Single ventricle (single- or double-inlet) complicated by subaortic stenosis: surgical options in infancy

The choice of palliative arterial switch operation as an alternative for selected cases in a single center: Experience and mid term results

INTRODUCTION AND OBJECTIVE

There are various management options for newborns with single ventricle physiology, ventriculoarterial discordance and subaortic stenosis, classically involving the early pulmonary banding and aortic arch repair, the restricted bulboventriculer foramen enlargement or the Norwood and the Damus-Kaye-Stansel procedures. The aim of this study is to evaluate our preferred technique and comment on the midterm results of our clinical experience with palliative arterial switch operation (pASO) for a certain subset of patients.

METHOD

We hereby retrospectively evaluate the charts of patients who went through pASO, as initial palliation through Fontan pathway, starting from 2014 till today.

RESULTS

Ten patients underwent an initial palliative arterial switch procedure. Eight of 10 patients survived the operation and discharged. Seven of 10 patients completed Stage II and 1 patient reached the Fontan completion stage and the other six of ten (6/10) patients are doing well and waiting for the next stage of palliation. There are two mortalities in the series (2/10) and one patient lost to follow-up (1/10).

CONCLUSION

In our opinion, the pASO can be considered as an alternative palliation option for patients with single ventricle physiology, transposition of the great arteries and systemic outflow tract obstruction despite longer cross clamp times compared to other methods, but It not only preserves systolic and diastolic ventricular function, but also provides a superior anatomic arrangement for following stages.

Modified Damus-Kaye-Stansel Connection for Systemic Outflow Tract Obstruction After Fontan Operation

Late systemic outflow tract obstruction following completion of the Fontan palliation is rarely seen and is a difficult problem to treat. Absence of the main pulmonary trunk and pulmonary valve at this stage makes a conventional Damus-Kaye-Stansel connection difficult to achieve. We report the case of a 37-year-old female who underwent Fontan completion as an adult and subsequently presented with systemic outflow tract obstruction. A valved conduit was interposed between the native pulmonary annulus and the ascending aorta to create a modified Damus-Kaye-Stansel type connection.

Late complications associated with the Fontan circulation

The recent significant reduction in operative mortality associated with surgical completion of the Fontan circulation is clearly multi-factorial. Better understanding of the fundamental physiological and anatomical issues have led to refinements in operative technique, early neutralization of potential risk factors, widespread use of a staged approach, and selective application of the concept of fenestration or incomplete partitioning. While further reduction of operative mortality is important, and may be anticipated in the future, major emphasis now must be placed on optimizing functional outcome, and understanding and managing the late complications associated with the unique physiology produced by the Fontan circulation.

Designing therapeutic strategies for patients with a dominant left ventricle, discordant ventriculo-arterial connections, and unobstructed flow of blood to the lungs

The palliation of the cyanotic child with a dominant morphologically left ventricle, discordant ventriculo-arterial connections, and obstruction to the pulmonary outflow tract has continued to evolve and mature. The evolution began in the early days of surgical palliation with the Blalock-Taussig shunt, extended to construction of cavopulmonary shunts, if required, and then to the Fontan procedure and its subsequent modifications. This journey took nearly 30 years to complete. There is increasing clinical data to document the beneficial effects of this approach, with ever-improving outcomes. Some aspects of the history of the cavopulmonary shunt have been previously reviewed in this journal and elsewhere, as have analysis of outcomes for some groups of patients considered for surgical completion of the Fontan circulation. While there has been some ongoing interest in ventricular septation since the early success of Sakakibara et al., this approach has largely been abandoned. Considerably more challenges and debate resonate in the surgical algorithms defined for patients whose hearts are characterized by a dominant left ventricle, discordant ventriculo-arterial connections, and unobstructed flow of blood to the lungs. This latter group will be the focus of this review, as will the aetiology of the myocardial hypertrophy that is particularly frequent in this group of patients, its clinical recognition, indeed its anticipation, and the multiple surgical strategies designed to prevent or treat it. All these manoeuvres are considered to optimise suitability for, and outcome from, creation of the Fontan circulation.

Surgical management of complex and tunnel-like subaortic stenosis

BACKGROUND

Relief of primary or secondary subaortic stenosis (SAS) remains a surgical challenge. Heart block, aortic valve regurgitation and recurrent obstruction have been persistent problems.

METHODS

Forty six patients who underwent surgery for complex and tunnel-like SAS between January 1990 and November 1998 were reviewed. In 45 of the 46 patients SAS developed following repair of a primary congenital heart defect and only one patient presented with de novo tunnel-like SAS. Fifteen of the 45 patients had undergone repair of double-outlet right ventricle (DORV) and the remaining 30 had undergone repair of a variety of defects. The median age at the time of surgery was 5 years. The modified Konno procedure was performed in 15 patients, Konno procedure in three, Ross-Konno procedure in two and resection of the conal septum in 12 patients. Five patients with DORV underwent replacement of the intraventricular baffle and two patients underwent an aortic valve-preserving procedure in conjunction with mitral valve replacement.

RESULTS

There were no deaths. None of the patients had an exacerbation of aortic regurgitation and none developed complete heart block. The median follow-up was 3 years (range 1 month-8.5 years). Two patients developed recurrent SAS defined as a gradient of 40 mmHg or greater diagnosed by transthoracic echocardiography. Freedom from SAS at 1, 3 and 5 years was 100, 94 and 86%, respectively.

CONCLUSIONS

We favor the modified Konno procedure and conal resection to the Konno or the Ross procedure, since insertion of a prosthetic valve or homograft is avoided and aortic valve function is preserved. Excellent relief of tunnel-like SAS can be achieved without damage to the conduction tissue.

Staged surgical approach to neonates with aortic obstruction and single-ventricle physiology

BACKGROUND

The surgical management of neonatal systemic outflow obstruction and complex single ventricle pathology is variable.

METHODS

In 15 neonates (12 boys and 3 girls) with complex forms of single-ventricle pathology and aortic coarctation or interruption, an initial strategy of banding the pulmonary artery and repair of the obstruction from a left thoracotomy was undertaken.

RESULTS

The median age at operation was 6 days (range 2 to 33 days) and the median weight was 3.3 kg (range 2 to 4.6 kg). There were no early deaths and one late death after the initial surgical palliation. Of the 14 survivors, 8 have undergone a bidirectional cavopulmonary anastomosis. The median age for bidirectional Glenn was 9.75 months (range 3.5 to 26 months). Seven infants have required Damus-Kaye-Stansel reconstruction for subaortic obstruction (one early death). The median age of the Damus-Kaye-Stansel procedure was 4 months (range 3 weeks to 9 months). Thirteen of 15 patients (87%) are alive and 6 have proceeded to a Fontan operation (median follow-up 68 months). A single failing Fontan required takedown to bidirectional Glenn and central shunt.

CONCLUSIONS

Our experience suggests that this high-risk subgroup of neonates with aortic obstruction and single-ventricle pathophysiology is safely managed by initial pulmonary artery banding palliation and repair of aortic obstruction. This strategy, careful surveillance, and early relief of subaortic stenosis can maintain acceptable anatomy and hemodynamics for later bidirectional Glenn and Fontan procedures.

Ventricular morphology and coronary arterial anatomy in hearts with isometric atrial appendages

BACKGROUND

Knowledge of the precise anatomy can be advantageous when striving to improve surgical results in patients with visceral heterotaxy.

METHODS

We studied the ventricular mass, and its coronary arterial supply, in 125 specimens with isomeric right and 58 with isomeric left appendages.

RESULTS

The situation in which each atrium connected to its own ventricle was the most common arrangement in hearts with isomeric left appendages. The pattern with both atriums connecting to the same ventricle was more frequently seen in those with isomeric right appendages. Concordant ventriculoarterial connections were seen in only 4% of cases with isomeric right appendages, but were seen in 45% of those with isomeric left appendages. Abnormal patterns in branching of the coronary arteries were commonly associated with abnormal ventricular architecture. The morphologically right or left ventricular arteries were frequently lacking in those hearts with a dominant ventricle and a rudimentary and incomplete ventricle. A solitary coronary artery was seen in 13%.

CONCLUSIONS

Recognition of these abnormalities is of clinical importance if optimal surgical strategies are to be established for patients with visceral heterotaxy.

Subaortic obstruction and the Fontan operation

Systemic outflow tract obstruction in the heart with a functional single ventricle promotes myocardial hypertrophy, and this has been shown to be an unequivocal risk factor for poor outcome at Fontan procedure. Such systemic outflow tract obstruction may be congenital or acquired. Those factors contributing to acquired systemic outflow tract obstruction in those patients with a double-inlet left ventricle, a rudimentary right ventricle, and a discordant ventriculoarterial connection include the size of the ventricular septal defect, previous pulmonary artery banding, and other volume unloading surgical procedures. Staging with a bidirectional cavopulmonary connection and construction of a proximal pulmonary artery-aortic connection or ventricular septal defect enlargement has neutralized this factor.

Early changes in ventricular septal defect size and ventricular geometry in the single left ventricle after volume-unloading surgery

OBJECTIVES

This study investigated the phenomenon of, and the relation between, alterations in ventricular geometry after acute surgical volume unloading of the ventricle and the development of subaortic stenosis in patients with a single ventricle and ventricular septal defect-dependent systemic flow.

BACKGROUND

Subaortic outflow obstruction has been observed to occur in patients with a single left ventricle after placement of a pulmonary artery band. The timing and etiology of this phenomenon are not well defined.

METHODS

The preoperative and postoperative echocardiograms of 18 patients 14.9 +/- 22.8 months old (mean +/- SD) with a diagnosis of single left ventricle who underwent pulmonary artery banding or cavopulmonary connection were reviewed. Postoperative studies were performed a mean of 7.0 +/- 6.5 days after operation. The ventricular septal defect diameter was measured in two orthogonal views and the area calculated using the formula for an ellipse. Interventricular septal and posterior wall thickness and left ventricular diameter and length were also measured.

RESULTS

Mean ventricular septal defect area indexed to body surface area diminished by 36 +/- 23% (3.1 +/- 2.7 to 2.0 +/- 1.8 cm2/m2, p < 0.01). Mean interventricular septal and posterior wall thickness increased significantly, and left ventricular diameter and length decreased significantly. A greater diminution in ventricular septal defect area was noted after cavopulmonary connection (41 +/- 19%, p < 0.01) than after pulmonary artery banding (25 +/- 28%, p = 0.22).

CONCLUSIONS

In the single left ventricle, diminution in ventricular septal defect size occurs early and is related to an acute alteration in ventricular geometry that accompanies the decrease in ventricular volume. Ventricular septal defect diminution was greater after volume unloading of the ventricle after cavopulmonary connection than after pulmonary artery banding.

Systemic obstruction in univentricular hearts: surgical options for neonates

BACKGROUND

The surgical management for bridging patients with univentricular heart and systemic obstruction to a Fontan procedure remains controversial.

METHODS

Twenty-seven of 96 patients with univentricular heart and unobstructed pulmonary blood flow referred for surgical palliation were seen with systemic obstruction. Twenty-six were neonates with coarctation of the aorta in 21 and subaortic stenosis in 5. In 8 other patients, subaortic stenosis developed after initial pulmonary artery banding. Four different palliative procedures were performed: coarctation repair with pulmonary artery banding (group I, n = 15); Norwood or Damus-Kaye-Stansel or arterial switch operation (group II, n = 9); coarctation repair with pulmonary artery banding and bulboventricular foramen enlargement (group III, n = 2); and orthotopic heart transplantation with coarctation repair (group IV, n = 1).

RESULTS

The mortality rate was 34.3% (n = 12) for all patients, 53.3% in group I, 33.3% in group II (p = 0.003 versus group I), and 50% in group III. Nine patients (8 in group I and 1 in group II) had development of subaortic stenosis and underwent a subsequent procedure: Damus-Kaye-Stansel operation in 5, arterial switch operation in 3, and bulboventricular foramen enlargement in 1. Three had a concomitant or subsequent Fontan procedure and 2, a bidirectional Glenn procedure. In group II, 1 patient underwent a subsequent Fontan procedure and another, a bidirectional Glenn anastomosis. Six of the 8 patients with subaortic stenosis after initial pulmonary artery banding underwent a second stage consisting of a Damus-Kaye-Stansel procedure (n = 3), bulboventricular foramen enlargement (n = 2), or creation of an aortopulmonary window (n = 1). Three had a concomitant Fontan procedure and 2, a bidirectional Glenn procedure. Actuarial 4-year survival was 65.5% +/- 8.4% (70% confidence limits) for all patients; it was 40% +/- 13.3% in group I and 66.6% +/- 16.3% in group II (p < 0.05).

CONCLUSIONS

Initial management of patients with univentricular heart and systemic obstruction by Norwood-like procedures provides a better outcome. Success of the Fontan operation relies on the ability to provide timely relief of subaortic stenosis.

Univentricular heart with systemic outflow obstruction: palliation by primary Damus procedure

In 24 consecutive infants (19 male and 5 female) with complex forms of single-ventricle physiology and systemic outflow obstruction, a modified Damus operation without the use of exogenous material was undertaken in conjunction with creation of an aortopulmonary shunt 3.5 mm in diameter. The median age at operation was 6 days (range, 1 to 170 days) and the median weight, 3.4 kg (range, 2.6 to 4.6 kg). There were nine early deaths. All 15 survivors (median follow-up, 6.5 months) were clinically well without major systemic ventricular dysfunction or atrioventricular or arterial valve regurgitation. Ten of them have undergone a superior vena cava-pulmonary shunt (one death), and 1 has required patch angioplasty of the aortic arch and innominate artery with revision of the aortopulmonary shunt. The 4 other survivors are awaiting a cavopulmonary shunt. Univariate analysis yielded the chronologic rank for an individual procedure (higher risk of death early in the series), presence of aortic arch atresia, and presence or absence of transposition of the great arteries as predictors of death. This aggressive surgical approach provides excellent early palliation, and because the operation prevents abnormal ventricular hypertrophy from pressure or volume overload, systemic ventricular function is optimally conserved for a future Fontan-type procedure.

Surgical management of neonatal coarctation

Between 1983 and 1994, 307 consecutive neonates underwent coarctation repair by a single surgical technique: extended end-to-end anastomosis. Mean age at operation was 13 +/- 8 days. Isolated coarctation was present in 95 patients (group 1), 102 patients had associated ventricular septal defect (group 2), and 110 patients had associated complex intracardiac lesions (group 3). Aortic arch hypoplasia was present in 81% of the patients (62% in group 1 versus 85% in group 2 and 93% in group 3: p < 0.001). In 271 patients, the aortic arch reconstruction was performed via a left thoracotomy with normothermia (100% of group 1, 95% of group 2, and 72% of group 3); in the other 36 patients, undergoing one-stage repair or palliation of the associated lesion, it was performed via a midline sternotomy during a short period of deep hypothermia and circulatory arrest (5% of group 2 and 28% of group 3). Pulmonary artery banding was performed in 94 patients. Spontaneous ventricular septal defect closure was observed in 39% of the patients of group 2 operated on via thoracotomy. Early mortality rates in groups 1 (2%) and 2 (2%) were significantly lower than in group 3 (17%) (p < 0.001). There were 29 late deaths, all related to associated cardiac lesions or their subsequent repair. The overall total mortality was 16.9%. In group 3 this rate was significantly higher in patients undergoing two-stage procedures (47%) than in those undergoing one-stage repair (23%) (p < 0.05). All but 14 survivors were followed up for a mean of 61 +/- 36 months. Actuarial survivals at 10 years were 98% in group 1, 94% in group 2, and 60% in group 3. The recoarctation rate was 9.8%, leading to 21 reoperations and three angioplasties without mortality. Patients with a more extended or severe form of aortic arch hypoplasia had a significantly higher risk of recoarctation (p < 0.001). Actuarial freedom from reoperation for recoarctation at 10 years was 93%. The findings of this study suggest that extended end-to-end anastomosis provides an adequate and safe repair of neonatal coarctation. Low recoarctation rate, owing to effective relief of the obstruction created by aortic arch hypoplasia and to complete resection of ductal tissue, freedom from major morbidity, and feasibility via both lateral and anterior approaches are the main advantages of the extended end-to-end anastomosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Radical aortic root enlargement in the infant and child

Complex multilevel left ventricular outflow tract obstruction includes some of the more challenging problems in congenital cardiac reconstructive surgery. Preoperative studies must carefully delineate the level of obstruction that may be entirely below the aortic annulus (i.e., subaortic stenosis), at the level of the aortic annulus (i.e., aortic annular hypoplasia), may be related to valve leaflet obstruction due to rigid or fused valve leaflets (i.e., aortic valve stenosis), or may be at the level of the tips of the commissures of the aortic valve (i.e., supravalvar aortic stenosis). Frequently, variable contributions are present from all these potential levels of obstruction. An important underlying goal in planning surgical therapy should be preservation of the child's own aortic valve, whenever possible. Operative procedures should preserve growth potential and minimize the need for repeat surgical procedures. A number of surgical options that incorporate these goals will be described.

Univentricular atrioventricular connection with subaortic stenosis: a staged surgical approach

A staged surgical approach was developed for the management of hearts with univentricular atrioventricular connection (double-inlet left ventricle or tricuspid atresia) and discordant ventriculoarterial connection with anatomical substrate for the development of subaortic stenosis. This consisted of initial palliation with pulmonary artery banding, followed by early elective relief of subaortic obstruction using a proximal pulmonary artery to ascending aorta anastomosis in infancy. Pulmonary blood flow was maintained at this time by creating a bidirectional superior cavopulmonary anastomosis. Over an 18-month period, 5 children, including 4 seen in the first week of life with aortic arch obstruction, were palliated with this approach. All patients survived operation and are asymptomatic with transcutaneous oxygen saturations of 80% to 85%. Completion of cavopulmonary repair is planned at 2 years of age. Although some authors have considered pulmonary artery banding contraindicated in these infants, the current staged approach offers an attractive alternative to the construction of a pulmonary artery to aorta anastomosis in the neonatal period.

Bulboventricular foramen size in infants with double-inlet left ventricle or tricuspid atresia with transposed great arteries: Influence on initial palliative operation and rate of growth

Bulboventricular foramen obstruction may complicate the management of patients with single left ventricle. Bulboventricular foramen size was measured in 28 neonates and infants greater than 5 months old and followed up for 2 to 5 years in those patients whose only systemic outflow was through the foramen. The bulboventricular foramen was measured in two planes by two-dimensional echocardiography, its area calculated and indexed to body surface area. One patient died before surgical treatment. The mean initial bulboventricular foramen area index was 0.94 cm2/m2 in 12 patients (Group A) in whom the foramen was bypassed as the first procedure in early infancy. The remaining 15 patients underwent other palliative operations but the bulboventricular foramen continued to serve as the systemic outflow tract. There was one surgical death. Six (Group B) of the 14 survivors developed bulboventricular foramen obstruction during follow-up (mean initial bulboventricular foramen area index 1.75 cm2/m2). The remaining eight patients (Group C) did not develop obstruction during follow-up and had an initial bulboventricular foramen larger than that in the other two groups (mean initial bulboventricular foramen area index 3.95 cm2/m2). All patients with an initial bulboventricular foramen area index less than 2 cm2/m2 who did not undergo early bulboventricular foramen bypass developed late obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Advantages of early relief of subaortic stenosis in single ventricle equivalents

Thirteen patients with single ventricle equivalents and subaortic stenosis underwent relief of the stenosis and subsequent Fontan operation. Nine patients, group 1, had the obstruction relieved at 3.6 +/- 1.6 years of age whenever the pressure gradient became apparent. Four patients, group 2, had the subaortic stenosis operated on at the neonatal period, 10.5 +/- 10 days old, before hemodynamic evidence of obstruction. Preoperative pressure gradient across the outflow tract was 44.2 +/- 4.7 mm Hg in group 1 versus 4.7 +/- 5 mm Hg in group 2 (p = 0.002). Ventricular muscle mass was 186% +/- 18% in group 1 versus 114% +/- 5% of normal in group 2 (p = 0.0001), and mass/volume ratio was 1.12 +/- 0.62 in group 1 versus 0.62 +/- 0.16 in group 2 (p = 0.003). Relief of subaortic stenosis was achieved by proximal pulmonary artery to ascending aorta or aortic arch anastomosis and by systemic to distal pulmonary artery shunt. There was no hospital mortality or complication related to the procedure. At evaluation before Fontan operation, 4.3 +/- 1.6 years after relief of subaortic stenosis in group 1 and 3.2 +/- 0.9 years in group 2, the pressure gradient across the ventricular outflow tract was 4 +/- 3 mm Hg in group 1 versus 3 +/- 2 mm Hg in group 2 (p = not significant), ventricular muscle mass was 184% +/- 31% in group 1 versus 114% +/- 5% of normal in group 2 (p = 0.003), and the mass/volume ratio was 1.17 +/- 0.2 in group 1 versus 0.62 +/- 0.2 in group 2 (p = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical management of severe aortic outflow obstruction in lesions other than the hypoplastic left heart syndrome: use of a pulmonary artery to aorta anastomosis

Between December 1985 and April 1990, 50 infants with a variety of congenital cardiac lesions other than the hypoplastic left heart syndrome underwent surgical relief of aortic outflow obstruction by creation of a pulmonary artery to aorta anastomosis. The patients were grouped anatomically by ventriculoarterial alignment. Nineteen had normally aligned great arteries (group I); 25 had transposition of the great arteries, all with a univentricular heart of left ventricular morphology (group II); and 6 had a double-outlet right ventricle (group III). All patients had either aortic stenosis with atresia, subaortic stenosis or a restrictive ventricular septal defect. Sixteen had normal arch anatomy; 34 had arch anomalies consisting of arch hypoplasia (n = 17), coarctation (n = 11), interruption of the arch (n = 4) and complex arch anomalies (n = 2). Surgery was performed at a median age of 10 days (range 2 to 184). Of the 50 infants, 33 survived. No significant difference in early survival (30 days) was noted among the groups of varying ventriculoarterial alignment (68% group I, 72% group II, 83% group III) (p greater than 0.05). Overall actuarial survival was 63% at 18 months. Analysis of actuarial survival by arch anatomy, although not statistically significant, revealed a trend toward better survival at 18 months postoperatively in infants with normal arch anatomy (81%) than in infants with arch anomalies (54%). Of the 33 survivors, 26 have proceeded to the next surgical stage, including the Fontan procedure in 8, superior cavopulmonary anastomosis in 13 and biventricular repair in 5.(ABSTRACT TRUNCATED AT 250 WORDS)

Operations for subaortic stenosis in univentricular hearts

Optimal prevention and treatment of subaortic stenosis (SAS) in the univentricular heart with subaortic outlet chamber and high pulmonary blood flow remains controversial, especially when complicated by aortic arch obstruction. Herein we analyze our surgical results. Group 1 consisted of 11 infants (mean age, 10 days) with univentricular heart and SAS. Ten required repair of interrupted aortic arch (n = 7) or coarctation with hypoplastic arch (n = 7). Four patients had relief of SAS by either Damus-Kaye-Stansel connection (n = 2) or aortopulmonary window (n = 2), with three operative deaths and one late death. Six had one-stage arterial switch and atrial septectomy with arch repair (5/6) with one operative death and one late death. Two survivors have progressed to bidirectional cavopulmonary shunt, a third has had a Fontan operation, and a fourth awaits Fontan. In group 2, 11 children required operation for acquired SAS after pulmonary artery banding. Nine have progressed to Fontan operation with either staged (n = 3) or concurrent (n = 6) relief of SAS by Damus-Kaye-Stansel connection or subaortic resection. Fontan mortality was 11% (70% confidence limits, 2% to 32%). Group 3 consisted of 3 patients without pulmonary artery banding who had SAS diagnosed at Fontan evaluation. All 3 survived Fontan operation and relief of SAS by Damus-Kaye-Stansel connection or subaortic resection. Group 4 consisted of 1 patient with previous pulmonary artery banding (no SAS) who underwent Fontan operation but required Damus-Kaye-Stansel connection 30 months later for SAS.(ABSTRACT TRUNCATED AT 250 WORDS)

Norwood operation for univentricular heart with subaortic stenosis in the neonate

In the setting of a single ventricle, subaortic stenosis may be enhanced by pulmonary artery banding and may later contraindicate a Fontan operation. The Norwood operation may prove a preferable alternative in some infants as a preparatory procedure. We have successfully used this procedure as the initial operation to palliate a newborn with tricuspid atresia, transposition of the great arteries, coarctation, and severe arch hypoplasia secondary to a restrictive bulboventricular foramen.

A reconsideration of risk factors for the Fontan operation

We reviewed our experience in 38 patients who underwent a Fontan operation. In the first five patients ages 7.5 to 23 years (mean, 15 years), a conduit was placed from the right atrium to the small right ventricle or the pulmonary artery (PA). The remaining 33 patients, ages 7 months to 14 years (mean, 4.8 years), had a modified Fontan operation with direct systemic venous or right atrial to PA anastomosis. The diagnoses were tricuspid atresia (n = 14), single ventricle (n = 10), hypoplastic right or left ventricle (n = 9), double-outlet right ventricle with inlet ventricular septal defect and pulmonary atresia or stenosis (n = 3), criss-cross ventricles and transposition of the great arteries (n = 1), and atrioventricular canal and anomalous pulmonary venous connection (n = 1). Thirty-two patients had previous surgery. Other procedures included PA banding (n = 7), systemic to PA shunts (n = 25), Norwood operation (n = 3), and a Damus-Kaye-Stansel anastomosis (n = 1), repair of total anomolous pulmonary venous connection (n = 1), a Blalock-Hanlon atrial septectomy (n = 1), and enlargement of a restrictive ventricular septal defect (n = 1). There were four operative deaths (10.5%), three from low cardiac output and one from subaortic obstruction. There were no deaths in patients younger than 3 years of age (n = 13). Subaortic obstruction developed in six of the seven patients who had pulmonary artery banding and resulted in three deaths. In our experience, diagnosis, previous surgery, type of previous operation, PA pressure, and younger age are not risk factors for early or late death. Subaortic obstruction is a major risk factor for late death. Accordingly we now perform a Damus-Kaye-Stansel anastomosis combined with a systemic to PA shunt in those children with excessive pulmonary blood flow who anatomically are likely to develop subaortic obstruction. A modified Fontan operation can be performed any time after 1 year of age and in some patients after 6 months of age, providing the anatomy and physiology of the patient are acceptable.

Tricuspid atresia: current concepts in diagnosis and treatment

Tricuspid atresia is the third most common cyanotic cardiac malformation, seen in 1 per cent of children with congenital heart disease. Anatomic details in each patient can be elucidated by echocardiography. Surgical treatment initially is palliation, usually with aortopulmonary shunt. Definitive treatment is with a Fontan operation, in which the systemic venous return is connected directly to the pulmonary arterial tree. Long-term results of the corrective procedure have been very good.

Treatment of bulboventricular foramen stenosis by ventricle-ascending aorta valved-conduit bypass

An 8-year-old girl with single ventricle and 1-transposition developed severe stenosis of the bulboventricular foramen. This became critical subsequent to pulmonary banding and a modified Fontan operation. Successful relief of the obstruction was achieved by placing a valved conduit between the ventricle and ascending aorta, thus bypassing the obstruction.

Palliation of complex cardiac anomalies with subaortic obstruction: new operative approach

The modified Fontan operation for complex cardiac anomalies associated with subaortic obstruction entails a high surgical risk. It is likely that ventricular hypertrophy secondary to chronic pressure overload plays a significant role. This problem was approached with a new type of palliative operation comprising both a proximal pulmonary artery to ascending aorta anastomosis and a bidirectional cavopulmonary anastomosis. This operation was performed in six children ranging in age from 26 to 63 months. There was one intraoperative death due to hemorrhage. In one patient, a pulmonary to aorta conduit caused compression of the right coronary artery; the problem was solved by lengthening the conduit with a second period of cardiopulmonary bypass. The five survivors experienced an uneventful postoperative course. Repeat cardiac catheterization in these five patients showed low pressure in the cavopulmonary system (mean 10 mm Hg), absence of a gradient at rest between the systemic ventricle and aorta and fair arterial oxygenation (mean 82%). A technetium-99m perfusion lung scan visualized a slight prevalence of pulmonary blood flow ipsilateral to the shunt in three cases, whereas in one case preferential flow to the right lung was associated with a narrowing at the site of the cavopulmonary anastomosis. Mild hypoperfusion of the anterior pulmonary segments was observed in two cases. Both pressure and volume overload are abolished with this procedure and a satisfactory oxygenation is provided. Low venous pressure in the coronary, hepatic and renal areas as well as the short bypass time may explain the smoothness of the postoperative course in our patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical management of subaortic obstruction in single left ventricle and tricuspid atresia

Subaortic obstruction caused by either a restrictive bulboventricular foramen in single left ventricle with an outflow chamber or by a restrictive ventricular septal defect in tricuspid atresia with transposition of the great arteries can lead to a hypertrophied, noncompliant ventricle and excessive pulmonary blood flow. This combination is disadvantageous to potential Fontan procedure candidates because they are dependent on good ventricular function and low pulmonary vascular resistance for survival. The results of surgical procedures to directly or indirectly relieve significant subaortic obstruction (gradient greater than 30 mm Hg) in 24 patients, 16 with single left ventricle and 8 with tricuspid atresia, were reviewed. Four patients had a left ventricular apex to descending aorta valved conduit; none survived. Seven patients had resection of subaortic tissue; four survived and four developed heart block at surgery. Adequate gradient relief was evident in only one of the four survivors. Thirteen patients had a main pulmonary artery to ascending aorta anastomosis or conduit; six survived. All survivors had adequate gradient relief. The overall survival was 42% (10 of 24). None of seven patients with a subaortic gradient greater than 75 mm Hg survived. These data show that: Surgical relief of established subaortic obstruction in patients with single left ventricle and tricuspid atresia carries a high mortality rate, especially if the subaortic gradient is greater than 75 mm Hg. The best procedure appears to be the pulmonary artery to ascending aorta anastomosis. A clearer understanding of the factors leading to the development of significant subaortic obstruction is necessary to prevent it or to devise improved therapeutic strategies.

Subaortic stenosis, the univentricular heart, and banding of the pulmonary artery: an analysis of the courses of 43 patients with univentricular heart palliated by pulmonary artery banding

Subaortic stenosis is well known to complicate the clinical course of patients with single ventricle or univentricular hearts, and we have previously suggested that the development of subaortic stenosis in such patients may be causal to and/or accelerated by previous banding of the main pulmonary trunk. To further define the relationship between banding of the pulmonary artery in patients with univentricular hearts and the development of subaortic stenosis, we examined the morphologic substrate and timing of the development of subaortic stenosis in 43 patients seen at our institution from January 1, 1970, through June 30, 1985. These 43 patients include all patients in this period with an unequivocal univentricular heart whose longitudinal data was available for follow-up. We excluded patients who died within 1 week of surgery, patients lost to follow-up, and patients with evidence of subaortic stenosis before banding. Thirty-one of 43 patients (72.1%) developed subaortic stenosis subsequent to banding of the main pulmonary artery. The mean age at banding of those patients who developed subaortic stenosis was 0.21 years, and subaortic stenosis was recognized at a mean age of 2.52 years. For the specific cohort of patients whose ventricular morphology was a main chamber of left ventricular type supporting the pulmonary artery and a rudimentary right ventricle supporting the transposed aorta (32 patients), 27 developed subaortic stenosis (84.4%). Subaortic stenosis in the classic form of single ventricle usually results from progressive restriction of a wholly muscular interventricular communication. Banding of the pulmonary artery by producing myocardial hypertrophy undoubtedly accelerates the potential for subaortic stenosis in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Subaortic obstruction in complex congenital heart disease: management by proximal pulmonary artery to ascending aorta end to side anastomosis

Six patients with univentricular heart and one patient with d-transposition of the great arteries had transection of the main pulmonary artery with an end to side anastomosis of the main pulmonary artery to the ascending aorta to relieve subaortic obstruction. Two operations were performed as a palliative procedure within the first 6 months of life and five were performed as part of a definitive repair (four modified Fontan procedures and one repair of transposition of the great arteries with ventricular septal defect). There was one surgical death (14%) occurring 1 day postoperatively from low cardiac output. The remaining six patients are doing well 1 to 19 months postoperatively (mean 11.4 months). The proximal pulmonary artery to ascending aorta end to side anastomosis is an effective means of bypassing subaortic obstruction associated with complex congenital heart disease.