Search PubMed⌕ Search

Biomedical subjects

K Kawachi

Publications and source records attributed to K Kawachi.

At least 73 records · Page 4Linked to original sources
PubMed1997

[Extended aortoplasty for supravalvular aortic stenosis with Williams syndrome].

We report a male case of supravalvular aortic stenosis associated with Williams syndrome requiring surgery at age 11. At 5 years of age, this boy presented with a harsh systolic heart murmur and was diagnosed as having a supravalvular aortic stenosis. In association with mental retardation, elfin face and bilateral inguinal hernias, he was diagnosed as a Williams syndrome confirmed by the chromosomal analysis revealing the deletion of 7q11.23. The pressure gradient across the stenotic lesion of the ascending aorta, which had been 35 mmHg at age 5, progressed to 80 mmHg at age 11 years. Extended aortoplasty was performed using a patch of 20 mm Hemashield graft prosthesis. Postoperative cardiac catheterization confirmed that the pressure gradient in the ascending aorta completely disappeared following surgery.

Aorta↗
PubMed1997

[Life-threatening ventricular tachyarrhythmia after CABG in a patient with poor LV function--an experience with the implantable cardioverter defibrillator].

A 52-year-old man with reduced left ventricular function (ejection fraction 0.27) due to myocardial infarction, underwent coronary artery bypass grafting (CABG; LITA-LAD, free RITA-4PD) for angina pectoris. He had suffered from recurrent sustained ventricular tachycardia (VT) since 5 hours after CABG. This arrhythmia was resistant to various antiarrhythmic agents such as Lidocaine, Mexiletine, Disopyramide, Procainamide and Propafenone. He required mechanical circulatory supports (intra-aortic balloon pumping and percutaneous cardiopulmonary support) for the maintenance of hemodynamics during repeated VT that required cardioversions of a total of 441 times during 18 days. Following the administration of Amiodarone, the VT was successfully suppressed. However, he had repeated episodes of VT on exercise, thus, he underwent insertion of the implantable cardioverter-defibrillator at the 98 post-operative day, and he was successfully discharged at the 134 post-operative day after CABG. The instrument was verified to be normal in function after the VT induction test.

Coronary Artery Bypass↗
PubMed1997

Increased risk of coronary artery bypass grafting for left ventricular dysfunction with dilated left ventricle.

UNLABELLED: The operative mortality and morbidity in patients with severe left ventricular dysfunction who undergo coronary artery bypass grafting (CABG) remain high. The low ejection fraction is the major risk factor for operative mortality. However, ejection fraction (EF) alone may not necessarily be an accurate predictor of operative mortality. We studied the correlation between indices of left ventricular volume and operative mortality. One thousand patients undergoing isolated coronary bypass operations were divided into three groups according to their preoperative ejection fraction. Fifty patients (group I) had severe left ventricular dysfunction (EF < or = 0.3), 56 patients (group II) had moderately left ventricular dysfunction (0.3 < EF < or = 0.4) and 894 patients (group III) had good left ventricular function (EF > 0.4). We analyzed the relationship between hospital mortality and left ventricular volume in 106 patients with an EF < or = 0.4. RESULTS: Cardiac index was not significantly different among the three groups. The left ventricular end-diastolic pressure (LVEDP) and mean pulmonary artery pressure in groups I an II were higher than those in group III. The left ventricular end-diastolic volume (LVEDV) was 146 +/- 44 ml/m2 in Group I, 112 +/- 31 ml/m2 in Group II and 82 + 30 ml/m2 in Group III, respectively (Group I versus II, p < 0.05, Group I and II versus III, p < 0.01). The left ventricular end-systolic volume (LVESV) was 111 +/- 38 ml/m2 in Group I, 72 +/- 21 ml/m2 in Group II and 30 +/- 14 ml/m2 in Group III, respectively (Group I versus II, p < 0.05, Group I and II versus III, p < 0.01). The LVEDV and LVESV were higher in Group I than in Group II and both in Groups I and II were higher than in Group III. The hospital mortality of any cause before discharge was 8.0% (4/50) in Group I, 3.6% (2/56) in Group II, and 2.0% (18/894) in Group III. The mortality in Group I was higher than that in Group III, but the mortality between Groups I and II was not different. We assessed correlations between large left ventricle with left ventricular dysfunction and operative mortality in 106 patients with ejection fractions of < or = 0.4. The hospital mortality in patients with both under fraction 0.4 and an LVESV > or = 140 ml/m2 was 50% (4/8). This rate was higher than in patients with an LVESV between 80 and 140 ml/m2 (1.8%, 1/55) (p = 0.0006) and an LVESV less than 80 ml/m2 (2.3%, 1/43), (p = 0.0013). The hospital mortality in patients with an LVEDV > or = 200 ml/m2 was 67% (4/6). It was also higher than that in patients with an LVEDV between 200 and 120 ml/m2 (1.7%, 1/58), (p = 0.0001), and an LVEDV less than 120 ml/m2 (2.4%, 1/42), (p = 0.0004). We conclude that patients with a low ejection fraction and an elevated LVESV or LVEDV are at increased risk for hospital death following CABG.

Cardiac Volume↗
PubMed1997

Decision support for psychiatric diagnosis based on a simple questionnaire.

This paper compares two classifiers: Pseudo Bayesian and Neural Network for assisting in making diagnoses of psychiatric patients based on a simple yes/no questionnaire which is provided at the outpatient's first visit to the hospital. The classifiers categorize patients into three most commonly seen ICD classes, i.e. schizophrenic, emotional and neurotic disorders. One hundred completed questionnaires were utilized for constructing and evaluating the classifiers. Average correct decision rates were 73.3% for the Pseudo Bayesian Classifier and 77.3% for the Neural Network classifier. These rates were higher than the rate which an experienced psychiatrist achieved based on the same restricted data as the classifiers utilized. These classifiers may be effectively utilized for assisting psychiatrists in making their final diagnoses.

Affective Symptoms↗
PubMed1996

High-speed voltage-sensitive dye imaging of an in vivo insect brain.

We have developed an improved optical recording technique with high spatio-temporal resolution to investigate neural activity from an in vivo insect brain. Optical images were acquired from hawk moth antennal lobe (AL) neurons. When activity was elicited by electrical stimulation of the antennal nerve using a stereoscopic microscope, depolarization followed by hyperpolarization was consistently recorded in the AL. When gamma-aminobutyric acid (GABA)-mediated synaptic transmission was blocked by the picrotoxin, the typical hyperpolarization was greatly reduced while no changes were observed in the depolarization. This suggests that the hyperpolarization results from inhibitory postsynaptic potentials (IPSPs) originating from GABA-sensitive chloride channels on the AL neurons.

Animals↗
PubMed1996

Annuloplasty for severe mitral regurgitation due to dilated cardiomyopathy.

We present a 74-year-old woman who underwent corrective annuloplasty for severe mitral regurgitation due to dilated cardiomyopathy. Postoperatively, congestive heart failure improved, with her New York Heart Association status changing from IV to II, although her cardiac functional improvement was minimal. Severe mitral regurgitation may be the indication for annuloplasty in symptomatic patients with dilated cardiomyopathy when cardiac transplantation is not indicated.

Aged↗
PubMed1996

Echocardiographic characteristics of the cryopreserved allograft aortic valve replacement assessed by intraoperative transoesophageal echocardiography.

Improvements in cryopreservation techniques have made possible excellent long-term results using aortic valve allografts. Few studies, however, have examined the echocardiographic characteristics of allograft aortic valves and postoperative valve function. Aortic allograft function was evaluated in 16 patients by intraoperative transoesophageal echocardiography, postoperative catheterization, and angiography. The mean(s.d.) coaptation zone length of the allograft leaflet was significantly greater (7.3(1.4) mm) than that of the normal aortic valve (3.2(0.8) mm) (P < 0.01). No regurgitation was noted in any patients with coaptation zone length of 7-11 mm (P < 0.01). The increment of the leaflet coaptation zone length did not produce a significant pressure gradient during exercise and appeared to be one of the important mechanisms for the prevention of postoperative aortic regurgitation, because commissural orientations may be distorted in the new aortic position. This finding is consistent with the report that allografts with the largest diameter implantable in the recipient annulus should be selected for use.

Adult↗
PubMed1996

A computational fluid dynamics study of tadpole swimming

The hydrodynamics and undulating propulsion of tadpoles were studied using a newly developed two-dimensional computational fluid dynamics (CFD) modeling method. The mechanism of thrust generation associated with the flow patterns during swimming is discussed. Our CFD analysis shows that the kinematics of tadpoles is specifically matched to their special shape and produces a jet-stream propulsion with high propulsive efficiency, as high as that achieved by teleost fishes. Investigation of the effect of Reynolds number indicates that the Froude efficiency increases with increasing Reynolds number with no ceiling in generating the jet-stream propulsion. Further studies using tadpole- and fish-shaped models with hindlimbs added to their body profiles reveal that the tadpole shape &shy; a globose head with a tapered tail and hindlimbs at the base of the tail &shy; allows tadpoles, but not fish, to develop hindlimbs with very little handicap on propulsion. The shapes and kinematics of tadpoles appear to be specially adapted to the requirement of these organisms to transform into frogs.

Journal Article↗
PubMed1996

[Ten-year survival and cardiac event-free rates in Japanese patients with the left anterior descending artery revascularized with internal thoracic artery or saphenous vein graft: a comparative study].

To evaluate the long-term results of surgical patients with coronary artery bypass grafting (CABG), we comparatively analyzed the 10-year survival and cardiac event-free rates between 713 patients group with at least one internal thoracic artery to the left anterior descending artery (LAD), (ITA-CABG) and 241 patients group revascularized with vein grafts alone (SVG-CABG). ITA-CABG patients had more progressed diseases with a higher incidence of risk factors than SVG-CABG patients: number of vessel diseased 2.5 +/- 0.7 vs 2.3 +/- 0.7, LMTD 20.2% vs 14.1%, diabetes mellitus 37.3% vs 27.0% and hyperlipidemia 38.0% vs 30.7%. The 10-year cumulative LAD graft patency and severe disease-free rate was 90.3 and 67.0% for ITAs and vein grafts in this series. The 10-year overall actuarial survival, cardiac death-free and cardiac event-free rates for ITA and SVG groups were 88.8 vs 79.5%, 97.4 vs 92.6% and 84.1 vs 73.1%, all with a statistical significance (generalized Wilcoxon or logrank method). For the patients with reduced ventricular systolic function (EF < or = 0.4), ITA-CABG offered a significantly better 10-year cardiac death free rate. Also, for the diabetic patients, ITA-LAD offered a significantly better 10-year cardiac event-free rate. In conclusion, the use of ITA graft can reduce postoperative cardiac events and enhance the long-term survival in Japanese patients. The ITA should be utilized at least for LAD in all CABG patients whenever feasible.

Coronary Artery Bypass↗
PubMed1996

[Radiation-induced coronary ostial stenosis, a case of redo coronary bypass for the restenosis following patch angioplasty].

The patient was a 45-year-old woman who had had a tumor resection for thymic carcinoid and subsequent mediastinal irradiation (50 Gy) 3 years before the onset of angina pectoris during exercise. Coronary angiography (CAG) revealed an isolated ostial stenosis of the left main coronary trunk (LMT). Angiography also showed an occluded right internal thoracic artery (ITA) at its origin. The patient underwent patch angioplasty of the LMT orifice using a piece of the saphenous vein graft (SVG). One month after the operation, CAG revealed a success of operation with an enlarged LMT orifice and she was discharged. However, 3 months after the operation, angina pectoris recurred and a repeated CAG showed a 90% stenosis of the LMT at the place 1 cm distal to the orifice. Emergency CABG (the left ITA to the LAD and the SVG to the LCX) was accomplished with disappearance of angina. Post-CABG angiography revealed patent left ITA and SVG in association with complete obstruction of the LMT. One year after the second operation, she was free from symptoms. This case as well as other reports concerning radiation-induced coronary stenosis suggest that patch angioplasty for this specific lesions may have a high incidence of stenosis recurrence. Coronary bypass grafting that can be performed at the place away from the active proliferative lesion may be a better selection.

Angioplasty↗
PubMed1996

[Surgery for WPW syndrome with concomitant CABG: a case report].

A 58-year-old man underwent simultaneous surgery for WPW syndrome complicated by frequent attacks of atrial tachyarrhythmia combined with angina pectoris persisting after anterior myocardial infarction. Repeated PTCA of 3 times failed and restenosis occurred with recurrent angina particularly when atrial tachyarrhythmia took place. The preoperative ECG suggested the presence of a left free wall accessory pathway confirmed by an electro-physiolosical study. Coronary bypass grafting (LITA-LAD, SVG-4 PD) and division with cryoalation of the accessory pathway were performed using a transseptal left atrial approach. The patient is doing well now and free from both angina and tachycardia.

Angina Pectoris↗
PubMed1996

[A case report of aortic root replacement with fresh aortic homograft for valve detachment due infective endocarditis].

A 28-year-old male received a redo aortic valve replacement (AVR) with a 19 mm St. Jude Medical mechanical valve 3 months after the initial AVR because of recurrent valve detachment. We re-operated on this patient by aortic root replacement using a fresh aortic homograft. The donor of the homograft was a 59-year-old female who died of a traffic accident. The aortic root and valve was harvested aseptically and stored in a nutrient medium including antibiotics at 4 degrees C for 4 days. At the 3rd operation, aortico-ventricular discontinuity and an annular-abcess-like cavity were found. After debridement, the cavity was closed with a homograft aortic wall and then aortic root replacement was performed using a fresh aortic homograft. At first, prosthetic valve detachment seemed to be caused by infective endocarditis on the basis of his clinical history. However, causative organisms had never been recovered from the blood or the specimens obtained at the time of operation and reoperation. Post-operative HLA examination revealed No. 51 on HLA-B locus and thus we suspected that valve detachment might have been due to inflammation of the aortic wall caused by a subtype of Behçet disease. The early post-operative course was uneventful with a low dose of predonine. Post-operative aortography showed no aortic regurgitation and normal coronary anastomosis. Unfortunately however, he died suddenly 8 months after the operation. Autopsy demonstrated the presence of aortic wall necrosis with massive infiltration of macrophages and leucocytes resulting in dehiscence of the coronary anastomotic site. The cause of homograft detachment could not be determined for sure but might be recurrent infective endocarditis, although causative organisms were never identified, or infective endocarditis in combination with Behçet vasculopathy.

Adult↗
PubMed1996

[Successful removal of an infected pacemaker electrode, drifted into the right atrium, by using a lead removal kit].

A 65-year-old male was suffered complications from an infected pacemaker in the left subclavian region. The generator was removed and its electrode was cut at the vascular entry. A new system was implanted on the other side. Two months later, he suffered from persistent fever which required administration of antibiotics for 2 months. 7 months later, the cut end of the infected electrode was found to have drifted into the right atrium. Its removal was performed to prevent a potential exacerbation of the systemic infection. We were able to pick up an end of the electrode using a basket catheter which was inserted through the right internal jugular vein to extract it. The lead was then successfully removed using a lead removal kit.

Aged↗
PubMed1996

Preservation of myocardial function and metabolism at subzero nonfreezing temperature storage of the heart.

BACKGROUND: The hypothermic simple immersion technique has been widely used to preserve the donor heart for transplantation. However, there is still controversy as to which temperature provides the best protection against prolonged ischemia. The low molecular weight solutes within cells depress the freezing point to -0.6 degree C. In practice, however, most cells do not freeze internally unless they are cooled below -10 degrees C. We investigated the effects of subzero nonfreezing storage at -1 degree C on the preservation of myocardial metabolism and function. METHODS: Isolated Wistar rat hearts were subjected to 6 hours of preservation with the intracellular type University of Wisconsin solution; the hearts of the subzero group were preserved at subzero nonfreezing (-1 degree C) temperature, and the hearts of the control group were at 4 degrees C. Recovery of cardiac function, myocardial adenine nucleotides content, and myocardial water content were evaluated after preservation. RESULTS: Subzero group resulted in significantly better aortic flow, cardiac output, and aortic systolic pressure than in the control group. Myocardial adenosine triphosphate, adenosine diphosphate, and total adenine nucleotides at end-storage were significantly better preserved in subzero group when compared with the control group. Myocardial water content at reperfusion significantly increased in the control group compared with the subzero group. CONCLUSIONS: Storage in the intracellular type solution at subzero nonfreezing (-1 degree C) temperature as compared with 4 degrees C appears to prolong myocardial preservation with respect to the enhancement of postischemic functional recovery, preservation of myocardial adenine nucleotides during ischemia, and prevention of myocardial edema at reperfusion.

Adenine Nucleotides↗