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Biomedical subjects

S Yamaki

Publications and source records attributed to S Yamaki.

At least 73 records · Page 4Linked to original sources
PubMed1986

Pulmonary vascular disease in secundum atrial septal defect with pulmonary hypertension.

Histopathologic and morphometric studies of small pulmonary arteries were performed in 16 cases of secundum atrial septal defect (ASD) and severe pulmonary hypertension. Besides typical plexogenic arteriopathies found in six cases, organized microthrombi and what we call "musculoelastosis," that is, proliferation of longitudinal smooth muscle bundles and elastic fibers, were seen in small pulmonary arteries in three and four cases, respectively. These changes were observed co-existing in the remaining three cases. Thrombi of the small pulmonary arteries and musculoelastosis were the forms of pulmonary vascular disease characteristically found in the older patients with both ASD and pulmonary hypertension. Yamaki's index of pulmonary vascular disease, though effective in describing severity of plexogenic arteriopathy, proved to be less so for the intimal lesions in old microthrombi and for musculoelastosis. Among the cases with plexogenic arteriopathy, there was a positive significant correlation between the medial thickness of small pulmonary arteries and peak arterial pressure, which, however, was not demonstrated when all the cases of ASD were included.

Adult↗
PubMed1986

Surgical management of pulmonary atresia, and critical pulmonary stenosis with intact ventricular septum.

Our experience with the surgical management of hypoplastic right ventricle with intact ventricular septum has included 20 patients with pulmonary atresia and 3 patients with critical pulmonary stenosis. Group 1 consisted of 7 infants who were treated by transarterial pulmonary valvotomy. Four of them were lost shortly after surgery. Group 2 included 11 neonates and one infant who were treated by systemic-pulmonary shunt with 2 operative death. Group 3 included 4 infants who underwent primary prosthetic enlargement of the right ventricular outflow tract. Two of the 4 were lost in the early postoperative period. Eight of 13 patients in groups 1 and 2 who survived the initial palliative procedures underwent additional operations to enlarge the right ventricular outflow tract, and 5 patients survived. However, adequate right ventricular and tricuspid valve growth was obtained in only patients in whom the prosthetic enlargement of the right ventricle was performed in early infancy. These findings strongly suggest the necessity to decompress the right ventricle completely, as early as possible. In conclusion, 1) transarterial pulmonary valvotomy seldom provided satisfactory decompression of the right ventricle, and operative risk was high. 2) systemic-pulmonary shunt to re-establish pulmonary blood flow improved neonatal survival, although this procedure may not provide a satisfactory long term palliation. 3) primary or secondary operative enlargement of the right ventricle in early infancy provided decompression of the right ventricle and accelerated substantial right ventricular growth. For patients without an infundibulum or for those in whom attempts to induce tricuspid valve growth had failed, a Fontan type procedure seemed to be the procedure of choice.

Female↗
PubMed1985

Frozen section diagnosis of hypertensive pulmonary vascular changes at surgery for congenital heart anomalies.

Frozen sections of lung biopsy were prepared in 30 cases of congenital heart anomalies with pulmonary hypertension, and evaluation of severity of the pulmonary vascular changes was made during the surgery. Statistically, significant differences was not found between the diagnosis made by frozen sections and those made by paraffin sections. It is concluded that rapid and accurate diagnosis of pulmonary vascular changes can be made by means of frozen section diagnosis. This method will prove to be clinically important by assisting during operation in rapid assessment of indication for total correction of congenital heart anomalies.

Child↗
PubMed1985

Comparison of primary plexogenic arteriopathy in adults and children. A morphometric study in 40 patients.

Pulmonary vascular changes were studied in histological sections from 15 children and 25 adults with primary plexogenic arteriopathy. The severity of medial hypertrophy and degree of vasoconstriction were measured in histological sections and there was a close correlation between these two variables in both children and adults. More advanced arterial changes, expressed as an index of pulmonary vascular disease, were more common in adults, and their severity correlated positively with the degree of medial hypertrophy. No such correlation was found in children. There were similar numbers of plexiform lesions per square centimetre in children and adults, so that the differences in the indices of pulmonary vascular disease were mainly due to the intimal changes. Concentric laminar intimal fibrosis was more severe in adults. It is suggested that intensive spastic vasoconstriction results in the development of fibrinoid necrosis and subsequently of plexiform lesions and that this may happen irrespective of the presence of severe intimal fibrosis. This suggests that children with primary plexogenic arteriopathy in whom plexiform lesions have not yet developed are more likely to respond to vasodilator treatment than are adults in whom irreversible changes associated with intimal fibrosis have developed.

Adolescent↗
PubMed1985

Pulmonary changes in congenital heart disease with Down's syndrome: their significance as a cause of postoperative respiratory failure.

Biopsy or necropsy specimens of lung from 28 patients with congenital heart disease and Down's syndrome were studied to establish the cause of the postoperative respiratory failure often seen in such cases. Changes in lungs seen after operation included interstitial emphysema and overdistension of peripheral air spaces, associated with hypoplastic alveoli and deficient elastic fibres in the alveolar wall. In specimens taken before operation alveolar hypoplasia was common but interstitial emphysema or overdistension of lower airways was found only rarely. Findings suggest that alveolar hypoplasia is characteristic of Down's syndrome and that distension of peripheral air spaces or interstitial emphysema was due to artificial inflation of the lung during surgery. The severity of the lesions correlated significantly with the duration of artificial respiration and with the severity of the respiratory failure. Hypoplastic lung tissue in patients with Down's syndrome appears to be more susceptible to mechanical stress, and this is likely to be the cause of postoperative respiratory failure.

Child↗
PubMed1985

Musculoelastosis: a change of small pulmonary arteries found in a case with atrial septal defect and pulmonary hypertension.

Interesting findings were obtained in the lung biopsy of a 46 year old female patient with secundum atrial septal defect and pulmonary hypertension. In the intima of small pulmonary arteries, there were a marked increase in elastic fibers and marked proliferation of longitudinal smooth muscle cells. The vascular lumen was markedly stenotic, but reconstruction of small pulmonary arteries indicated that all vascular lumina were patent. The case was accordingly diagnosed as operable and closure of atrial septal defect was undertaken. Three years postoperatively, the patient is well with much improved condition and lowered pulmonary arterial pressure was demonstrated by cardiac catheterization. This case had apparently serious vascular lesions due to severe intimal thickening which we labeled "musculoelastosis", but it was found that such thickening alone did not cause peripheral pulmonary arterial occlusion. It is therefore thought to be a benign pulmonary vascular condition.

Diabetic Angiopathies↗
PubMed1984

Severe pulmonary vascular disease consisting of ventricular septal defect and patent ductus arteriosus. A case diagnosed as the indication for total correction by the hemodynamic study.

A 12-year-old girl with ventricular septal defect, patent ductus arteriosus and pulmonary hypertension was hemodynamically diagnosed as the indication for total correction by the initial cardiac catheterization. However, histologic assessment by lung biopsy revealed the terminal stage of plexogenic pulmonary arteriopathy, i.e. plexiform lesions, dilatation lesions and fibrinoid necrosis of the media which denied the possibility of corrective surgery. We would like to stress that the open lung biopsy should be performed when the hemodynamic study indicates marginal operability, especially in older children and adults in order to investigate the grade of occlusive pulmonary vascular disease.

Child↗
PubMed1983

Quantitative analysis of pulmonary vascular disease in simple cardiac anomalies with the Down syndrome.

Intimal changes and medial thickness of small pulmonary arteries were morphometrically examined in 21 cases of simple cardiac anomalies with the Down syndrome, and their correlations with age and with pulmonary arterial peak pressure were then compared with those of 20 cases of simple cardiac anomalies without the Down syndrome and 17 cases of complete transposition of the great arteries (TGA). Results indicate that (1) intimal changes developed at an earlier age in patients with simple cardiac anomalies and the Down syndrome than in those without the Down syndrome, (2) the intimal changes were more severe than those in simple cardiac anomalies without the Down syndrome at the same level of pulmonary arterial pressure and milder than those in TGA, and (3) the media of small pulmonary arteries in simple cardiac anomalies with the Down syndrome was thinner than the media in cases without the syndrome at the same radius and the same level of pulmonary arterial pressure but thicker than the media in TGA. Retarded development of medial hypertrophy in the Down syndrome or TGA in response to pulmonary hypertension appears to make the pulmonary arteries susceptible to even moderate pressure load and appears to be responsible for early development of severe intimal changes.

Adolescent↗
PubMed1983

Isolated aortic origin of right pulmonary artery. Report of a case with special reference to pulmonary vascular disease in the left and right lungs.

Morphometric study of the pulmonary vasculature was performed on lung biopsy specimens from a one-year-old girl who underwent anatomic repair of isolated aortic origin of the right pulmonary artery. Medial hypertrophy of small pulmonary arteries in the right lung was much less remarkable than that in the left lung. In contrast, intimal lesions in the right lung were much more advanced than those in the left lung. Fully oxygenated blood in the right pulmonary artery might suppress medial hypertrophy in response to high pressure and thin media fail to protect intima from high pressure, resulting in severe intimal lesions. This situation in the right lung resembles that in complete transposition of the great arteries.

Aorta↗
PubMed1983

Progressive pulmonary vascular disease after surgery in a case of patent ductus arteriosus with pulmonary hypertension.

In a 15-month-old girl with patent ductus arteriosus (PDA) with pulmonary hypertension, division of the PDA was undertaken, but she died of heart failure 7 months post-operatively. Morphometric study of biopsy and autopsy lungs showed that medial hypertrophy and pulmonary intimal lesions developed markedly after surgery. Severe pulmonary hypertension and hypoxemia were present preoperatively. The pulmonary hypertension remaining postoperatively and aggravated pulmonary hypoxemia are thought to have caused postoperative constriction of the pulmonary vessels and to bring about unusual medial hypertrophy. Since it is known that marked hypertrophy of the media can easily cause vasospasms, it is thought that, in the present case, the smooth muscle cells of the media became necrotic, which brought about damage to endothelial cells. Such damage, in turn, led to the development of occlusive pulmonary vascular disease.

Ductus Arteriosus, Patent↗