cell sarcoma, round cell sarcoma, osteosarcoma, renal cell carcinoma, and leiomyosarcoma. In four of the cases, the tumor extended or metastasized from other organs, while in the other three cases it originated in the heart. Before the cardiac operation, an above-knee amputation, left nephrectomy, transarterial embolization, or extended right hepatic lobectomy had been performed to treat the primary site of the tumor. Tumor resection using cardiopulmonary bypass was performed in every case. The NYHA classification of heart failure was significantly improved (preop: 3.3+/-0.8, postop: 1.9+/-0.7 [P<0.001]). The mean survival period of the patients who died was 8.8+/-7.0 months. A patient with renal cell carcinoma is still alive after 87 months of follow-up. In summary, surgical treatment of malignant tumors of the right heart can improve the QOL in patients with cardiac failure. However, its effectiveness was temporary in all cases except one case of renal cell carcinoma.

Adult↗
PubMed2002

Glove retractor for left circumflex coronary artery bypass grafting.

BACKGROUND: During off-pump coronary artery bypass grafting (OPCAB), displacing the heart to expose the left circumflex artery (LCX) results in hemodynamic disturbance. The objective of this study was to evaluate, in a canine model, the hemodynamic impact on the beating heart of using a glove retractor instead of conventional retraction to expose the LCX. METHODS: Six mongrel dogs ranging in weight from 19.7 to 25 kg were used. Hemodynamic parameters were continuously monitored at a fixed rate of 80 beats/min. After the baseline data had been obtained, the LCX was exposed by applying an Octopus system. Each dog was then placed in the Trendelenburg position. Subsequently, the glove retractor was applied and its effects were examined both with and without the Trendelenburg position. RESULTS: LCX exposure decreased aortic flow to 35.2 +/- 12.8% of the baseline value (p< 0.001 vs. baseline), and this decrease was not fully reversed even by the Trendelenburg position (67.6 +/- 14.3%). Glove retractors tend not to interfere with right ventricular expansion so that hemodynamic disturbance is mild, and in the Trendelenburg position aortic flow (88.9 +/- 9.9%) and mean aortic pressure (95.0 +/- 5.1%) during LCX exposure were completely maintained with the glove retractor in place. CONCLUSION: Glove retractors can be used to displace the canine heart to expose the LCX, minimizing hemodynamic impairment, with normalization of hemodynamic parameters by the Trendelenburg position. This technique may offer an alternative hemodynamic support method in some patients undergoing OPCAB.

Animals↗
PubMedDate not supplied

Multichannel monitoring of cerebral circulatory and oxygenation status using optical topography during deep hypothermic retrograde cerebral perfusion.

In this study, we evaluated changes in the cerebral circulatory and oxygenation status during deep hypothermic total circulatory arrest (TCA) and retrograde cerebral perfusion (RCP) using optical topography, a form of multichannel near-infrared spectrophotometry, to monitor the broad area perfused by the middle cerebral artery. Seven patients underwent thoracic aortic surgery with TCA and RCP via the superior vena cava. Pressure-regulated RCP was performed under pH-stat. No postoperative neurologic complications occurred. Using optical topography, the relative changes in oxy-, deoxy-, and total hemoglobin (oxy-Hb, deoxy-Hb, total Hb) were simultaneously measured from 24 points in both hemispheres. Deoxy-Hb was used for evaluating the regional oxygenation status under RCR The values of deoxy-Hb at the beginning of RCP were regarded as the basal values, and the rate of increase in deoxy-Hb per minute (deoxy-Hb/min) was calculated at each site. Deoxy-Hb/min during TCA was also calculated. In every case, both oxy-Hb and total Hb decreased and deoxy-Hb increased during TCA. When RCP was initiated, the decrease in oxy-Hb and the increase in deoxy-Hb were attenuated. Deoxy-Hb/min was significantly lower under RCP than during TCA in all portions. There was no significant difference of deoxy-Hb/min between any portions during RCP Our results showed that the status of circulation and oxygenation might be uniform in the brain during RCP and better than that under TCA.

Adult↗