[Unilateral pulmonary venous obstruction: a case report].

A 3-month-old girl with right common pulmonary venous obstruction and severe pulmonary hypertension underwent pulmonary venous reconstruction (venoplasty). However, pulmonary hypertension persisted and she died on the 69th postoperative day. Autopsy revealed a widely opened pulmonary vein at the site of the venoplasty. Histological examination showed thickened alveolar walls, thromboembolism in pulmonary arterioles and venous hypoplasia in the right lung. The venoplasty for unilateral pulmonary venous obstruction with severe pulmonary hypertension may not be the proper treatment, since pulmonary hypertension usually continues or progresses postoperatively. Pneumonectomy may be a better choice to be applied.

[An inordinate elevation in pacing threshold after myocardial electrode implantation].

An inordinate elevation in pacing threshold beyond a maximal output of the pulse generator was observed in 4 patients during the acute interval following permanent pacemaker implantation using a myocardial electrode. Pacemaker implantation was performed in these patients (9 months, 11 months, 5 years and 32 years of age) for the treatment of brady-arrhythmias (complete A-V block or atrial fibrillation) developed following open heart surgery. In two infants, hypopotassemia caused transient pacing failure due to an increase in threshold over 5 volt. In other two patients, threshold increased to levels more than 10 volt within 36 and 12 days probably due to unsuitable pacing site, and then the pulse generators were removed. It is important to measure threshold periodically after permanent pacemaker implantation and to consider the possibility of an inordinate elevation in threshold.

[Pulmonary vascular disease in shunted and nonshunted patients with tetralogy of Fallot].

Histometric analysis of pulmonary vascular disease was performed in 21 nonshunted patients and in 13 shunted patients with tetralogy of Fallot and in 29 normal controls. There was no significant difference in the medial thickness of the small pulmonary arteries between cases of tetralogy of Fallot and normal controls. However, the media in the shunted cases of tetralogy of Fallot gave the impression of being thicker than these in the nonshunted cases. Intimal fibrosis, regarded as organized thrombi, and thrombi of small pulmonary arteries were observed generally after 4 years of age in shunted and nonshunted cases of tetralogy of Fallot. Intimal proliferation of musculoelastosis which was formed longitudinal smooth muscle bundles and elastic fibers was characteristic in shunted patients, especially after the central palliation procedure, Waterston anastomosis and modified Blalock-Taussig (B-T) anastomosis using a Gore-Tex tube graft. However, musculoelastosis was not usually seen in the B-T anastomosis cases. Unexpected pulmonary hypertension due to shunt operation is thought to be the cause of musculoelastosis, because musculoelastosis was observed even in a patient with pulmonary hypertension 3 weeks following surgery. We, therefore, recommend original B-T anastomosis as the shunt procedure. When considering use of the other shunt operations which entail pressure load on the pulmonary vascular bed, attention must be given to the size of the anastomosis or artificial tube graft.

Surgical closure of ventricular septal defect in the first year of life: forty-three consecutive successful cases.

Forty-three infants (less than 12 months of age) underwent VSD closure without operative mortality between June 1982 and December 1987. Average age and body weight at the operation were 6.9 months and 5.3 kg, respectively. Associated cardiac anomalies were PDA (11 patients), ASD (5) and PS (1). Preoperative pulmonary to systemic peak pressure ratio (Pp/Ps), resistance ratio and flow ratio, and pulmonary vascular resistance were 0.79 +/- 0.15, 0.29 +/- 0.16, 2.52 +/- 0.60 and 3.05 +/- 1.94 unit.m2, respectively. VSD was closed under combined surface/perfusion hypothermia with total circulatory arrest in 25 patients and standard cardiopulmonary bypass in 18. All patients were discharged from the hospital in good condition, but there was one late death due to pneumonia. Postoperative Pp/Ps decreased to 0.39 +/- 0.11. Most of the patients demonstrated satisfactory body weight gain after VSD closure. These results support our current policy of aggressive surgical intervention for refractory VSD in the early stage of life.

Secundum atrial septal defect with severe pulmonary hypertension. Open lung biopsy diagnosis of operative indication.

In 14 of 15 patients ranging in age from 1 to 62 years (mean of 34) with secundum atrial septal defect (ASD) and pulmonary hypertension over 60 mm Hg peak pressure, operative indication was determined by morphometric diagnosis of open biopsy of lung specimens. In one patient, open lung biopsy was also performed during corrective surgery. Pulmonary arterial changes in the 15 patients were grouped into four classifications as follow: (1) plexogenic pulmonary arteriopathy (six patients); (2) thromboembolism in small pulmonary arteries (three patients); (3) "musculoelastosis," intimal proliferation of longitudinal smooth muscle bundles and elastic fibers (three patients); and (4) combinations of (1), (2) or (1), (3) (three patients). We conclude concerning the operative indication that group 2 patients are operable in all cases and group 1 patients with Yamaki's index of pulmonary vascular disease of 2.2 or less; group 3 patients with the absence of complete occlusion of the small pulmonary arterial lumen are operable, and patients with clear evidence of severe plexogenic pulmonary arteriopathy in group 4 are not operable. Comparative analysis of pulmonary pathology and hemodynamic performance revealed that open lung biopsy should be performed to determine operative candidacy in cases with a pulmonary vascular resistance greater than 8 unit X m2, which is considered to represent the borderline of operability.

Long-term results of open heart repair of ventricular septal defect.

Long-term follow-up results of 321 patients who underwent open heart repair of ventricular septal defect in our institute and have lived for more than five years were analyzed using questionnaires. The follow-up period was up to 24 years with an average of 12.9 years. The questionnaire mainly concerned the patient's state of health. Beside this, IQ was measured in 52 children, ECG was analyzed in 92 patients and heart catheterization was performed on 21 patients with preoperative severe pulmonary hypertension (PH). From this survey, it was ascertained that no deaths resulted from cardiac disorders; physical activity and development were satisfactory in nearly all patients; the scholastic achievement score was within the normal range in nearly all school children; among 30 live births from 24 adult female patients, two babies with simple cardiac anomalies were found and there remained very few patients suffering from residual PH, residual shunt or conduction disturbances. IQ as tested by individual intelligence tests was within the normal range in all children. On ECG, complete right bundle branch block with left anterior hemiblock was found in 9% and complete atrioventricular block in 7%. Amelioration of PH was achieved especially in those who underwent operations in their younger years.

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.

Postoperative growth of the left subclavian artery in a case after a modified Blalock-Park procedure.

Various kinds of operations for coarcation of the aorta in infancy are life saving, but they still carry a high operative mortality rate and are followed frequently by residual or recurrent coarctation. Fifteen years ago we performed a modified Blalock-Park procedure on a 12 month old male infant with preductal coarctation, a large VSD and PDA. Recently a follow-up study was performed on this patient. Aortography revealed a normally developed aortic arch without any sign of stenosis. The intraaortic pressure tracings revealed no pressure gradient through the aortic arch and thoracic aorta. These findings suggest that this procedure is recommendable for the treatment of infants with severely hypoplastic aortic isthmus.

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.

Successful surgical treatment of pulmonary artery sling and partial anomalous pulmonary venous drainage in an infant.

A 8 month old infant with pulmonary artery sling and partial anomalous pulmonary venous drainage was reported. The patient was seen initially with severe stridor. Diagnosis was made by barium swallow study, echocardiography, bronchoscopy, and pulmonary arteriography. The patient was operated on through a median sternotomy; the left pulmonary artery was dissected deep between the trachea and esophagus, and then reimplanted to the side of the main pulmonary artery. Systemic heparinization and microsurgical technique were used. Simultaneous intracardiac repair was carried out by means of extracorporeal circulation. The patient improved dramatically after operation. Postoperative pulmonary arteriogram revealed a wide patent left pulmonary artery, and postoperative perfusion lung scan confirmed improved perfusion of the left lung. It is concluded that pulmonary artery sling should be treated surgically as soon as diagnosed. From the surgical point of view, the left pulmonary artery should be anastomosed to the main pulmonary artery with micro-surgical technique to avoid late occlusion of the left pulmonary artery.

The importance of colloid osmotic pressure during open heart surgery in infants.

Fifty-five infants with transposition of the great arteries and with total anomalous pulmonary venous return underwent intracardiac repair under combined surface/perfusion hypothermia and total circulatory arrest in 1975 to 1983. Although cardiopulmonary bypass (CPB) time is limited when hypothermic circulatory arrest is employed, fluid balance derangement is one of the major postoperative complications. Fluid balance at the end of CPB averaged +299.5 ml (+63.4 ml/kg) when hemodilution with lactated Ringer's was utilized (Group A). Since colloid osmotic pressure (COP) plays an important role in regulating fluid balance, colloid hemodilution prime (whole blood and plasma) was employed in the last 3 years (Group B). COP and total protein concentration during CPB with colloid prime were maintained at around 19 mmHg and 5 g/100 ml, respectively. In Group B, fluid balance at the end of CPB averaged +81.1 ml (+16.3 ml/kg) and was significantly less than in Group A (p less than 0.01). The ICU stay period for survivors in Group B (average 10.9 days) was reduced to half the period in Group A (average 20.6 days) (p less than 0.05). The mortality rate in Group A was 42%, whereas 23% in Group B. It was concluded that well-maintained COP levels during CPB with colloid hemodilution prime reduced fluid accumulation in the body and made patient care easier following open heart surgery in infants.

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.

Mustard procedure for simple transposition of the great arteries.

From May 1980 through April 1982, 9 patients underwent the Mustard operation for simple transposition of the great arteries (simple TGA) at the Tohoku University Hospital, Sendai. There was no early postoperative death, although one patient was lost with pulmonary venous obstruction in the late postoperative period. No pulmonary venous obstruction occurred since the introduction of expanded polytetrafluoroethylene (EPTFE) intraatrial baffle. Normal sinus rhythm has been preserved in all patients since direct, high superior vena cava cannulation was adopted. Postoperative hemodynamic study at an average 12 months after surgery revealed normal right ventricular function at rest. Work-function curve which is related to the right ventricular end-diastolic pressure and minute work index revealed good response of the right ventricle in two of three patients after methoxamine infusion test. All late survivors are acyanotic and clinically well. The Mustard procedure has dramatically improved the survival rate and quality of life for those with simple TGA. Presently, we continue to utilize the Mustard procedure for simple TGA until the superiority of other operations are demonstrated.

[Valve replacement for congenital valvular disease].

Among 365 cases of mitral and aortic valve replacement (MVR, AVR) done in our institute during the period between 1968 and 1983, there were 20 congenital cases (5.5%), who were pointed out to have valvular disease since birth or early childhood and had no evident history of infectious disease. Mean ages at operation of MVR and AVR groups were 5.6 +/- 3.6 and 22.4 +/- 6.0 years respectively. Predominant pathology of mitral valve was regurgitation in 9 and stenosis in 2 cases. Seven cases were associated with other cardiac anomalies. Cumulative follow-up period was 34.3 patient-years (p-y). There were 3 late deaths resulted from xenograft calcification. In AVR group, predominant pathology of the valve was regurgitation in 8 cases and stenoregurgitation in one case. All cases were associated with other cardiac anomalies. There were 2 late deaths within the cumulative follow-up period of 39.5 p-y. Cumulative survival rates at 15 years, both in MVR and AVR groups were lower in congenital group than in the group of acquired disease. The incidences of prosthesis malfunction, prosthesis related complication and late death in the both MVR and AVR groups were higher in congenital group, when compared to that in the group of acquired disease.

[Recent experience in cardiovascular surgery in neonates and infants less than 3 months of age].

In past ten years, 43 neonates and 73 infants less than 3 months of age underwent cardiovascular surgery in our institute. The surgical mortality was as high as 46% in neonate, and 45% in infant in this series. Recently, results of surgery for pulmonary atresia, transposition of the great arteries, total anomalous pulmonary venous drainage, and coarctation of the aorta has been improved significantly. The use of non-invasive diagnostic technique such as echocardiography and radial angiography, and the use of prostaglandin-E1 as preoperative management has contributed to recent improvement. Further refinement of surgical procedure is mandatory to minimize various postoperative complications and improve late result of those infants.