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Biomedical subjects

H Shirotani

Publications and source records attributed to H Shirotani.

At least 37 records · Page 2Linked to original sources
PubMed1988

Factors affecting biventricular function following surgical repair of tetralogy of Fallot.

Right and left ventricular functions were assessed in children following surgical repair of tetralogy of Fallot. The results were analyzed with regard to the relative contribution of preoperative, perioperative and postoperative factors to postoperative functional abnormalities. Pulmonary regurgination of our Grade 3 or more depressed right and left ventricular ejection fractions and enlarged right ventricular end-diastolic volume. Right and left ventricular ejection fractions in patients with residual right ventricular outflow pressure gradients over 30 mmHg were significantly lower than those in patients with pressure gradients of 30 mmHg or less. The majority of those pressure gradients were at the pulmonary annulus or central pulmonary artery. Right and left ventricular ejection fractions were significantly lower in patients with a preoperative aortic oxygen saturation of less than 80% than in patients with one of 80% or more. The 3 variables of pulmonary regurgitation, residual pulmonary stenosis, preoperative aortic oxygen saturation were statistically independent. Left ventricular ejection fraction and end-diastolic volume correlated with the right ventricular ejection fraction and end-diastolic volume, respectively (r = 0.63, r = 0.68). These results show that severe pulmonary regurgitation, significant annular or central pulmonary stenosis and preoperative hypoxia are major contributing factors to right ventricular dysfunction after surgical repair of tetralogy of Fallot. The postoperative left ventricular dysfunction can be largely attributed to dysfunction of the right ventricle.

Cardiac Catheterization↗
PubMed1986

Postoperative long-term results in total correction of tetralogy of Fallot: with special reference to method and degree of relief of right ventricular outflow tract obstruction.

Late results were studied in 63 patients who underwent complete repair of tetralogy of Fallot. Mild pulmonary stenosis (PS) was present in 73%, moderate PS in 17% and severe PS in 10% of the patients. When a transannular patch was used, wider enlargement of the pulmonary annulus did not always relate to a decrease in right ventricular pressure and right ventricular to pulmonary artery pressure gradient in the late postoperative period. Pulmonary regurgitation (PR) of grade 2 or less did not relate to the late postoperative hemodynamics and cardiac function. PR of grade 3 or over led to right ventricular and pulmonary artery hypertension, and to increases in right ventricular end-diastolic volume and CTR. PR of grade 4 impaired left ventricular function. PR of grade 3 or over with moderate PS led to elevation in right ventricular end-diastolic pressure. In patients with mild PS and PR of grade 2 or less, late postoperative hemodynamics and cardiac function were excellent. To maintain excellent postoperative hemodynamics and cardiac function, it is imperative to obtain PR of grade 2 or less and to use a procedure which will lead to excellent development of the pulmonary annulus. In conventional procedures using a transannular patch, a CSAI of less than 2.5 cm2/m2 and precise coaptation between the original pulmonary cusp and the cusp mounted on the patch will aid in avoiding significant PR.

Adolescent↗
PubMed1984

Reconstruction of pulmonary artery with substitute valve--with special reference to size of conduit and valve.

Operative risk factors and postoperative late results were evaluated in 26 patients undergoing pulmonary artery reconstruction with a substitute valve. Seventeen extracardiac conduits bearing a valve were used in 16 patients and an in situ pulmonary valve insertion was carried out in the other 10. The surgical results were influenced by complexity of the underlying cardiac lesions and pulmonary vascular status, with a high mortality rate in patients with several cardiac defects including single ventricle, asplenia syndrome, complete atrioventricular canal etc. The mortality rate was 6% in patients with an immediate post-repair Ppv/sv of less than 0.75 and 77.8% in those with a Ppv/sv over 0.75. Postoperative Ppv/sv was mainly regulated by valve area index and a close correlation was obtained for the regression equation Ppv/sv = 0.41/(VAI)2 + 0.36 (r = -0.61, p less than 0.05). To obtain excellent hemodynamics with a Ppv/sv of less than 0.50, valve area index should be over 1.7 cm2/M2, and to eliminate re-implantation of the conduit after reaching adulthood, the diameter of the conduit should be 18 mm or more and the valve size 23 A, or more when a SJM valve is used.

Adolescent↗
PubMed1983

Angiocardiographic evaluation of ventricular septal defect--pre- and post-operative cardiac volume characteristics.

The characteristics of the left and the right heart volume in isolated ventricular septal defect were investigated in 62 patients before surgery and in 17 after corrective surgery, which was undergone at ages ranging from 0.5 to 13. Postoperative cardiac catheterization was performed one to two months after surgery. Preoperatively, the right atrial maximal volume increased in accordance with the pulmonary to systemic pressure ratio, and the left ventricular end-diastolic volume, the left atrial maximal volume and the right ventricular end-diastolic volume increased in accordance with the degree of the left-to-right shunt. These volumes decreased considerably after surgery, although they still remained above normal. The left ventricular mass also increased in accordance with the degree of the left-to-right shunt preoperatively and did not decrease postoperatively. The left and the right ventricular ejection fractions were close to or within normal limits preoperatively and remained so after surgery. On the basis of our results and the findings previously published in the literature, factors which may influence the postoperative cardiac function in ventricular septal defects were discussed.

Adolescent↗
PubMed1983

[Current status of surgical treatment of univentricular heart disease and complicated cardiac anomalies associated with asplenia and polysplenia syndrome].

Current status and problems in diagnosis and surgical treatment for complicated cardiac anomalies were assessed by analyzing surgical cases consisted of 32 univentricular heart cases, 27 asplenia syndrome cases, and 8 polysplenia cases. Univentricular heart cases consisted of 3 cases of type A, 8 cases of type B and 21 cases of type C. All of 7 cases performed corrective surgery were with bidirectional cross blood flow. Corrective surgery was performed on 7 cases including 6 cases of ventricular septation procedure with blood flow conversion and a case of modified Fontan procedure, and 2 were survived. Anatomical corrective surgery was performed for complicated cardiac anomalies on 4 cases with asplenia syndrome and 7 cases with polysplenia syndrome, and 2 and 6 cases were survived respectively. It was possible to perform functional corrective surgery on some cases who had difficulties for anatomical corrective surgery. For anatomical corrective surgery, it is preferable to use left ventricle as systemic ventricle. In splenic dysgenesis cases, main causes of late deaths were infection (asplenia syndrome) and complete A-V block (polysplenia syndrome) and it is necessary to clarify the immune mechanism and conduction system of the heart.

Abnormalities, Multiple↗
PubMed1982

Anatomically corrected malposition of the great arteries--case reports and a review.

Anatomically corrected malposition of the great arteries (ACM) is an extremely uncommon cardiac disease in which the great arteries arise from their appropriate ventricles despite abnormal spatial interrelations. Two patients with this malformation underwent successful surgical intervention for their associated anomalies. One was of situs solitus, d-loop and l-malposition and the other of situs inversus, l-loop and d-malposition of the great arteries. Fifty-three cases with accurate anatomical description were collected from the literature, and anatomical characteristics and associated anomalies were investigated. From the standpoint of anatomy and hemodynamics, we considered that ACM should be classified into atrioventricular concordant ACM, atrioventricular discordant ACM and ACM with situs ambiguus. Heart position and conus were variable. Dextrocardia and mesocardia were frequent. Bilateral conus was characteristic in concordant ACM, and subpulmonary conus was prominent in discordant ACM. The hypoplasia of the right heart and juxtaposition of the atrial appendages were in high incidence in cases of ACM. Surgical intervention was also discussed.

Angiocardiography↗
PubMed1982

Surgical results and factors affecting operative mortality in total anomalous pulmonary venous drainage.

Factors affecting the surgical results of total anomalous pulmonary venous drainage were evaluated in 17 patients in an attempt to establish an appropriate plan of management. The mortality rate correlated with age, size of interatrial communication, arterial oxygen saturation and left heart volume but not with pulmonary to systemic systolic pressure ratio, vascular resistance ratio and right ventricular volume. In cases where the symptoms appeared early in life, left heart volume was small and clinical features were severe. Four children with a left ventricular end-diastolic volume of less than 65% of normal died of low cardiac output syndrome. In those with an unusually small left heart, enlargement of the left atrium and/or delayed ligation of the anomalous vertical vein were considered more favorable. Left atrial and ventricular volumes were restored to normal after the surgery.

Age Factors↗