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Biomedical subjects

Y Senoo

Publications and source records attributed to Y Senoo.

At least 55 records · Page 3Linked to original sources
PubMed1989

Evaluation of the left ventricular reserve by dynamic exercise echocardiography after surgery for valvular heart diseases.

Dynamic ergometer exercise in a supine position was applied to 64 patients more than 1 year after valvular heart surgery, and the left ventricular reserve was evaluated echocardiographically. The left ventricular reserve declined in the mitral stenosis-mitral valve replacement group, while it was better maintained in the mitral stenosis-mitral commissurotomy, aortic regurgitation and aortic stenosis groups. The patients were divided into 3 groups depending on whether the percentage increase during exercise of stroke index, an index of left ventricular pump function, increased, unchanged, or decreased. The percentage increase of mean velocity of circumferential fibre shortening (y) and that of left ventricular end-diastolic diameter (x) during exercise were plotted for each group. The increased group was isolated from the unchanged group by the line of y = -5.02x + 30.1; the unchanged group was isolated from the decreased group by that of y = -5.68x-10.0, and the increased and unchanged groups were clearly isolated from the decreased group by that of y = -6.86x-4.76. We conclude that dynamic ergometer exercise echocardiography is useful for evaluating the left ventricular reserve of postoperative patients with valvular heart disease. It was also thought that the subclinical state of cardiac failure can be effectively detected by the present method.

Adult↗
PubMed1989

Return to work after heart valve replacement.

One hundred patients who underwent heart valve replacement during the years 1977 to 1985 were reviewed an average of 57 months after surgery. The overall rate of reemployment after the operation was 78%. The most important factors influencing the return to work were the employment status before surgery, age at the time of surgery, the number and site of the diseased valve, the preoperative New York Heart Association (NYHA) functional class and the number of times cardiac surgery was performed. These factors were closely related to the optimal timing of heart valve replacement. It was suggested that the rate of return to work and the quality of life would be improved if the heart valve replacement had been performed at an earlier stage of the disease.

Adolescent↗
PubMed1989

Successful extended hypothermic cardiopulmonary preservation for heart-lung transplantation.

The inability to obtain sufficiently extended hypothermic organ preservation is a major restriction on clinical heart-lung transplantation. We used core cooling, nonrecirculating retrograde heart perfusion, and lung immersion with liposomal recombinant human superoxide dismutase in an attempt to provide effective 12-hour cardiopulmonary preservation. Donor dogs supported by cardiopulmonary bypass were rapidly cooled to 15 degrees C with cardioplegic arrest, and heterotopic heart and unilateral left lung transplantations were performed. In control dogs (n = 7), hearts and lungs, harvested after core cooling and cardioplegic arrest, were transplanted with a total mean ischemic time of 88 +/- 5 minutes. In group II (n = 7), heart-lung blocks were similarly excised but preserved at 4 degrees C for 12 hours (756 +/- 30 minutes) and then transplanted. During preservation, the lungs were immersed in hyperosmolar extracellular solution. For the heart, retrograde coronary sinus perfusion was performed with intracellular solution containing perfluorochemicals at a temperature of 4 degrees C and a rate of 30 ml/hr for 12 hours. In group III (n = 7), donor organs were similarly excised and preserved for 12 hours (726 +/- 39 minutes), except that liposomal recombinant human superoxide dismutase was administered during harvest, preservation, and reperfusion. Myocardial function, assessed by the ratio of end-systolic pressure to end-systolic dimension, after the 12-hour preservation period in both experimental groups was similar to that of the control group 4 and 6 hours after transplantation. The mean arterial oxygen capacity of the transplanted left lung during ventilation with an inspired oxygen concentration of 40% was also similar in each group. In contrast, the 12-hour preservation of pulmonary function assessed by pulmonary vascular resistance, the accumulation of extravascular lung water, and histologic evidence of alveolar wall injury, interstitial edema, and perivascular hemorrhage were significantly impaired in the absence of liposal recombinant human superoxide dismutase. These findings suggest that successful extended cardiopulmonary preservation for heart-lung transplantation is possible with core cooling, nonrecirculating retrograde heart perfusion, and hypothermic lung immersion incorporating liposomal recombinant human superoxide dismutase.

Animals↗
PubMed1989

[High energy phosphates and mitochondrial respiratory function after 24 hours cardiac preservation--comparison between simple hypothermic immersion and continuous hypothermic perfusion].

Cardiac preservation is one of the most important step during heart transplantation. Prolonged preservation period is necessary to get the greater donor pool. To get safe prolonged preservation two methods, simple hypothermic immersion method (group A) and continuous hypothermic perfusion method (group B), were compared in this report by evaluating the myocardiac high energy phosphate level and mitochondrial respiratory function. The values of ATP, TAN and Energy charge were significantly higher in group B than group A (p less than 0.001). Mitochondrial respiratory function such as state 3 QO2, state 4 QO2, RCI and ADP/O also showed significantly higher values in group B than group A (p less than 0.001). These date indicate that continuous hypothermic perfusion method provides better preservation than simple hypothermic immersion method for 24 hours cardiac preservation.

Adenosine Triphosphate↗
PubMed1989

[Preoperative perspective versus postoperative functional assessment of surgery in chronic mitral regurgitation].

Thirty patients with chronic pure mitral regurgitation who underwent mitral valve replacement during 1981 to 1986 were evaluated for pre- and one year postoperative left ventricular function using two dimensional echogram. Indicators in their evaluation were DdI, DsI, MassI and systolic and diastolic R/Th. Postoperatively, patients (n = 7) were placed in a group of abnormal responses if even one of these indicators of left ventricular function became worse than preoperative performance, patients in this group were symptomatic and two subsequently died. The postoperative FS and mVcf data fort this group were significantly lower than the patients with normal response group (n = 23). These two groups could not be differentiated by preoperative assessments of either DdI, MassI, systolic/diastolic T/Th or normalized systolic/diastolic peak velocity. However, a combination of normalized systolic peak velocity lower than 1.70 and diastolic peak velocity lower than 2.20 of left ventricular wall motion proved to be good predictors of postoperative results.

Chronic Disease↗
PubMed1989

[A case of infective endocarditis with the mycotic aortic valve aneurysm].

A 49-year old man was admitted with a complaint of syncopal attack. Transient A.V block was detected and permanent pacemaker (DDD) was implanted. Five months later he was re-admitted because of dyspnea and palpitation. Infective endocarditis with aortic regurgitation and mycotic aortic valve aneurysm was diagnosed by echocardiography and cineangiography. The aortic valve and valve aneurysm were resected and AVR was performed using Björk-Shiley disc valve (23A) in the usual manner. But 6 months later he suffered from acute cardiac failure due to perivalvular leakage. He died in spite of re-AVR with translocation method.

Aneurysm, Infected↗
PubMed1989

[Mitral valve replacement following myomectomy for idiopathic hypertrophic subaortic stenosis].

A patient is reported with IHSS where mitral valve replacement was performed 3 years following myomectomy because of a residual pressure gradient of left ventricular outflow tract. After mitral valve replacement, the left ventricular outflow tract obstruction was almost completely relieved not only at rest but also at provocation by isoproterenol. The patient successfully returned to work with no symptoms.

Adult↗
PubMed1989

[Emergency surgery for thrombosed Björk-Shiley mitral valve prosthesis].

A case of a thrombosed Björk-Shiley mitral valve with severe pulmonary edema which developed six years following an initial operation was reported. Doppler echocardiography was one of the most useful tools to evaluate prosthetic mitral valve dysfunction. Peak blood flow velocity was high (2.7 m/sec) compared to the data (1.7 m/sec) obtained six months before the reoperation. Emergency surgery disclosed the thrombosed valve prosthesis which was replaced with a St. Jude Medical valve. The patient recovered successfully with no problems.

Adult↗
PubMed1988

Core-cooling, heart-perfusion, lung-immersion technique provides successful cardiopulmonary preservation for heart-lung transplantation.

Mongrel dogs underwent heterotopic heart-orthotopic left lung transplantation. In Group I (N = 6), donor organs procured following core cooling to 15 degrees C on cardiopulmonary bypass (CPB) with cardioplegic arrest were immediately transplanted. In Group II (N = 6), following cardioplegic arrest without CPB core-cooling, the pulmonary artery was flushed with modified Collins' solution. Heart-lung blocks were immersed in extracellular solution for 6 hours and then transplanted. In Groups III and IV (N = 6 each), following CPB core-cooling to 15 degrees C and cardioplegic arrest, the organ blocks were immersed in extracellular solution (Group III) and the heart was perfused with oxygenated extracellular solution (Group IV). Evaluation of lung function using differences in arterial oxygen tension between the left and right atria demonstrated no differences between groups. However, extravascular lung water and pulmonary vascular resistance were significantly elevated in Group II. Cardiac function assessed by the ratio of end-systolic pressure to end-systolic dimension was significantly better in Group IV than in Groups II and III. Thus, adequate 6-hour hypothermic cardiopulmonary preservation with core cooling plus heart perfusion can be achieved for heart-lung transplantation.

Animals↗
PubMed1988

Efficacy of intra-aortic balloon pumping for failing Fontan circulation.

The Fontan circulation occasionally cannot be sustained by currently available medical treatment. In these circumstances, mechanical assistance to the Fontan circulation should be considered. We have experienced three cases where Fontan circulation was assisted by intra-aortic balloon pumping (IABP). The hemodynamic improvement and weaning from IABP were successfully achieved in all cases. One patient survived the serious postoperative course with the aid of IAPB, and two patients died following multiorgan failure, though the circulation had eventually been re-established. By studying the postoperative hemodynamics assisted by IABP, it is concluded that IABP is a reasonable, efficacious strategy to support and to re-establish the failing Fontan circulation, though the changes in hemodynamic variables will not immediately coincide with IABP application.

Adolescent↗
PubMed1988

Results of surgery for aortic regurgitation due to aortic valve prolapse.

The clinical, hemodynamic and pathological findings of 13 patients with aortic regurgitation due to aortic valve prolapse caused by advanced myxomatous degeneration were evaluated. Eleven patients showed a favorable outcome with no complications resulting from surgery. One patient died from aortic dissection, and another died suddenly from an unknown cause. Five patients had mitral valve prolapse as a complication. Ten patients (77%) had a long-standing history of hypertension. Twelve patients (92%) were male. None of the patients had the stigmata of Marfan's syndrome. All patients had marked myxomatous degeneration of the aortic valves without any inflammatory changes. Two patients showed microcalcification; 7 demonstrated moderate fibrosis. Five patients showed severe fragility of the cusps which appeared redundant, gelatinous and softened by degenerative changes. Myxomatous degeneration of the aortic valve is not rare, and, in fact, it may be one of the most common pathologic and clinical entities associated with pure aortic insufficiency.

Adult↗
PubMed1988

Improvement of left ventricular function after surgical correction of chronic aortic regurgitation.

Serial left ventricular (LV) echocardiographic studies were performed in 21 patients before and after aortic valve replacement for chronic aortic regurgitation. The effect of valve replacement on LV dimensions, cross-sectional area of the LV muscle and LV function was determined from the echocardiographic data. The relation between degeneration of the myocardium and surgical outcome was also investigated. The average LV end-diastolic dimension decreased from 66.0 +/- 8.3 mm to 46.3 +/- 5.7 mm twelve months postoperatively. The average LV end-systolic dimension also fell from 43.4 +/- 8.1 mm to 31.1 +/- 5.0 mm. The muscle cross-sectional area decreased from 33.1 +/- 5.1 cm2 to 24.5 +/- 4.0 cm2, indicating a decrease in LV mass. The indices of contractility (fractional shortening, ejection fraction and mean velocity of circumferential fibre shortening) had a tendency to decrease one month after surgery, but they subsequently increased to the normal level 12 months after surgery. Nineteen out of 21 patients showed a favorable outcome as to the functional status. The remaining two patients had a large LV dimension and subnormal contractility, and they failed to show a significant reduction in the follow-up period. The muscle score in the two patients was greater than 8 points, which indicated irreversible impairment of the myocardium. Patients with persistent postoperative LV enlargement have a poor prognosis and should be identified so that aggressive medical treatment can be instituted.

Adolescent↗
PubMed1988

Activity and stability of recombinant human superoxide dismutase in buffer solutions and hypothermic perfusates.

The stability of recombinant human superoxide dismutase (r-hSOD) in buffer solutions was studied in solutions at various pH and temperatures. Additionally, we studied the effects of incubation with proteases, serum and two types of hypothermic perfusates. R-hSOD was stable in the pH range of 6-11 and at temperatures up to 80 degrees C for 30 min. R-hSOD activity was not affected by incubation with trypsin, aminopeptidase M or serum for 2 h. R-hSOD activity determined at various temperatures (4-37 degrees C) did not vary remarkably. R-hSOD in hypothermic perfusates was stable at 4-37 degrees C for 24 h.

Buffers↗
PubMed1988

Oxygenated perfluorocarbon, recombinant human superoxide dismutase, and catalase ameliorate free radical induced myocardial injury during heart preservation and transplantation.

The effect of free radical scavengers on free radical-induced myocardial injury during heart preservation and transplantation was examined. Four groups of nine hearts each were harvested from mongrel dogs (12.5 to 16.5 kg) and orthotopically transplanted to size-matched recipients. All hearts received a continuous perfusion of oxygenated modified Collins' solution (group A). In addition, groups B, C, and D received Fluosol DA and albumin. Preservation perfusion was performed for 18 hours, at 4 degrees C, pH = 7.4, and 20 mm Hg. In group C, recombinant human superoxide dismutase (4,080 U/mg, 20 mg/kg) and bovine catalase (46,200 U/mg, 20 mg/kg) were administered only during preservation perfusion. In group D, these scavengers were administered just before and during reperfusion for 1 hour. Hemodynamic studies were performed before excision of the donor hearts and 1 hour after the termination of cardiopulmonary bypass. Creatinine kinase MB isoenzyme and thiobarbituric acid reactive substance levels in the coronary effluent were determined during preservation perfusion and reperfusion. Only group A showed a significant heart weight gain (p less than 0.05) and a decline in passive compliance (p less than 0.05) during preservation. Lactate release was higher in group A than in the groups receiving Fluosol DA. In contrast, pyruvate levels in group A were lower than in other groups. The generation of free radicals stayed at a low level during preservation, but significantly increased during reperfusion and was associated with a corresponding increase in creatinine kinase MB isoenzyme. Perfusion with a perfluorochemical solution (group B) inhibited the sharp rise in levels of thiobarbituric acid reactive substances and of creatinine kinase MB isoenzyme and improved cardiac function during reperfusion (versus group A). Exogeneous free radical scavengers administered just before and during reperfusion (group D) significantly ameliorated thiobarbituric acid reactive substances and creatinine kinase MB isoenzyme levels and also induced a significant hemodynamic improvement during reperfusion. However, administration of scavengers during preservation did not. This study demonstrates that the generation of free radicals is primarily significant during reperfusion and reoxygenation after ischemia. Thus the best time for administration of scavengers is just before and just after the onset of reperfusion. Furthermore, perfusion with perfluorochemicals effectively maintains aerobic metabolism and ameliorates free radical damage during this period.

Animals↗