Outcomes after bidirectional cavopulmonary shunt in infants less than 6 months old

Current management of infants and children with single ventricle anatomy

Children with single ventricle anatomy are among the most complicated and challenging patients encountered in pediatric cardiology. Current management involves staged surgical procedures, beginning with neonatal palliation and followed by a bidirectional cavopulmonary anastomosis in infancy and culminating in the Fontan procedure. The Fontan procedure, despite separating the circulation, remains a palliative procedure with many long-term concerns. This report discusses the staged surgical management of patients with single ventricle anatomy and the nursing issues relevant to each stage.

[The bidirectional Glenn operation in 100 cases with complex congenital heat diseases: factors influencing surgical results]

OBJECTIVE

The bidirectional Glenn shunt is a well established surgical technique in children with complex congenital heart disease. The present study is a retrospective analysis of patients undergoing this operation in order to assess the influence of different variables in the outcome.

PATIENTS AND METHOD

From December 1990 to June 2000, 100 patients received a bidirectional Glenn shunt. Two groups were defined, based on the outcome. Group A (n = 15, unsuccessfully result) including death and need to reoperate, and Group B (n = 85, patients with good outcome).

RESULTS

The mortality was 8%. Eight patients were reoperated at follow-up. The survivors were followed for a mean of 3.5 years. Mean pulmonary artery pressure 7 mmHg was a factor associated with poor clinical progress. Other variables (age less than 1 year, excessive pulmonary blood flow, double Glenn operation, significant anatomic anomalies, and arrythmias), were also associated with outcome. Significant variations were observed in the time of by-pass or the need for aortic clamp in cases with simultaneous operative repair of pulmonary branch stenosis. Actuarial survival rate, most more than 1 year was 92%, and freedom from reoperation at 3 years was 90%.

CONCLUSIONS

The bidirectional Glenn shunt is an excellent palliation in patients with functionally single ventricle. Mean pulmonary artery pressure was the most important variable related with the outcome. We are encouraged to continue with tendency to perform bidirectional Glenn shunt preferably early, avoiding, whenever possible, previous palliative surgery.

[Clinical guidelines of the Spanish Society of Cardiology in congenital cardiopathy of the newborn]

The use of diagnostic and therapeutic techniques is very important to ensure optimum, effective treatment in patients with heart disease to thereby obtain an adequate cost-benefit relationship. The aim of establishing guidelines for the evaluation and management is to achieve this relationship, but these guidelines are difficult to establish in pediatric cardiology despite 50 years of experience in this field. The physiopathologic peculiarities of newborns, in addition to the complex anatomical features of many heart diseases and their clinical presentation, diagnostic and therapeutic difficulties and the presence of residue, sequela and complications of the surgical technique make the elaboration of such guidelines at this age complex. Guidelines for some heart diseases are presented together with a descriptive analysis and a therapeutic schedule of other congenital heart diseases.

Quantitative assessment of ventricular function in children with single ventricles using the Doppler myocardial performance index

Assessment of ventricular function in patients with functionally single ventricles and unusual ventricular geometry is difficult. The Doppler myocardial performance index (MPI) may provide a method of assessing function in these patients. The purposes of this study were to compare the MPI in normal children and in children with a functionally single ventricle, and to compare the MPI in patients with single ventricles before and after bidirectional cavopulmonary anastamosis (BCPA). Echocardiograms of all patients who underwent BCPA between January 1994 and December 1998 were reviewed before and after surgical palliation. Age-matched normal subjects (n = 30) served as controls. The MPI was calculated from Doppler tracings of ventricular inflow and outflow. Of the 60 patients with single ventricles who underwent BCPA, 41 had adequate preoperative Doppler studies to allow calculation of the MPI, and 21 of 41 had adequate studies before and after BCPA. The MPI was higher in patients with single ventricles than in normal controls (0.67 +/- 0.14 vs 0.32 +/- 0.10, p < 0.001). There was no significant difference in the MPI in patients with single ventricles before and after surgery (0.70 +/- 0.16 vs 0.66 +/- 0.15). However, patients who had a BCPA at < 1 year of age had a significant decrease in the MPI after surgery (0.71 +/- 0.10 vs 0.61 +/- 0.11, p = 0.01). Compared with controls, the MPI was significantly higher in patients with single ventricles suggesting an altered hemodynamic state consistent with decreased ventricular function. The MPI decreased in patients who underwent BCPA at < 1 year of age, suggesting an improvement in ventricular function. The MPI provides an objective method of assessing and following ventricular function in patients with single ventricles that is independent of ventricular geometry.

Effectiveness of low dose captopril versus propranolol therapy in infants with severe congestive failure due to left-to-right shunts

To evaluate the therapeutical effects of the angiotensin converting enzyme inhibitor Captopril to the beta-blocker Propranolol in infants with congestive failure due to pulmonary overcirculation, we retrospectively analysed clinical, neurohormonal and hemodynamic data in 22 infants, 11 of whom were treated with Captopril (Group 1), 11 with Propranolol (Group 2). Age, weight, number of palliative operations, plasma renin activities and pulmonary to systemic flow ratios (3.5 vs. 3.5) were not significantly different prior to Captopril or Propranolol therapy. If treatment with digoxin and diuretics did not succeed, the infants were additionally treated with Captopril (1 mg/kg) for a mean of 7.4 months, or with 1.9 mg/kg Propranolol for 9.2 months.

RESULTS

1 mg/kg Captopril did not effectively suppress angiotensin converting enzyme in the steady state at trough level (92+/-52 vs. 87+/-50 nmol/min/ml). In the Propranolol group, the clinical heart failure score (2.6+/-1.5 vs. 7. 4+/-2.5) and plasma renin activities (14+/-10 vs. 101+/-70 ng/ml/h) were significantly lower, compared to the Captopril group. Length of hospital stay (23+/-9 vs. 52+/-24 days) was lower and weight gain (126+/-38 vs. 86+/-84 g/week) was higher within 3 months after starting Propranolol therapy. Significantly lower left atrial pressures (6.2+/-2.2 vs. 13.4+/-9.2 mmHg) and lower endiastolic ventricular pressures (7.6+/-2.5 vs. 12.6+/-4.0 mmHg) during pre-operative cardiac catheterization indicated a better diastolic ventricular function under chronic Propranolol treatment.

CONCLUSION

Although high dose Captopril was not evaluated in this study, when compared to patients on low Captopril dosages, infants who received Propranolol treatment showed improvement in heart failure scores, shorter lengths of hospital stay, lower plasma renin activities and better diastolic ventricular functions.

Bubble contrast echocardiography in detecting pulmonary arteriovenous shunting in children with univentricular heart after cavopulmonary anastomosis

OBJECTIVES

We sought to compare bubble contrast echocardiography and pulmonary angiography in detecting pulmonary arteriovenous malformation (PAVM) in children with cavopulmonary anastomosis (CPA), and to examine anatomic and physiologic variables associated with the development of PAVM.

BACKGROUND

Development of PAVM in patients with CPA may cause profound cyanosis. Pulmonary arteriovenous malformation has been traditionally diagnosed by pulmonary angiography with reported incidence of 20% to 25% in patients with CPA.

METHODS

Fourteen patients (age 1.1 to 12.6 years) with any forms of CPA and normal pulmonary venous drainage formed the study population. All patients underwent cardiac catheterization and pulmonary angiography. Bubble contrast echocardiographic studies were performed with injection of 10 ml of agitated saline solution into branch pulmonary arteries. Transthoracic echocardiograms using an apical view were performed to assess the appearance of bubble contrast in the systemic ventricles. We compared the results of pulmonary angiograms and contrast echocardiograms, and findings of contrast echocardiograms between lungs with hepatic venous blood flow and lungs without hepatic venous blood.

RESULTS

Ten of the 14 patients (71%) had positive contrast echocardiographic studies, compared with three (21%) detected by pulmonary angiograms (p = 0.01). No difference was found in pulmonary artery pressure, transpulmonary gradient or presence of heterotaxy syndrome between patients with positive contrast echocardiographic studies and patients with negative studies. However, patients with positive contrast echocardiograms tended to have lower oxygen saturation (81%) and higher hemoglobin (16.4 g/dl) compared with patients with negative studies (88% and 14.7 g/dl, p = 0.10 and p = 0.18 respectively). Patients with Glenn shunt or unidirectional Fontan had higher incidence of PAVM (10/11) compared with patients with classic or lateral tunnel Fontan (0/3, p = 0.01). All 12 lungs with no perfusion of hepatic venous blood had positive contrast echocardiographic studies. Lungs with no hepatic venous blood flow were more likely to develop PAVM compared with lungs with hepatic venous blood flow (12/12 and 3/16 respectively, p < 0.01).

CONCLUSIONS

Bubble contrast echocardiography is more sensitive in detecting PAVM compared with pulmonary angiography. The prevalence of PAVM in patients with CPA may be much higher than what had been reported previously. Lungs with no hepatic venous blood flow are more likely to develop PAVM than lungs with hepatic venous blood flow.

Early results of the extracardiac conduit Fontan operation

BACKGROUND

Among the modifications of the Fontan operation, the extracardiac approach may offer the greatest potential for optimizing early postoperative ventricular and pulmonary vascular function, insofar as it can be performed with short periods of normothermic partial cardiopulmonary bypass and without cardioplegic arrest in most cases. In this study, we reviewed our experience with the extracardiac conduit Fontan operation, with a focus on early postoperative outcomes.

METHODS AND RESULTS

Between July 1992 and April 1997, 51 patients (median age 4.9 years) underwent an extracardiac conduit Fontan operation. Median cardiopulmonary bypass time was 92 minutes and has decreased significantly over the course of our experience. Intracardiac procedures were performed in only 5 patients (10%), and the aorta was crossclamped in only 11 (22%). Intraoperative fenestration was performed in 24 patients (47%). There were no early deaths. Fontan failure occurred in 1 patient who was a poor candidate for the Fontan procedure. Transient supraventricular tachyarrhythmias occurred in 5 patients (10%). Median duration of chest tube drainage was 8 days. Factors significantly associated with prolonged resource use (mechanical ventilation, inotropic support, intensive care unit stay, and hospital stay) included longer bypass time and higher Fontan pressure. At a median follow-up of 1.9 years, there was 1 death from bleeding at reoperation.

CONCLUSIONS

The extracardiac conduit Fontan procedure can be performed with minimal mortality and morbidity. Improved results may be related to advantages of the extracardiac approach and improved preservation of ventricular and pulmonary vascular function.

Additional pulmonary blood flow with the bidirectional Glenn anastomosis: does it make a difference?

BACKGROUND

The bidirectional cavopulmonary shunt has become a mainstay in the palliation of patients with a functional single-ventricle heart. However, there remain a number of unresolved issues regarding this procedure, many of which concern the response of the pulmonary vasculature to this unique circulatory physiology. Among the issues of debate are the role and effects of an additional source of pulmonary blood flow.

METHODS

Between January 1990 and April 1997, 160 patients underwent bidirectional cavopulmonary anastomosis. Median age at operation was 7.8 months, and age ranged from 24 days to 43 years. An additional source of pulmonary blood flow was included in 93 patients (58%). A retrospective review of our experience with this cohort was performed with a focus on the role of additional pulmonary blood flow.

RESULTS

Eight patients (5%) died in the early postoperative period, and the overall early failure rate (death or take-down) was 7.5% (n=12). Eleven other patients underwent early reoperation to decrease (n=8) or increase (n=3) the amount of pulmonary blood flow. Early survivors were followed up for a median of 23 months, during which time 5 patients died and 30 patients underwent Fontan completion. Including early and late mortality, actuarial survival rates at 1 and 2 years were 91% and 88%, respectively.

CONCLUSIONS

The bidirectional cavopulmonary shunt is a useful procedure in the early or intermediate-term management of patients with a functional univentricular heart. However, there is much still to be learned about this unique physiologic system. The role of accessory pulmonary blood flow remains unclear, as does the use of the bidirectional cavopulmonary shunt as long-term palliation. Pulmonary arteriovenous fistulas are a serious concern, especially in young patients with heterotaxy syndrome.