Norwood Operation with Right Ventricular-Pulmonary Artery Shunt Versus Comprehensive Stage II After Bilateral Pulmonary Artery Banding Palliation

As a strategy for the primary Norwood operation, the right ventricular-pulmonary artery shunt is associated with satisfactory early outcome. However, use of this shunt after bilateral pulmonary artery banding remains controversial. This study compared the operative outcomes and late hemodynamics in patients who underwent the Norwood operation, preceded by bilateral pulmonary artery banding, with a right ventricular-pulmonary artery shunt or with bidirectional Glenn anastomosis (comprehensive stage II strategy). We retrospectively reviewed 38 patients who underwent the Norwood operation preceded by bilateral pulmonary artery banding between 2004 and 2017. Of these, 17 underwent the Norwood operation with a right ventricular-pulmonary artery shunt (Group S), whereas 21 underwent the comprehensive stage II strategy (Group G). 5 years after the Norwood operation, 10 (60%) and 17 (81%) patients in Group S and Group G, respectively, underwent the Fontan procedure. Group S showed significantly lower pressure in the superior vena cava after bidirectional Glenn anastomosis than Group G (13 ± 2 mmHg vs. 18 ± 3 mmHg; p < 0.01), but pressures were similar after the Fontan procedure. The right ventricular end-diastolic volume at 1 year post-Fontan procedure was significantly higher in Group S than in Group G (142 ± 41% vs. 91 ± 28%; p < 0.01). In terms of early outcomes, the Norwood operation with a right ventricular-pulmonary artery shunt enabled low pressure in the superior vena cava, but in the long term, this shunt adversely influenced the right ventricular volume.

Valved Sano conduit improves immediate outcomes following Norwood operation compared with nonvalved Sano conduit

OBJECTIVE

Use of a valved Sano during the Norwood procedure has been reported previously, but its impact on clinical outcomes needs to be further elucidated. We assessed the impact of the valved Sano compared with the nonvalved Sano after the Norwood procedure in patients with hypoplastic left heart syndrome.

METHODS

We retrospectively reviewed 25 consecutive neonates with hypoplastic left heart syndrome who underwent a Norwood procedure with a valved Sano conduit using a femoral venous homograft and 25 consecutive neonates with hypoplastic left heart syndrome who underwent a Norwood procedure with a nonvalved Sano conduit between 2013 and 2022. Primary outcomes were end-organ function postoperatively and ventricular function over time. Secondary outcomes were cardiac events, all-cause mortality, and Sano and pulmonary artery reinterventions at discharge, interstage, and pre-Glenn time points.

RESULTS

Postoperatively, the valved Sano group had significantly lower peak and postoperative day 1 lactate levels (P = .033 and P = .025, respectively), shorter time to diuresis (P = .043), and shorter time to enteral feeds (P = .038). The valved Sano group had significantly fewer pulmonary artery reinterventions until the Glenn operation (n = 1 vs 8; P = .044). The valved Sano group showed significant improvement in ventricular function from the immediate postoperative period to discharge (P < .001). From preoperative to pre-Glenn time points, analysis of ventricular function showed sustained ventricular function within the valved Sano group, but a significant reduction of ventricular function in the nonvalved Sano group (P = .003). Pre-Glenn echocardiograms showed competent conduit valves in two-thirds of the valved Sano group (n = 16; 67%).

CONCLUSIONS

The valved Sano is associated with improved multi-organ recovery postoperatively, better ventricular function recovery, and fewer pulmonary artery reinterventions until the Glenn procedure.

Increased utilization of the hybrid procedure is not associated with improved early survival for newborns with hypoplastic left heart syndrome: a single-centre experience

OBJECTIVES

The primary objectives were to examine utilization of the Hybrid versus the Norwood procedure for patients with hypoplastic left heart syndrome or variants and the impact on hospital mortality. The Hybrid procedure was 1st used at our institution in 2004.

METHODS

Review of all subjects undergoing the Norwood or Hybrid procedure between 1 January 1984 and 31 December 2022. The study period was divided into 8 eras: era 1, 1984-1988; era 2, 1989-1993; era 3, 1994-1998; era 4, 1999-2003; era 5, 2004-2008; era 6, 2009-2014; era 7, 2015-2018 and era 8, 2019-2022. The primary outcome was in-hospital mortality. Mortality rates were computed using standard binomial proportions with 95% confidence intervals. Rates across eras were compared using an ordered logistic regression model with and adjusted using the Tukey-Kramer post-hoc procedure for multiple comparisons. In the risk-modelling phase, logistic regression models were specified and tested.

RESULTS

The Norwood procedure was performed in 1899 subjects, and the Hybrid procedure in 82 subjects. Use of the Hybrid procedure increased in each subsequent era, reaching 30% of subjects in era 8. After adjustment for multiple risk factors, use of the Hybrid procedure was significantly and positively associated with hospital mortality.

CONCLUSIONS

Despite the increasing use of the Hybrid procedure, overall mortality for the entire cohort has plateaued. After adjustment for risk factors, use of the Hybrid procedure was significantly and positively associated with mortality compared to the Norwood procedure.

Inpatient Resource Utilization for Hypoplastic Left Heart Syndrome from Birth Through Fontan

Completing 3-stage palliation for hypoplastic left heart syndrome requires significant resources. An analysis of recent data has not been performed. We aimed to determine total charges necessary to complete all 3 stages of single-ventricle palliation, including interstage encounters. We also aimed to determine overall resource utilization, including hospital days, interstage admissions, and interstage procedures. We performed a retrospective cohort study using data from the Pediatric Health Information System database between 2016 and 2021, including all patients who completed 3-stage palliation for hypoplastic left heart syndrome. We identified 199 patients who underwent 3-stage palliation of hypoplastic left heart syndrome between 2016 and 2021. Median total adjusted charges (interquartile range, IQR) over the course of 3-stage palliation were $1,475,800 ($1,028,900-2,191,700). Median adjusted charges (IQR) for stage 1, 2, and 3 hospitalizations were $604,300 ($419,000-891,400), $234,000 ($164,300-370,800), and $256,260 ($178,300-345,900), respectively. Median hospital length of stay (IQR) for stages 1, 2, and 3 was 36 (26,53), 9 (6,17), and 10 (7,14) days, respectively. Pulmonary artery stenosis was the most common admitting diagnosis for interstage hospitalizations (3.4% of hospitalizations). Cardiac catheterization (24.1% of procedures) and feeding tube placement (10.0% of procedures) were the most common principal procedures during interstage hospitalizations. Total inpatient charges incurred throughout 3-stage palliation of hypoplastic left heart syndrome are substantial and have risen since prior studies. Gastrointestinal comorbidities and feeding optimization contribute considerably to this resource utilization.

Longitudinal analysis of systemic ventricular function and atrioventricular valve function after the Norwood procedure

OBJECTIVES

To evaluate longitudinal systemic ventricular function and atrioventricular valve regurgitation in patients after the neonatal Norwood procedure.

METHODS

Serial postoperative echocardiographic images before Fontan completion were assessed in neonates who underwent the Norwood procedure between 2001 and 2020. Ventricular function and atrioventricular valve regurgitation were compared between patients with modified Blalock-Taussig shunt and right ventricle to pulmonary artery conduit.

RESULTS

A total of 335 patients were identified including 273 hypoplastic left heart syndrome and 62 of its variants. Median age at Norwood was 8 (7-12) days. Modified Blalock-Taussig shunt was performed in 171 patients and the right ventricle to pulmonary artery conduit in 164 patients. Longitudinal ventricular function and atrioventricular valve regurgitation were evaluated using a total of 4352 echocardiograms. After the Norwood procedure, ventricular function was initially worse (1-30 days) but thereafter better (30 days to stage II) in the right ventricle to pulmonary artery conduit group (P < 0.001). After stage II, the ventricular function was inferior in the right ventricle to the pulmonary artery conduit group (P < 0.001). Atrioventricular valve regurgitation between the Norwood procedure and stage II was more frequent in the modified Blalock-Taussig shunt group (P < 0.001). After stage II, there was no significant difference in atrioventricular valve regurgitation between the groups (P = 0.171).

CONCLUSIONS

The effect of shunt type on haemodynamics after the Norwood procedure seems to vary according to the stage of palliation. After the Norwood, the modified Blalock-Taussig shunt is associated with poorer ventricular function and worse atrioventricular valve regurgitation compared to right ventricle to pulmonary artery conduit. Whereas, after stage II, modified Blalock-Taussig shunt is associated with better ventricular function and comparable atrioventricular valve regurgitation, compared to the right ventricle to pulmonary artery conduit.

Higher Cumulative Dose of Opioids and Other Sedatives are Associated with Extubation Failure in Norwood Patients

BACKGROUND

The primary purpose of this study is to evaluate the relationship between sedation usage and extubation failure, and to control for the effects of hemodynamic, oximetric indices, clinical characteristics, ventilatory settings pre- and post-extubation, and echocardiographic (echo) findings in neonates with hypoplastic left heart syndrome (HLHS) post-Norwood procedure.

METHODS

Single-center, retrospective analysis of Norwood patients during their first extubation post-surgery from January 2015 to July 2021. Extubation failure was defined as reintubation within 48 h of extubation. Demographics, clinical characteristics, ventilatory settings, echo findings (right ventricular function, tricuspid regurgitation), and cumulative dose of sedation medications before extubation were compared between patients with successful or failed extubation.

RESULTS

The analysis included 130 patients who underwent the Norwood procedure with 121 (93%) successful and 9 (7%) failed extubations. Univariate analyses showed that vocal cord anomaly (p = 0.05), lower end-tidal CO2 (p < 0.01), lower pulse-to-respiratory quotient (p = 0.02), and ketamine administration (p = 0.04) were associated with extubation failure. The use of opioids, benzodiazepines, dexmedetomidine, and ketamine are mutually correlated in this cohort. On multivariable analysis, the vocal cord anomaly (OR = 7.31, 95% CI 1.25-42.78, p = 0.027), pre-extubation end-tidal CO2 (OR = 0.80, 95% CI 0.65-0.97, p = 0.025), and higher cumulative dose of opioids (OR = 10.16, 95% CI 1.25-82.43, p = 0.030) were independently associated with extubation failure while also controlling for post-extubation respiratory support (CPAP/BiPAP/HFNC vs NC), intubation length, and echo results.

CONCLUSION

Higher cumulative opioid doses were associated with a greater incidence of extubation failure in infants post-Norwood procedure. Therefore, patients with higher cumulative doses of opioids should be more closely evaluated for extubation readiness in this population. Low end-tidal CO2 and low pulse-to-respiratory quotient were also associated with failed extubation. Consideration of the pulse-to-respiratory quotient in the extubation readiness assessment can be beneficial in the Norwood population.

From Surgical to Total Transcatheter Stage I Palliation: Exploring Evidence and Perspectives

Neonates with single ventricle physiology and ductal-dependent systemic circulation, such as those with hypoplastic left heart syndrome, undergo palliation in the first days of life. Over the past decades, variations on the traditional Stage 1 palliation, also known as Norwood operation, have emerged. These include the hybrid palliation and the total transcatheter approach. Here, we review the current evidence and data on different Stage 1 approaches, with a focus on their advantages, challenges, and future perspectives. Overall, although controversy remains regarding the superiority or inferiority of one approach to another, outcomes after the Norwood and the hybrid palliation have improved over time. However, both procedures still represent high-risk approaches that entail exposure to sternotomy, surgery, and potential cardiopulmonary bypass. The total transcatheter Stage 1 palliation spares patients the surgical and cardiopulmonary bypass insults and has proven to be an effective strategy to bridge even high-risk infants to a later palliative surgery, complete repair, or transplant. As the most recently proposed approach, data are still limited but promising. Future studies will be needed to better define the advantages, challenges, outcomes, and overall potential of this novel approach.

Safety and feasibility of adjunct autologous cord blood stem cell therapy during the Norwood heart operation

BACKGROUND

We conducted this phase I, open-label safety and feasibility trial of autologous cord blood (CB) stem cell (CBSC) therapy via a novel blood cardioplegia-based intracoronary infusion technique during the Norwood procedure in neonates with an antenatal diagnosis of hypoplastic left heart syndrome (HLHS). CBSC therapy may support early cardiac remodeling with enhancement of right ventricle (RV) function during the critical interstage period.

METHODS

Clinical grade CB mononucleated cells (CBMNCs) were processed to NetCord-FACT International Standards. To maximize yield, CBSCs were not isolated from CBMNCs. CBMNCs were stored at 4 °C (no cryopreservation) for use within 3 days and delivered after each cardioplegia dose (4 × 15 mL).

RESULTS

Of 16 patients with antenatal diagnosis, 13 were recruited; of these 13 patients, 3 were not treated due to placental abruption (n = 1) or conditions delaying the Norwood for >4 days (n = 2) and 10 received 644.9 ± 134 × 106 CBMNCs, representing 1.5 ± 1.1 × 106 (CD34+) CBSCs. Interstage mortality was 30% (n = 3; on days 7, 25, and 62). None of the 36 serious adverse events (53% linked to 3 deaths) were related to CBMNC therapy. Cardiac magnetic resonance imaging before stage 2 (n = 5) found an RV mass index comparable to that in an exact-matched historical cohort (n = 22), with a mean RV ejection fraction of 66.2 ± 4.5% and mean indexed stroke volume of 47.4 ± 6.2 mL/m2 versus 53.5 ± 11.6% and 37.2 ± 10.3 mL/m2, respectively. All 7 survivors completed stage 2 and are alive with normal RV function (6 with ≤mild and 1 with moderate tricuspid regurgitation).

CONCLUSIONS

This trial demonstrated that autologous CBMNCs delivered in large numbers without prior cryopreservation via a novel intracoronary infusion technique at cardioplegic arrest during Norwood palliation on days 2 to 3 of life is feasible and safe.

Utility of the NEONATE Score at an Institution that Routinely Performs the Hybrid Procedure for Hypoplastic Left Heart Syndrome

NEONATE score > 17 has been proposed as a risk factor for interstage mortality/cardiac transplant (IM/T) for patients with single ventricle physiology. Hybrid procedure is assigned 6 points, the highest possible score for that surgical variable. Most centers reserve the hybrid procedure for high-risk patients. Goal of this study was to evaluate the NEONATE score at a center that routinely performs the hybrid procedure. Retrospective chart review of patients undergoing the hybrid procedure was performed (2008-2021). Demographics and variables used for the NEONATE score were collected. Maximization of Youden's J Statistic used to determine cohort-specific optimal threshold for patients undergoing comprehensive Stage II procedure (H-CSII) versus those with IM/T (H-IM/T). Total of 120 patients met inclusion criteria (H-CSII = 105, H-IM/T = 15). Gestational age was median 39 weeks (IQR 38, 39) and birth weight was 3.18 kg (2.91, 3.57). No patient was discharged with opiates or required post-operative extracorporeal circulatory support. Optimal threshold, as selected by maximizing Youden's J Statistic, was 22. Score > 22 had a positive predictive value of 0.33 (95% CI 0.12-0.62), negative predictive values of 0.90 (95% CI 0.83-0.95), and accuracy of 0.83 (95% CI 0.75-0.90) for IM/T. At a center that routinely performs the hybrid procedure, value of > 22 had the highest accuracy. This suggests that the hybrid procedure is not necessarily intrinsically a risk-factor for IM/T, but rather patient selection for the hybrid procedure may play a larger role at centers that do not routinely perform this procedure.

Associations of Home Monitoring Data to Interventional Catheterization for Infants with Recurrent Coarctation of the Aorta and Hypoplastic Left Heart Syndrome

The post-Norwood interstage period for infants with hypoplastic left heart syndrome is a high-risk time with 10-20% of infants having a complication of recurrent coarctation of the aorta (RCoA). Many interstage programs utilize mobile applications allowing caregivers to submit home physiologic data and videos to the clinical team. This study aimed to investigate if caregiver-entered data resulted in earlier identification of patients requiring interventional catheterization for RCoA. Retrospective home monitoring data were extracted from five high-volume Children's High Acuity Monitoring Program®-affiliated centers (defined as contributing > 20 patients to the registry) between 2014 and 2021 after IRB approval. Demographics and caregiver-recorded data evaluated include weight, heart rate (HR), oxygen saturation (SpO2), video recordings, and 'red flag' concerns prior to interstage readmissions. 27% (44/161) of infants required interventional catheterization for RCoA. In the 7 days prior to readmission, associations with higher odds of RCoA included (mean bootstrap coefficient, [90% CI]) increased number of total recorded videos (1.65, [1.07-2.62]) and days of recorded video (1.62, [1.03-2.59]); increased number of total recorded weights (1.66, [1.09-2.70]) and days of weights (1.56, [1.02-2.44]); increasing mean SpO2 (1.55, [1.02-2.44]); and increased variation and range of HR (1.59, [1.04-2.51]) and (1.71, [1.10-2.80]), respectively. Interstage patients with RCoA had increased caregiver-entered home monitoring data including weight and video recordings, as well as changes in HR and SpO2trends. Identifying these items by home monitoring teams may be beneficial in clinical decision-making for evaluation of RCoA in this high-risk population.

The effect of clinical and haemodynamic variables on post-operative length of stay immediately upon admission after biventricular repair with Yasui operation following an earlier Norwood operation

BACKGROUND

There are a variety of approaches to biventricular repair in neonates and infants with adequately sized ventricles and left-sided obstruction in the presence of a ventricular septal defect. Those who undergo this in a staged manner initially undergo a Norwood procedure followed by a ventricular septal defect closure such that the neo-aorta is entirely committed to the left ventricle and placement of a right ventricular to pulmonary artery conduit (Yasui operation). This study aimed to determine clinical and haemodynamic factors upon paediatric cardiac ICU admission immediately after the two-stage Yasui operation that was associated with post-operative length of stay.

METHODS

This was a retrospective review of patients who underwent the Yasui procedure after the initial Norwood operation between 1 January 2011 and 31 December 2020. Patients with complete data on admission were identified and analysed using Bayesian regression analysis.

RESULTS

A total of 15 patients were included. The median age was 9.0 months and post-operative length of stay was 6days. Bayesian regression analysis demonstrated that age, weight, heart rate, mean arterial blood pressure, central venous pressure, pulse oximetry, cerebral near infrared spectroscopy, renal near infrared spectroscopy, pH, pCO2, ionised calcium, and serum lactate were all associated with post-operative length of stay.

CONCLUSION

Discrete clinical and haemodynamic factors upon paediatric cardiac ICU admission after staged Yasui completion are associated with post-operative length of stay. Clinical target ranges can be developed and seem consistent with the notion that greater systemic oxygen delivery is associated with lower post-operative length of stay.

Cardiac Magnetic Resonance Imaging to Determine Single Ventricle Function in a Pediatric Population is Feasible in a Large Trial Setting: Experience from the Single Ventricle Reconstruction Trial Longitudinal Follow up

The Single Ventricle Reconstruction (SVR) Trial was a randomized prospective trial designed to determine survival advantage of the modified Blalock-Taussig-Thomas shunt (BTTS) vs the right ventricle to pulmonary artery conduit (RVPAS) for patients with hypoplastic left heart syndrome. The primary aim of the long-term follow-up (SVRIII) was to determine the impact of shunt type on RV function. In this work, we describe the use of CMR in a large cohort follow up from the SVR Trial as a focused study of single ventricle function. The SVRIII protocol included short axis steady-state free precession imaging to assess single ventricle systolic function and flow quantification. There were 313 eligible SVRIII participants and 237 enrolled, ages ranging from 10 to 12.5 years. 177/237 (75%) participants underwent CMR. The most common reasons for not undergoing CMR exam were requirement for anesthesia (n = 14) or ICD/pacemaker (n = 11). A total of 168/177 (94%) CMR studies were diagnostic for RVEF. Median exam time was 54 [IQR 40-74] minutes, cine function exam time 20 [IQR 14-27] minutes, and flow quantification time 18 [IQR 12-25] minutes. There were 69/177 (39%) studies noted to have intra-thoracic artifacts, most common being susceptibility artifact from intra-thoracic metal. Not all artifacts resulted in non-diagnostic exams. These data describe the use and limitations of CMR for the assessment of cardiac function in a prospective trial setting in a grade-school-aged pediatric population with congenital heart disease. Many of the limitations are expected to decrease with the continued advancement of CMR technology.

Attributable mortality benefit of digoxin treatment in hypoplastic left heart syndrome after the Norwood operation: An instrumental variable-based analysis using data from the Pediatric Health Information Systems Database

BACKGROUND

Observational studies have demonstrated an association between the use of digoxin and reduced interstage mortality after Norwood operation for hypoplastic left heart syndrome (HLHS). Digoxin use has increased significantly but remains variable between different hospitals, independent of case-mix. Instrumental variable analyses have the potential to overcome unmeasured confounding, the major limitation of previous observational studies and to generate an estimate of the attributable benefit of treatment with digoxin.

METHODS

A cohort of neonates with HLHS born from January 1, 2007 to December 31, 2021 who underwent Norwood operation at Pediatric Health Information Systems Database hospitals and survived >14 days after operation were studied. Using hospital-specific, 6-month likelihood of administering digoxin as an instrumental variable, analyses adjusting for both unmeasured confounding (using the instrumental variable) and measured confounders with multivariable logistic regression were performed.

RESULTS

The study population included 5,148 subjects treated at 47 hospitals of which 63% were male and 46% non-Hispanic white. Of these, 44% (n = 2,184) were prescribed digoxin. Treatment with digoxin was associated with superior 1-year transplant-free survival in unadjusted analyses (85% vs 82%, P = .02). This survival benefit persisted in an instrumental-variable analysis (OR: 0.71, 95% CI: 0.54-0.94, P = .01), which can be converted to an absolute risk reduction of 5% (number needed to treat of 20).

CONCLUSIONS

In this observational study of patients with HLHS after Norwood using instrumental variable techniques, a significant benefit in 1-year transplant-free survival attributable to digoxin was demonstrated. In the absence of clinical trial data, this should encourage the use of digoxin in this vulnerable population.

Sustained Total All-Region Perfusion During the Norwood Operation and Postoperative Recovery

We developed a technique for the Norwood operation utilizing continuous perfusion of the head, heart, and lower body at mild hypothermia named Sustained Total All-Region (STAR) perfusion. We hypothesized that STAR perfusion would be associated with shorter operative times, decreased coagulopathy, and expedited post-operative recovery compared to standard perfusion techniques. Between 2012 and 2020, 80 infants underwent primary Norwood reconstruction at our institution. Outcomes for patients who received successful STAR perfusion (STAR, n = 37) were compared to those who received standard Norwood reconstruction utilizing regional cerebral perfusion only (SNR, n = 33), as well as to Norwood patients reported in the PC⁴ national database during the same timeframe (n = 1238). STAR perfusion was performed with cannulation of the innominate artery, descending aorta, and aortic root at 32-34°C. STAR patients had shorter median CPB time compared to SNR (171 vs 245 minutes, P < 0.0001), shorter operative time (331 vs 502 minutes, P < 0.0001), and decreased intraoperative pRBC transfusion (100 vs 270 mL, P < 0.0001). STAR patients had decreased vasoactive-inotropic score on ICU admission (6 vs 10.8, P = 0.0007) and decreased time to chest closure (2 vs 4.5 days, P = 0.0004). STAR patients had lower peak lactate (8.1 vs 9.9 mmol/L, P = 0.03) and more rapid lactate normalization (18.3 vs 27.0 hours, P = 0.003). In-hospital mortality in STAR patients was 2.7% vs 15.1% with SNR (P = 0.06) and 10.3% in the PC⁴ aggregate (P = 0.14). STAR perfusion is a novel approach to Norwood reconstruction associated with excellent survival, decreased transfusions, shorter operative time, and improved convalescence in the early post-operative period.

The pediatric heart network's study on long-term outcomes of children with HLHS and the impact of Norwood Shunt type in the single ventricle reconstruction trial cohort (SVRIII): Design and adaptations

BACKGROUND

The Single Ventricle Reconstruction (SVR) Trial was the first randomized clinical trial of a surgical approach for treatment of congenital heart disease. Infants with hypoplastic left heart syndrome (HLHS) and other single right ventricle (RV) anomalies were randomized to a modified Blalock Taussig Thomas shunt (mBTTS) or a right-ventricular-to-pulmonary-artery shunt (RVPAS) at the time of the Norwood procedure. The aim of the Long-term Outcomes of Children with HLHS and the Impact of Norwood Shunt Type (SVR III) study is to compare early adolescent outcomes including measures of cardiac function, transplant-free survival, and neurodevelopment, between those who received a mBTTS and those who received an RVPAS.

METHODS

Transplant-free survivors of the SVR cohort were enrolled at 10 to 15 years of age for multifaceted in-person evaluation of cardiac function (cardiac magnetic resonance [CMR], echocardiogram and exercise test) and neurodevelopmental evaluation. Right ventricular ejection fraction measured by CMR served as the primary outcome. Development of arrhythmias, protein losing enteropathy, and other comorbidities were assessed through annual medical history interview. Through the course of SVR III, protocol modifications to engage SVR trial participants were designed to enhance recruitment and retention.

CONCLUSIONS

Evaluation of long-term outcomes will provide important data to inform decisions about the shunt type placed at the Norwood operation and will improve the understanding of cardiovascular and neurodevelopmental outcomes for early adolescents with HLHS.

Ductal arch decoded: the use of its spatial fingerprint to design a Norwood type of patch

Reconstruction of the aortic arch for the Norwood procedure remains a focus of attention in terms of the management of the distal anastomosis [1,2], patch design and material [3,4], and fashioning the Damus-Kaye-Stansel itself [5]. The reconstructed aorta supplies the coronaries and the head and neck vessels and directs flow to the descending aorta. As the fetus develops, the right ventricle shunts to the aorta through the ductal arch, supporting a great percentage of the systemic and the placental circulation. We have developed a method of designing a Norwood patch by decoding the 3-dimensional geometry of the arterial duct and its arch.

Factors Associated with Inability to Discharge After Stage 1 Palliation for Single Ventricle Heart Disease: An Analysis of the National Pediatric Cardiology Quality Improvement Collaborative Database

Patient-level characteristics associated with survival for single ventricle heart disease following initial staged palliation have been described. However, the impact of peri-operative events on hospital discharge has not been examined. To characterize patient-level characteristics and peri-operative events that were associated with inability to be discharged after Stage 1 palliation (S1P). Analysis of the National Pediatric Cardiology Quality Improvement Collaborative Dataset including patients who underwent a S1P procedure between 2016 and 2019 (Norwood or Hybrid Stage 1 procedure). We examined patient-level characteristics and peri-operative events as possible predictors of inability to discharge after S1P. We constructed multivariate logistic regression models examining post-S1P discharge and in-hospital mortality, adjusting for covariates. 843 patients underwent a S1P and 717 (85%) patients were discharged home or remained inpatient until Stage 2 for social but not medical concerns. Moderate or greater pre-operative atrioventricular valve regurgitation (odds ratio (OR) 4.6, 95% confidence interval (CI) 1.8-12), presence of high-risk pre-operative adverse events (OR 1.5, 95%CI 1.0-2.3), peri-operative events: temporary dialysis (OR 5.4, 95%CI 1.5-18.9), cardiac catheterization or cardiac surgery (OR 2.9, 95%CI 1.8-4.6), sepsis (OR 2.7, 95%CI 1.2-6.2), junctional tachycardia (OR 2.6, 95%CI 1.0-6.3), necrotizing enterocolitis (OR 2.6, 95%CI 1.3-5.2), ECMO (OR 2.5, 95%CI 1.4-4.3), neurological injury (OR 2.1, 95%CI 1.1-4.1), and re-intubation (OR 1.8, 95%CI 1.1-2.9) were associated with inability to discharge after Stage 1. Cardiac anatomical factors, pre-operative adverse events, post-operative re-intubation, post-operative ECMO, infectious complications, and unplanned catheter or surgical re-interventions were associated with inability to discharge after S1P. These findings suggest that quality improvement efforts aimed at reducing these peri-operative events may improve Stage 1 survival and likelihood of discharge.

Relation of Norwood Shunt Type and Frequency of Arrhythmias at 6 Years (from the Single Ventricle Reconstruction Trial)

The Norwood procedure with a right ventricular to pulmonary artery shunt (RVPAS) decreases early mortality, but requires a ventriculotomy, possibly increasing risk of ventricular arrhythmias (VAs) compared with the modified Blalock-Taussig shunt (MBTS). The effect of shunt and Fontan type on arrhythmias by 6 years of age in the SVRII (Single Ventricle Reconstruction Extension Study) was assessed. SVRII data collected on 324 patients pre-/post-Fontan and annually at 2 to 6 years included antiarrhythmic medications, electrocardiography (ECG) at Fontan, and Holter/ECG at 6 years. ECGs and Holters were reviewed for morphology, intervals, atrioventricular conduction, and arrhythmias. Isolated VA were seen on 6-year Holter in >50% of both cohorts (MBTS 54% vs RVPAS 60%), whereas nonsustained ventricular tachycardia was rare and observed in RVPAS only (2.7%). First-degree atrioventricular block was more common in RVPAS than MBTS (21% vs 8%, p = 0.01), whereas right bundle branch block, QRS duration, and QTc were similar. Antiarrhythmic medication usage was common in both groups, but most agents also supported ventricular function (e.g., digoxin, carvedilol). Of the 7 patients with death or transplant between 2 and 6 years, none had documented VAs, but compared with transplant-free survivors, they had somewhat longer QRS (106 vs 93 ms, p = 0.05). Atrial tachyarrhythmias varied little between MBTS and RVPAS but did vary by Fontan type (lateral tunnel 41% vs extracardiac conduit 29%). VAs did not vary by Fontan type. In conclusion, at 6-year follow-up, benign VAs were common in the SVRII population. However, despite the potential for increased VAs and sudden death in the RVPAS cohort, these data do not support significant differences or increased risk at 6 years. The findings highlight the need for ongoing surveillance for arrhythmias in the SVR population.

[Early and long-term results after the Norwood procedure]

OBJECTIVE

To assess the early and long-term results after the Norwood procedure and to identify predictors of aortic recoarctation and arterial hypertension.

MATERIAL AND METHODS

We have operated on 2789 infants in the department of congenital heart diseases of the Meshalkin National Medical Research Center between January 2015 and December 2018. The current single-center prospective cohort study included 39 (1.4%) patients with hypoplastic left heart syndrome who underwent the Norwood procedure.

RESULTS

In-hospital mortality was 15.3% (n=6). An inter-stage mortality was 10.2% (n=4). Recoarctation of the aorta and Sano shunt stenosis in inter-stage period occurred in 8 (24.2%) and 4 patients (12.1%), respectively. Body mass <3 kg was the only risk factor of recoarctation (OR 7.08, 95% CI 1.17; 42.79, p=0.033). We found no risk factors of Sano shunt stenosis. There were no signs of recoarctation and Sano shunt dysfunction in the early postoperative period. Arterial hypertension developed in 14 (48.3%) patients. We found the correlation between systolic blood pressure and ventricular ejection fraction (β coefficient -0.88, 95% CI -1.33; -0.44, p=0.001). The only risk factor of arterial hypertension was increased stiffness of the aorta.

CONCLUSION

The early and inter-stage mortality are still the issues after the Norwood procedure. Postoperative reduced ejection fraction of single ventricle is one of the most common complications that could be related with residual arterial hypertension.

OUP accepted manuscript

Association between hypoplastic left heart syndrome and valvular pulmonary stenosis is very rare. Severity of valvular pulmonary stenosis in this setting limits management options. Consequently, patients with this condition are considered poor candidates for Norwood stage one reconstruction. Herein, we describe a newborn with hypoplastic left heart syndrome and significantly dysplastic pulmonary valve who successfully underwent the Norwood procedure with neoaortic valve reconstruction. Therefore, the Norwood procedure with neoaortic valve reconstruction might be an option for this difficult condition.

Cardiovascular Drug Therapy during Interstage After Hybrid Approach: A Single-Center Experience in 51 Newborns with Hypoplastic Left Heart

BACKGROUND

Newborns with hypoplastic left heart (HLH) are usually palliated with the Norwood procedure or a hybrid stage I procedure. Hybrid is our preferred approach. Given the critical relationship between stage I, interstage, and comprehensive stage II or advanced biventricular repair, we hypothesized that appropriate drug treatment is a significant therapeutic cornerstone, especially for the management of the high-risk interstage.

METHODS

We report a single-center observational study addressing the cardiovascular effects of, in particular, oral β-blockers and the additional use of angiotensin-converting enzyme (ACE) and mineralocorticoid inhibitors.

RESULTS

In total, 51 newborns-30 with HLH syndrome (HLHS) and 21 with HLH complex (HLHC)-with a median bodyweight of 3.0 kg (range 1.9-4.4; nine with bodyweight ≤ 2500 g) underwent an uneventful "Giessen hybrid approach" using a newly approved duct stent. All patients were discharged home with a single, double or triple therapy consisting of ß-blockers, ACE and mineralocorticoid inhibitors; 90% of the patients received bisoprolol, 10% received propranolol, 72% received lisinopril, and 78% received spironolactone. Resting heart rate decreased from 138 bpm (range 112-172; n = 51) at admission to 123 bpm (range 99-139; n = 51) at discharge and 110 bpm before stage II/biventricular repair/heart transplantation (range 90-140; n = 37) accompanied by favorable bodyweight gain. No side effects were evident.

CONCLUSION

In view of drug risk/benefit profiles, as well as the variable morphology and hemodynamics, the highly selective β1-adrenoceptor blocker bisoprolol is our preferred drug for treatment of HLHS/HLHC in the interstage. We avoid using ACE inhibitor monotherapy and exclude potential risks for coronary and cerebral perfusion pressure beforehand.

Incidence and Timing of Thrombosis After the Norwood Procedure in the Single-Ventricle Reconstruction Trial

Background Thrombosis is common in infants undergoing staged surgeries for single-ventricle congenital heart disease. The reported incidence and timing of thrombosis varies widely, making it difficult to understand the burden of thrombosis and develop approaches for prevention. We aimed to determine the timing and cumulative incidence of thrombosis following the stage I Norwood procedure and identify clinical characteristics associated with thrombosis. Methods and Results We analyzed data from the Pediatric Heart Network Single Ventricle Reconstruction trial from 2005 to 2009 and identified infants with first-time thrombotic events. In 549 infants, the cumulative incidence of thrombosis was 21.2% (n=57) from stage I through stage II. Most events occurred during stage I (n=35/57, 65%), with a median time to thrombosis of 15 days. We used a Cox proportional hazards model to estimate the association of clinical variables with thrombosis. After adjusting for baseline variables, boys had a higher hazard of thrombosis (adjusted hazard ratio [HR], 2.69; 95% CI, 1.44-5.05; P=0.002), non-hypoplastic left heart syndrome cardiac anatomy was associated with a higher early hazard of thrombosis (adjusted HR, 3.93; 95% CI, 1.89-8.17; P<0.001), and longer cardiopulmonary bypass time was also associated with thrombosis (per 10-minute increase, adjusted HR, 1.07; 95% CI, 1.01-1.12; P=0.02). Lower oxygen saturation after the Norwood procedure increased the hazard for thrombosis in the unadjusted model (HR, 1.08; 95% CI, 1.02-1.14; P=0.011). Conclusions Thrombosis affects 1 in 5 infants through Stage II discharge, with most events occurring during stage I. Male sex, non-hypoplastic left heart syndrome anatomy, longer cardiopulmonary bypass time, and lower stage I oxygen saturation were associated with thrombosis.

Interstage Home Monitoring for Infants With Single Ventricle Heart Disease: Education and Management: A Scientific Statement From the American Heart Association

This scientific statement summarizes the current state of knowledge related to interstage home monitoring for infants with shunt‐dependent single ventricle heart disease. Historically, the interstage period has been defined as the time of discharge from the initial palliative procedure to the time of second stage palliation. High mortality rates during the interstage period led to the implementation of in‐home surveillance strategies to detect physiologic changes that may precede hemodynamic decompensation in interstage infants with single ventricle heart disease. Adoption of interstage home monitoring practices has been associated with significantly improved morbidity and mortality. This statement will review in‐hospital readiness for discharge, caregiver support and education, healthcare teams and resources, surveillance strategies and practices, national quality improvement efforts, interstage outcomes, and future areas for research. The statement is directed toward pediatric cardiologists, primary care providers, subspecialists, advanced practice providers, nurses, and those caring for infants undergoing staged surgical palliation for single ventricle heart disease.

Cobra-Head Cuffed Vascular Graft as Right Ventricle-to-Pulmonary Artery Shunt in Norwood Procedure

BACKGROUND

Right ventricle-to-pulmonary artery (RV-PA) shunt as a part of the Norwood procedure underwent many modifications. We present our experience with a commercially available polytetrafluoroethylene vascular graft with cobra-head cuff as an RV-PA shunt.

METHODS

A consecutive series of 52 children with hypoplastic left heart syndrome (median age 8 [range, 2-68] days, median weight 3200 [range, 2060-4400] g) underwent the Norwood procedure with a cobra-head cuffed RV-PA shunt (6 mm). The cuffed end was used for the central PA reconstruction. A retrospective analysis of clinical results, PAs development, and shunt-related complications, interventions, and technique of Glenn operation was performed. The study endpoint was Glenn operation with shunt removal or interstage death.

RESULTS

The hospital and late interstage mortality was 3.8% (n = 2 of 52) and 4% (n = 2 of 50), respectively, and was not shunt-related. During mean follow of 3.7 ± 2.5 years, 48 (92.3%) children underwent Glenn operation at a median age of 6 (range, 2.6-9.1) months. Angiography before the second stage revealed satisfactory branch PAs development (maximum and minimum McGoon ratio of 1.95 ± 0.36 and 1.38 ± 0.38, respectively). The mean maximal diameter of the left PA was smaller than that of the right PA (7.13 ± 2.1 mm vs 8.42 ± 2.2 mm; P = .017), without differences in mean minimal diameter. Two infants required stent implantation in proximal shunt end and 1 required urgent Glenn operation because distal shunt thrombosis. During Glenn operation, 11 (22.9%) children required patch reconstruction of central PAs.

CONCLUSIONS

The cobra-head cuffed graft allowed easy and reproducible reconstruction of the central PA during the Norwood procedure. Using this technique, the development of PAs is satisfactory, the rate of shunt-related complications and interventions is low, and the second stage can be performed without patch material.

Deep Learning for Improved Risk Prediction in Surgical Outcomes

The Norwood surgical procedure restores functional systemic circulation in neonatal patients with single ventricle congenital heart defects, but this complex procedure carries a high mortality rate. In this study we address the need to provide an accurate patient specific risk prediction for one-year postoperative mortality or cardiac transplantation and prolonged length of hospital stay with the purpose of assisting clinicians and patients' families in the preoperative decision making process. Currently available risk prediction models either do not provide patient specific risk factors or only predict in-hospital mortality rates. We apply machine learning models to predict and calculate individual patient risk for mortality and prolonged length of stay using the Pediatric Heart Network Single Ventricle Reconstruction trial dataset. We applied a Markov Chain Monte-Carlo simulation method to impute missing data and then fed the selected variables to multiple machine learning models. The individual risk of mortality or cardiac transplantation calculation produced by our deep neural network model demonstrated 89 ± 4% accuracy and 0.95 ± 0.02 area under the receiver operating characteristic curve (AUROC). The C-statistics results for prediction of prolonged length of stay were 85 ± 3% accuracy and AUROC 0.94 ± 0.04. These predictive models and calculator may help to inform clinical and organizational decision making.

Impact of Hybrid Stage 1 Palliation for Hypoplastic Left Heart Syndrome: Histopathological Findings

The purpose of the study is to analyze the impact of hybrid stage 1 palliation on right ventricular myocardial pathology in hypoplastic left heart syndrome. Sufficient amount of right ventricular biopsies could be obtained from 16 of 32 patients who underwent Norwood operation between 2007 and 2013. Histopathological findings of right ventricle in patients who underwent primary Norwood operation (primary group, n = 5), patients with aortic atresia (HS1P AA group, n = 6) or aortic stenosis (HS1P AS group, n = 5) who underwent staged Norwood palliation following hybrid stage 1 palliation were compared. To eliminate the influence of right ventricular pressure afterload, right ventricular biopsies were obtained from patients with truncus arteriosus communis (TAC group, n = 6) at total correction. The percentage of myocardial fibrosis was significantly higher in both HS1P groups than in TAC group; moreover, it was significantly higher in HS1P AA group than in primary group. Capillary vascular density was significantly lower in all hypoplastic left heart syndrome groups than in TAC group. At the sub-endocardial layer, collagen type I/III ratios were higher in HS1P AA group than in other hypoplastic left heart syndrome groups. The proportions of N-cadherin immunolocalized to myocyte termini were lower in all hypoplastic left heart syndrome groups than in TAC group. Right ventricle in hypoplastic left heart syndrome showed more significant ischemic change and myocardial immaturity than that in truncus arteriosus communis. Hybrid stage 1 palliation for aortic atresia would be a risk factor for further right ventricular myocardial ischemia.

Evolution of Ventricular Energetics in the Different Stages of Palliation of Hypoplastic Left Heart Syndrome: A Retrospective Clinical Study

Hyperplastic left heart syndrome (HLHS) patients are palliated by creating a Fontan-type circulation passing from different surgical stages. The aim of this work is to describe the evolution of ventricular energetics parameters in HLHS patients during the different stages of palliation including the hybrid, the Norwood, the bidirectional Glenn (BDG), and the Fontan procedures. We conducted a retrospective clinical study enrolling all HLHS patients surgically treated with hybrid procedure and/or Norwood and/or BDG and/or Fontan operation from 2011 to 2016 collecting echocardiographic and hemodynamic data. Measured data were used to calculate energetic variables such as ventricular elastances, external and internal work, ventriculo-arterial coupling and cardiac mechanical efficiency. From 2010 to 2016, a total of 29 HLHS patients undergoing cardiac catheterization after hybrid (n = 7) or Norwood (n = 6) or Glenn (n = 8) or Fontan (n = 8) procedure were retrospectively enrolled. Ventricular volumes were significantly higher in the Norwood circulation than in the hybrid circulation (p = 0.03) with a progressive decrement from the first stage to the Fontan completion. Ventricular elastances were lower in the Norwood circulation than in the hybrid circulation and progressively increased passing from the first stage to the Fontan completion. The arterial elastance and Rtot increased in the Fontan circulation. The ventricular work progressively increased. Finally, the ventricular efficiency improves passing from the first to the last stage of palliation. The use of ventricular energetic parameters could lead to a more complete evaluation of such complex patients to better understand their adaptation to different pathophysiological conditions.

Effect of acid-base balance on postoperative course in children with hypoplastic left heart syndrome after the modified Norwood procedure

Hypoplastic left heart syndrome (HLHS) is a congenital heart defect that requires 3-stage cardiac surgical treatment and multidirectional specialist care. The condition of newborns in the first postoperative days following the modified Norwood procedure is characterized by considerable hemodynamic instability that may result in a sudden cardiac arrest. It is believed that the most important cause of hemodynamic instability is the fluctuations in redistribution between pulmonary and systemic blood flow.The paper analyzes the postoperative course in 40 neonates with HLHS following the modified Norwood procedure performed under deep hypothermic cardiopulmonary bypass hospitalized in Cardiac Surgical Intensive Care Unit (CSICU) in the years 2014-2015. For all hospitalized children, the arterial blood acid-base balance (ABB) parameters (pH, pO2, pCO2, HCO3, base excess (BE), and lactic acid) were measured 2 times a day during the first 5 postoperative days. The main goal of the studies is to analysis of ABB parameters and their influence on the clinical state of newborns with HLHS. Several descriptors were concerned to describe the neonates clinical state: the date of the surgery (the day of life when the child was operated on), the duration (number of days) of mechanical ventilation employment, the time of hospitalization in intensive care unit, and the total duration of treatment in CSICU.The statistical analysis of the particular ABB parameters revealed a significant dependence (P < .001) between the values of pH, pO2, pCO2, HCO3, BE, lactic acid, and all concerned descriptors of the newborn clinical state.The article shows that monitoring the ABB parameters, proper interpretation of the results, and appropriate modification of pharmacotherapy and respiratory treatment are crucial for therapeutic results and survival rates in neonates with HLHS after the modified Norwood procedure.

Modified Hybrid Procedure in Hypoplastic Left Heart Syndrome: Initial Experience of a Center in Northeastern Brazil

INTRODUCTION:

Although it only corresponds to 2.5% of congenital heart defects, hypoplastic left heart syndrome (HLHS) is responsible for more than 25% of cardiac deaths in the first week of life. Palliative surgery performed after the second week of life is considered an important risk factor in the treatment of HLHS.

OBJECTIVE:

The aim of this study is to describe the initial experience of a medical center in Northeastern Brazil with a modified off-pump hybrid approach for palliation of HLHS.

METHODS:

From November 2012 through November 2015, the medical records of 8 patients with HLHS undergoing hybrid procedure were retrospectively evaluated in a tertiary private hospital in Northeastern Brazil. The modified off-pump hybrid palliation consisted of stenting of the ductus arteriosus guided by fluoroscopy without contrast and banding of the main pulmonary artery branches. Demographic and clinical variables were recorded for descriptive analysis.

RESULTS:

Eight patients were included in this study, of whom 37.5% were female. The median age and weight at the time of the procedure was 2 days (p25% and p75% = 2 and 4.5 days, respectively) and 3150 g (p25% and p75% = 3077.5 g and 3400 g, respectively), respectively. The median length in intensive care unit stay was 6 days (p25% and p75% = 3.5% and 8 days, respectively). There were no in-hospital deaths. Four patients have undergone to the second stage of the surgical treatment of HLHS.

CONCLUSION:

In this series, the initial experience with the modified off-pump hybrid procedure showed to be safe, allowing a low early mortality rate among children presenting HLHS.

Ductal stenting using side-branch cell dilation for aortic coarctation in high-risk patients with hypoplastic left heart syndrome

For high-risk neonates with hypoplastic left heart syndrome (HLHS) undergoing Norwood operation, the strategy of bilateral pulmonary artery banding and ductal stenting is risky in case of coarctation of the aorta (CoA), often resulting in death. Therefore, we devised a new method of ductal stenting with side-branch cell dilation, which could overcome the constriction of the ductal arch with CoA in two HLHS patients. This is the first report that presents this method and the results. © 2015 Wiley Periodicals, Inc.

Staged biventricular repair for neonates with left ventricular outflow tract obstruction, ventricular septal defect, and aortic arch obstruction

BACKGROUND

The purpose of this study is to evaluate clinical outcomes of neonates who underwent a Norwood operation as a first step of a planned biventricular repair and the impact of associated risk factors.

METHODS

A retrospective cohort study was performed on all neonates (n = 44) undergoing the Norwood operation as the first stage of a biventricular (Norwood-Rastelli) repair from January 2000 to December 2012 at a single center. Multivariable analysis was performed to identify predictors of survival.

RESULTS

Stage one mortality was 9%. The interstage survival for nonsyndromic and syndromic patients was 100% versus 46%, respectively (p < 0.001). Twenty-four patients (55%) underwent biventricular completion repair with no mortality. Freedom from reintervention after biventricular completion was 53% at 6 years. The overall survival for nonsyndromic patients versus syndromic patients was 86% versus 43%, respectively (p = 0.01). Genetic syndromes and prematurity were significant predictors of interstage mortality on multivariable analysis.

CONCLUSIONS

Staged biventricular repair for patients with complex left ventricular outflow tract obstruction, ventricular septal defect, and aortic arch obstruction can be achieved with excellent outcomes for neonates without genetic syndromes. The staged approach is associated with longer time to reintervention after the biventricular completion.

Longitudinal assessment of growth in hypoplastic left heart syndrome: results from the single ventricle reconstruction trial

BACKGROUND

We sought to characterize growth between birth and age 3 years in infants with hypoplastic left heart syndrome who underwent the Norwood procedure.

METHODS AND RESULTS

We performed a secondary analysis using the Single Ventricle Reconstruction Trial database after excluding patients <37 weeks gestation (N=498). We determined length-for-age z score (LAZ) and weight-for-age z score (WAZ) at birth and age 3 years and change in WAZ over 4 clinically relevant time periods. We identified correlates of change in WAZ and LAZ using multivariable linear regression with bootstrapping. Mean WAZ and LAZ were below average relative to the general population at birth (P<0.001, P=0.05, respectively) and age 3 years (P<0.001 each). The largest decrease in WAZ occurred between birth and Norwood discharge; the greatest gain occurred between stage II and 14 months. At age 3 years, WAZ and LAZ were <-2 in 6% and 18%, respectively. Factors associated with change in WAZ differed among time periods. Shunt type was associated with change in WAZ only in the Norwood discharge to stage II period; subjects with a Blalock-Taussig shunt had a greater decline in WAZ than those with a right ventricle-pulmonary artery shunt (P=0.002).

CONCLUSIONS

WAZ changed over time and the predictors of change in WAZ varied among time periods. By age 3 years, subjects remained small and three times as many children were short as were underweight (>2 SD below normal). Failure to find consistent risk factors supports the strategy of tailoring nutritional therapies to patient- and stage-specific targets.

CLINICAL TRIAL REGISTRATION URL

http://clinicaltrials.gov/. Unique identifier: NCT00115934.

[Improvement of outcomes in the surgical treatment of hypoplastic left heart syndrome (HLHS) with staged Norwood operation]

On behalf of rapid progress of diagnostic technologies and new development of surgical technique or strategy, outcomes of surgical treatment of hypoplastic left heart syndrome (HLHS) has remarkably improved in the current practice. One of such approaches is the staged Norwood operation. We have reviewed our patients (n=54) between 2003 and 2013. A half of the patients with the staged group accomplished Norwood procedure and concomitant bidirectional cavopulmonary shunt at the mean age of 4 months old. An another half of the patients underwent secondary Norwood operation with Blalock-Taussig( BT) shunt or right-ventricle to pulmonary artery( RV-PA) conduit, because of ductal closure in spite of prostaglandin, or progressive reversed coarctation. Cardiac catheterization showed good results in both the primary (n=17) and the staged approach (n=37), partly because even in the primary Norwood group we used a smaller calibered graft for BT shunt or RV-PA conduit to unload the ventricle as much as possible. In conclusion, since the surgical mortality of staged group was superior to that of the primary group and the mid-term survival in the staged seemed to be better than that of primary, we would pursue our strategy of the staged approach in the surgical treatment of hypoplastic left heart syndrome.

[Bilateral pulmonary artery banding using ligation clips and facile Norwood-Glenn procedure]

Bilateral pulmonary artery banding( BPAB), though a less-invasive surgical option for hypoplastic left heart syndrome (HLHS), entails considerable risk of residual pulmonary artery stenosis after de-banding. Autologous aortic reconstruction in Norwood procedure is attractive in terms of growth potential, but technically demanding. To overcome these drawbacks, we modified the 2 techniques. Eight patients with HLHS underwent BPAB whereby ligation clips were half-closed into rhombic shape to deform bilateral pulmonary arteries. The arterial duct was kept patent by prostaglandin E1 infusion. One patient died of sepsis( age 8 months), while the 7 survivors underwent Norwood-Glenn procedure. Both pulmonary arteries were excised from the pulmonary trunk with minimal cuffs. Resultant defect in the pulmonary trunk was longitudinally closed. After arterial duct excision, pulmonary trunk-to descending aorta continuity was reconstructed by end-to-end anastomosis. Ascending aorta-to-aortic arch complex was anastomosed to the pulmonary trunk in a side-to-side fashion. After bilateral pulmonary artery continuity was reconstructed, Glenn anastomosis was made. One patient died of pneumonia(age 5 months). Currently, the 6 surviving patients(age 4∼30 months), enjoy good health. Four of them have completed Fontan procedure. Our modified techniques are facile, reproducible, and pose low risk of residual pulmonary artery stenosis or aortic stenosis.

Intervention for recoarctation in the single ventricle reconstruction trial: incidence, risk, and outcomes

BACKGROUND

Recoarctation after the Norwood procedure increases risk for mortality. The Single Ventricle Reconstruction (SVR) trial randomized subjects with a single right ventricle undergoing a Norwood procedure to a modified Blalock-Taussig shunt or a right ventricle-pulmonary artery shunt. We sought to determine the incidence of recoarctation, risk factors, and outcomes in the SVR trial.

METHODS AND RESULTS

Recoarctation was defined by intervention, either catheter based or surgical. Univariate analysis and multivariable Cox proportional hazard models were performed with adjustment for center. Of the 549 SVR subjects, 97 (18%) underwent 131 interventions (92 balloon aortoplasty, 39 surgical) for recoarctation at a median age of 4.9 months (range, 1.1-10.5 months). Intervention typically occurred at pre-stage II catheterization (n=71, 54%) or at stage II surgery (n=38, 29%). In multivariable analysis, recoarctation was associated with the shunt type in place at the end of the Norwood procedure (hazard ratio, 2.0 for right ventricle-pulmonary artery shunt versus modified Blalock-Taussig shunt; P=0.02), and Norwood discharge peak echo-Doppler arch gradient (hazard ratio, 1.07 per 1 mm Hg; P<0.01). Subjects with recoarctation demonstrated comorbidities at pre-stage II evaluation, including higher pulmonary arterial pressures (15.4±3.0 versus 14.5±3.5 mm Hg; P=0.05), higher pulmonary vascular resistance (2.6±1.6 versus 2.0±1.0 Wood units·m(2); P=0.04), and increased echocardiographic volumes (end-diastolic volume, 126±39 versus 112±33 mL/BSA(1.3), where BSA is body surface area; P=0.02). There was no difference in 12-month postrandomization transplantation-free survival between those with and without recoarctation (P=0.14).

CONCLUSIONS

Recoarctation is common after Norwood and contributes to pre-stage II comorbidities. Although with intervention there is no associated increase in 1-year transplantation/mortality, further evaluation is warranted to evaluate the effects of associated morbidities.

Midterm survival of infants requiring postoperative extracorporeal membrane oxygenation after Norwood palliation

This study reports the mid-term survival for neonates undergoing extracorporeal membrane oxygenation (ECMO) after Norwood palliation at a single center. Limited data exist on the mid-term survival of patients undergoing ECMO after Norwood palliation. We reviewed our ECMO experience from July 1994 to October 2008 and compared two groups: patients who required ECMO after Norwood palliation and patients who underwent Norwood palliation without ECMO. We analyzed 30-day survival, survival to hospital discharge, and survival to most recent follow-up. One hundred sixty patients underwent Norwood palliation for hypoplastic left heart syndrome (HLHS) and its variants. A total of 32 patients (20%) required postoperative ECMO. Using Kaplan-Meier analysis, the predicted survival rates for Norwood/non-ECMO patients to 30 days, 1 year, and 3 years after the procedure are 87.6% (CI 79.5-91.5%), 62.5% (CI 54.3-71.0%), and 59.9% (CI 50.8-67.8%), respectively. Survival to 30 days, 1 year, and 3 years after Norwood was significantly decreased in Norwood/ ECMO patients, with predicted survival rates of 50.0% (CI 31.9-65.7%), 24.6% (CI 11.4-40.4), and 13.2% (CI 3.9-28.3%), respectively (p < 0.0001). Risk factors for hospital mortality included nonelective or emergency placement onto ECMO, longer duration of ECMO support, and the development of acute renal failure while on ECMO. Of the original Norwood/ECMO hospital survivors, only half of these patients survived a mean of nearly 4 years. ECMO after Norwood palliation is associated with significant mortality. Our data suggest that neonates who require ECMO after Norwood palliation are prone to continued attrition once discharged from the hospital.

Head and neck vessel size by angiography predicts neo-aortic arch obstruction after Norwood/Sano operation for hypoplastic left heart syndrome

OBJECTIVES

To identify and predict neo-aortic arch obstruction (NAAO) in children after Norwood/Sano operation (NO) for hypoplastic left heart syndrome (HLHS).

BACKGROUND

NAAO is associated with morbidity and mortality after NO for HLHS and no objective measure has predicted the initial occurrence of NAAO. Computational flow models of aortic coarctation demonstrate increased wall shear stress (WSS) in vessels proximal to the coarctation segment, which we believe also occurs with NAAO. These vessels respond by increasing their luminal diameter to maintain normal WSS. We hypothesized that the relative increase in diameters of head and neck vessels to the isthmus, as measured by angiography, would identify hemodynamically significant NAAO and predict future NAAO.

METHODS

Retrospective review of patients with HLHS and at least one catheterization with aortic angiography after NO. Diameters of head and neck vessels were totaled and divided by the isthmus diameter to give a head and neck index (HNI), which was compared to coarctation index (CI) for identifying and predicting future NAAO.

RESULTS

Forty-four patients were identified, 17 with and 27 without NAAO. Receiver operator characteristic analysis using a value for CI ≤0.5 showed a sensitivity of 47% and specificity of 89%. For HNI, a value >2.65 gave a sensitivity of 77% and specificity of 93%. Three patients who developed NAAO after their initial catheterization had CI >0.5, but abnormally high HNI >2.65.

CONCLUSIONS

HNI is a more robust indicator of hemodynamically significant NAAO than CI and may predict its future occurrence after NO for HLHS.

Interventions after Norwood procedure: comparison of Sano and modified Blalock-Taussig shunt

Improved results have evolved from the modified Norwood procedure (NP). This study compares the incidence of interventions after NP with the Sano (n = 37) and modified Blalock-Taussig (BT n = 70) shunt. Incidence, location, interval of interventions, and weight were retrospectively analysed for 107 neonates undergoing NP during the period from October 2002 to December 2009. Forty-six (43.0 %) patients underwent interventions, mostly for dilatation of the aortic arch ([DAA] n = 26 [24.3 %]; Sano n = 10, BT n = 16, p = 0.6), dilatation of the shunt ([DS] n = 15 [14.0 %]; Sano n = 11, BT n = 4; p = 0.002), or closure of aortopulmonary collaterals ([APC] n = 15 [14.0 %]; Sano n = 3, BT n = 12; p = 0.08). Mean interval after NP and body weight at DAA, DS, and APC were 72.4 ± 18.9, 108.5 ± 15.8, and 110.7 ± 17.8 days and 4.5 ± 1.3, 4.9 ± 1.9, 5.3 ± 1.2 kg, respectively. The interventions were not associated with mortality but with a greater rate of complications (9 of 46 [21.4 %]) compared with the rate after diagnostic catheterization (0 of 45, p = 0.03). Complications included closure of the femoral or subclavian artery (n = 5), cerebral embolic or bleeding events (n = 4), cardiopulmonary resuscitation (n = 3), and temporary heart block (n = 2). Actuarial survival was similar from the postoperative month 8 onward at 78.6 ± 4.9 % (95 % confidence interval [CI] 67.0-86.5 %) for Sano and 78.4 ± 6.8 % (95 % CI 61.4-88.6 %) for BT (p = 0.95). Interventions after NP were common irrespective of shunt type. However, a significantly greater rate of shunt interventions was noted in the Sano group. In particular, interventions addressing the aortic arch and the shunt were related with a significant rate of complications.

Individualized approach in the management of patients with hypoplastic left heart syndrome (HLHS)

Over the past decade new variations on the "classic" first stage palliation (the Norwood/BT shunt) for patients with Hypoplastic Left Heart Syndrome have emerged and been vetted by the medical community. A "one size fits all" approach may not be adequate anymore. In this review, the optimal indications for the various palliative options (Norwood/BT shunt, Norwood/RV-PA conduit, Hybrid Stage I with or without ductal stenting, heart transplantation) are reviewed from a standpoint of the initial anatomy and physiology of the patient, letting it guide clinical management. Current knowledge useful for decision-making is also reviewed as objectively as possible.

The Norwood procedure: in favor of the RV-PA conduit

Evolution of the Norwood procedure has culminated in there currently being three treatment strategies available for initial management: the 'classical' Norwood (utilizing a Blalock-Taussig shunt), the Norwood with right-ventricle to pulmonary artery (RV-PA) conduit, and the 'hybrid' Norwood procedure utilizing bilateral pulmonary artery banding and ductal stenting. Each variant has its potential advantages and disadvantages, and this paper looks to examine the evidence in favor of each strategy, with emphasis on the supportive data for the RV-PA conduit. The 'classical' procedure has the benefit of the greatest accumulated surgical experience and avoids any incision into the ventricle. However, the diastolic run-off of the Blalock-Taussig shunt can cause hemodynamic instability and unpredictable coronary steal phenomenon. The RV-PA conduit has the advantage of maintaining diastolic pressure with a more stable postoperative course, but at the cost of a ventriculotomy that may have detrimental long-term sequelae. The 'hybrid' procedure has the advantage of avoiding cardiopulmonary bypass, but does not always secure coronary blood flow and has a high inter-stage morbidity and reintervention rate. The evidence shows that each technique may have its place in future management, and that treatment algorithms could emerge that direct the choice of procedure for specific patient groups.

Effect of endovascular stenting of right ventricle to pulmonary artery conduit stenosis in infants with hypoplastic left heart syndrome on stage II outcomes

There is growing awareness that the Norwood procedure with the Sano modification is prone to early right ventricular to pulmonary artery (RV-PA) conduit stenosis resulting in systemic oxygen desaturation, increased interstage morbidity, and death. We report our experience with endovascular stent placement for conduit stenosis and compare the outcomes at stage II surgery between stented and nonstented infants. The medical records of all patients with hypoplastic left heart syndrome who received an RV-PA conduit at Norwood palliation from May 2005 to January 2010 were reviewed. The preoperative anatomy, demographics, operative variables, and outcomes pertaining to the Norwood and subsequent stage II surgeries were obtained and compared between stented and nonstented infants. The pre- and post-stent oxygen saturation, stenosis location, type and number of stents implanted, concomitant interventions, procedure-related complications, and reinterventions were collected. Of the 66 infants who underwent the Norwood procedure with RV-PA conduit modification, 16 (24%) received stents. The anatomy, demographics, and outcome variables after the Norwood procedure were similar between the stented and nonstented infants. The age at catheterization was 93 ± 48 days, and the weight was 4.9 ± 1.2 kg. The oxygen saturation increased from 66 ± 9% before intervention to 82 ± 6% immediately after stenting (p <0.0001). No interstage surgical shunt revisions were performed in either group. Age, weight, pre-stage II echocardiographic variables, oxygen saturation, and operative and outcome variables, including mortality, were similar between the 2 groups. In conclusion, endovascular stent placement for RV-PA conduit stenosis after the Norwood procedure leads to improved systemic oxygen levels and prevents early performance of stage II surgery without compromising stage II outcomes.

Technical description of the use of selective perfusion techniques during the Norwood procedure for hypoplastic left heart syndrome

Since the introduction of the Norwood procedure for surgical palliation of hypoplastic left heart syndrome in 1983, refinements have been made to the original procedure to improve patient outcomes while still accomplishing the original goals of the procedure. One of these refinements has been the introduction of regional selective perfusion to limit the duration of circulatory arrest times and optimize the regional flow distribution. In this paper we describe our technique for performing selective cerebral and lower body perfusion during the Norwood procedure.

Stage 1 palliation for hypoplastic left heart syndrome without the use of allogeneic tissue, with reduced allogeneic blood product exposure: a case report

In the 30 years since Norwood described the palliative procedure for hypoplastic left heart syndrome (HLHS), many modifications have been described which have increased the survival rate of children born with this lesion. We describe further modifications which result in reduced cardiopulmonary bypass time, no cooling or circulatory arrest time, and decreased banked blood exposure. A 16-day-old infant with HLHS undiagnosed during pregnancy presented for stage 1 palliation incorporating the Mee modification, Sano right ventricle to pulmonary artery conduit, dual arterial cannulation of the innominate artery and descending aorta, single venous cannulation of the right atrium, and a bypass prime volume of 130 mL. Anticoagulation and hemostasis were monitored with the Hepcon HMS Plus Hemostasis Management System (Medtronic USA, Minneapolis, MN). Bypass commenced at normothermia. A 5.0 Gore-Tex shunt was placed for the Sano Shunt, and the aortic arch was repaired without use of homologous tissue or synthetic material using a modification of the Mee technique. Bypass time was 92 minutes with a 10 minutes cardiac ischemic time. Modified ultrafiltration (MUF) was performed for 12 minutes and heparinization was reversed with protamine. There was no significant bleeding and no indication to transfuse clotting factors. The patient's only allogeneic donor exposure was 350 mL of red blood cells during bypass necessary to achieve a post MUF hematocrit of 50% per our current institution policy for cyanotic infants. Using modified surgical and perfusion techniques along with low prime bypass circuits can result in reduced cross clamp and bypass times as well as a decrease in blood donor exposure. Hypothetical benefits include reduced operating room, ventilation, intensive care unit, and hospital times, improved neurodevelopmental outcomes, and an overall reduction in the cost of care for infants with HLHS.

Norwood procedure with non-valved right ventricle to pulmonary artery shunt improves ventricular energetics despite the presence of diastolic regurgitation: a theoretical analysis

When the Norwood procedure is conducted for the hypoplastic left heart syndrome using a non-valved right ventricle (RV) to pulmonary artery (PA) shunt, diastolic regurgitation from PA to RV may have an adverse effect on postoperative hemodynamics. In this study, we examined the impact of the diastolic regurgitation on ventricular energetics by computational analysis using a combination of a time-varying elastance chamber model and a modified three-element Windkessel vascular model. This study revealed that use of the valved or non-valved RV-PA shunt eliminated pulmonary over-circulation which was observed when using the systemic to pulmonary artery shunt (modified Blalock-Taussig shunt). Although the valved RV-PA shunt improved pulmonary blood supply and consequently increased pulmonary artery flow and oxygen saturation compared to the non-valved RV-PA shunt, the non-valved RV-PA shunt improved ventricular energetics in spite of the presence of PA to RV regurgitation.

The complex relationship between center volume and outcome in patients undergoing the Norwood operation

BACKGROUND

Norwood outcomes vary across centers, and a relationship between center volume and outcome has been previously described. It is unclear whether this volume-outcome relationship exists across all levels of patient risk or holds true for all centers. We evaluated the impact of patient risk status on the relationship between center volume and outcome, and the extent to which differences in center volume account for between-center variation in outcome.

METHODS

Infants in The Society of Thoracic Surgeons Congenital Heart Surgery Database undergoing the Norwood operation (2000 to 2009) were included. Mortality associated with annual Norwood volume overall and across patient preoperative risk tertiles was evaluated in multivariable analysis. We also estimated the proportion of between-center variation in mortality explained by center volume.

RESULTS

The cohort included 2,557 infants from 53 centers: 34 centers with 0 to 10 Norwood cases per year; 13 centers with 11 to 20 cases per year; and 6 centers with more than 20 cases per year. Unadjusted in-hospital mortality was 22%. In multivariable analysis, lower center volume was associated with higher mortality (odds ratio in low-volume versus high-volume centers 1.54, 95% confidence interval: 1.02 to 2.32, p=0.04). The volume-outcome relationship did not differ across preoperative risk tertiles (p=0.7). Norwood volume explained an estimated 14% of the between-center variation in mortality observed, and significant between-center variation in mortality remained after adjusting for volume (p<0.001).

CONCLUSIONS

Center volume is modestly associated with outcome after the Norwood operation independent of patient risk status. However, this relationship explains only a portion of the between-center variation in mortality in this cohort.

Celiac artery flow pattern in infants with single right ventricle following the Norwood procedure with a modified Blalock-Taussig or right ventricle to pulmonary artery shunt

A potential advantage of the right ventricle to pulmonary artery versus modified Blalock-Taussig shunt in patients undergoing the Norwood procedure is limitation of diastolic runoff from the systemic to pulmonary circulation. We evaluated mesenteric flow patterns and gastrointestinal outcomes following the Norwood procedure associated with either shunt type. Patients randomized to a right ventricle to pulmonary artery versus modified Blalock-Taussig shunt in the Pediatric Heart Network Single Ventricle Reconstruction Trial at centers participating in this ancillary study were eligible for inclusion; those with active necrotizing enterocolitis, sepsis, or end-organ dysfunction were excluded. Celiac artery flow characteristics and gastrointestinal outcomes were collected at discharge. Forty-four patients (five centers) were included. Median age at surgery was 5 days [interquartile range (IQR) = 4-8 days]. Median celiac artery resistive index (an indicator of resistance to perfusion) was higher in the modified Blalock-Taussig shunt group (n = 19) versus the right ventricle to pulmonary artery shunt group (n = 25) [1.00 (IQR = 0.84-1.14) vs. 0.82 (IQR = 0.74-1.00), p = 0.02]. There was no difference in interstage weight gain, necrotizing enterocolitis, or feeding intolerance episodes between the groups. The celiac artery resistive index was higher in patients with the modified Blalock-Taussig shunt versus the right ventricle to pulmonary artery shunt but was not associated with measured gastrointestinal outcomes.