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

Quantification of ventricular stress in univentricular hearts during early childhood using age-independent zlog-NT-proBNP

BACKGROUND

Children with univentricular hearts (UVH) undergo up to three palliative surgical procedures to achieve complete circulatory separation (Fontan circulation). As a marker of cardiac wall stress, NT-proBNP is a promising tool to assess systemic ventricular load in these patients. However, different reference intervals (RI) apply to each stage, as NT-proBNP is highly age-dependent.

METHODS

Children undergoing systemic-to-pulmonary (SP) shunt placement (stage 1), bidirectional cavopulmonary shunt (BCPS, stage 2) or total cavopulmonary connection (TCPC, stage 3) between 2011 and 2021 with NT-proBNP measurement within 7 days before surgery were included. Furthermore, outpatients after TCPC with NT-proBNP measurement were enrolled. Biomarker levels were evaluated using its age-adjusted z-score ("zlog-NT-proBNP"; age-independent RI, -1.96 to +1.96), allowing comparison between different stages and revealing changes in systemic ventricular load independent of the marked physiological decline in RI with age.

RESULTS

Overall, 289 children (227 before, 62 after TCPC) met the eligibility criteria. Median time between blood sampling and surgery (SP shunt/BCPS/TCPC) was 2 [1-3] days and 3.2 [2.0-4.5] years after TCPC. Age-adjusted zlog-NT-proBNP levels were 3.47 [2.79-3.93] in children with native UVH (before SP shunt), 3.10 [1.89-3.58] at stage 1 (before BCPS), 1.08 [0.51-1.88] at stage 2 (before TCPC), and 1.09 [0.72-1.75] at stage 3 (after TCPC/Fontan completion). Consequently, BCPS revealed the strongest decrease (median - 2.02 logarithmized standard deviations, p < 0.001).

CONCLUSIONS

In children with UVH undergoing staged Fontan palliation, zlog-NT-proBNP is a highly promising tool for course assessment of systemic ventricular load, independent of the age-related decline in physiological NT-proBNP concentration.

Impact of Antegrade Pulmonary Blood Flow as Patients Progress Through Single-Ventricle Palliations

BACKGROUND

The impact of antegrade pulmonary blood flow (APBF) during single-ventricle (SV) palliation continues to be debated. We sought to assess its impact on the hemodynamic profile and the short- and long-term outcomes of patients progressing through stages of SV palliation.

METHODS

A retrospective single-center study was conducted of SV patients who underwent surgery between January 2010 and December 2020. Patients with APBF were matched to those with no APBF by a propensity score based on body surface area, sex, and type of systemic ventricle. Analysis was performed using appropriate statistics with a significance level of P = .05.

RESULTS

Sixty-three patients with APBF were matched with 95 patients with no APBF. At the pre-stage 2 catheterization, APBF patients had a larger left pulmonary artery diameter (z score, 0.1 vs -0.8; P < .042). Patients with APBF had shorter cardiopulmonary bypass time (57.0 vs 79.0 minutes), shorter duration of mechanical ventilation (14.1 vs 17.4 hours), and shorter hospital length of stay (5.0 vs 7.0 days) at stage 2 palliation (P < .05). In the multivariable Cox regression analysis, patients with hypoplastic pulmonary arteries (z scores < -2; adjusted hazard ratio, 9.17) and patients with chromosomal abnormalities/genetic syndrome (adjusted hazard ratio, 4.03) were at increased risk for poor outcomes (P < .05). During the follow-up period, there was no significant difference in risk of the composite poor outcome and long-term survival between groups.

CONCLUSIONS

SV patients with APBF had shorter cardiopulmonary bypass time, duration of mechanical ventilation, and hospital length of stay after stage 2 palliation. Patients with hypoplastic pulmonary arteries or chromosomal abnormalities/genetic syndromes had increased risk for poor outcomes. Maintaining APBF has better short-term outcomes, but there are no long-term hemodynamic or survival benefits.

A complicated Glenn procedure: risk factors and association with adverse long-term neurodevelopmental and functional outcomes

OBJECTIVES

To determine potentially modifiable risk factors for a complicated Glenn procedure (cGP) and whether a cGP predicted adverse neurodevelopmental and functional outcomes. A cGP was defined as post-operative death, heart transplant, extracorporeal life support, Glenn takedown, or prolonged ventilation.

METHODS

All 169 patients having a Glenn procedure from 2012 to 2017 were included. Neurodevelopmental assessments were performed at age 2 years in consenting survivors (n = 156/159 survivors). The Bayley Scales of Infant and Toddler Development-3rd Edition (Bayley-III) and the Adaptive Behavior Assessment System-2nd Edition (ABAS-II) were administered. Adaptive functional outcomes were determined by the General Adaptive Composite (GAC) score from the ABAS-II. Predictors of outcomes were determined using univariate and multiple variable linear or Cox regressions.

RESULTS

Of patients who had a Glenn procedure, 10/169 (6%) died by 2 years of age and 27/169 (16%) had a cGP. Variables statistically significantly associated with a cGP were the inotrope score on post-operative day 1 (HR 1.04, 95%CI 1.01, 1.06; p = 0.010) and use of inhaled nitric oxide post-operatively (HR 7.31, 95%CI 3.19, 16.76; p < 0.001). A cGP was independently statistically significantly associated with adverse Bayley-III Cognitive (ES -10.60, 95%CI -17.09, -4.11; p = 0.002) and Language (ES -11.43, 95%CI -19.25, -3.60; p = 0.004) scores and adverse GAC score (ES -14.89, 95%CI -22.86, -6.92; p < 0.001).

CONCLUSIONS

Higher inotrope score and inhaled nitric oxide used post-operatively were associated with a cGP. A cGP was independently associated with adverse 2-year neurodevelopmental and functional outcomes. Whether early recognition and intervention for risk of a cGP can prevent adverse outcomes warrants study.

Factors affecting the outcomes after bidirectional Glenn shunt: two decades of experience from a tertiary referral center

BACKGROUND

Despite the improved management of patients with a single ventricle, the long-term outcomes are not optimal. We reported the outcomes of the bidirectional Glenn procedure (BDG) and factors affecting the length of hospital stay, operative mortality, and Nakata index before Fontan completion.

RESULTS

This retrospective study included 259 patients who underwent BDG shunt from 2002 to 2020. The primary study outcomes were operative mortality, duration of hospital stay, and Nakata index before Fontan. Mortality occurred in 10 patients after BDG shunt (3.86%). By univariable logistic regression analysis, postoperative mortality after BDG shunt was associated with high preoperative mean pulmonary artery pressure (OR: 1.06 (95% CI 1.01-1.23); P = 0.02). The median duration of hospital stay after BDG shunt was 12 (9-19) days. Multivariable analysis indicated that Norwood palliation before BDG shunt was significantly associated with prolonged hospital stay (β: 0.53 (95% CI 0.12-0.95), P = 0.01). Fontan completion was performed in 144 patients (50.03%), and the pre-Fontan Nataka index was 173 (130.92-225.34) mm²/m². Norwood palliation (β: - 0.61 (95% CI 62.63-20.18), P = 0.003) and preoperative saturation (β: - 2.38 (95% CI - 4.49-0.26), P = 0.03) were inversely associated with pre-Fontan Nakata index in patients who had Fontan completion.

CONCLUSIONS

BDG had a low mortality rate. Pulmonary artery pressure, Norwood palliation, cardiopulmonary bypass time, and pre-BDG shunt saturation were key factors associated with post-BDG outcomes in our series.

Outcomes After Bidirectional Glenn Shunt in a Tertiary-Care Pediatric Hospital in South Africa

OBJECTIVES

Large data sets have been published on short- and long-term outcomes following bidirectional Glenn surgery (BDG), or partial cavopulmonary connection, in high-income countries. Data from low-income and middle-income countries are few and often limited to the immediate postoperative period. The primary outcome was any in-hospital postoperative complication, assessed according to predefined criteria, in children who underwent BDG surgery at Red Cross War Memorial Children's Hospital.

DESIGN

A retrospective cohort study.

SETTING

A tertiary teaching hospital.

PARTICIPANTS

The study authors identified 61 children (<18 years of age) who underwent BDG over 8 years. The median age of patients undergoing BDG was 2.5 years (interquartile range, 1.4-5.5 years).

INTERVENTIONS

BDG surgery.

MEASUREMENTS AND MAIN RESULTS

Thirty-five patients (57.4%) had a postoperative complication, with some patients (17 of 61, 27.9%) having more than 1 complication. The most frequent complications were infective (29.5%). Univariate analysis found that postoperative complications were associated with the use of nitric oxide (p = 0.004) and a longer duration of anesthesia (p = 0.045) and surgery (p = 0.004). Patients with complications spent longer in the pediatric intensive care unit (ICU) (p < 0.001) and in the hospital (p < 0.012). On multivariate analysis, a priori risk factors based on previous studies were not found to be statistically significant. A total of 37.3% of patients completed their single-ventricle palliation, and 30.5% of patients were lost to follow-up.

CONCLUSIONS

Important findings were the older age at which the BDG was performed compared to high-income countries, an acceptable mortality rate of 3.3%, infection being the most common complication, the association of a complication with increased ICU and hospital lengths of stay, and the high rate of patients lost to follow-up.

Early outcomes after the on pump bidirectional Glenn procedure: A single center experience

OBJECTIVE

Bidirectional Glenn procedure is a staged palliative procedure for patients with the univentricular hearts or complex congenital heart disease. We in our study, attempted to evaluate the preoperative characteristics, operative data and the early postoperative outcomes in the patients who underwent Bidirectional Glenn procedure at our center.

METHODS

In our single center retrospective experience, 115 patients underwent Bidirectional Glenn procedure from January 2015 to December 2019.

RESULTS

The mean age of the patients was 6.55 ± 6.5 years (range from 9 months to 48 years) and a median of 5 years. The most common anatomic diagnosis was double outlet right ventricle (n = 49, 42.6%). The primary diagnosis and the additional cardiac anamolies were not associated with the adverse outcomes. The increased cardiopulmonary bypass and operative time affect the postoperative outcomes. The median oxygen saturation in the patients postoperatively was 82%. The median postoperative stay was 8 days. The early postoperative complications were seen in 29 patients (25.2%). There were 12 early deaths (10.4%) in our study. The late age of presentation and poor preoperative nutrition, increased the risk of the postoperative morbidity and mortality.

CONCLUSION

Bidirectional Glenn procedure is an effective procedure to improve efficacy of the gas exchange and reduce volume overload on the single ventricle at early as well as late stages. However, the late age of presentation increases the risk of the postoperative outcomes.

The outcomes of bidirectional Glenn before and after 4 months of age: A comparative study

OBJECTIVE

We aim to present our experience with the bidirectional Glenn (BDG) in patients less than 4 months of age and to compare their outcomes with the patients who underwent BDG after the age of 4 months.

METHODS

A retrospective review of data was performed for patients who underwent the BDG procedure from 2002 to 2018 at our institutions. We reviewed the patients' demographics, echocardiographic findings, cardiac catheterization data, operative details, postoperative data, and outcome variables.

RESULTS

The study was conducted on 213 patients. At the time of the BDG operation, 32 patients were younger than 4 months (younger group) and 181 patients were older than 4 months (older group). The preoperative mean pulmonary artery pressure was significantly higher in the younger group (p = .035) but there were no significant differences between both groups in Qp/Qs, ventricular end-diastolic pressure, indexed pulmonary vascular resistance, and preoperative oxygen saturation. However, the initial postoperative oxygen saturation of the younger group was lower than the older group (p = .007). The duration of mechanical ventilation, duration of pleural drainage, ICU stay, and hospital stay after BDG were significantly longer in the younger group compared to the older group. The early mortality was higher in the younger group, but this difference did not reach statistical significance (p = .283).

CONCLUSION

Performing BDG procedure in infants less than 4 months of age is safe, with favorable outcomes. Early BDG is associated with a less-smooth postoperative course without a significant increase in early or late mortality.

Risk factors for morbidity and mortality after a bidirectional Glenn shunt in Northern Thailand

OBJECTIVES

Owing to the evolution of surgical techniques, the survival rate of patients undergoing a bidirectional Glenn shunt has improved. However, the morbidity and mortality are still high. The aims of this study were to determine the survival rate and risk factors influencing the morbidity and mortality in patients with a functional univentricular heart after a bidirectional Glenn shunt.

METHODS

One hundred and fifty-one patients who had undergone a bidirectional Glenn operation were enrolled. Early worse outcomes were defined as postoperative death within 30 days and a hospital stay ≥ 30 days.

RESULTS

The median age was 7.1 years (range 0.3-26 years). The median age at the time of the Glenn operation was 2.2 years (range 0.2-15.9 years). The survival rates of patients at 1-, 5-, 10- and 15-year after the Glenn operation were 89%, 79%, 75%, and 72%, respectively. The predictors for the mortality were preoperative mean pulmonary artery pressure ≥ 17 mmHg, preoperative pulmonary vascular resistance index ≥ 3.1 Wood Units·m² and atrioventricular valve regurgitation. In addition, the independent predictors of an early worse outcome included preoperative mean pulmonary artery pressure ≥ 17 mmHg and diaphragmatic paralysis.

CONCLUSION

The presence of preoperative atrioventricular valve regurgitation, preoperative mean pulmonary artery pressure ≥ 17 mmHg, preoperative pulmonary vascular resistance index ≥ 3.1 Wood Units·m², or diaphragmatic paralysis were found to be independent risk factors requiring the good patients' selection for the Glenn operation and early aggressive management of the diaphragmatic paralysis for reducing morbidity to ensure successful candidature for Fontan completion.

Energetic performance index improvement after Glenn and Damus-Kaye-Stansel procedure using vector flow mapping analysis: a case report

Background

Echocardiography vector flow mapping can assess dynamic flow to treat congenital heart diseases. We evaluated intracardiac flow, energy loss, left ventricular output kinetic energy, and energetic performance index using vector flow mapping during Glenn and Damus-Kaye-Stansel procedures in order to assess the efficacy of the surgery.

Case presentation

A 9-month-old boy underwent Glenn and Damus-Kaye-Stansel procedures. The energy loss depends on the left ventricular preload; therefore, energy loss decreased after the Glenn procedure. After the Damus-Kaye-Stansel procedure, the kinetic energy would increase owing to the integrated systemic outflow; however, in our case, kinetic energy decreased, which was potentially explained by the fact that kinetic energy also depends on the left ventricular preload. After the Glenn and Damus-Kaye-Stansel procedures, we detected an improvement in energetic performance index, indicating that the cardiac workload improved as well.

Conclusion

We revealed the efficiency of the Glenn and Damus-Kaye-Stansel procedures using vector flow mapping.

Results of surgery on adults with functional single ventricle without prior cardiac surgery in childhood

OBJECTIVES

Patients with unoperated functional single ventricle (FSV) rarely survive into adulthood with good functional status and there are few reports about surgical results of adult patients with FSV. This study retrospectively reviews our experience with surgery in adult patients with FSV.

METHODS

From January 2008 to September 2017, 65 adult patients with FSV underwent surgery in our hospital. Twenty underwent Blalock-Taussig shunt or bidirectional Glenn procedures in other hospitals prior, and four were lost to follow-up. Finally, 41 patients were included in this study.

RESULTS

The early postoperative mortality was 7.3% (3/41). Postoperative systemic arterial oxygen saturation (SpO₂ , 83.7% ± 4.8%) was significantly higher than preoperative SpO₂ (77.9% ± 10.1%, P < .01). The mean follow-up time was 3.9 ± 3.1 years (range 1-11 years). There was only one case of late mortality and massive hemoptysis was the cause of death. Right ventricular morphology and severe atrioventricular valve regurgitation (AVVR) were the risk factors of postoperative death for patients with pulmonary stenosis(PS). There was no death case in patients who received Fontan procedure. In a follow-up, we found the grade of AVVR was reduced and the grade of heart function (New York Heart Association) was improved.

CONCLUSIONS

Adult patients with FSV can also undergo surgery. The mortality was acceptable and late results were satisfactory. After surgery, oxygen saturations increased, grades of AVVR decreased and the heart functions improved. Right ventricular morphology and severe AVVR were risk factors for patients with PS.

Younger age remains a risk factor for prolonged length of stay after bidirectional cavopulmonary anastomosis

OBJECTIVE

This study sets out to determine the influence of age at the time of surgery as a risk factor for post-operative length of stay after bidirectional cavopulmonary anastomosis.

METHODS

All patients undergoing a Glenn procedure between January 2010 and July 2015 were included in this retrospective cohort study. Demographic data were examined. Standard descriptive statistics was used. A univariable analysis was conducted using the appropriate test based on data distribution. A propensity score for balancing the group difference was included in the multi-variable analysis, which was then completed using predictors from the univariable analysis that achieved significance of p&lt;0.1.

RESULTS

Over the study period, 50 patients met the inclusion criteria. Patients were separated into two cohorts of ⩾4 months (28 patients) and &lt;4 months (22 patients). Other than height and weight, the two cohorts were indistinguishable in their pre-operative saturation, medications, catheterisation haemodynamics, atrioventricular valve regurgitation, and ventricular function. After adjusting group differences, younger age was associated with longer post-operative length of hospitalisation - adjusted mean 15 (±2.53) versus 8 (±2.15) days (p=0.03). In a multi-variable regression analysis, in addition to ventricular dysfunction (β coefficient=8.8, p=0.05), Glenn procedures performed before 4 months were independently associated with longer length of stay (β coefficient=-6.9, p=0.03).

CONCLUSION

We found that Glenn procedures performed after 4 months of age had shorter post-operative length of stay when compared to a younger cohort. These findings suggest that balancing timing of surgery to decrease the inter-stage period should take into consideration differences in post-operative recovery with earlier operations.

Impact of age at bidirectional cavopulmonary anastomosis on haemodynamics after Fontan operation

BackgroundsThe aim of this study was to assess the impact of age at bidirectional cavopulmonary anastomosis on haemodynamics after total cavopulmonary connection.

METHODS

We conducted a retrospective analysis of 100 consecutive patients who underwent total cavopulmonary connection from 2010 to 2014. All patients had previously undergone bidirectional cavopulmonary anastomosis. These patients were classified into two groups according to age at bidirectional cavopulmonary anastomosis: younger group, 6 months (n=67).

RESULTS

The proportion of hypoplastic left heart syndrome was higher in the younger group (48 versus 4%). After total cavopulmonary connection, the chest tube period was longer in the younger group (10.1±6.6 versus 6.7±4.5 days; p=0.009). Catheterisation 6 months after total cavopulmonary connection revealed that pulmonary artery pressure was higher (11.5±1.9 versus 10.4±2.1 mmHg; p=0.017) and Nakata index was lower (219±79 versus 256±70 mm2/m2; p=0.024) in the younger group. In patients with a non-hypoplastic left heart syndrome, there was no difference in post-operative haemodynamics between two groups, but the total amount of chest drainage after total cavopulmonary connection was larger in the younger group (109±95 versus 55±40 ml/kg; p=0.044).

CONCLUSIONS

Early bidirectional cavopulmonary anastomosis did not affect the outcome of total cavopulmonary connection. Longer chest tube period, smaller pulmonary artery, and higher pulmonary artery pressure after total cavopulmonary connection were recognised in early bidirectional cavopulmonary anastomosis patients, especially in hypoplastic left heart syndrome.

Numerical Investigation of the Effect of Additional Pulmonary Blood Flow on Patient-Specific Bilateral Bidirectional Glenn Hemodynamics

The effect of additional pulmonary blood flow (APBF) on the hemodynamics of bilateral bidirectional Glenn (BBDG) connection was marginally discussed in previous studies. This study assessed this effect using patient-specific numerical simulation. A 15-year-old female patient who underwent BBDG was enrolled in this study. Patient-specific anatomy, flow waveforms, and pressure tracings were obtained using computed tomography, Doppler ultrasound technology, and catheterization, respectively. Computational fluid dynamic simulations were performed to assess flow field and derived hemodynamic metrics of the BBDG connection with various APBF. APBF showed noticeable effects on the hemodynamics of the BBDG connection. It suppressed flow mixing in the connection, which resulted in a more antegrade flow structure. Also, as the APBF rate increases, both power loss and reflux in superior venae cavae (SVCs) monotonically increases while the flow ratio of the right to the left pulmonary artery (RPA/LPA) monotonically decreases. However, a non-monotonic relationship was observed between the APBF rate and indexed power loss. A high APBF rate may result in a good flow ratio of RPA/LPA but with the side effect of bad power loss and remarkable reflux in SVCs, and vice versa. A moderate APBF rate could be favourable because it leads to an optimal indexed power loss and achieves the acceptable flow ratio of RPA/LPA without causing severe power loss and reflux in SVCs. These findings suggest that patient-specific numerical simulation should be used to assist clinicians in determining an appropriate APBF rate based on desired outcomes on a patient-specific basis.

Energetic performance analysis of staged palliative surgery in tricuspid atresia using vector flow mapping

Background

Staged palliative surgery markedly shifts the balance of volume load on a single ventricle and pulmonary vascular bed. Blalock-Taussig shunt necessitates a single ventricle eject blood to both the systemic and pulmonary circulation. On the contrary, bidirectional cavopulmonary shunt release the single ventricle from pulmonary circulation.

Case presentation

We report a case of tricuspid atresia patient who underwent first palliative surgery and second palliative surgery. Volume loading condition was assessed by energetic parameters (energy loss, kinetic energy) intraoperatively using vector flow mapping. These energetic parameters can simply indicate the volume loading condition.

Conclusion

Vector flow mapping was useful tool for monitoring volume loading condition in congenital heart disease surgery.

Electronic supplementary material

The online version of this article (10.1186/s12947-017-0118-3) contains supplementary material, which is available to authorized users.

Optimal Transducer Level for Atrial and Pulmonary Arterial Pressure Measurement in Patients with Functional Single Ventricle

This study aimed to investigate the optimal transducer level for accurate measurement of atrial and pulmonary arterial pressures in the supine position for patients with functional single ventricle. Contrast-enhanced chest computed tomographic images of 108 patients who underwent either the bidirectional cavopulmonary shunt (BCPS) placement or the Fontan procedure were reviewed. Vertical distances from the skin of the back to the uppermost levels of fluid in the single atrium or the pulmonary artery confluence and their ratios to the greatest anteroposterior (AP) diameter of the thoracic cage were determined. In patients who underwent BCPS, the ratios of the uppermost levels of blood in the atrium and pulmonary artery confluence to the greatest AP diameter of the thorax were 76.0 ± 8.1 and 56.3 ± 5.5 %, respectively. The distance (mm) between these two levels was calculated as 24.2 + 0.31 × age (years) (r ² = 0.08, P < 0.03). In patients who underwent the Fontan procedure, the ratios were 79.3 ± 10.0 and 58.3 ± 5.8 %, respectively. The distance (mm) between these two levels was calculated as 31.1 + 0.44 × age (years) (r ² = 0.05, P < 0.11). The optimal transducer levels for measuring atrial and pulmonary arterial pressures in the supine position are 75-80 and 55-60 % of the AP diameter of the thorax, respectively, in patients with functional single ventricle. We should consider the difference of the pressure when atrial and pulmonary arterial pressures were measured with the same level of transducers.

Current outcomes of the bi-directional cavopulmonary anastomosis in single ventricle patients: analysis of risk factors for morbidity and mortality, and suitability for Fontan completion

OBJECTIVES

The bi-directional cavopulmonary anastomosis forms an essential staging procedure for univentricular hearts. This review aims to identify risk factors for morbidity, mortality, and suitability for Fontan completion.

METHODS

A total of 114 patients undergoing cavopulmonary anastomosis between 1992 and 2012 were reviewed to assess primary - mortality and survival to Fontan completion - and secondary outcome endpoints - re-intubation, new drain, and ICU stay. Median age and weight were 8 months and 6.9 kg, respectively. In 83% of patients, 1-3 interventions had preceded. Norwood-type procedures became more prevalent over time.

RESULTS

Extubation occurred after a median of 4 hours, median ICU stay was 2 days; 10 patients (8.8%) needed re-intubation and 18 received a new drain. Higher central venous pressure and transpulmonary gradient were risk factors for new drain insertion (p<0.01). Higher pre-operative pulmonary pressure correlated with increased inotropic support and prolonged intubation (p=0.01). Need for re-intubation was significantly affected by younger age at operation (p=0.01). Hospital and pre-Fontan mortality were 11.4 and 5.3%, respectively. Operative mortality was independently affected by younger age (p=0.013), lower weight (p=0.02), longer bypass time (p=0.04), and re-intubation (p=0.004). Interstage mortality was mainly influenced by moderate ventricular function (p=0.03); 82% of survivors underwent or are candidates for Fontan completion.

CONCLUSION

The cavopulmonary anastomosis remains associated with adverse outcomes. Age at operation decreases with rising prevalence of complex univentricular hearts. Considering the important impact of re-intubation on hospital mortality, peri-operative management should focus on optimising cardio-respiratory status. Once this selection step is taken, successful Fontan completion can be expected, provided that ventricular function is maintained.

Increased systemic cardiac output improves arterial oxygen saturation in bidirectional cavopulmonary shunt

The low arterial oxygen saturation (SaO2) after bidirectional cavopulmonary shunt (BCPS) predicts poor prognosis. The venous oxygen saturation of inferior vena cava (SivcO2), as well as the pulmonary blood flow/systemic blood flow ratio (Q p/Q s) affects the SaO2. The purpose of this study is to determine whether SivcO2 or Q p/Q s should be increased to achieve better outcomes after BCPS. Forty-eight patients undergoing BCPS were included. Data of patients' age and body weight, SivcO2, Q p/Q s, pulmonary artery (PA) pressure and resistance, PA area index, morphology of ventricle, atrioventricular valve regurgitation, and history of PA plasty were collected. Stepwise multiple logistic regression analyses were used to investigate which of the factors most affected the SaO2 after BCPS. There was a significant correlation between SivcO2 and SaO2 (r = 0.771, P < 0.00001). There was no strong correlation between Q p/Q s and SaO2 (r = 0.358, P < 0.05). Stepwise multiple logistic regression analyses revealed that both SivcO2 (r = 0.49, 95 % confidence interval (CI) 0.37-0.62, P < 0.0001) and Q p/Q s (r = 11.1, 95 % CI 3.3-18.9, P = 0.007) most affected SaO2 after BCPS. Since the SivcO2 has a stronger correlation than Q p/Q s with SaO2, despite the fact that both raising Q p/Q s and raising cardiac output can increase SaO2, raising cardiac output should be considered prior to Q p/Q s to raise the SaO2 after BCPS.

Risk factors for prolonged length of stay after the stage 2 procedure in the single-ventricle reconstruction trial

BACKGROUND

The single-ventricle reconstruction trial randomized patients with single right ventricle lesions to a modified Blalock-Taussig or right ventricle-to-pulmonary artery shunt at the Norwood. This analysis describes outcomes at the stage 2 procedure and factors associated with a longer hospital length of stay (LOS).

METHODS

We examined the association of shunt type with stage 2 hospital outcomes. Cox regression and bootstrapping were used to evaluate risk factors for longer LOS. We also examined characteristics associated with in-hospital death.

RESULTS

There were 393 subjects in the analytic cohort. Median stage 2 procedure hospital LOS (8 days; interquartile range [IQR], 6-14 days), hospital mortality (4.3%), transplantation (0.8%), median ventilator time (2 days; IQR, 1-3 days), median intensive care unit LOS (4 days; IQR, 3-7 days), number of additional cardiac procedures or complications, and serious adverse events did not differ by shunt type. Longer LOS was associated (R(2) = 0.26) with center, longer post-Norwood LOS (hazard ratio [HR], 1.93 per log day; P < .001), nonelective timing of the stage 2 procedure (HR, 1.78; P < .001), and pulmonary artery (PA) stenosis (HR, 1.56; P < .001). By univariate analysis, nonelective stage 2 (65% vs 32%; P = .009), moderate or greater atrioventricular valve (AVV) regurgitation (75% vs 24%; P < .001), and AVV repair (53% vs 9%; P < .001) were among the risk factors associated with in-hospital death.

CONCLUSIONS

Norwood LOS, PA stenoses, and nonelective stage 2 procedure, but not shunt type, are independently associated with longer LOS. Nonelective stage 2 procedure, moderate or greater AVV regurgitation, and need for AVV repair are among the risk factors for death.

Postoperative arrhythmia in patients with bidirectional cavopulmonary anastomosis

OBJECTIVES

Bidirectional cavopulmonary anastomosis (BDCPA) is part of the staged Fontan palliation for congenital heart defects with single-ventricle morphology. The aim of this study was to describe incidence and characteristics of early postoperative arrhythmias in patients undergoing BDCPA.

METHODS

Retrospective analysis of 60 patients undergoing BDCPA at the age of <12 months from 2001 to 2008 at a single centre. Arrhythmias were subclassified in sinus bradycardia, premature atrial/ventricular contraction, supraventricular tachycardia and atrioventricular block. The groups were compared according to age at operation and diagnosis. Postoperative follow-up data were included until Fontan completion.

RESULTS

Postoperative arrhythmia was observed in 20 patients: 12 temporary and 8 persisting until hospital discharge. Sinus bradycardia is a common postoperative arrhythmia and occurred in 16 patients (9 transient, 7 persistent until hospital discharge). One patient undergoing BDCPA and a Damus-Kaye-Stansel procedure had a persisting first-degree atrioventricular block. The occurrence of a postoperative arrhythmia was independent of age and diagnostic group (hypoplastic left heart vs non-hypoplasic left heart). After hospital discharge, five of the eight arrhythmia resolved spontaneously resulting in 2 patients with sinus bradycardia and 1 patient with a first-degree AV block immediately before the Fontan completion was undertaken.

CONCLUSIONS

Postoperative arrhythmias in patients with BDCPA occur early after surgery and are temporary. Severe and life-threatening arrhythmias are rare although the interventions are complex and the patients very young. The most common arrhythmia is sinus bradycardia.

Outcomes of infants undergoing superior cavopulmonary connection in the presence of ventricular dysfunction

Outcomes in patients with ventricular dysfunction undergoing superior cavopulmonary connection (SCPC) are not well known. We reviewed records of patients undergoing SCPC at our center from December 2005 to October 2009 and studied those whose pre-SCPC echocardiograms demonstrated at least moderate systemic ventricular dysfunction. Of the 213 patients undergoing SCPC, 19 (9%) met inclusion criteria. Diagnoses were hypoplastic left heart syndrome (n = 18) and rightward unbalanced atrioventricular canal with pulmonary stenosis (n = 1). In those surviving >2 months after SCPC, ventricular function was assessed by echocardiography 4.9 (range 3.5 to 9.7) months after SCPC and was improved in ten of 17 (59%), unchanged in six of 17 (35%), and worsened in one of 17 (16%) patients. After SCPC, three patients died, and one underwent heart transplant 21.9 months after SCPC. Transplant-free survival was attained by 15 of 19 (79%) patients during follow-up of 33.0 months (range 10.8 to 51.4). Fontan completion was performed on six survivors on reaching an appropriate age. Ventricular dysfunction before SCPC is not uncommon and occurs primarily in patients with a morphologic right ventricle. Ventricular performance improves in the majority of patients after SCPC, and midterm outcomes are comparable with previous reports, suggesting that these patients remain candidates for staged palliation.

Extracardiac Fontan Operation after Late Bidirectional Glenn Shunt

The outcomes of 33 consecutive extracardiac Fontan operations performed between 1999 and 2008 in patients who mostly had initial Glenn shunts beyond infancy were reviewed. Preoperatively, the median oxygen saturation was 76.2% and mean pulmonary artery pressure was 10.5 mm Hg. The median age was 4.1 years at Glenn shunt procedure and 10 years at Fontan operation. The duration of chest tube drainage was longer in these patients than in series where Glenn shunts were created at a younger age. All patients received warfarin for 1 year, then warfarin and/or aspirin. At follow-up (median, 14 months), there was no significant ventricular dysfunction. Median oxygen saturation at the last follow-up was 92%. All patients in sinus rhythm preoperatively continued in this status. There was no Fontan failure or mortality. All patients were in New York Heart Association class I or II, although objective cardiopulmonary exercise evaluation in 8 patients showed impaired exercise tolerance. Despite a trend towards prolonged pleural effusion, there was no adverse outcome in the short or intermediate term. Long-term follow-up is required to see whether delayed creation of a Glenn shunt is associated with late disadvantages.

Bidirectional cavopulmonary shunt with additional pulmonary blood flow

There are some controversies regarding the usefulness of leaving additional pulmonary blood flow when establishing a bidirectional cavopulmonary shunt. From April 2002 to September 2008, 13 patients (mean age, 24 +/- 16 months) underwent a bidirectional cavopulmonary shunt procedure with fine adjustment of additional pulmonary blood flow, as an intermediate step before the Fontan operation. There were no hospital deaths. Modified Blalock-Taussig shunts were left during the bidirectional cavopulmonary shunt operation in 7 patients, and pulmonary bands were tightened in 4. The main pulmonary artery with a previous pulmonary band was left open in one case. Oxygen saturation increased from 74.5% +/- 7.4% to 84.6% +/- 1.9% after the operation, cardiothoracic ratio decreased from 55.9% +/- 6.1% to 53.2% +/- 3.4%, Left ventricular end-diastolic pressure decreased from 11.0 +/- 2.6 to 7.8 +/- 3.0 mm Hg, and mean pulmonary arterial pressure from 14.7 +/- 7.5 to 10.2 +/- 3.1 mm Hg. Pulmonary artery index did not change significantly. In our experience, additional pulmonary blood flow with adjustment in each patient at the time of shunt construction was an excellent temporary palliation prior to the Fontan operation.

Preoperative pulmonary hemodynamics and assessment of operability: is there a pulmonary vascular resistance that precludes cardiac operation?

Preoperative pulmonary vascular disease remains an important risk factor for death or right-heart failure in selected children undergoing two-ventricle repair, single-ventricle palliation, or heart transplantation. Preoperative criteria for poor outcome after operation remain unclear. The purpose of this review is to critically assess both the historic and current data and make recommendations where appropriate. An extensive literature search was undertaken in October 2009. Data were analyzed by an expert multidisciplinary team and recommendations were made by consensus. PubMed was searched in October 2009. Data were analyzed and recommendations were made by consensus of a multidisciplinary team. In patients with suspected pulmonary vascular disease anticipating a two-ventricle repair, although preoperative testing via cardiac catheterization with vasodilators is reasonable, the preoperative parameters and the precise values of these parameters that best correlate with early and late outcome remain unclear. Further investigation is warranted in selected populations, such as the growing group of children with congenital heart disease complicated by chronic lung disease of prematurity, and in the developing world where patients may be more likely to present late with advanced pulmonary vascular disease. In patients with a functional single ventricle, there is growing evidence that mean pulmonary artery pressure of >15 mm Hg may be associated with both early and late mortality after the Fontan operation. The relationship of preoperative pulmonary hemodynamics to early and late morbidity remains to be defined. There most likely is a level of preoperative pulmonary vascular disease that puts an individual patient at increased risk for death or severe cyanosis after a bidirectional cavopulmonary anastomosis. It remains unclear, however, how to best assess this risk preoperatively. The limitations in obtaining an accurate assessment of pulmonary vascular disease in the complex single ventricle are discussed. In children awaiting cardiac transplantation with elevated pulmonary vascular disease of >6 U.m and/or transpulmonary gradient of >15 mm Hg, heart transplantation is deemed feasible in most transplant centers if the administration of inotropes or vasodilators can decrease the pulmonary vascular disease to <6 U.m or transpulmonary gradient to <15 mm Hg. In patients with preoperative pulmonary vascular disease, there may be contributing factors to the pulmonary vascular disease, such as the specifics of the cardiac lesion (atrioventricular valve regurgitation, low cardiac output), parenchymal and/or airway issues, and/or individual genetic predisposition. Amelioration of any reversible factors before operation and optimization of their management in the preoperative and postoperative period are recommended.

Outcomes of the bidirectional Glenn procedure in patients less than 3 months of age

OBJECTIVE

The bidirectional Glenn procedure is a well-established procedure performed as part of the single-ventricle palliation pathway. Numerous studies have highlighted the potential benefits of an "early" BDG procedure. The ideal age to perform the BDG procedure, however, remains uncertain. We report our experience with the BDG procedure in patients younger than 3 months.

METHODS

One hundred sixty-nine consecutive patients from 1998 to 2007 undergoing the BDG procedure were divided into 2 groups: younger than 3 months (n = 20) and older than 3 months. The groups were compared for 26 variables. All data were analyzed with Kaplan-Meier survival analysis and the Cox proportional hazard regression test to assess the probability of survival after the BDG procedure in both groups. A stepwise regression analysis was performed for identification of independent factors for postoperative oxygen saturation at hospital discharge.

RESULTS

The groups were comparable, with an equal distribution of patients with right-sided or left-sided single-ventricle anatomy. Although intensive care unit length of stay, ventilation time, and hospital length of stay were longer in the younger group, room air oxygen saturations at discharge, both early and late mortality, and time to the Fontan procedure were similar between groups. The independent variables found for death after the BDG procedure were preoperative mean pulmonary artery pressure, atrioventricular valve regurgitation, and postoperative oxygen saturations at hospital discharge. Survival in patients with hypoplastic left heart syndrome was comparable between groups after 5 years of follow-up.

CONCLUSION

The BDG procedure is feasible and safe in patients as young as 2 months of age, with early and late mortality equivalent to that seen in older patients.

Factors Influencing Survival in Patients after Bidirectional Glenn Shunt

Clinical characteristics, echocardiographic values, and catheterization data of 45 patients with a functional univentricular heart who had a bidirectional Glenn shunt instituted between November 1994 and October 2006 were retrospectively reviewed. Median age at operation was 20 months (range, 9 months to 19 years). Median follow-up time after the bidirectional Glenn operation was 4 years (range, 1 day to 11 years). The early mortality rate was 4/45 (8.9%); overall mortality was 24.4%. Actuarial survival after a bidirectional Glenn shunt was 73% ± 8% at 5 years and 55% ± 17% at 10 years. In multivariate Cox proportional hazards analysis, heterotaxy syndrome and systemic right ventricle were independent predictors of mortality after the bidirectional Glenn shunt. Age at operation, oxygen saturation, previous surgery, a pulsatile Glenn shunt, cardiopulmonary bypass, postoperative pulmonary artery pressure, bilateral superior venae cavae, and Nakata index were not predictive of mortality. The presence of heterotaxy syndrome and systemic right ventricle in patients with a functional univentricular heart should lead to aggressive investigation and management strategies.

Outcomes after bidirectional Glenn operation: Blalock-Taussig shunt versus right ventricle-to-pulmonary artery conduit

BACKGROUND

There are distinct physiologic differences between patients with single-ventricle lesions who have undergone the Norwood procedure with a right ventricle-to-pulmonary artery conduit (NW-RVPA) compared with those patients who have undergone the Norwood operation with a Blalock-Taussig shunt (NW-BTS). We evaluated bidirectional Glenn operation outcomes and compared the two groups to assess whether the type of Norwood operation influenced outcomes.

METHODS

A retrospective chart review compared bidirectional Glenn operation outcomes for children undergoing the Norwood operation with NW-RVPA or NW-BTS at Children's Hospital Boston from January 1, 2002, to December 31, 2003.

RESULTS

Of 80 patients undergoing the Norwood operation, 56 (NW-BTS, 27 versus NW-RVPA, 29) returned for the bidirectional Glenn operation at our institution. The NW-RVPA group had a lower median age at presentation for bidirectional Glenn (4.5 months versus 5.8 months; p = 0.01), but had better weight gain (20.6 g/day versus 16.5 g/day; p = 0.03) than the NW-BTS group. No interstage deaths occurred in the NW-RVPA group. There were no differences in morbidity or mortality after the BDG between the two groups.

CONCLUSIONS

There were no differences in morbidity and mortality outcomes after the bidirectional Glenn operation between the NW-RVPA and NW-BTS groups. Despite younger age at presentation, the NW-RVPA patients had better growth rate, which may have contributed to the similar postoperative outcomes.

New developments in the treatment of hypoplastic left heart syndrome

In the current decade, the prognosis of newborns with hypoplastic left heart syndrome, previously considered a uniformly fatal condition, has dramatically improved through refinement of rapidly evolving treatment strategies. These strategies include various modifications of staged surgical reconstruction, orthotopic heart transplantation, and hybrid palliation using ductal stenting and bilateral pulmonary artery banding. The variety of treatment approaches are based on different surgical philosophies, and each approach has its unique advantages and disadvantages. Nonetheless, multiple experienced centers have reported improved outcomes in each one of those modalities. The purpose of this review is to outline recent developments in the array of currently available management strategies for neonates with hypoplastic left heart syndrome. Because the vast majority of deaths in this patient population occur within the first months of life, the focus of the review will be evaluation of the impact of these management strategies on survival in the neonatal and infant periods.

Optimal timing of the second stage of palliation for hypoplastic left heart syndrome facilitated through home monitoring, and the results of early cavopulmonary anastomosis

For children with hypoplastic left heart syndrome, contemporary management over three stages includes a window of high risk for sudden death between the initial stage of palliation, the Norwood operation itself, and the second stage, creation of the bidirectional superior cavopulmonary connection. The risk is highest at a time when patients have been discharged from the hospital to grow and prepare for the second stage,1–4and has persisted despite the remarkable improvements in immediate postoperative and hospital survival after the initial surgery.5,6Potential contributing factors to the increased vulnerability to sudden death between the stages include the limited circulatory reserve inherent in the parallel circulations supported by a functionally univentricular heart, the reliance on a prosthetic shunt which is susceptible to thrombosis, and congenital or acquired anatomical cardiovascular abnormalities such as aortic atresia, residual obstruction in the aortic arch, tricuspid valvar insufficiency, or right ventricular dysfunction.7–12

Management of systemic venous anomalies in the pediatric cardiovascular surgical patient

Systemic venous anomalies are rare and heterogeneous entities. Although these anomalies are rare in the general population, they occur more frequently in the subpopulation with congenital heart disease. In and of themselves, most of these lesions have no physiologic significance. However, in the setting of congenital heart disease these lesions may significantly alter surgical treatment. This review is dedicated to these lesions.

Matching procedure to morphology improves outcomes in neonates with tricuspid atresia

OBJECTIVE

This study was undertaken to characterize morphologic substrate of tricuspid atresia with ventriculoarterial concordance and discriminate management strategies that lead to successful definitive repair.

METHODS

From 1999 to 2004, a total of 150 babies with type I tricuspid atresia were enrolled from first diagnosis at 26 institutions. Antegrade pulmonary blood flow was absent in 19%, restricted in 54%, and unrestricted in 28%. Competing-risk methodology determined the time-related prevalence and risk factors for death versus cavopulmonary anastomosis and subsequent death versus Fontan completion.

RESULTS

Overall 5-year survival was 86%. Initial palliation included systemic-pulmonary arterial shunt in 64%, pulmonary artery banding in 11%, and cavopulmonary anastomosis in 24%. Median age at cavopulmonary anastomosis was 6 months, with 83% undergoing bidirectional Glenn shunt and 17% undergoing hemi-Fontan procedure. By the age of 2 years, 89% had cavopulmonary anastomosis, 6% were dead, and 4% remained alive without cavopulmonary anastomosis. Risk factors for death without cavopulmonary anastomosis included presence of mitral regurgitation (P = .03) and palliation with systemic-pulmonary arterial shunts not originating from the innominate artery (P = .04). Factors associated with decreased transition rate to cavopulmonary connection included patient variables (younger admission age to a participating institution, noncardiac anomalies) and procedural variables (larger systemic-pulmonary arterial shunt diameter, previous palliation). Of patients undergoing cavopulmonary anastomosis, 75% had undergone a Fontan operation within 3 years.

CONCLUSION

Smaller shunt size and decreased pulmonary blood flow decrease mortality after initial palliation and increase the rate of successful transition to cavopulmonary anastomosis. Outcomes can be improved by placing smaller shunts from the innominate artery, especially in patients with any mitral regurgitation.

Does a bidirectional Glenn shunt improve the oxygenation of right ventricle–dependent coronary circulation in pulmonary atresia with intact ventricular septum?

OBJECTIVE

There is a risk of myocardial ischemia in patients with pulmonary atresia and intact ventricular septum associated with the right ventricle-dependent coronary circulation. In this patient group, the oxygen delivery to the myocardium depends on the oxygen saturation of the right ventricular cavity. We hypothesized that bidirectional Glenn shunt would improve the oxygenation of right ventricle-dependent coronary circulation relative to a systemic-pulmonary artery shunt. The reduction of systemic venous return to the right atrium due to a bidirectional Glenn shunt could increase the oxygen saturation of the right ventricle in the clinical setting, when the mixture of systemic and pulmonary venous blood is unchanged at the atrial level.

METHODS

Patients with right ventricle-dependent coronary circulation were defined as those with right ventricle-coronary artery fistulas plus stenoses of the right or left coronary arteries. For 7 patients with right ventricle-dependent coronary circulation before and after bidirectional Glenn shunt, cardiac catheterization was performed and the oxygen saturation of the right ventricular cavity was measured.

RESULTS

For all 7 patients, the bidirectional Glenn shunt was performed at a mean age of 18 months. Ischemic changes in the electrocardiogram before the bidirectional Glenn shunt improved after the procedure in 2 patients. The oxygen saturation of the right ventricular cavity before the bidirectional Glenn shunt was 54.6 +/- 8.8%, and that after the BGS significantly increased to 75.6% +/- 5.8% (P < .01). All 7 patients have subsequently undergone the Fontan procedure with excellent results.

CONCLUSION

Early bidirectional Glenn shunt could prevent progression of myocardial ischemia in pulmonary atresia with intact ventricular septum with right ventricle-dependent coronary circulation.

Brain versus lung: hierarchy of feedback loops in single-ventricle patients with superior cavopulmonary connection

BACKGROUND

CO2 vasodilates and O2 vasoconstricts the cerebral vascular bed; the opposite is true in the lungs. When the brain and lungs are connected exclusively in series, which feedback loop predominates is unknown. The circulation of the superior cavopulmonary connection (SCPC) provides a unique physiology to answer this question.

METHODS AND RESULTS

To determine cerebral and pulmonary blood flow and to establish the hierarchy of cerebral and pulmonary feedback mechanisms, 12 intubated, ventilated, single-ventricle patients in SCPC physiology (age 2.2+/-0.5 years) underwent magnetic resonance imaging velocity mapping of their jugular veins and aorta in room air, hypercarbia, and 100% O2. Flows in these vessels and arterial blood gases were measured. With 22+/-6 torr CO2 (Pco2) increased from 40 to 63 mm Hg, P<0.01), flow to the brain and lungs increased (1.5 to 2.7 L/min per m2, P=0.0003), Po2 improved (48 to 60 mm Hg, P=0.0004), and cardiac index increased (4.3 to 5.4 L/min per m2, P=0.0003). The increased cardiac index accounted for the increased cerebral and pulmonary blood flow (R=0.73, P=0.02) and cerebral O2 transport increased by 80% (P=0.0005) while preserving body O2 delivery. Hyperoxia did not change cerebral and pulmonary blood flow; Po2 increased 94% (P=0.01).

CONCLUSIONS

The cerebral CO2 feedback loop predominates over the pulmonary one when they directly compete with each other. CO2 has a major impact on flow distribution whereas O2 has little impact. Increased CO2 improves cerebral oxygenation in SCPC patients. This may provide a clue in determining neurological sequelae in SC physiology and may influence timing of Fontan completion.

Home monitoring of infants after stage one palliation for hypoplastic left heart syndrome

Despite improved early results with the Norwood procedure (stage one palliation), patients remain with at-risk anatomy and interstage mortality continues to be a limitation of staged single ventricle palliation. Retrospective analyses have implicated residual or recurrent anatomic lesions as well as intercurrent illness as causes of interstage mortality. We hypothesized that potentially life-threatening anatomic lesions and illnesses would be manifest before serious physiologic impact by alteration in arterial saturation, failure to gain weight or in the case of dehydration, acute weight loss. As a result, we developed a home monitoring program of daily weights and oxygen saturations to earlier identify those patients at increased risk for interstage death. Frequent monitoring of these physiologic variables between stage one and two palliation identified life-threatening anatomic lesions and illness and permitted timely intervention that ultimately improved survival. All 36 survivors of the stage one palliation discharged from the hospital and entered into the home monitoring program survived the interstage period.

Home surveillance program prevents interstage mortality after the Norwood procedure

OBJECTIVE

To determine whether early identification of physiologic variances associated with interstage death would reduce mortality, we developed a home surveillance program.

METHODS

Patients discharged before initiation of home surveillance (group A, n = 63) were compared with patients discharged with an infant scale and pulse oximeter (group B, n = 24). Parents maintained a daily log of weight and arterial oxygen saturation according to pulse oximetry and were instructed to contact their physician in case of an arterial oxygen saturation less than 70% according to pulse oximetry, an acute weight loss of more than 30 g in 24 hours, or failure to gain at least 20 g during a 3-day period.

RESULTS

Interstage mortality among infants surviving to discharge was 15.8% (n = 9/57) in group A and 0% (n = 0/24) in group B (P =.039). Surveillance criteria were breached for 13 of 24 group B patients: 12 patients with decreased arterial oxygen saturation according to pulse oximetry with or without poor weight gain and 1 patient with poor weight gain alone. These 13 patients underwent bidirectional superior cavopulmonary connection (stage 2 palliation) at an earlier age, 3.7 +/- 1.1 months of age versus 5.2 +/- 2.0 months for patients with an uncomplicated interstage course (P =.028). A growth curve was generated and showed reduced growth velocity between 4 and 5 months of age, with a plateau in growth beyond 5 months of age.

CONCLUSION

Daily home surveillance of arterial oxygen saturation according to pulse oximetry and weight selected patients at increased risk of interstage death, permitting timely intervention, primarily with early stage 2 palliation, and was associated with improved interstage survival. Diminished growth identified 4 to 5 months after the Norwood procedure brings into question the value of delaying stage 2 palliation beyond 5 months of age.

Hypoventilation improves oxygenation after bidirectional superior cavopulmonary connection

OBJECTIVE

Bidirectional superior cavopulmonary connection may be complicated by systemic hypoxemia. Previous work has shown that hyperventilation worsens systemic oxygenation in patients after bidirectional superior cavopulmonary connection. The likely mechanism is that hyperventilation-induced hypocarbia decreases cerebral, superior vena caval, and pulmonary blood flow. The aim of the current study was to determine whether the converse approach, hypoventilation, improves oxygenation after bidirectional superior cavopulmonary connection.

METHODS

This is a prospective, patient-controlled study of 15 patients (median age 8.0 months, range 4.7-15.5) who underwent bidirectional superior cavopulmonary connection. Patients were studied in the intensive care unit, within 8 hours of surgery, while sedated, paralyzed, and mechanically ventilated. To avoid acidosis during hypoventilation, sodium bicarbonate was administered before hypoventilation. Cerebral blood flow velocity was measured by transcranial Doppler sonography of the middle cerebral artery.

RESULTS

Hypoventilation following administration of sodium bicarbonate (pH-buffered hypoventilation) produced hypercarbia (mean Pco(2) = 58 mm Hg versus 42 mm Hg at baseline). During hypoventilation, there were significant increases in both mean arterial Po(2) (from 50 mm Hg at baseline to 61 mm Hg; P <.05) and mean systemic oxygen saturation (from 86% at baseline to 90%; P <.05). These increases occurred despite accompanying, small increases in pulmonary artery pressure and transpulmonary gradient. Hypoventilation also produced an increase in mean cerebral blood flow velocity (from 37 cm/s at baseline to 55 cm/s; P <.05) and a decrease in the arteriovenous oxygen saturation difference across the upper body (from 33% at baseline to 23%; P <.05), consistent with increased cerebral blood flow.

CONCLUSIONS

This study demonstrates that hypoventilation improves systemic oxygenation in patients after bidirectional superior cavopulmonary connection. The likely mechanism for this effect is that hypoventilation-induced hypercarbia decreases cerebral vascular resistance, thus increasing cerebral, superior vena caval, and pulmonary blood flow. Hypoventilation may be a useful clinical strategy in patients who are hypoxemic in the early postoperative period after bidirectional superior cavopulmonary connection.

Single-ventricle physiology

The patient with single-ventricle physiology presents a significant challenge to the intensive care team at all stages of management. An integrated approach that applies a working knowledge of cardiac anatomy, cardiopulmonary physiology, and the basic principles of intensive care is essential to guide management for each individual patient. This management requires cooperative and constructive involvement of surgeons, cardiologists, and intensivists, as well as a nursing and respiratory care team experienced in the management of single-ventricle patients. The outcome of each stage of palliation for single-ventricle lesions should continue to improve as new ideas are developed and as older ideas are subjected to rigorous scientific analyses.

Same patient, different advice: a study into why doctors vary

AIM

To understand why doctors differ in their recommendations in situations where there is little certainty about the long term outcomes of the possible treatment options.

METHODS

A correlational design was used to examine the relation between preference for different treatment options and beliefs about likely outcomes for these options. Eighty doctors, with a mean of nine years in paediatric cardiology/surgery, attending a conference on serious congenital heart disease were studied. Main outcome measures were: ratings of the extent to which each of four treatment options were favoured; and subjective probabilities for three outcomes-death, survival with "good heart function" (New York Heart Association functional class (NYHA) I or II), and survival with "poor heart function" (NYHA III or IV)-for different treatment options over a 20 year time frame.

RESULTS

Preference for one treatment option over another was most closely associated with the subjective estimate of the additional years with "good heart function" that it offered 10-20 years after surgery (Pearson's r = 0.66, p < 0.001). In influencing a preference, the possibility of early death was subordinate to optimising the late outcome.

CONCLUSIONS

Doctors' treatment preferences are consistent with selecting the option that maximises the chance of the best outcome (long term survival with good heart function). Doctors' recommendations imply that they place more value on years of life in the child's far future than on life-years in the immediate future.

A combined stage 1 and 2 repair for hypoplastic left heart syndrome: anaesthetic considerations

Therapy of hypoplastic left heart syndrome (HLHS) consists of the staged Norwood procedure or cardiac transplantation. Stenting the ductus arteriosus and subsequent banding of the pulmonary arteries allows the combination of neoaortic reconstruction with the establishment of a bidirectional cavopulmonary connection (combined stage 1 and 2 procedure) in a later session. We report the anaesthetic management in eight infants ranging from 107 to 195 days undergoing a combined stage 1 and 2 procedure. Nonselective pulmonary vasodilators and nitric oxide were needed in all cases to improve oxygen saturation in the postbypass period. Phosphodiesterase inhibitors and epinephrine were required in all patients for inotropic support during and after weaning off cardiopulmonary bypass. The procedure was successful in seven patients. One patient died intraoperatively because of right heart failure. The physiological changes of this new surgical strategy for palliation of HLHS offers a challenge for the anaesthetist primarily in the early postbypass period.