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Biomedical subjects

K Ueyama

Publications and source records attributed to K Ueyama.

At least 37 records · Page 2Linked to original sources
PubMed1999

Evaluation of coronary artery bypass grafts using helical scan computed tomography.

The patency of coronary artery bypass grafts was evaluated by helical computed tomographic (CT) scan. One hundred forty patients who received an enhanced chest CT scan and a coronary angiography after bypass surgery were studied before discharge at the Fukui Cardiovascular Center. Among them was a total of 398 grafts and 436 anastomoses. For the evaluation of 248 vein grafts, the CT scan showed a 99.5% correct positive ratio and an overall accuracy of 96.4%. In 122 internal thoracic arteries tested, an overall accuracy of 64.7% was obtained. In gastroepiploic artery tests the overall accuracy was 33.3% and in radial artery tests it was 45.5%. Thirty-seven venous sequential anastomoses in 34 grafts and 1 internal thoracic artery sequential anastomosis were also evaluated. In the venous sequential anastomosis, the CT scan showed a 73.0% of accuracy overall. This study showed that the helical CT scan was useful to evaluate graft patency following bypass surgery.

Adolescent↗
PubMed1999

A new method of double cardiomyoplasty: "contractile muscular sling".

BACKGROUND: In several experimental studies, double cardiomyoplasty using both latissimus dorsi muscles did not provide sufficient assist to the failing heart and did not clearly show improvement compared with single cardiomyoplasty. This study demonstrated the superior efficacy of our method of double cardiomyoplasty compared with single cardiomyoplasty. METHODS: In 16 dogs, the two latissimus dorsi muscles were crossed in front of the heart and directly sutured to each other behind the heart. Control hemodynamic measurements were obtained, and acute heart failure was induced by intravenous administration of propranolol. After the hemodynamic changes with bilateral latissimus dorsi muscle assistance were measured, single cardiomyoplasty was done in the same dog, and the hemodynamic variables were measured. RESULTS: With our double cardiomyoplasty, aortic systolic pressure increased by 25% (p < 0.001); pulmonary artery systolic pressure, by 40% (p < 0.001); end-systolic elastance, by 155% (p < 0.001); and cardiac output, by 55% (p < 0.001). There were significant increases in aortic pressure, pulmonary artery pressure, end-systolic elastance, stroke volume, and cardiac output with our double cardiomyoplasty compared with single cardiomyoplasty. CONCLUSIONS: In this study, our double cardiomyoplasty provided significant hemodynamic improvement compared with single cardiomyoplasty.

Animals↗
PubMed1999

Multiple minimally invasive direct coronary artery bypass grafting for the complete revascularization of the left ventricle.

BACKGROUND: Single-vessel coronary artery bypass grafting of the left internal mammary artery to the left anterior descending coronary artery using a minithoracotomy has been shown to produce excellent results with a very low mortality rate. However, this procedure cannot be used in patients with double- or triple-vessel disease. Our goal was to develop a minimally invasive direct coronary artery bypass grafting without cardiopulmonary bypass for total revascularization of the left ventricle using multiple arterial grafts. METHODS: Limited lateral thoracotomy was performed in the fourth or fifth intercostal spaces, exposing the left anterior descending coronary artery and left circumflex coronary artery. Two or three arterial grafts were harvested. Revascularization of the left anterior descending coronary artery and the left circumflex coronary artery were performed in 20 patients without cardiopulmonary bypass through the limited lateral thoracotomy using complex performed arterial grafts. In 4 patients, triple- and quadruple-vessel grafting was performed. RESULTS: The mean coronary cross-clamp time was 14.5+/-4.0 minutes for the left anterior descending coronary artery and 16.8+/-5.1 minutes for the left circumflex coronary artery. No early deaths or postoperative complications occurred. There were no late deaths or angina during the mean follow-up of 7.0 months (range, 2 to 22 months). Postoperative coronary angiography demonstrated widely patent grafts in all patients. CONCLUSIONS: Minimally invasive approach through a limited thoracotomy in multiple coronary artery bypass graftings are technically feasible and may be an alternative approach in the complete revascularization of the left ventricle. Mechanical immobilization of the coronary artery enhances early graft patency and is an essential part of this procedure.

Aged↗
PubMed1999

On-line assessment of regional ventricular wall motion by transesophageal echocardiography with color kinesis during minimally invasive coronary artery bypass grafting.

OBJECTIVE: Our objective was to determine the changes in regional ventricular wall motion during minimally invasive direct coronary artery bypass grafting by color kinesis using transesophageal echocardiography. METHODS: Minimally invasive coronary artery bypass grafting was performed in 34 patients, during which transesophageal echocardiography was used. Thirteen patients had isolated disease of the left anterior descending artery. Regional ventricular wall motion was analyzed by color kinesis with the SONOS 2500 transesophageal echocardiograph (Hewlett-Packard Co, Andover, Mass). On-line assessment of regional wall motion was continued during the operation. RESULTS: Wall motion abnormalities during ischemia were present in 4 cases, left ventricular mid-anterior hypokinesis in 3 cases, and left ventricular apical-lateral hypokinesis in 1 case. In all cases, wall motion was maintained after bypass. In patients with total coronary occlusion, changes in wall motion did not occur during anastomosis. CONCLUSIONS: Color kinesis allowed us to evaluate the change in regional ventricular wall motion induced by myocardial ischemia during minimally invasive coronary artery bypass grafting both objectively and quantitatively.

Aged↗
PubMed1999

P300 event-related potentials in probable dissociative generalized amnesia.

1. To investigate whether abnormalities in objective neurophysiologic measures are observable in patients with probable dissociative generalized amnesia, the P300 and N100 event-related potentials were evaluated in six such patients in both acute stage and after recovery from amnesia. Findings were compared with those in 12 age- and gender-matched healthy subjects. 2. While latencies did not differ from those of control subjects, P300 amplitudes in acute-stage recordings were lower than those in controls. Repeated recordings in the patients showed a significant increase in P300 amplitude after recovery from amnesia. 3. Amplitude and latency of N100 did not differ between the patient and control groups, nor changed significantly after retrieval of memory. 4. These findings suggest that some unknown biological and/or psychologic mechanisms that cause retrograde autobiographic amnesia may impair cognitive function as reflected in an objective neurophysiologic measure such as the P300.

Adolescent↗
PubMed1999

Human retinoic X receptor beta: complete genomic sequence and mutation search for ossification of posterior longitudinal ligament of the spine.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by ectopic bone formation in the ligament. OPLL is a very common disorder, in fact it constitutes the leading cause of myelopathy among Japanese. In the previous report, we provided the genetic linkage evidence that the genetic susceptibility of OPLL mapped to HLA complex of chromosome 6. As a candidate gene approach, retinoic X receptor beta (RXR beta), assigned to chromosome 6p21.3 adjacent to HLA class II, was analyzed for a possible causality. To start screening for the molecular variants of RXR beta in OPLL subjects, we first obtained P1 phage genomic clones containing the entire human RXR beta and elucidated the genomic organization of the gene. The human RXR beta is composed of 10 exons spanning over 6.2 kb of genomic DNA. Sequence analysis of the promoter region revealed a GC-rich sequence without TATA motif. We have identified three distinct molecular variants, one was in exon 10 and two were in the intergenic region between RXR beta and collagen 11A2 (COL11A2). Two variants in the intergenic region, 3' end + 140 and 3' end + 561, exhibit statistically significant associations with OPLL in case-control study (p = 0.0028 for 3' end + 140 and p = 0.034 for 3' end + 561). These results indicate that the genetic causality of OPLL lies within or close to the RXR beta/COL11A2 locus.

Adult↗
PubMed1999

[Coronary artery bypass surgery in octogenarian].

Between May 1992 and December 1997, 14 parents aged 80 or older underwent CABG with cardiopulmonary bypass. (Group A: mean age 82.1 +/- 1.73). This group was compared with 127 patients aged 70s. (Group B: mean 73.3 +/- 0.70). Left main trunk stenosis was more frequent in group A (p < 0.05), and number of patient who had old myocardial infarction was also frequent (p < 0.05). Emergency operation and preoperative use of intra aortic balloon pump was frequent in group A (p < 0.05). While there was no significant change in the number of graft per patient and used number of internal thoracic artery between the two groups, postoperative complications such as atrial arrhythmia and respiratory failure was appeared more frequently in group A (p < 0.05). The hospital mortality did not differ between the groups (21.4% for group A and 14.2% for group B). In group A, 11 patients are alive without recurrence of angina. In conclusion, while there is many problems pre and post operative term, CABG in over 80 years patients of age was satisfactory result, so we should not exclude octogenarian because of age alone.

Aged↗
PubMed1998

Cholesterol efflux effect of high density lipoprotein is impaired by whole cigarette smoke extracts through lipid peroxidation.

It has been reported that high density lipoprotein (HDL) plays an anti-atherogenic role by stimulating cholesterol efflux from the foam cells in the atheromatous lesion. In this study, we prepared a novel modified form of HDL (CS-HDL) by incubating HDL with whole cigarette smoke (CS) extracts containing both particulate matter and gas-phase smoke, and examined its effect on cholesterol efflux. CS-HDL showed a marked increase of conjugated dienes and denaturation of apoA-I, a major protein component of HDL. The cholesterol efflux effect of CS-HDL was remarkably reduced to the same level as that of oxidatively modified HDL induced by copper ion (Ox-HDL). Addition of 20 microg/ml superoxide dismutase (SOD) during the CS-modification of HDL caused retrieval of cholesterol efflux activity by 53% and a remarkable decrease in the conjugated dienes level. SOD, however, had no ameliorative effect on apoA-I denaturation. When HDL was incubated only with gas-phase smoke (gasCS-HDL), neither increase of conjugated dienes nor impairment of the cholesterol efflux effect was observed, whereas apoA-I was denaturated to the same extent as seen in CS-HDL. These results indicate that whole CS-extracts, but not gas-phase smoke, reduces cholesterol efflux effect of HDL and that lipid peroxidation associated with superoxide anion is involved in this functional impairment.

Animals↗
PubMed1998

Pathological Analysis of the Radial and Internal Thoracic Artery.

To evaluate the usefulness of the radial artery (RA) as a graft material for coronary artery bypass grafting (CABG), histologic studies of the RA were performed and compared with the internal thoracic artery (ITA). Specimens were obtained from both ends of 12 RAs and the distal side of the ITA during the operation. The degree of arteriosclerosis was evaluated using an NIH Image 1.57 system. The pathological index of arterioslerotic change was expressed as the ratio of cross-section (Rx: internal luminal area/tunica media area). The mean arteriosclerotic ratio (Rx) of the 12 proximal sides of the RA specimens was 0.18 +/- 0.03, the 12 distal sides 0.27 +/- 0.17, and the 12 ITAs was 0.14 +/- 0.05, respectively. There was significant difference between the distal side of the RA and the ITA. The distal side of the RA was a little greater than the proximal, but there was no significant difference between the proximal side of the RA and the ITA. From the microscopic findings, the tunica media of the RA is poor in elastic fibers and rich in smooth muscle cells compared with the ITA. The internal elastic lumina of the RA is developed as well as the ITA, but more calcification was found in the distal RA than in the others. According to these results, although care must be taken for arteriosclerosis of the distal RA, it can be expected to be a suitable bypass material for CABG.

Journal Article↗
PubMed1998

Bilateral thoracoscopic minimally invasive direct coronary artery bypass grafting using internal thoracic arteries.

BACKGROUND: Single-vessel coronary artery bypass grafting of the left internal mammary artery (ITA) to the left anterior descending coronary artery using a minithoracotomy has been shown to produce excellent results with a very low mortality. However, this procedure cannot be used in patients with double- or triple-vessel disease. Our goal was to develop a minimally invasive direct coronary artery bypass grafting procedure without cardiopulmonary bypass for patients with multivessel disease. METHODS: Both ITAs were thoracoscopically harvested using video imaging. Limited bilateral anterior thoracotomies were performed in the fourth intercostal spaces, thus exposing the right coronary artery and the left anterior descending coronary artery. The right ITA-right coronary artery and ITA-left anterior descending coronary artery anastomoses were performed without cardiopulmonary bypass using 8-0 polypropylene sutures. RESULTS: This procedure was successfully performed in 3 patients. The patients were extubated in the operating room. Postoperative angiographic studies showed patent left ITA and right ITA grafts. CONCLUSIONS: Bilateral thoracoscopic minimally invasive direct coronary artery bypass grafting can be used to treat patients with a proximally diseased left anterior descending coronary artery and right coronary artery. Bilateral thoracoscopic ITA harvesting is a less invasive surgical technique that may become an option for the management of multivessel coronary artery disease.

Aged↗
PubMed1998

[A successful case of minimally invasive direct coronary artery bypass (MIDCAB) followed by PTCA].

A 70-year-old man who developed angina pectoris underwent cardiac catheterization, which showed total occlusion of the left anterior descending coronary artery (LAD), associated with 75% stenosis of the right coronary artery (RCA) and 90% stenosis of the small circumflex coronary artery (CX). The LAD received good collateral flow from the RCA. The patient was scheduled to undergo the MIDCAB for the LAD using the internal thoracic artery (ITA), combined with percutaneous transluminal coronary angioplasty (PTCA) for the RCA subsequently. A left anterior submammarian skin incision of 10 cm in length was made. The fifth costal cartilage was removed. The left ITA was directly harvested from the chest wall from the 4th to 7th intercostal space, and was anastomosed to the midportion of the LAD without cardiopulmonary bypass. The patient was quickly recovered after the operation. On the 8th postoperative day, the patient successfully underwent the PTCA for the RCA after the ITA-LAD graft had been verified to be patent. The MIDCAB could be indicated for multivessel coronary disease in conjunction with the PTCA.

Aged↗
PubMed1998

[Minimally invasive direct coronary artery bypass grafting (MIDCAB) for right and circumflex coronary artery systems].

BACKGROUND: Single-vessel coronary bypass grafting of the left internal thoracic artery (LITA) to the left anterior descending coronary artery (LAD) with mini-thoracotomy has been shown to produce excellent results with almost no mortality. However this procedure cannot be used in patients with double or triple vessel disease. METHODS: Between Aug. 96 and Dec. 97, 17 pts underwent minimally invasive direct coronary artery bypass (MIDCAB) to right (RCA) and circumflex coronary artery (CX). LITA and RITA were thoracicscopically harvested and the right gastroepiploic artery (RGEA), inferior epigastric artery, and radial artery were then harvested. A limited left thoracotomy in combination with limited anterior right thoracotomy (n = 3) or right lower parasternal incision extending to below the xiphoid process (n = 6) were made. The double MIDCAB as performed in 16 pts and triple in 1 pt. RESULTS: There was no operative death. At follow up, all pts are alive and well. The postoperative angiographic studies showed 30/31 grafts were patent. CONCLUSION: The utility of multi-vessel MIDCAB for the LAD, CX and RCA with in-site arterial grafts has been demonstrated in the present study. This less invasive surgical technique may become a viable option for the management of multi-vessel coronary artery disease.

Aged↗
PubMed1997

Diagnosis and operation for anomalous circumflex coronary artery.

BACKGROUND: Origin of the left circumflex coronary artery from the right sinus of Valsalva is the most common anatomic variation of the coronary artery circulation. However, there are few reports about the operative approach to this anomalous vessel. METHODS: Forty patients having this anomaly were identified from 10,216 adult cardiac catheterization procedures. Forty percent of the anomalous circumflex coronary arteries (ACCAs) had critical atherosclerotic lesions. Eighty cases needed bypass grafting. RESULTS: For diagnosis of ACCA, the aortic root sign was positive in 94.9% of the diagnosed patients and the nonperfused myocardium sign was found in 92.5%. Eighty percent of ACCAs were larger than 2 mm in radiographic diameter before their passage into the atrioventricular groove. However, after emerging from the atrioventricular groove, 70% measured less than 1.5 mm. Consequently, a technique was developed to bypass the proximal ACCA and was used in 2 cases. Six other patients with more distal disease and larger vessels underwent conventional bypass grafting. CONCLUSIONS: The aortic root sign and nonperfused myocardium are useful in diagnosing ACCA. The ACCA is usually too small for use of the conventional graft technique. Therefore, a technique was developed to graft more proximally and was applied successfully in 2 cases.

Adult↗
PubMed1997

Clinical variables influencing the appearance of right bundle branch block after cardiac surgery.

Right bundle branch block following coronary surgery is a common occurrence. Among 759 coronary surgery cases, 104 patients (13.7%) had a new right bundle branch block. Of these right bundle branch blocks, 62 were transient, and 42 (40.4%) were permanent. The large number of bypasses (3.20 versus 2.75, P = 0.0001) and stenosis of the right coronary artery (81.7% versus 66.5%, P = 0.003) was strongly associated with a new right bundle branch block. In the analysis of the permanent right bundle branch block, blood cardioplegia prevented the block from becoming permanent (35.7% versus 75.8%, P = 0.0001). Therefore, it is concluded that perioperative right bundle branch block occurs predominantly in patients who have a critical stenosis in an artery which supplies the conduction system and in those undergoing more extensive procedures. In addition, blood cardioplegia affects the conduction system less severely than does crystalloid cardioplegia.

Adult↗
PubMed1997

Effects of ultrathin silicone coating of porous membrane on gas transfer and hemolytic performance.

To assess the effect of an ultrathin (0.2 microm) silicone-coated microporous membrane oxygenator on gas transfer and hemolytic performance, a silicone-coated capillary membrane oxygenator (Mera HP Excelung-prime, HPO-20H-C, Senko Medical Instrument Mfg. Co., Ltd., Tokyo, Japan) was compared with a noncoated polypropylene microporous membrane oxygenator of the same model and manufacturer using an in vitro test circuit. The 2 oxygenators showed little difference in the oxygen (O2) transfer rate over a wide range of blood flow rates (1 L/min to 8 L/min). The carbon dioxide (CO2) transfer rate was almost the same in both devices at low blood flow rates, but the silicone-coated oxygenator showed a decrease of more than 20% in the CO2 transfer rate at higher blood flow rates. This loss in performance could be partly attenuated by increasing the gas/blood flow ratio from 0.5 or 1.0 to 2.0. In the hemolysis study, the silicone-coated membrane oxygenator showed a smaller increase in plasma free hemoglobin than the noncoated oxygenator. The pressure drop across both oxygenators was the same. These results suggest that the ultrathin silicone-coated porous membrane oxygenator may be a useful tool for long-term extracorporeal lung support while maintaining a sufficient gas transfer rate and causing less blood component damage.

Adult↗
PubMed1997

Comparison of the Gyro C1E3 and BioMedicus centrifugal pump performances during cardiopulmonary bypass.

The compact eccentric inlet port (C1E3) centrifugal blood pump was developed as a cardiopulmonary bypass (CPB) pump. The C1E3 pump incorporated a sealless design with a blood stagnation free structure. The pump impeller was magnetically coupled to the driver magnet in a sealless manner. To develop an atraumatic and antithrombogenic centrifugal pump without a shaft seal junction, a double pivot bearing system was introduced. Recently, a mass production model of the C1E3 was fabricated and evaluated. The ratio of the normalized index of hemolysis (NIH) of the C1E3 was 0.007 g/ 100 L, in comparison to the NIH of the BP-80, 0.018 g/ 100 L, each in a CPB condition of 5 L/min against 325 mm Hg. Both pumps were compared in identical in vitro circuits. To further evaluate the pumps during cardiopulmonary bypass for reliability and function, 6 h of CPB was performed on each of 8 bovines using either the C1E3 or BP-80 centrifugal pump. The BP-80 and C1E3 provided pump flows of 50-60 ml/kg/min without incident. The hemodynamics were stable, and the hematology and biochemistry data were within normal ranges. There were no statistically significant differences between the 2 groups. Concerning the plasma free hemoglobin values, a mass production model of the C1E3 pump had the same hemolysis levels as the BP-80. Our preliminary studies reveal that the C1E3 pump is reliable. Also, the C1E3 will satisfy clinical requirements as a cardiopulmonary bypass pump.

Alanine Transaminase↗