The dinosaur and banding of the main pulmonary trunk in the heart with functionally one ventricle and transposition of the great arteries: a saga of evolution and caution

Physiological Fontan Procedure

Objective: The conventional Fontan circulation deviates the superior vena cava (SVC = 1/3 of the systemic venous return) toward the right lung (3/5 of total lung volume) and the inferior vena cava (IVC = 2/3 of the systemic venous return) toward the left lung (2/5 of total lung volume). A "physiological" Fontan deviating the SVC toward the left lung and the IVC toward the right lung was compared with the conventional setting by computational fluid dynamics, studying whether this setting achieves a more favorable hemodynamics than the conventional Fontan circulation. Materials and Methods: An in-silico 3D parametric model of the Fontan procedure was developed using idealized vascular geometries with invariant sizes of SVC, IVC, right pulmonary artery (RPA), and left pulmonary artery (LPA), steady inflow velocities at IVC and SVC, and constant equal outflow pressures at RPA and LPA. These parameters were set to perform finite-volume incompressible steady flow simulations, assuming a single-phase, Newtonian, isothermal, laminar blood flow. Numerically converged finite-volume mass and momentum flow balances determined the inlet pressures and the outflow rates. Numerical closed-path integration of energy fluxes across domain boundaries determined the flow energy loss rate through the Fontan circulation. The comparison evaluated: (1) mean IVC pressure; (2) energy loss rate; (3) kinetic energy maximum value throughout the domain volume. Results: The comparison of the physiological vs. conventional Fontan provided these results: (1) mean IVC pressure 13.9 vs. 14.1 mmHg (= 0.2 mmHg reduction); (2) energy loss rate 5.55 vs. 6.61 mW (= 16% reduction); (3) maximum kinetic energy 283 vs. 396 J/m3 (= 29% reduction). Conclusions: A more physiological flow distribution is accompanied by a reduction of mean IVC pressure and by substantial reductions of energy loss rate and of peak kinetic energy. The potential clinical impact of these hemodynamic changes in reducing the incidence and severity of the adverse long-term effects of the Fontan circulation, in particular liver failure and protein-losing enteropathy, still remains to be assessed and will be the subject of future work.

Decision-Making for Surgery in the Management of Patients with Univentricular Heart

A series of technical refinements over the past 30 years, in combination with advances in perioperative management, have resulted in dramatic improvements in the survival of patients with univentricular heart. While the goal of single-ventricle palliation remains unchanged - normalization of the pressure and volume loads on the systemic ventricle, the strategies to achieve that goal have become more diverse. Optimal palliation relies on a thorough understanding of the changing physiology over the first years of life and the risks and consequences of each palliative strategy. This review describes how to optimize surgical decision-making in univentricular patients based on a current understanding of anatomy, physiology, and surgical palliation.

Bidirectional Glenn and antegrade pulmonary blood flow: temporary or definitive palliation?

BACKGROUND

We sought to investigate the role of the bidirectional Glenn with antegrade pulmonary blood flow in the surgical history of children with univentricular hearts.

METHODS

A series of 246 patients, from three joint institutions, having univentricular heart with restricted but not critical pulmonary blood flow received a bidirectional cavopulmonary shunt with additional forward pulmonary blood flow. All patients have been studied according to their progression, or not, to Fontan operation. Two hundred and eight (84.5%) patients underwent bidirectional cavopulmonary anastomosis as primary palliation. Twenty patients (8.1%) with previous pulmonary artery banding were also enrolled in the study. Patients who had received additional pulmonary blood flow through a previous systemic to pulmonary artery shunt for the critical pulmonary blood flow were excluded.

RESULTS

No in-hospital death occurred. Follow-up was complete at 100%. Mean follow-up was 4.2 +/- 2.8 years (range, 6 months to 7 years). During the observational period 73 (29.7%) patients, considered optimal candidates, underwent Fontan completion for increasing cyanosis and (or) hematocrit and (or) fatigue with exertion. Three patients expired after total cavopulmonary connection (3 of 73; 4.1% mortality rate). The remaining 173 (70.3%) patients are alive with initial palliation. All patients were still well palliated with an arterial oxygen saturation at rest about 90%.

CONCLUSIONS

According to our experience and results, bidirectional Glenn with antegrade pulmonary blood flow may be an excellent temporary palliation prior to a Fontan operation, which can be performed at the onset of symptoms. Bidirectional Glenn may also be the best possible palliation for a suboptimal candidate for Fontan.

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.

The infant with single ventricle and excessive pulmonary blood flow: results of a strategy of pulmonary artery division and shunt

BACKGROUND

The infant with a single ventricle and excessive pulmonary blood flow requires early protection of the pulmonary vascular bed to insure suitability for a subsequent Fontan procedure. The traditional approach, pulmonary artery banding, has had disappointing results. We have pursued an alternate strategy: division of the pulmonary artery, and placement of a systemic-to-pulmonary artery shunt. Potential sites of systemic outflow tract obstruction are simultaneously bypassed, by either a Damus-Kaye-Stansel, or modified Norwood procedure.

METHODS

From January 1996 to June 2001, 22 infants were treated by this strategy. Patients with hypoplastic left heart syndrome were excluded. Median age was 18 days (range 2 days to 6 months). In addition to pulmonary artery division and shunt, 3 of 22 patients underwent a Damus-Kaye-Stansel procedure, and 13 of 22 patients underwent a modified Norwood procedure.

RESULTS

There were no operative deaths, and one late death. Actuarial survival beyond 30 months was 90%. At follow-up catheterization in 22 patients, median transpulmonary gradient was 7 mmHg (range 4 to 18), and median pulmonary vascular resistance 1.9 Wood units (range 0.9 to 3.3). Twenty-one patients have undergone a subsequent bidirectional superior cavopulmonary connection, and 6 a Fontan procedure, with no deaths. No patient developed subaortic stenosis, or aortic arch obstruction. Neoaortic insufficiency was none or trivial in 12 patients, mild in 3, and moderate in 1.

CONCLUSIONS

In patients with a functional single ventricle and excessive pulmonary flow, a strategy of pulmonary artery division and shunt, along with prophylactic bypass of systemic outflow obstruction, carries low operative and midterm mortality. It provides consistent protection of the pulmonary vascular bed, avoids subaortic stenosis and aortic arch obstruction, minimizes neoaortic insufficiency, and ensures suitability for progression along a Fontan pathway. These results provide a comparison for alternate strategies, including pulmonary artery banding.

Long-term results of relief of subaortic stenosis in univentricular atrioventricular connection with discordant ventriculoarterial connections

BACKGROUND

We set out to examine the long-term results of relief of subaortic stenosis by enlargement of ventricular septal defect in patients with univentricular atrioventricular connection to a dominant left ventricle and discordant ventriculoarterial connections.

METHODS

Twenty-four patients underwent enlargement of ventricular septal defect between 1985 and 1998 at a median age of 3.2 years (range, 3 weeks to 14 years). Ten patients were younger than 1 year of age. Eighteen had undergone previous banding of the pulmonary trunk, 9 of whom also required repair of coarctation of the aorta. The median subaortic gradient before enlargement was 46 mm Hg. Twenty-three patients had a patch to enlarge the rudimentary right ventricle.

RESULTS

Five patients (21%) died in the early postoperative period. The overall survival at 1 and 3 years was 73%, and at 5 and 10 years was 68% and 60%, respectively. Complete heart block requiring insertion of a pacemaker occurred in 2 patients (8%). A Fontan operation was performed in 10 patients, 5 underwent a bidirectional Glenn procedure, and 2 required cardiac transplantation. Follow-up was complete in all survivors at a median time of 6.7 years (range, 8 months to 13 years). From the earlier part of the series, 3 patients experienced aortic insufficiency and 2 had recurrent obstruction. Factors adversely affecting survival were age younger than 1 year at operation and presence of obstruction within the aortic arch.

CONCLUSIONS

Our experience shows that, in patients with univentricular atrioventricular connection to a dominant left ventricle and subaortic stenosis, enlargement of the ventricular septal defect provides satisfactory relief of obstruction except in those younger than 1 year of age, and those who have associated obstruction in the aortic arch.

Repair of coarctation of the aorta during infancy minimizes the risk of late hypertension

BACKGROUND

Recent surgical reports on coarctation of the aorta have primarily focused on the relative merits of various operative techniques. However, appropriate timing for elective repair remains unclear.

METHODS

In a retrospective analysis we examined the surgical outcomes in 176 consecutive patients undergoing repair of coarctation of the aorta in our institution over a 25-year period. Ninety-nine percent of the patients had follow-up for a median of 7.5 years.

RESULTS

A total of 13 patients have died (7.4% overall mortality). Nine of these patients had associated complex intracardiac anomalies. There was no mortality in the 113 patients with isolated coarctation. Residual or recurrent coarctation occurred in 27 patients (15.3%). The age at operation and the type of surgical repair did not have an effect on the incidence of recurrence. Persistent or late hypertension was identified in 18 of the 107 patients who have been followed up for more than 5 years (16.8%). A total of 48 patients operated on during infancy have been followed up for more than 5 years. Only 2 have developed late hypertension (4.2%). Both of these patients had recurrence. In contrast, 16 of the 59 patients operated on after a year of age had late hypertension (27.1%).

CONCLUSIONS

To minimize the risk of persistent hypertension, elective repair of coarctation should be performed within the first year of life.

Does banding the pulmonary artery affect pulmonary valve function after the Damus-Kaye-Stansel operation?

BACKGROUND

The Damus-Kaye-Stansel (DKS) operation can be an effective palliation in patients who have single-ventricle physiology and systemic outflow obstruction. Pulmonary artery banding (PAB) may be used as a preliminary procedure in these patients to limit overperfusion of the pulmonary circulation. In some series, the DKS operation has been associated with pulmonary insufficiency (PI). We retrospectively analyzed medical records of our patients who had PAB and later DKS to determine the incidence of PI in these patients.

METHODS

Between 1982 and 1996, 15 patients underwent PAB before DKS. Median age at PAB placement was 7 days and median duration of PAB was 7 months. Echocardiograms obtained before PAB, before DKS, and at the most recent post-DKS follow-up were reviewed.

RESULTS

Follow-up ranged from 1 to 15 years (mean follow-up, 7.5 years). One patient had trivial PI before PAB, which progressed to moderate PI at the last follow-up. Only 1 other patient had mild PI, but only at the last follow-up after DKS.

CONCLUSIONS

These findings suggest that prior PAB does not appear to cause significant PI in patients slated for DKS, and the incidence of significant PI after the DKS operation is relatively low.

Usefulness of banding of the pulmonary trunk with single ventricle physiology at risk for subaortic obstruction

This study addresses the effects of early banding of the pulmonary trunk and subsequent management of subaortic obstruction on the attainment of acceptable pre-Fontan hemodynamics in patients with a single left ventricle and aorta arising from an outflow chamber. We report our experience with 26 patients seen at our institution between January 1984 and December 1994 with a diagnosis of double-inlet left ventricle or tricuspid atresia and transposed great arteries, who were initially managed with pulmonary artery banding in the first 6 months of life. Pulmonary artery band placement was performed at an age of 2.1 +/- 1.8 months (mean +/- SD). Associated aortic arch abnormalities were present in 8 patients (31%). There were 19 patients (73%) who underwent treatment with a Damus-Kaye-Stansel procedure or ventricular septal defect (VSD) enlargement for a significant subaortic gradient or morphologically small VSD, alone or in conjunction with a Glenn or Fontan procedure. Eighteen of 26 patients (69%) underwent cardiac catheterization to assess their candidacy for the Fontan operation. Of this group, 16 were classified as low to moderate risk and 2 as high-risk Fontan candidates, based on hemodynamic criteria. The cumulative mortality for the entire cohort was 19%. Our results suggest that this high-risk group of patients can undergo effective pulmonary artery banding as an initial palliative step, with subsequent intervention for subaortic ob- struction when it is documented or highly suspected, and that acceptable pre-Fontan hemodynamic parameters can be achieved.

Intraoperative epicardial echocardiography in assessing pulmonary artery banding procedures

BACKGROUND

Accurate perioperative assessment of the adequacy of pulmonary artery banding has hitherto relied on oximetry and direct pressure measurements. We report the use of epicardial Doppler echocardiography for assessing banding procedures.

METHODS

Six consecutive infants (3 male, 3 female; median age, 17 days) who underwent pulmonary artery banding for complex defects were studied by intraoperative epicardial Doppler echocardiography.

RESULTS

Excellent visualization of the relation of the band to the pulmonary valve and branch arteries was obtained, enabling or confirming optimal positioning. Doppler echocardiographic estimation of the pressure drop across the band was possible in each patient and resulted in further tightening of the band in 2 patients (33%) with satisfactory increases in transband pressure gradients. Intraoperative echocardiographic estimates of the transband gradients (median, 57 mm Hg; range, 52 to 71 mm Hg; mean +/- standard deviation, 59 +/- 7 mm Hg) correlated well with those obtained at subsequent transthoracic echocardiography (median gradient, 66 mm Hg; range, 52 to 67 mm Hg; mean +/- standard deviation, 63 +/- 6 mm Hg).

CONCLUSIONS

Epicardial echocardiography is a valuable adjunct to direct pressure and saturation measurements for adjustment of final band size and aids in confirming accurate band placement.

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.

Systemic ventricular outflow obstruction progresses after the Fontan operation

To evaluate the course of systemic ventricular outflow obstruction after the Fontan operation, the records of 57 hospital survivors of that procedure were reviewed. Ventricular outflow obstruction was identified in 7 patients (group 1) and was absent in 50 patients (group 2). Overall, the ventricular outflow gradient in group 1 was 6.3 +/- 2.9 mm Hg (mean +/- standard error) before the Fontan operation and 7.6 +/- 3.9 mm Hg at hospital discharge. Ventricular outflow obstruction subsequently progressed to 80.1 +/- 17.3 mm Hg (range, 33 to 165 mm Hg; p < 0.02) a mean of 28 months postoperatively. One patient died of severe progressive ventricular outflow obstruction. Group 1 did not differ from group 2 in age, ventricular morphology, presence of a subaortic outflow chamber, prior shunt, or length of follow-up. Compared with group 2, however, patients in group 1 more commonly had an aorta arising from a hypoplastic ventricle (p < 0.001) and had undergone prior pulmonary artery banding (p = 0.005). We conclude that systemic ventricular outflow obstruction occurs commonly after a Fontan procedure (incidence, 12%; 70% confidence interval, 9% to 18%) and is a progressive lesion.

Damus-Stansel-Kaye procedure: current indications and results

Between October 1983 and August 1991, 29 consecutive Damus-Stansel-Kaye procedures were performed. Indications for operation included restrictive bulboventricular foramen or subaortic stenosis associated with complex univentricular congenital heart disease (25) and Taussig-Bing heart, subaortic stenosis, or both associated with complex biventricular congenital heart disease (4). Twelve patients underwent concurrent Fontan procedures. Average age at operation was 39.8 months (range, 1 to 132 months). Average outflow tract gradient was 28 mm Hg (range, dynamic to 80 mm Hg). Of the 29 patients, 23 were male and 6 were female. There were three early deaths (10%), two in patients who had a concurrent Fontan procedure. Although there was a trend toward lower age and higher outflow tract gradients in nonsurvivors, these and other factors were not statistically significant predictors of death. Actuarial freedom from cardiac-related death was 88% at 5 years (n = 7). In a mean follow-up of 3.5 years (range, 0.1 to 7.7 years), 3 patients have required reoperation (10%), 2 for aortic valve insufficiency (5 days and 2.75 years) and 1 for a gradient across the anastomosis (5.75 years). Actuarial freedom from reoperation related to a failed Damus-Stansel-Kaye procedure was 90% at 4 years and 75% at 6 years (n = 7).

Tricuspid atresia presenting in infancy. Survival and suitability for the Fontan operation

BACKGROUND

The Fontan operation is the usual goal of therapy for children with tricuspid atresia. The influences of morphology and different management strategies on survival and subsequent suitability for this procedure are crucial but unstudied in an unselected population during the Fontan era.

METHODS AND RESULTS

The fates of 237 consecutive infants with tricuspid atresia were reviewed (1972-1987; median follow-up, 8.0 years). Overall actuarial survival was 72% at 1 year, 53% at 5 years, and 46% at 10 years. Univariate risk factor analysis established that discordant ventriculoarterial connections (24% of the group; relative risk, 2.7), pulmonary atresia (14%, 2.3), aortic arch obstruction (7%, 2.9), and subaortic stenosis (8%, 4.2) were associated with poor survival, whereas pulmonary stenosis (60%, 0.52), balanced pulmonary blood flow (9%, 0.25), and older age at presentation (33%, 0.42) were beneficial. Multivariate analysis allowed the creation of predictive patient-specific survival curves and two additive indexes. Survival was worse for patients who underwent banding of the pulmonary trunk with aortic arch repair than for other individual palliative procedures (p < 0.001). On retrospective review, 204 patients (86%) were judged suitable for a future Fontan procedure at presentation. However, 99 (48%) of these are known to have died before a Fontan operation or became unsuitable for such surgery during follow-up, mostly because of death after palliative surgery (23 patients, 11%), sudden death (18 patients, 9%), and new adverse features (32 patients, 16%) such as subaortic stenosis, pulmonary arterial distortion, and ventricular dysfunction.

CONCLUSIONS

Management in infancy must aim to ensure survival and maintain suitability for a Fontan-type operation. The accumulating incidence of adverse events with increasing age would argue in favor of undertaking definitive surgery in early childhood in most patients.

Damus-Kaye-Stansel with cavopulmonary connection for single ventricle and subaortic obstruction

Infants with single ventricle and transposition of the great arteries with or without aortic arch obstruction have a poor prognosis due in large part to the development of systemic outflow obstruction, a frequent consequence of pulmonary artery banding. Thus, the initial palliation and long-term treatment options are critical in terms of surgical choices and timing. We report our experience with 9 patients managed by neonatal pulmonary artery banding and early debanding, a Damus-Kaye-Stansel procedure, and either a modified Glenn shunt or a modified Fontan procedure. Some evidence of subaortic stenosis developed in every patient as manifested by a resting gradient across the systemic outflow tract (21.4 +/- 4.2 mm Hg), a small ventricular septal defect relative to the body surface area (1.57 +/- 0.39 cm2/m2), and a small ventricular septal defect relative to the aortic root cross-sectional area (0.70 +/- 0.04 cm2/m2). There were 1 early death and 1 late death after the Damus-Kaye-Stansel procedure. With the exception of 1 patient, the in-hospital course of the survivors was relatively uncomplicated. Two patients with levotransposition of the great arteries have required pacemakers. None of the survivors have residual systemic outflow obstruction. There is trivial or mild pulmonic insufficiency in 5 patients, which is not progressing. One patient had mild to moderate pulmonic insufficiency but died late presumably of an arrhythmia. We conclude that neonatal pulmonary artery banding coupled with planned early debanding, a Damus-Kaye-Stansel procedure, and cavopulmonary anastomosis is a relatively low-risk course for patients with this complex physiology.

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)

The Damus-Fontan procedure

The Damus-Kaye-Stansel operation is a useful technique for the treatment of complex cyanotic congenital heart disease when there is obstruction between the systemic ventricle and the aorta. Modifications of the technique include transection of the aorta and the pulmonary artery, anastomosis of the contiguous aortic and pulmonary walls, and connection of the distal aorta to the perimeter of the new bivalved proximal great artery. In addition, the bidirectional cavopulmonary shunt technique can be used with or without the Fontan procedure. Six patients underwent a Damus-Fontan operation, and all survived. Two patients underwent the Damus-cavopulmonary shunt (hemi-Fontan) procedure, and 1 survived. The postoperative status of the 7 survivors is good to excellent. Follow-up ranges from 2 months to 7 1/2 years.

Double-inlet single left ventricle: echocardiographic anatomy with emphasis on the morphology of the atrioventricular valves and ventricular septal defect

The echocardiographic anatomy of double-inlet single left ventricle was studied in 57 patients, aged 1 day to 27 years (mean 6 years); the variables examined included morphology, size and function of the atrioventricular (AV) valves and ventricular septal defect and their relation to pulmonary stenosis, aortic stenosis and aortic arch obstruction. The visceroatrial situs was solitus and the heart was in the left side of the chest in all 57 patients. A d-loop ventricle was present in 21 patients and an l-loop ventricle in 36. The great arteries were normally related (Holmes heart) in 8 patients and transposed in 49. In all hearts, the right AV valve was anterior to the left AV valve. In 53 patients, the tricuspid valve (right valve in d-loop and left valve in l-loop) was closer to and had attachments on the septum. The tricuspid valve straddled the outflow chamber in eight patients. No significant difference was noted in the mean AV valve diameter when comparing mitral and tricuspid valves within the same group or between the groups with a d- or l-loop ventricle. The right AV valve diameter had a significant direct correlation with the aortic valve diameter and the size of the ventricular septal defect regardless of ventricular loop. Both AV valves were functionally normal in 34 patients. Among patients with AV valve dysfunction, the tricuspid valve tended to be stenotic in patients with an l-loop ventricle and regurgitant in patients with a d-loop ventricle. Mitral valve dysfunction was uncommon. The ventricular septal defect (46 patients) was separated from the semilunar valves in 24 patients (muscular defect) and adjacent to the anterior semilunar valve as a result of hypoplasia or malalignment, or both, of the infundibular septum (subaortic defect) in 19 patients. Multiple defects were present in three patients. The defect was unrestrictive in 26 patients, restrictive in 23 and could not be evaluated in 8. Pulmonary artery banding had been performed in 8 of the 26 patients with an unrestrictive defect and in 10 of the 23 patients with a restrictive defect. Only 4 of 19 subaortic defects compared with 16 of 24 muscular defects were restrictive. The size of the defect was significantly correlated with the measured pressure gradient. Among patients with transposition, only 2 of 13 with pulmonary stenosis had a restrictive ventricular septal defect compared with 15 of 30 without pulmonary stenosis. In patients with transposition, the defect size was significantly smaller when coarctation was present.

Ventricular function in the single ventricle before and after Fontan surgery

To better delineate the importance of ventricular function in patients with a single ventricle and assess its relation to outcome after the Fontan procedure, 47 patients with a single ventricle were studied. Ventricular ejection fraction was estimated by radionuclide angiocardiography. Before Fontan surgery, ejection fraction was 0.57 +/- 0.10 (mean +/- standard deviation). This differed significantly from the normal mean left ventricular ejection fraction of 0.68 +/- 0.09 (p less than 0.001) derived in our laboratory by radionuclide angiocardiographic methods. Age, ventricular morphology and the presence of pulmonary artery band or systemic to pulmonary artery shunts had no statistical relation to ventricular ejection fraction in patients with a single ventricle. Serial preoperative evaluation in 15 patients over 3.8 +/- 1.3 years revealed no significant change in ventricular ejection fraction; however, increased atrioventricular valve regurgitation was documented in 4 of these 15. Modified Fontan procedure was performed in 24 of the 47 study patients; 7 have died, 1 has undergone cardiac transplantation and 1 faces possible transplantation. No difference was noted in preoperative ejection fraction between survivors and nonsurvivors. Ventricular morphology, age at Fontan surgery and operative factors such as bypass and cross-clamp time were not related to functional outcome. Preoperative ejection fraction of 0.52 +/- 0.08 decreased to 0.39 +/- 0.11 (p less than 0.001) when evaluated 1.16 +/- 0.44 years after Fontan surgery. In patients with a single ventricle (1) ventricular ejection fraction is less than that of the normal systemic ventricle; (2) during childhood, ejection fraction is not related to age or ventricular morphology; and (3) ventricular ejection fraction frequently decreases after a Fontan repair.(ABSTRACT TRUNCATED AT 250 WORDS)

Is banding of the pulmonary trunk obsolete for infants with tricuspid atresia and double inlet ventricle with a discordant ventriculoarterial connection? Role of aortic arch obstruction and subaortic stenosis

Banding the pulmonary trunk may exacerbate or promote the development of subaortic stenosis in patients with double inlet ventricle or tricuspid atresia with a dominant left ventricle and discordant ventriculoarterial connection and, therefore, may be an inappropriate palliative procedure for such patients. To examine this possibility, 102 consecutive infants were studied who presented with this anatomy between 1972 and 1987. Obstruction of the aortic arch was present in 52 patients. In 28 patients (17 with aortic arch obstruction), subaortic stenosis was already apparent at presentation. Of the remaining 74 patients, 19 received no palliative surgery and 55 underwent banding of the pulmonary trunk either with (n = 22) or without (n = 33) aortic arch repair. Outcome was significantly worse in patients with associated aortic arch obstruction. All such patients either died or developed subaortic stenosis by 3 years of age (survival free of subaortic stenosis 0 of 22 versus 22 of 33 for patients with isolated banding of the pulmonary trunk, p less than 0.001). After isolated banding, there was a lower ratio of the ventricular septal defect to ascending aorta diameters at presentation in the patients who developed subaortic stenosis than in the patients who did not (0.60 +/- 0.08 versus 1.03 +/- 0.15, p less than 0.001). Of the latter, 18 (95%) of 19 patients fulfilled criteria for a Fontan procedure at recatheterization. Thus, the presence of aortic arch obstruction is associated with rapid development of subaortic stenosis after banding of the pulmonary trunk. Alternative initial surgery, even though high risk, may be indicated. In the absence of such obstruction, banding the pulmonary trunk can be performed at reasonable risk and, provided that the ventricular septal defect is of adequate size, satisfactorily prepares most patients for a later Fontan procedure.

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.

Pulmonary artery banding revisited

Pulmonary artery (PA) banding to reduce pulmonary blood flow was described by Muller and Dammann in 1952. This review describes the outcome of 170 children who had PA banding at the University of Virginia Medical Center between 1955 and 1988. One hundred and one of the patients were banded between 1958 and 1970; fewer bands were placed in later years because early total correction was feasible for certain conditions. When analyzed by preoperative diagnoses, the data reveal that children with a single ventricle undergoing banding had a significantly lower 30-day mortality rate of 12% compared to other preoperative diagnoses, including atrioventricular canal, truncus arteriosus, and ventricular septal defect (VSD) at 30% (p less than 0.05). The late overall mortality for all patients was approximately 10%, an attrition rate of 1% per year. PA banding still has a role in management of patients with congenital heart disease, particularly for infants with a single ventricle. Actuarial survival at 10 years for patients with this condition is 92%. Interestingly, this indication for pulmonary banding is the same one cited in the original report.

Course of tricuspid atresia in the Fontan era

Tricuspid atresia is an uncommon form of congenital heart disease and long-term survival was rare before the Fontan era. It was thought that the long-term survival of patients with tricuspid atresia would be improved by the introduction of the Fontan procedure and its subsequent modifications. This study reviews the clinical course of 84 patients with tricuspid atresia identified in the first year of life in the Fontan era. Prior palliative operations, their results and their ultimate application for the Fontan procedure were considered. Eleven patients died before surgical intervention and 5 did not undergo catheterization or echocardiographic confirmation before death. Five children underwent the Fontan procedure without prior palliation and 1 child does not require palliation at the present time. Sixty-seven patients (80%) had surgical procedures before evaluation for the suitability of a Fontan operation. Thirty-four patients had a second surgical palliation and 9 patients had a third palliation. The surgical mortalities for the first, second and third palliative surgery were 17.9, 17.6 and 0%, respectively. Thirty-two patients (38%) underwent the Fontan procedure and 2 deaths occurred (6%). An estimate of the probability of surviving for 1 year was 64% (95% confidence limits 54 to 74%) and that of 8 years was 55% (95% confidence limits 44 to 66%).

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)

Hearts with one ventricle: current concepts and management

Images

Fate of the pulmonic valve after proximal pulmonary artery-to-ascending aorta anastomosis for aortic outflow obstruction

Transection of the main pulmonary artery and end-to-side anastomosis of the proximal pulmonary artery to the ascending aorta has been increasingly used in palliative surgery for cardiac malformations such as single ventricle with small outlet foramen (bulboventricular foramen) and hypoplastic left-heart syndrome. To evaluate pulmonary valve competence after this operation, we used color Doppler flow mapping to examine 45 survivors of pulmonary artery-to-ascending aorta anastomosis a median of 202 days postoperatively. Of 37 patients with hypoplastic left heart syndrome, mild regurgitation was detected in 9 (24%) and moderate regurgitation in 1 (3%). Of 8 with other lesions, mild regurgitation was observed in 2 and moderate regurgitation in 1. Seven of 11 patients imaged greater than or equal to 12 months postoperatively had regurgitation. In summary, one-fourth of survivors developed mild pulmonary regurgitation. Its presence should not be considered a contraindication to eventual application of Fontan's principle, although further follow-up appears warranted because the long-term fate of pulmonary valve function is not yet known.