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Biomedical subjects

S Takamoto

Publications and source records attributed to S Takamoto.

At least 55 records · Page 3Linked to original sources
PubMed2001

Intraoperative echocardiographic imaging of coronary arteries and graft anastomoses during coronary artery bypass grafting without cardiopulmonary bypass.

BACKGROUND: No accepted approach exists for the intraoperative evaluation of the quality of coronary arteries and the technical adequacy of graft anastomoses during coronary artery bypass grafting without cardiopulmonary bypass. METHODS AND RESULTS: We assessed the accuracy of high-frequency epicardial echocardiography and power Doppler imaging in evaluating coronary arteries during coronary artery bypass grafting without cardiopulmonary bypass. To validate measurements of coronary arteries and graft anastomoses by high-frequency epicardial echocardiography and power Doppler imaging, we compared luminal diameters determined by these methods with diameters determined histologically in a study of off-pump coronary artery bypass grafting in 20 dogs. Technical errors were deliberately created in 10 grafts (stenosis group). The results of these animal validation studies showed that the maximum luminal diameters of coronary arteries and graft anastomoses measured by high-frequency epicardial echocardiography (HEE) and power Doppler imaging (PDI) correlated well with the histologic measurements: HEE = 1.027 x Histologic measurements + 0.005 (P <.0001); PDI = 0.886 x Histologic measurements + 0.0453 (P =.0001). Similar results were found in the evaluation of the stenosis group: PDI = 0.991 x Histologic measurements + 0.074 (P <.0001). Subsequently, we demonstrated the clinical applicability of this approach in 12 patients who underwent minimally invasive or off-pump coronary artery bypass grafting. Twenty graft anastomoses were examined intraoperatively by high-frequency epicardial echocardiography and power Doppler imaging, and luminal diameters determined by power Doppler imaging were compared with those determined by postoperative coronary angiography. The results demonstrated that graft anastomosis by power Doppler imaging correlated well with the angiographic measurements: PDI = 1.018 x Angiographic measurements - 0.106 (P <.0001). CONCLUSION: High-frequency epicardial echocardiography can provide meaningful information on the target coronary artery, and power Doppler imaging can accurately measure graft anastomoses and can detect technical errors and inadequacies during coronary artery bypass grafting without cardiopulmonary bypass.

Aged↗
PubMed2001

Predictive risk factors for pulmonary oxygen transfer in patients undergoing coronary artery bypass grafting.

UNLABELLED: The ratio of arterial oxygen tension to inspired oxygen fraction (PaO2/FiO2) is a useful indicator for weaning patients from mechanical ventilation and a reliable predictor of pulmonary dysfunction after cardiac surgery. The aim of this study was to elucidate the patient characteristics and variables that affect the PaO2/FiO2 ratio. Between 1994-1998, 167 patients who underwent coronary artery bypass grafting (CABG) were examined retrospectively. Spearman's correlation coefficients were calculated between the PaO2/FiO2 ratio and intubation period, and length of ICU stay. Patients were then divided into two groups with a PaO2/FiO2 ratio < 350 and PaO2/FiO2 ratio > or = 350. Univariate analysis of the putative risk factors was performed. A logistic regression model was developed to evaluate factors that would influence the PaO2/FiO2 ratio. A significant correlation was observed between the PaO2/FiO2 ratio and intubation period, and length of ICU stay. Univariate predictors of a PaO2/FiO2 ratio < 350 were low body weight, low preoperative PaO2 long operation time, high FiO2, low postoperative PaO2 history of smoking, hypertension and opening of pleura (p < 0.05). Excellent prediction was found with a model consisting of preoperative PaO2 and hypertension. CONCLUSION: The results of this study suggest that patients with a low preoperative PaO2 or hypertension may need more careful peri- and postoperative management since these factors are closely associated with the PaO2/FiO2 ratio.

Adult↗
PubMed2001

Experimental study of small arterial anastomosis with gelatin-resorcin-formaldehyde glue and collagen sheet.

In cardiovascular surgery, the manual continuous suture has often been used for microvascular anastomosis, but the luminal irregularity often causes thrombotic stenosis in the anastomosis sites. The purpose of this study was to examine the feasibility of the combined use of gelatin-resorcin-formaldehyde (GRF) glue and a collagen sheet for the anastomosis of small arteries 3 to 4 mm in diameter in experimental animals. End-to-end anastomoses of the carotid and femoral arteries of mongrel dogs were carried out with the combined use of GRF glue and collagen sheet. The physical strength of the anastomosis, the histopathologic condition of the vassels, and the absorptivity and the inflammatory response of the glue were evaluated. The physical strength of the anastomosis sites was good and their flexibility optimal, the smooth luminal surface appeared excellent for preventing thrombotic stenosis in all follow-up periods, and the glue was absorbed almost completely within 12 weeks postoperatively. The combined use of GRF glue and collagen sheet would be feasible for the anastomosis of small arteries 3 to 4 mm in diameter and could substitute for the conventional suture method.

Anastomosis, Surgical↗
PubMed2001

[Indications for and results of cryopreserved homograft valve replacement].

The cryopreserved aortic homograft valve is one of the most reliable of the stentless biological prosthesis if implanted properly. Due to the limited availability of homograft valves in Japan, the indications for their use are different from those in other countries. The first indication is active infective endocarditis in the aortic valve position, especially infection surrounding artificial implants. Another indication is for reconstruction of the right ventricular outflow tract during pulmonary autografting. Finally, aortic valve replacement in young women of childbearing age who wish become pregnant is an accepted indication. Since 1992, cryopreserved homograft valves have been used in Japan, and the number of surgeries performed with them has gradually increased. While efforts have been made to expand the homograft bank system in some areas, the supply remains insufficient. Because the demand for homografts is high, it is extremely important to establish a nationwide tissue bank system as soon as possible.

Aortic Valve↗
PubMed2001

Favorable results in patients with small size CarboMedics heart valves in the aortic position.

Hemodynamic performance of the CarboMedics heart valve in the aortic position and its clinical impacts were investigated in 126 consecutive patients. The actuarial survival rates of patients who had undergone isolated aortic valve replacement and concomitant aortic and mitral valve replacement were 82.6+/-5.7% and 71.0+/-9.2% at 8 years, respectively. Morbid events were rare, and almost all late survivors were free from evident cardiac symptoms regardless of the valve size. Echocardiography revealed suboptimal transvalvular pressure gradients and effective orifice areas of 19 mm and 21 mm valves. However, relief of the left ventricular overload and improvement of the clinical symptoms as well as cardiac function were comparable to those of patients with larger valves. Valve function measured by echocardiography did not show significant correlation to late outcome. Good results can be expected even in the presence of echocardiographic data such as peak pressure gradient over 40 mmHg, effective orifice area less than 1.0 cm(2), and effective orifice area index less than 0.7 cm(2)/m(2).

Adolescent↗
PubMed2001

[A case of primary lung adenocarcinoma with diffuse calcification in the tumor by psamoma bodies].

A 78-year-old asymptomatic woman was referred to our department for the treatment of a right lung tumor. The patient had been suffering from rheumatoid arthritis and followed up in outpatient clinic. On March 6, 1995, abnormal shadow in the right upper lobe was pointed out by routine chest X-ray. Chest CT revealed calcification in the shadow, and benign lesion, such as old pulmonary tuberculosis, was suspected. During follow-up, the size of the shadow and calcification area in the shadow gradually increased. Malignancy was suspected based on the increasing size of the tumor. On July 12, 2000, video-assisted right upper lobectomy with hilar and mediastinal lymph node sampling was performed. Pathological examination revealed that the tumor was primary lung adenocarcinoma containing psamoma bodies in the tumor.

Adenocarcinoma↗
PubMed2000

Costs of videothoracoscopic surgery versus open resection for patients with of lung carcinoma.

BACKGROUND: The costs of videothoracoscopic procedures for patients with lung carcinoma were compared with those of patients who underwent open thoracotomy in Japan. METHODS: The cost of surgical treatment in 1997 and 1998 for patients with resectable primary or metastatic lung carcinoma was analyzed from itemized statements of hospital charges. For patients with lung carcinoma who are in relatively poor health, the authors chose videothoracoscopic lobectomy or partial resection of the lung instead of an open thoracotomy. For patients with solitary pulmonary metastasis, the authors routinely performed thoracoscopic partial resection of the lung. RESULTS: Among 102 patients who were selected for the analysis, 79 patients had primary lung carcinoma, and 23 had metastatic lung carcinoma. Sixty-six open thoracotomies and 36 thoracoscopic surgeries were performed. The mean hospital charge for the entire group of patients was $11,348 (U.S.). The total charges accrued in the operating room amounted to 63% of the hospital charges. Hospitalization was significantly shorter in the group of patients who underwent videothoracoscopy (17.3 days) compared with the group of patients who underwent open thoracotomy (23.8 days). The charges for laboratory examinations, anesthesia, disposable equipment, and hospitalization were significantly higher in patients who underwent open thoracotomy compared with the patients who underwent videothoracoscopy. There were no statistically significant differences in the charges for medication or surgical fees between the two groups. CONCLUSIONS: The hospital charges for patients undergoing videothoracoscopic surgery were lower than the charges for patients undergoing open thoracotomy at the authors' hospital. The lower cost was attributable mainly to the less invasive nature of thoracoscopic surgical procedures, which also may be beneficial for decreasing the risk of postsurgical complications in patients in who are in relatively poor health.

Adult↗
PubMed2000

Gene therapy for attenuating cardiac allograft arteriopathy using ex vivo E2F decoy transfection by HVJ-AVE-liposome method in mice and nonhuman primates.

Cardiac allograft arteriopathy, which limits the long-term survival of recipients, is characterized by diffuse intimal thickening composed of proliferative smooth muscle cells. The transcription factor E2F plays a pivotal role in the coordinated transcription of cell-cycle regulatory genes. To test the hypothesis that double-stranded DNA with specific affinity for E2F (E2F decoy) is effective in preventing intimal hyperplasia, we performed ex vivo single intraluminal delivery of E2F decoy into cardiac allografts of mice and Japanese monkeys using the hemagglutinating virus of Japan (HVJ) artificial viral envelope-liposome method. In murine models, antisense cyclin-dependent kinase 2 (cdk2) kinase oligodeoxynucleotide (ODN) and no transfers were performed to compare the effects. Severe intimal thickening was observed, and multiple cell-cycle regulatory genes were enhanced in untreated allografts. E2F decoy prevented neointimal formation and suppressed these genes for up to 8 weeks, whereas antisense cdk2 kinase ODN had limited effects. In primate models, E2F decoy dramatically prevented neointimal thickening and suppressed multiple cell-cycle regulatory genes, whereas intimal thickening developed in the nontransfected or mismatch decoy-transfected allografts. Gel mobility shift assay proved the specific effects of E2F decoy, and reverse transcriptase-polymerase chain reaction documented that neither complication nor dissemination of HVJ into other organs was observed. We demonstrate that ex vivo gene delivery to allografts is a potent strategy to modify allograft gene expression, resulting in prevention of graft arteriopathy without systemic adverse effects.

Animals↗
PubMed2000

Ontogeny of antipig xenoantibody and hyperacute rejection.

BACKGROUND: Neonatal primates have been reported to receive pig hearts without hyperacute rejection (HAR). We examined the ontogeny of the anti-pig xenoantibody (XenoAb) and HAR in the neonatal and infant monkeys. METHODS: Twenty-six serum samples from 15 monkeys ages 14-192 days were subjected to hemagglutination titration against pig erythrocytes. Ten pig hearts were heterotopically transplanted into the monkeys. RESULTS: Six monkeys, ages 52-114 days, received pig hearts without HAR, and those ages 129-191 days hyperacutely rejected them. XenoAb titers were increased according to the age (Spearman's rank correlation value=0.909 (P<0.01)). XenoAb titers in 16 monkeys <4 months were significantly (P<0.01) lower than those in 10 monkeys >4 months. CONCLUSIONS: Anti-pig XenoAb titers increased with the age of the monkeys. XenoAb levels in monkeys >4 months are high enough to reject pig hearts hyperacutely.

Acute Disease↗
PubMed2000

Results from surgical treatment for thymoma. 43 years of experience.

OBJECTIVE: The biological behavior of thymoma and its prognosis after surgical intervention remain still controversial. The efficacy of surgical treatment for thymoma was investigated by examining long-term follow-up data. SUBJECTS AND METHODS: Follow-up data for patients undergoing surgical resection of histopathologically-confirmed thymoma between 1954 and 1997 were obtained and were retrospectively analyzed. Clinical staging was based on Masaoka's staging system, and histological classification on Rosai's proposed criteria. RESULTS: Data for 140 patients were collected. Sixty-four patients had stage I, 32 had stage II, 28 had stage III, and 16 had stage IV thymoma. There were significant differences in survival between patients with stage I and stage III, stage I and stage IV and stage II and stage III disease, but not between those with stage I thymoma and stage II thymoma. No significant difference in survival was observed between the 56 patients with myasthenia gravis (MG) and the 84 without MG. The 38 patients classified as having a predominantly-epithelial thymoma had a poorer prognosis than the 41 with a predominantly-lymphocytic thymoma. Until 1975, there were four patients with stage I thymomas who later showed recurrence, compared with 21 among those with stage II, III and IV diseases. Since 1976, extended thymectomy with thymomectomy under median sternotomy has been adopted as the standard operation for a thymoma, and there has been no recurrence in stage I patients. CONCLUSIONS: Patients with stage III or IV invasive thymoma have a poorer prognosis and a higher recurrence rate than those with encapsulated thymoma, and patients with a predominantly-epithelial thymoma have a poorer prognosis than those with a predominantly-lymphocytic thymoma. Extended thymectomy with thymomectomy under median sternotomy can be considered as adequate treatment for a stage I thymoma. Myasthenia gravis does not appear to affect the prognosis of patients with a thymoma.

Adult↗
PubMed2000

Upper hemisternotomy as conversion from minimally-invasive coronary artery bypass grafting.

A seventy-year-old man was admitted to hospital for ischemic heart disease and abdominal aortic aneurysm. In the cardiac procedure, we employed a technique for conversion from minimally invasive coronary artery bypass grafting. This technique entailed cardiopulmonary bypass using standard instruments and technique, and the exposure for grafting was the same as for the simple minimally-invasive coronary artery bypass grafting. Moreover, the incision we reported in this case was simply extendable even to a full sternotomy if necessary.

Aged↗
PubMed2000

Cardiac function evaluated by transesophageal echocardiography during cardiopulmonary bypass.

OBJECTIVE: To evaluate cardiac function at cardiopulmonary bypass weaning, we applied a new technique clinically to determine the approximated Emax without using a conductance catheter. METHODS: Subjects were 5 patients. The left ventricular end-systolic pressure was obtained by overlaying the radial arterial pressure curve on the left ventricular pressure curve. Left ventricular end-systolic volume was assessed by a transesophageal echographic apparatus. At cardiopulmonary bypass weaning, volume loading was applied to increase left atrial pressure by a few mmHg while fixing the pump flow rate at half flow. Changes in left ventricular end-systolic volume and approximated left ventricular end-systolic pressure for total heart beat were plotted during this period, and the gradient of the regression line was taken as approximated Emax. RESULTS: Approximated Emax ranged from 1.29 to 3.28 (mean 2.13 +/- 0.72), and its correlation coefficient was 0.80 +/- 0.06. CONCLUSION: Our new technique is useful in evaluating cardiac function during cardiopulmonary bypass.

Adult↗
PubMed2000

Metastatic hepatocellular carcinoma obstructing the right ventricular outflow tract.

A 49-year-old female with a past history of liver resection due to hepatocellular carcinoma was referred to our Department for treatment of a metastatic cardiac tumor obstructing the right ventricular outflow tract. She underwent operation twice with cardiopulmonary bypass, and symptoms were relieved. Metastasis from hepatocellular carcinoma to the heart is very rare, but should be taken into consideration during follow-up after treatment for a primary liver tumor.

Carcinoma, Hepatocellular↗
PubMed2000

Hypertrophic obstructive cardiomyopathy associated with mitral regurgitation due to infective endocarditis.

A 25-year-old woman treated for hypertrophic obstructive cardiomyopathy and suffering from mitral regurgitation due to infective endocarditis was referred to our department for surgery. Preoperative examinations revealed asymmetric septal hypertrophy, a large left ventricular outflow gradient (100 mmHg), and perforation of the anterior mitral leaflet resulting in severe mitral regurgitation. The entire mitral complex was resected and septal myectomy conducted to dilate the left ventricle. A bioprosthetic valve was then implanted. Although postoperative heart failure was severe, cardiac function has gradually recovered. The left ventricular outflow gradient has decreased to 8 mmHg, the diastolic left ventricular diameter has increased from 26 to 30 mm, and her New York Heart Association classification has improved from IV to I.

Adult↗
PubMed2000

Altered expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in acutely rejected myocardium and coronary arteriosclerosis in cardiac allografts of nonhuman primates.

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are important in any process of tissue remodeling. However, there is no report evaluating their expression in cardiac allografts in human or non-human primates. Heterotopic cardiac transplantation was performed on Japanese monkeys. Subjects were treated with chimeric anti-human lymphocyte function-associated antigen-1 monoclonal antibody for 2 weeks. Heart grafts were harvested at days 1-95 (n = 7). Native monkey hearts were used as controls (n = 2). We examined expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 using immunohistochemistry and in situ reverse transcriptase polymerase chain reaction (RT-PCR). In the myocardium, the expression of MMP-2 was increased in the spindle-shaped cells of acutely rejected myocardial interstitium and prior to the presence of mononuclear cell infiltration at days 1-41. TIMP-1 and 2 expression was enhanced in association with the progression of fibrosis at days 40-95. In the coronary arteries of chronically rejected allografts, enhanced MMP and decreased TIMP expression was observed in both thickened intima and media at days 40-95. The medial MMP mRNA expression was observed before the development of intimal thickening occurred at days 7-28. MMPs are critical for the progression of acute and chronic rejection, and TIMP predominance plays important roles in fibrosis in association with acute rejection. Expression of MMPs and TIMPs is a sensitive indicator of acute and chronic cardiac rejection.

Acute Disease↗
PubMed2000

Conventional coronary artery bypass grafting in patients with total occlusion of the internal carotid artery.

The number of patients with coexisting disease of the coronary and carotid arteries is increasing. Patients with total occlusion of the carotid artery may have a higher risk of stroke during cardiopulmonary bypass surgery and in the perioperative period. We report our results for coronary artery bypass grafting (CABG) in patients with total occlusion of the carotid artery. We examined 269 patients who underwent carotid artery duplex scanning (CADS) before CABG between November 1995 and January 1998. Among them, 11 patients (4.1%) had total occlusion of a carotid artery. Four patients underwent elective CABG and five underwent emergency CABG. One patient underwent anastomosis of the superficial temporal artery to the middle cerebral artery (STMC) and one patient underwent a combined CABG and carotid endoarterectomy (CEA) procedure. A transient neurological event occurred in only one patient (9.1%). The other patients recovered uneventfully. Our results suggest that CABG can be performed without stroke in patients with total unilateral occlusion of a carotid artery using our strategies.

Aged↗