Total extracardiac right heart bypass

BACKGROUND

Total cavopulmonary connection has been proposed as a rational alternative to atriopulmonary connection for complex Fontan operations. In addition to fluid dynamic advantages proposed by de Leval, total right heart bypass may address an emerging important issue after repair of single ventricle: late atrial arrhythmias. The purpose of this study is to document the postoperative hemodynamic findings in 22 consecutive patients who received a total extracardiac right heart bypass with an inferior vena cava-to-pulmonary artery extracardiac Dacron conduit with a modified Glenn anastomosis (superior vena cava-to-pulmonary artery anastomosis).

METHODS AND RESULTS

Twenty-eight patients with complex congenital heart disease underwent this surgical procedure. One patient died (early mortality, 3.5%). Mean follow-up was 13.9 months. Postoperative cardiac catheterization and echo Doppler studies were performed in 22 of the 27 survivors. In 18 of 22 patients, hemodynamic data were satisfactory; a preferential direction of caval flows to both lungs was observed. Echo Doppler assessments show that forward cavopulmonary flow appears as a predominant early diastolic event, in contrast to what occurs in atriopulmonary connections. This hemodynamic model emphasizes the possible role of the diastolic ventricular performance (as a "suction pump") in Fontan circulation. Early postoperative atrial arrhythmias were observed in two of the survivors.

CONCLUSIONS

The technical advantages and the hemodynamic benefits of this form of right heart bypass are encouraging. Although the use of artificial material in this procedure is extensive, none of the survivors showed thromboembolic complications or peel formations with narrowing and/or obstruction. Further investigations during a longer follow-up are needed to confirm the early and intermediate results, especially the reduction of late atrial arrhythmias.

Epicardial damage induced by topical cooling during paediatric cardiac surgery

OBJECTIVE

To study electrocardiographic changes in infants and children in whom topical cooling was used during surgical repair of congenital heart defects.

DESIGN

A retrospective study of all patients who had surgical repair of congenital heart disease during cold blood cardioplegia and topical cooling from January to August 1990. Eleven patients (group 1) had topical cooling with ice and 15 (group 2) with cold saline.

PATIENTS

All 36 paediatric patients operated on during this period. All the available electrocardiographic records were analysed. Ten patients in whom reliable records were not available were excluded. Twenty six patients entered in this retrospective study.

INTERVENTIONS

Topical cooling with ice or with a slush of cold saline.

MAIN OUTCOME MEASURE

Recordings from all the precordial leads were examined and scored as the sum of the maximum ST elevation (mV) in each precordial lead. The score obtained for each electrocardiogram was recorded together with the timing of the electrocardiogram (preoperative, arrival in intensive care unit immediately after surgery, postoperatively in the intensive care unit, and at discharge).

RESULTS

There were no differences between the two groups in terms of demographic data, diagnosis, duration of ischaemia, and postoperative myocardial performance. There was temporary ST elevation during the first 48 postoperative hours in all the children in group 1 but in only seven of the 15 children in group 2 (Fisher's test, p less than 0.005). The mean (SD) score for maximum ST elevation was 1.34 (0.83) mV in group 1 and 0.52 (0.64) mV in group 2 (Student's t test, p less than 0.01).

CONCLUSIONS

These temporary electrocardiographic changes in the presence of adequate myocardial performance were attributed to epicardial damage induced by hypothermicosmotic injury. The use of ice for topical cooling may damage the epicardium in children.

"Acquired" subvalvular aortic stenosis after repair of a ventricular septal defect

Of 353 children who underwent surgical repair of a congenital heart defect, including closure of a ventricular septal defect (VSD), 12 patients (four with tetralogy of Fallot, five with a VSD, and three with a double-outlet right ventricle) developed subaortic stenosis, which was diagnosed one to six years after the surgical procedure. Five patients required surgical treatment of the subaortic stenosis, and one required percutaneous balloon angioplasty. Postsurgical subaortic stenosis appears to be an uncommon progressive acquired disease.

Combined repair of transposed great arteries and total anomalous pulmonary venous connection

We report an unusual association of transposition of the great arteries and total anomalous pulmonary venous connection in the right atrium that was successfully repaired by a modified Mustard procedure.

Atrioventricular canal in Down syndrome. Prevalence of associated cardiac malformations compared with patients without Down syndrome

The atrioventricular canal is the "classic" congenital heart anomaly in Down syndrome. We may learn more of the nature of this disorder by careful study of the anatomic characteristics of the cardiac lesions and by comparing these lesions in patients with and patients without Down syndrome. We reviewed the clinical characteristics (echocardiographic and angiocardiographic) of 220 patients with atrioventricular canal and compared the prevalence of anatomic types and associated cardiac malformations in children with (105) and without (115) Down syndrome. In patients with Down syndrome, the complete form of atrioventricular canal was prevalent, with a high frequency of associated Fallot's tetralogy. Partial atrioventricular canal and left-sided anomalies were more common in patients without Down syndrome. Down syndrome is associated with a simpler type of atrioventricular canal when compared with patients with a normal chromosome configuration.

Inferior vena cava-pulmonary artery extracardiac conduit. A new form of right heart bypass

From November 1988 to May 1989, four patients underwent total right heart bypass by means of bidirectional cavopulmonary anastomosis and interposition of an extracardiac conduit from the inferior vena cava to the pulmonary artery. All of them had an uneventful postoperative course, and there have been no early or late deaths. We propose this technique as an alternative surgical option in candidates for a Fontan procedure with (1) hypoplasia or atresia of the left atrioventricular valve, (2) common atrioventricular valve, (3) anomalies of systemic and pulmonary venous return, or (4) auricular juxtaposition.

Airway obstructions associated with congenital heart disease in infancy

Significant airway obstruction may complicate the natural and surgical history of infants with congenital heart diseases. Airway obstruction occurred in 12 infants who had operations for congenital heart disease. In all cases tracheography demonstrated the cause of airway obstruction. Significant mortality (5/12, 41.7%) and morbidity in this group of infants were the result of airway obstruction. To reduce the complications caused by airway obstruction in infants with congenital heart disease, we recommend (1) preoperative identification of patients with potential airway obstruction, (2) preoperative tracheography in high-risk infants, (3) appropriate choice of the surgical procedure, especially when insertion of a prosthetic conduit is required, (4) early recognition of the problem during the postoperative period, (5) prompt diagnosis by postoperative tracheography, with or without angiography, and (6) therapy directed at the cause of airway obstruction.

Ventricular septal defect in Down syndrome. Anatomic types and associated malformations

Ventricular septal defect is a common cardiac anomaly in Down syndrome. To detect the prevalence of anatomic types and associated cardiac malformations we analyzed the echocardiographic and angiocardiographic findings of 73 children with ventricular septal defect and Down syndrome. We compared these results with those obtained in 303 patients with ventricular septal defect without Down syndrome. The prevalence of inlet ventricular septal defect was significantly higher in patients with Down syndrome, while muscular and subpulmonary ventricular septal defects were present only in patients without Down syndrome. The incidence of a cleft of the mitral valve was significantly higher in Down syndrome, while left-ventricular inflow and outflow obstructions were present only in patients without Down syndrome. Different patterns of ventricular septal defect and associated anomalies exist in patients with and without Down syndrome.

Total anomalous pulmonary venous connection: surgical repair with a double-patch technique

A double-patch technique has been used to repair total anomalous pulmonary venous connection in 35 patients (mean age, 4.9 months; mean weight, 4.2 kg). In all patients with supracardiac or subdiaphragmatic type of total anomalous pulmonary venous connection, repair has been accomplished by enlarging the "new" left atrium. There were three early deaths (3 of 35 = 8.6%) and no late deaths in a mean follow-up of 30 months (3 to 71 months). We propose this double-patch technique as an alternative surgical option for total anomalous pulmonary venous connection.

[Surgical correction of atrioventricular canal without heart catheterization]

In our department, 35 patients with atrioventricular canal underwent elective surgery between June 1983 and May 1989. The diagnosis was based on clinical and echocardiographic assessment without cardiac catheterization. Nineteen patients (age 2-12 years; mean 6.6 years) had a partial atrioventricular canal and 16 (age 5-8 months; mean 7 months) presented a complete atrioventricular canal. The echocardiographic diagnosis was confirmed at surgery in all but one patient (2.8%). The latter was diagnosed as having a complete canal but at surgery a transitional canal with a restrictive ventricular septal defect was found. We based our patient selection on the natural history which excluded cases with early heart failure and pulmonary hypertension. We also relied on an accurate morphological study using two-dimensional echocardiography which excluded cases with associated cardiac malformations. Our recent experience (1986-1989) showed that 50% of the patients with complete canal and 60% of patients with partial canal underwent surgery without cardiac catheterization.

Pediatric cardiac surgery guided by echocardiography. Established indications and new trends

Cardiac surgery in 602 children was not preceded by cardiac catheterization, the diagnosis being based on clinical findings and two-dimensional and Doppler echocardiography. In the 355 operations without cardiopulmonary bypass there were nine major and seven minor diagnostic errors (2.5% and 2%). Among the 247 cases with open-heart surgery there were no major and eight (3.2%) minor errors. The malformations most suitable for nonbypass surgery without catheterization seem to be those with reduced pulmonary blood flow requiring systemic-pulmonary artery shunt, aortic coarctation and patent ductus arteriosus. For open-heart surgery without invasive investigation, atrial septal defect, partial atrioventricular canal, aortic and pulmonary stenosis, cardiac tumor and isolated valve disorder are 'classic' candidates. Recent experience indicated that selected cases of complete atrioventricular canal, tetralogy of Fallot, truncus arteriosus, total anomalous pulmonary venous connection and transposition of the great arteries may safely undergo primary repair without cardiac catheterization. Because of its diagnostic potentialities, pediatric cardiac surgeons must become familiar with echocardiography.

Systemic atrioventricular conduit for extracardiac bypass of hypoplastic systemic atrioventricular valve

The management of severe congenital mitral stenosis in infants and children is still controversial. We describe our experience with the use of a systemic atrioventricular (SAV) extracardiac conduit to bypass a hypoplastic systemic atrioventricular valve. An SAV extracardiac conduit has been used in six patients (left atrium--left ventricle in five, right atrium--right ventricle in one). One hospital death occurred due to mediastinitis and there were two late deaths, one due to progressive subaortic stenosis and one sudden, possibly due to arrhythmia. Postoperative cardiac catheterization performed in five patients showed reduction of the transmitral gradient from a mean of 16 mmHg to a mean of 5 mmHg. Calcification of the bioprosthetic valve occurred in two patients 3 1/2 years and 2 years respectively after the operation; one died from concomitant subaortic stenosis and one underwent conduit replacement. Although its long-term efficacy is limited, the SAV conduit seems the most reliable surgical option for infants and children with hypoplastic systemic atrioventricular valves unsuited to conventional surgery.

Surgical options for complex transposition of the great arteries

Between September 1976 and November 1987, 53 patients underwent surgical treatment by the same surgeon for "complex transposition of the great arteries" with ventricular septal defect or severe left ventricular outflow tract obstruction, or both. Six patients with transposition and left ventricular outflow tract obstruction underwent atrial rerouting and direct relief of the left ventricular outflow tract obstruction. Twenty-two patients presented with transposition plus ventricular septal defect; 15 of these patients underwent atrial rerouting and ventricular septal defect closure and 7 underwent an arterial switch procedure. Twenty-five patients presented with transposition plus ventricular septal defect and left ventricular outflow tract obstruction, 23 of whom underwent a Rastelli procedure. There were one early death (mortality rate 1.9%; 90% confidence limits 0-7%) and three late deaths (mortality rate 5.8%) during a mean follow-up period of 42 months (range 2 to 124). These results show that 1) atrial rerouting is an appropriate surgical procedure for transposition of the great arteries with left ventricular outflow tract obstruction; 2) the arterial switch procedure provides excellent early correction of transposition with ventricular septal defect and is currently the preferred procedure for this lesion; and 3) the Rastelli procedure can be performed with a low early mortality rate and excellent long-term results for transposition with ventricular septal defect and left ventricular outflow tract obstruction.

Discrete subaortic stenosis. Surgery in children based on two-dimensional and Doppler echocardiography

Twenty pediatric patients underwent surgical resection of a "discrete" subaortic membrane. The diagnosis and the surgical indication were based on two-dimensional and Doppler echocardiography without cardiac catheterization and angiography. In all patients the echocardiographic diagnosis was confirmed at surgery in terms of presence, dimension and location of the membrane and in ten patients in terms of pressure gradients. Two-dimensional and Doppler echocardiography has proved to be a very reliable tool for the diagnosis and surgical indication in pediatric patients with a DSAS. Our criteria for the selection of surgical patients are the following: (1) isolated form of discrete subaortic stenosis with a short base of attachment to the ventricular septum; (2) pressure gradients higher than 25 mm Hg; (3) presence of significant aortic insufficiency. All of this information can be consistently obtained with two-dimensional and Doppler echocardiography.

[Pulmonary atresia with an intact septum: indications for the neonatal surgical treatment guided by 2-dimensional and Doppler echocardiography]

Twelve neonates with pulmonary atresia and intact ventricular septum underwent surgical treatment based on two-dimensional and Doppler echocardiography. Ten patients with adequate morphology of the right ventricular outflow tract portion shown by means of two-dimensional echocardiography underwent pulmonary valvulotomy and systemic-to-pulmonary shunt. Two neonates with atresia of the right ventricular infundibulum on two-dimensional echocardiography underwent systemic-to-pulmonary artery shunt without valvulotomy. In all patients the qualitative and quantitative echocardiographic diagnosis was confirmed at surgery and/or with the subsequent angiocardiographic study. Two-dimensional and Doppler echocardiography is a precise diagnostic method for planning surgical treatment in neonates with pulmonary atresia and intact ventricular septum.

Bidirectional cavopulmonary shunts: clinical applications as staged or definitive palliation

A standard Glenn anastomosis between the superior vena cava and the right pulmonary artery has been the accepted mode of treatment for patients with complex cyanotic congenital heart disease. We report our experience in 18 patients with such disease who underwent a bidirectional cavopulmonary shunt because of increasing cyanosis and growth cessation. All patients were considered less than "ideal" candidates for a Fontan procedure. We divided the patients into two groups: group 1 had azygos continuation and group 2 did not. Fourteen patients required hypothermic cardiopulmonary bypass. Bidirectional pulmonary blood flow was achieved in all patients. Only 1 death occurred (group 2). The improvement in oxygen saturation and overall clinical condition of these patients, together with the low mortality and morbidity, is encouraging. However, long-term follow-up is mandatory for a comprehensive evaluation of this surgical approach as definitive palliation or as a first stage for a Fontan operation.

[Seroma: a complication of systemic-pulmonary shunt with a tubular prosthesis]

The accumulation of clear fluid leaking from a tubular prosthesis and confined within a fibrous pseudomembrane has been defined as a "seroma". Both the literature and our experience on this complication have been reviewed. Fifty-three cases of seroma have been reported after implantation of a tubular prosthesis. In our experience, from June 1982 to September 1988 we observed 11 cases (11/108 = 10.1%) of seroma complicating a modified Blalock-Taussig procedure. The mean age of these patients was 2 years 2 months. The diameter of the implanted tubular prostheses was always 5 mm. Among these cases, we report the details of a child, 1 year 10 months old, in whom the seroma significantly complicated the surgical history. According to the data derived from the literature and from our experience, we derived the following risk factors for the occurrence of seroma: age of the patient, size of the prosthesis, surgical manipulations, arterial-venous gradient, transprosthetic flow.

Long-term results after extracardiac valved conduits implanted for complex congenital heart disease

Between August 1982 and December 1986, 56 patients survived implantation of an extracardiac valved conduit for complex congenital heart disease. The mean age at operation was 4.2 years (16 days to 24 yrs) and the mean weight was 15.9 kg (2.4 to 93.0 kg). The diagnosis was pulmonary atresia (PA) with ventricular septal defect (VSD) in 13 patients, tetralogy of Fallot in 11, transposition of the great arteries (TGA) with VSD in 8, truncus arteriosus, in 7, complex left ventricular outflow tract obstruction (LVOTO) in 6, complex left atrioventricular valve obstruction in 4, double outlet right ventricle with VSD and subaortic obstruction in 3, univentricular heart with pulmonary stenosis in 2, TGA with LVOTO in 1, and PA with intact ventricular septum in 1. In 35 patients, a preclotted conventional Dacron conduit (CDC) with bioprosthetic valve was used, in 19 patients a collagen-sealed Tascon valved conduit (TC) was implanted, and in 1 patient an aortic homograft was used. In a mean follow-up of 32.5 months (9 to 64 mo), there were two deaths (2/56, 3.6%) that were not related to the conduit. All survivors have been evaluated by two-dimensional and Doppler echocardiography, and 29/56 (51.8%) underwent cardiac catheterization. Nine patients (9/56, 16.1%) underwent successful valved conduit replacement, in seven cases with a nonvalved conduit. There was a significant difference (P = .011) with regard to the incidence of conduit replacement between the group with CDC (2/36, 5.5%) and the group with TC (7/19, 36.8%). Five patients underwent percutaneous transluminal balloon dilatation of the prosthetic conduit, with adequate relief of the gradient in four patients.(ABSTRACT TRUNCATED AT 250 WORDS)