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Biomedical subjects

M Shigenobu

Publications and source records attributed to M Shigenobu.

88 records · Page 5Linked to original sources

Factors influencing long-term survival after mitral valve replacement.

Thirty-seven consecutive cases of mitral valve replacement have been retrospectively reviewed. The prognostic significance of preoperative clinical, hemodynamic and quantitative angiographic factors for survival has been evaluated. In the Mitral stenosis (MS) group, all of the patients who showed small Stroke volume index (SVI) (less than 45 ml/m2) with pulmonary hypertension died from the low output syndrome. The prognosis was poor in patients who had large cardiothoracic ratio (CTR) in the MS group. Aortic valve replacement must be considered when moderate aortic regurgitation is associated with mitral valve disease. In the MR factors for predicting the survival. The eccentricity ratio is also a sensitive parameter for recognizing a patient who will have a poor prognosis after mitral valve replacement. The main mode of death was found to be heart failure due to myocardial impairment.

Adolescent↗

Thirteen years' experience with the Kay-Shiley disc valve for tricuspid replacement in Ebstein's anomaly.

From August, 1965, to November, 1974, 11 patients underwent operation for Ebstein's anomaly. In 1 patient operated on on August 16, 1965, the early Kay-Shiley disc valve was used. In the remaining 10 patients, the Kay-Shiley muscle guard valve was inserted. This valve was designed to prevent the prosthesis from encroaching on the right ventricle, thereby increasing the flow around the disc. One patient with a history of Wolff-Parkinson-White syndrome died of dysrhythmia on the first postoperative day. The other 10 patients have been followed from 4 to 13 years (mean, 6 years 2 months) after operation. Seven patients are working full-time without difficulty, 2 are housewives, and 1 attends school. All patients have improved at least one class in the New York Heart Association Functional Classification.

Adolescent↗

Factors influencing long-term survival after aortic valve replacement.

In the aortic stenosis group, the left ventricular (LV) muscle mass index was a good parameter for predicting the prognosis. Associated mitral valve disease had no influence on long term survival after aortic valve replacement. In the aortic insufficiency group, associated mitral valve disease had a marked influence on the results of aortic valve replacement. In general, the aortic insufficiency group had less clinical improvement postoperatively than the aortic stenosis group. In the annuloaortic ectasia group, left ventricular enddiastolic pressure (LVEDP) might be the predictor to the prognosis. This group had the worst prognosis, of the three groups. Early operation should be considered for patients who have no, or only mild symptoms of, aortic valve disease.

Adolescent↗

Surgery for mitral and tricuspid insufficiency associated with secundum atrial septal defect.

Pure mitral insufficiency associated with secundum atrial septal defect is not an unusual finding. Thirteen patients with significant mitral insufficiency and an associated secundum defect were operated upon. Two of these patients also had severe tricuspid insufficiency. The mitral valve was repaired in 12 patients and replaced in one. The tricuspid valve was reapired in the two patients with associated tricuspid insufficiency. There were two early deaths due to mediastinitis and one late death due to a cerebral embolus in the only patient who had valve replacement; this patient died 3 years after the operation. It is concluded that mitral and tricuspid valve repair should be performed for patients with significant mitral and tricuspid insufficiency associated with atrial septal defect of the secundum variety. Replacement of the values should be avoided if possible.

Adolescent↗

An electron microscopic study of the vascular factor in hemorrhagic diathesis.

Experimental diapedetic hemorrhage (oozing) was produced by streptokinase in rabbits and the fine structures of mesenterial microvessels were observed. Diapedesis of erythrocytes was seen in the venular side of microcirculation. On the contrary, no diapedesis was seen in true capillary on the arteriolar side. Sticking of erythrocytes to venular wall prior to diapedesis was proved, electron microscopically, to be the state in which red blood cells were trapped in the gaps on the endothelial junction. It was considered to be the morphological findings of the prediapedetic state. Erythrocytes passed through gaps on the endothelial junctions with high plasticities under any diapedetic conditions mentioned above. Furthermore, in author's experiments by ruthenium red staining, erythrocytes were observed just passing through the basement membrane under electron microscopy, in spite of its high speed process. It was found that the basement membrane is a very important barrier in erythrocyte diapedesis.

Animals↗

Surgical correction of Ebstein's anomaly by tricuspid valve replacement and its late problems.

The choice between valve replacement and plasty for surgical management of Ebstein's anomaly still remains controversial. Since 1960, we have treated 16 cases of Ebstein's anomaly, and 7 of the 16 cases have undergone surgical correction. Tricuspid valve replacement (TVR) without plication of the atrialized ventricle was applied in 4 cases, and Hardy's procedure was adopted in three cases. The division of the Bundle of Kent was carried out simultaneously in 2 cases with Wolff-Parkinson-White (W-P-W) syndrome of the TVR group. All patients have survived the operation. Early and late (as long as 14 years) postoperative evaluations have demonstrated superiority of the TVR group. However, the late echocardiographic findings have revealed new problems in the TVR group, such as hypokinetic or paradoxical motion of the atrialized ventricle in two cases and hypofunction of the left as well as the right heart.

Adolescent↗