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Biomedical subjects

H Miyamura

Publications and source records attributed to H Miyamura.

At least 73 records · Page 4Linked to original sources
PubMed1992

Limited vertical skin incision for median sternotomy.

The cosmetic deformity of the vertical skin incision for median sternotomy was decreased by using a mechanical traction system to increase exposure at the superior margin of a shorter wound. The limited vertical skin incision did not impede technical surgical maneuvers and produced a scar that was more acceptable than submammary incision or right anterior thoracotomy. The limited skin incision is especially useful in young women with congenital heart disease.

Adolescent↗
PubMed1992

Myocardial protection of neonatal heart by cardioplegic solution with recombinant human superoxide dismutase.

The effectiveness of high-potassium cardioplegic solution in the neonatal heart remains controversial. Our previous study indicated that the protection afforded by a cardioplegic solution was inadequate in the neonatal heart. On the hypothesis that oxyradicals were responsible for the ineffectiveness of cardioplegic solution in neonatal heart, the effects of a cardioplegic solution (a modified St. Thomas' Hospital cardioplegic solution) with recombinant human superoxide dismutase on the isolated perfused neonatal guinea pig hearts (within 2 days after delivery, body weight of 60 to 120 g) were studied in comparison with those on the adult hearts (6 to 8 weeks after delivery, body weight of 300 to 500 g). After arrest induced by modified St. Thomas' Hospital cardioplegic solution, hearts were subjected to 120 min of ischemia at 20 degrees C, during which time the cardioplegic solution was injected every 30 minutes. Then the heart was reperfused for 60 minutes at 37 degrees C. Under this condition, the left ventricular developed pressure recovered to 84.4% +/- 4.0% of the preischemic value in the adult heart, whereas the recovery was only 68.1% +/- 3.1% in the neonatal heart. Thiobarbituric acid-reactive substance level, a parameter of lipid peroxidation by oxyradicals, significantly increased during ischemic arrest both in the adult and neonatal heart. However, the increase was much greater in the neonatal heart than in the adult. Cardioplegia with recombinant human superoxide dismutase (300 and 1,000 U/mL) significantly inhibited this accumulation of thiobarbituric acid-reactive substance in the neonatal heart; at 1,000 U/mL, the myocardial function of the reperfused neonatal heart recovered to the level of the adult heart.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1992

[Late postoperative outcome of plastic operation versus valve replacement for mitral regurgitation].

Between January 1980 and August 1991, 99 patients underwent operation for mitral valve regurgitation (MR). The ages of the patients ranged from 12 to 67 years, (49.4 +/- 11.9 years), and there were 39 males and 60 females. Pathological cause of regurgitation, which was determined by intraoperative inspection and histological findings of excised leaflets, was rheumatic in 46, degenerative in 38, infective endocarditis in 9, ischemic in 4 and unknown in 2 patients. Cardiac rhythm was atrial fibrillation in 73, normal sinus rhythm in 24 and junctional rhythm in 2 patients. Our principles for valve repair were (1) excision of responsible segment and repair for prolapsed leaflet due to torn chordae, (2) shortening of elongated chordae, (3) annuloplasty, and (4) repair of perforated leaflet. Finally, 19 patients endured plastic operation, and 80 patients underwent prosthetic valve replacement. The rate of plastic procedure was 62.5% (10/16) in degenerative MR with mural chordal lesions, 42.9% (3/7) in rheumatic MR without stenosis, 22.2% (2/9) in infective endocarditis and 100% (2/2) in MR with unknown etiology. Mitral valve repair was failed both in rheumatic MR associated with stenosis (39 patients) and in ischemic MR (4 patients). A ten-year survival rate after operation was 92.2 +/- 3.1% in patients with valve replacement and 83.6 +/- 10.0% with valve repair (N.S.), and a proportion of event-free survival in patients with valve replacement was similar to valve. Late postoperative cardiac catheterization revealed decreased left ventricular volume indices and increased left ventricular end-systolic stress/volume ratio in both groups compared to preoperative values, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[A surgical repair of complete endocardial cushion defect associated with single atrium, persistent left superior vena cava draining into the left atrium, hemiazygos connection and double orifice mitral valve].

Successful surgical repair of a 1-year-old girl of complete endocardial cushion defect associated with single atrium, persistent left superior vena cava draining into the left atrium, hemiazygos connection and double orifice mitral valve was reported. We repaired the endocardial cushion defect by using an endocardial cushion prosthesis and a new atrial septum was created to allow the left superior vena cava draining into the right atrium. We made no treatment for the accessory mitral valve orifice because of no regurgitation.

Azygos Vein↗
PubMed1992

[Surgery of vascular rings associated with complex intracardiac anomaly].

Two rare cases with surgically treated vascular ring associated with complex congenital cardiac anomaly are reported. Each case showed vascular ring due to right aortic arch, right descending aorta, aberrant left subclavian artery and left ductus arteriosus. Case 1 was a 2-year-old boy associated with ligamentum arteriosum and total anomalous pulmonary venous connection (TAPVC), and presented dyspnea and dysphagia. Case 2 was a 3-year-old girl associated with patent ductus arteriosus (PDA) and tetralogy of Fallot (TOF). In case 1, the two-staged operation was performed because of the necessity of mechanical ventilation and of recurrent respiratory infection. Division of the ligamentum, dissection of bronchus and esophagus was performed at the first operation through left thoracotomy, and the intracardiac repair of TAPVC was done three months later. In case 2, PDA division and the intracardiac repair of TOF was done simultaneously through median sternotomy because of the mild symptom of vascular ring and technical feasibility. Each case was successfully treated and became completely asymptomatic.

Abnormalities, Multiple↗
PubMed1991

[Surgical management of valve replacement in children].

From 1965 to 1990, 49 valve replacements were performed on 43 patients under the age of 15. Mitral valve replacements were performed on 21 patients, and re-replacements were done on 4 of them afterwards. In the first 9 mitral valve replacements before 1974, Starr-Edwards (S-E) ball valves were used. Five of these patients died in the hospital (early mortality rate was 56%). Since 1975, bioprosthetic valves were used in three cases, but all of these valves ceased to function due to primary tissue failure (PTF) within 3 years. Consequently, SJM valves are now used as a first choice. Ten aortic valve replacements were performed on 9 patients with the results of one early death, two late deaths, and one late re-operation. Tricuspid valve replacements were performed on 11 patients, 5 of whom utilized S-E ball valves. Three of the five patients died in the hospital. One patient was re-operated on, swapping the S-E ball valve for the SJM valve. SJM valves were used primarily in 2 patients, and bioprosthetic valves in 4. Two patients died, one with a SJM valve, and the other with a bioprosthetic valve. Two pulmonary valve replacements were performed, one employing a SJM valve, the other a bioprosthetic valve. Two adult patients with SJM valve in the right side of the heart had thrombotic complications, though the patients with bioprosthetic valves had none. Atrioventricular valve replacements were performed on 5 patients under the age of 3, but all of them died.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[Surgical management of congenital aortic valve stenosis in neonates and infants].

From 1985 to 1989, 4 neonates or infants (3 males and 1 female) underwent open valvotomy for severe aortic valve stenosis. In all patients, preoperative echocardiograms showed abnormal findings of endocardial fibroelastosis and/or poor performance of left ventricle. All patients underwent valvotomy using cardiopulmonary bypass. There was one early death from left ventricular failure. All other patients survived and the pressure gradient through aortic valve was reduced from 50-100 mmHg to 25-50 mmHg postoperatively. We conclude that infants with severe aortic valve stenosis should undergo open valvotomy before the manifestation of endocardial fibroelastosis and/or left ventricular muscle damage, and that open aortic valvotomy using cardiopulmonary bypass is most suitable method for severe aortic valve stenosis in infants.

Aortic Valve↗
PubMed1990

Heart-lung transplantation--Harefield experience.

One hundred and fifty-nine combined heart and lung transplantations were performed on 152 patients at Harefield Hospital from 1980 to February 1988. The age of the recipients ranged from 10 weeks to 52 years. The transplantation was indicated for pulmonary vascular disease on 106 patients (69.7 per cent), and for parenchymal lung disease on 46 patients (30.3 per cent). Eisenmenger syndrome was the commonest disease that required the heart-lung transplantation. A combination of cyclosporin A and azathioprine was administered for immunosuppression therapy postoperatively, and oral steroids were not routinely used. The hospital mortality rate was 32.2 per cent, and 103 patients were discharged from the hospital. The first-year actuarial survival rate was 64 per cent, and the second-year was 61 per cent. Although pulmonary deterioration due to obliterative bronchiolitis was a serious late complication, most of the recipients enjoyed a good quality of life after transplantation. Heart and lung transplantation offers the patient a chance of marked improvement both in survival and in quality of life.

Actuarial Analysis↗
PubMed1990

Successful surgical treatment of incessant automatic atrial tachycardia with atrial aneurysm.

A 9-year-old boy with heart failure and long-term incessant atrial tachycardia mimicking dilated cardiomyopathy was treated surgically. Intraoperatively he was found to have atrial aneurysm, and the ectopic automatic focus was located at the base of it. Excision of the aneurysm including the focus without using cardiopulmonary bypass cured the tachycardia and heart failure.

Child↗
PubMed1990

Ventricular tachycardia with two possible exits from one re-entrant circuit.

A case of sustained ventricular tachycardia (VT) with two possible exits from one re-entrant circuit is described in this paper. The patient was a 27-year-old female who had undergone corrective surgery for tetralogy of Fallot at the age of 8, and developed VT of distinctly different QRS configurations. The exit of one VT was at the right ventricular (RV) outflow tract and the other at the RV apex as determined by endocardial and pace-mapping. Continuous and split activities were observed at the RV outflow tract during both types of VT. One VT was entrained by rapid pacings, and the causal mechanism was thought to be re-entry and common re-entrant circuit was established for two QRS configurations of VTs. A discrepancy was observed between the site of the earliest activation and the site of the pace-mapping which resulted in QRS configuration of VT of the RV apex origin. The findings in this paper should be considered when contemplating aggressive therapy such as electrical ablation.

Adult↗
PubMed1990

[Long-term follow-up (20 to 25 years) of tetralogy of Fallot after correction].

Eighty patients with tetralogy of Fallot who underwent corrective surgery between 1965 and 1970 were followed and evaluated. Late death was observed in 8 patients, and 3 of them were cardiac deaths. The survival rate at 10-year was 96.2%, at 20-year was 91.7%, and at 24-year was 89.0%. Of the surviving patients, 78% to 85% are spending normal social life. Twenty female patients experienced 31 deliveries, and no babies with cardiac anomaly were born. Most of the complaints come from late arrhythmias, and this is the main problem in the long-term period. Right ventricular function is considered to be moderately reduced by catheter analysis. The importance of preservation of right ventricular function during the surgery should be stressed.

Adolescent↗
PubMed1990

[Long-term results of valve replacement in the right side of the heart in congenital heart disease--comparative study of bioprosthetic valve and mechanical valve].

Valve replacements in the right side of the heart (TVR and PVR) were done on 16 patients with congenital heart disease, mainly tetralogy of Fallot and Ebstein anomaly. Including reoperations, 19 operations were performed on them and 20 artificial valves were inserted. Ten mechanical valves (7 St. Jude Medical valves, 3 Starr-Edwards valves) and 10 bioprosthetic valves (7 Carpentier-Edwards valves, 3 Ionescu-Shiley valves) were used. Age at valve replacement ranged from 9 to 52 years (mean 23.0 years), and the follow-up period was 1.28-19.8 years (mean 5.7 years). Including 2 sudden deaths, late death occurred in 4 patients, on all of whom mechanical valve replacements were done at the primary operation. Five-year survival rate of all patients was 76.4 +/- 12.1%, and 10-year survival rate was 63.6 +/- 15.4%. All the patients who received bioprosthesis at the primary operation survived at the time of this follow-up study. On the contrary, long-term results of mechanical valve was unsatisfactory with the 5-year survival of 62.5 +/- 17.1%. In spite of anti-coagulation therapy with warfarin, three patients with mechanical valve complicated thrombotic valves, which necessitated re-operations. Calcified bioprosthetic valve occurred in one patient with I-S valve 8.5 years after the implantation. Five-year complication-free rate was 87.5 +/- 11.7% for bioprosthesis, whereas it was 50.0 +/- 15.8% for mechanical valve (p less than 0.056). It is concluded that the bioprosthesis is the first choice for the valve replacement in the right side of the heart in congenital heart disease.

Adolescent↗
PubMed1990

[Delayed sternal closure following open-heart surgery in infants and children].

Between January, 1982, and December, 1987, 14 patients failed to approximate sternum after open-heart surgery in infants and children. The indications for keeping sternum open were enlarged heart, myocardial edema, severe depression of myocardial contractility and reduced lung compliance due to pulmonary edema. Of the 14 patients, 9 underwent delayed sternal closure between 2nd and 13th postoperative day, and 4 were long-term survivals. All the rest of five patients who were left their sternum open, died of intractable cardiac failure within 16th postoperative day. During the sternum open, three patients suffered from complications-myocardial bleeding in one, and mediastinitis in two. But none of them directly related to the death, and one patient with mediastinitis successfully healed with closed mediastinal irrigation. Although the employment of the delayed sternal closure is rare and limited to the patient with severe heart failure, its judicious use adds advantages in the management of low cardiac output state in infants and children immediately postoperative period.

Cardiac Surgical Procedures↗
PubMed1989

Tricuspid and pulmonary atresia with coarctation of the aorta: a rare combination possibly explained by persistence of the fifth aortic arch with a systemic-to-pulmonary arterial connection.

A ten-day old baby was found to have tricuspid and pulmonary atresia, and a "ductal-dependent" pulmonary circulation that was prostaglandin-sensitive. An unusual coarctation of the aorta was not recognised until an autopsy was performed, some 11 days after construction of an aortopulmonary shunt. A previously undefined anomaly in this neonate was persistence of the fifth aortic arch with a systemic-to-pulmonary artery connection on the same side as the definitive aorta. The histology of the fifth aortic arch is consistent with the pattern of an arterial duct.

Aorta, Thoracic↗
PubMed1989

[Intermediate-term results after Fontan type operation for single ventricle].

From 1983 to 1985, Fontan type operation were successfully performed on five patients with single ventricle. Marked cyanosis disappeared soon after the surgery, and normal exercise tolerance was obtained in all cases but one in the late postoperative period. Compared to marked improvement in the exercise tolerance test, cardiac output remained subnormal both at rest and during exercise even in the late postoperative period. Several types of asymptomatic arrhythmias were observed during the acute postoperative days, but they were not recognized in the intermediate-term postoperative period. Routine blood chemistry studies showed that hepatic function was within normal limits, but hepatic dysfunction was suggested by Indocyanine Green clearance test. Renal function was well preserved after Fontan type procedure. Though cardiac output is subnormal, Fontan type procedure is a safe and effective operation, and intermediate-term state is satisfactory without any signs of heart failure.

Adolescent↗
PubMed1989

[Scimitar syndrome with left pulmonary hypertension and right pulmonary artery stenosis in childhood--report of a case of successful surgical repair].

An one-year old child with Scimitar syndrome (anomalous drainage of the right pulmonary vein to inferior vena cava with right lung hypoplasia) associated with left side pulmonary hypertension and right pulmonary artery stenosis underwent surgical repair. The anomalous pulmonary vein was anastomosed to right atrium with 10 mm PTFE graft interposition and drained to left atrium through equine pericardial intra-atrial baffle. The stenotic portion of right pulmonary artery was enlarged with porcine pericardial patch. To our knowledge, this is the first successful surgical case of Scimitar syndrome with pulmonary hypertension in childhood reported in literature. A repair of anomalous pulmonary venous drainage to inferior vena cava in childhood is difficult, and a meticulous selection of surgical procedure is necessary.

Blood Vessel Prosthesis↗
PubMed1989

[Myocardial infarctectomy in the acute stage].

Seven patients with ventricular septal perforation or left ventricular free-wall rupture underwent myocardial resection in the acute stage of myocardial infarction. One of them received direct closure of the left ventricle, and the others replacement of myocardium with a Dacron prosthesis. One patient died of cardiac failure 5 days after surgery, and 4 in the late-stage between 2 months and 4 years. The following conclusions are obtained in our patients: 1. Echocardiography is very important for the diagnosis of cardiac free-wall rupture and determination of emergency surgery. 2. An intra-aortic balloon should be inserted in patients with VSP as soon as possible. If general state of the patients had been improved by the procedure, surgery might be withheld until the recovery, otherwise emergency surgery should be considered. 3. Myocardial replacement with a prosthesis seems to be useful when the left ventricular cavity is predicted to be small after resection of the myocardium. 4. The development of assisted circulation would improve a survival rate after the surgery. 5. Systemic managements are also important because the patients sometimes become fatal by non-cardiac complications even if they have survived from circulatory failure.

Aged↗