Opinion: on the importance of maintaining the functional form of explanatory variables.

In medical research, continuous variables are often categorised into two or more groups before being included in the analysis; this practice often comes with a cost, such as loss of power in analysis, less reliable estimates, and can often leave residual confounding in the results. In this research report, we show this by way of estimates from a regression analysis looking at the association between acute kidney injury and post-operative mortality in a sample of 194 neonates who underwent the Norwood operation. Two models were developed, one using a continuous measure of renal function as the main explanatory variable and second using a categorised version of the same variable. A continuous measure of renal function is more likely to yield reliable estimates and also maintains more statistical power in the analysis to detect a relation between the exposure and outcome. It also reveals the true biological relationship between the exposure and outcome. Categorising a continuous variable may not only miss an important message, it can also get it wrong. Additionally, given a non-linear relationship is commonly encountered between the exposure and outcome variable, investigators are advised to retain a predictor with a linear term only when supported by data. All of this is particularly important in small data sets which account for the majority of clinical research studies.

Characteristics of Interstage Death After Discharge from Stage I Palliation.

BACKGROUND: Interstage mortality (IM) remains high for patients with single-ventricle congenital heart disease (SVCHD) in the period between Stage 1 Palliation (S1P) and Glenn operation. We sought to characterize IM. METHODS: This was a descriptive analysis of 2184 patients with SVCHD discharged home after S1P from 60 National Pediatric Cardiology Quality Improvement Collaborative sites between 2008 and 2015. Patients underwent S1P with right ventricle-pulmonary artery conduit (RVPAC), modified Blalock-Taussig-Thomas shunt (BTT), or Hybrid; transplants were excluded. RESULTS: IM occurred in 153 (7%) patients (median gestational age 38 weeks, 54% male, 77% white), at 88 (IQR 60,136) days of life, and 39 (IQR 17,84) days after hospital discharge; 13 (8.6%) occurred ≤ 30 days after S1P. The mortality rate for RVPAC was lower (5.2%; 59/1138) than BTT (9.1%; 65/712) and Hybrid (20.1%; 27/134). More than half of deaths occurred at home (20%) or in the emergency department (33%). The remainder occurred while inpatient at center of S1P (cardiac intensive care unit 36%, inpatient ward 5%) or at a different center (5%). Fussiness and breathing problems were most often cited as harbingers of death; distance to surgical center was the biggest barrier cited to seeking care. Cause of death was unknown in 44% of cases overall; in the subset of patients who underwent post-mortem autopsy, the cause of death remained unknown in 30% of patients, with the most common diagnosis being low cardiac output. CONCLUSIONS: Most IM occurred in the outpatient setting, with non-specific preceding symptoms and unknown cause of death. These data indicate the need for research to identify occult causes of death, including arrhythmia.

Bilateral Pulmonary Artery Banding before Norwood Procedure: Survival of High-Risk Patients.

BACKGROUND: This study reports midterm results of high-risk patients with hypoplastic left ventricle treated with initial bilateral pulmonary artery banding (PAB) before secondary Norwood procedure (NP). METHODS: Retrospective study of 17 patients admitted between July 2012 and February 2017 who underwent this treatment strategy because diagnosis or clinical status was associated with high risk for NP. Survival was compared with that of patients who underwent primary NP. RESULTS: Mean Aristotle comprehensive complexity score for NP would have been 19.7 ± 2.6. Risk factors included obstructed pulmonary venous return (n = 9), body weight < 2.5 kg (n = 7), total anomalous pulmonary venous connection (n = 3), and necrotizing enterocolitis (n = 1). Ten patients had a score ≥ 19.5. Early survival after PAB was 82.4% (14/17). NP was performed in 14 patients after improvement of clinical condition at a median age of 56 days and a weight ≥2,500 g. There was no 30-day mortality, but one interstage death. One patient died later after Glenn operation. One-year survival after primary PAB followed by NP was 70.6 ± 11.1%. During the same period, 35 patients with overall lower risk factors underwent primary NP; early postoperative survival and 1-year survival were 88.6 ± 5.4% and 68.6 ± 7.8%, respectively. There was no significant difference in survival between the two groups (p = 0.83) despite higher risk in the secondary Norwood group (p <0.0001). CONCLUSIONS: PAB before NP in high-risk patients constituted salvage management. Primary PAB provided enough time for stabilization and control of most risk factors. It allowed midterm survival equivalent to the survival after primary NP in lower risk neonates.

Impact of Confounding on Cost, Survival, and Length-of-Stay Outcomes for Neonates with Hypoplastic Left Heart Syndrome Undergoing Stage 1 Palliation Surgery.

The objective of this analysis was to update trends in LOS and costs by survivorship and ECMO use among neonates with hypoplastic left heart syndrome (HLHS) undergoing stage 1 palliation surgery using 2016 data from the Healthcare Cost and Utilization Project Kids' Inpatient Database. We identified neonates ≤ 28 days old with HLHS undergoing Stage 1 surgery, defined as a Norwood procedure with modified Blalock-Taussig (BT) shunt, Sano modification, or both. Multivariable regression with year random effects was used to compare LOS and costs by hospital region, case volume, survivorship, and ECMO vs. no ECMO. An E-value analysis, an approach for conducting sensitivity analysis for unmeasured confounding, was performed to determine if unmeasured confounding contributed to the observed effects. Significant differences in total costs, LOS, and mortality were noted by hospital region, ECMO use, and sub-analyses of case volume. However, other than ECMO use and mortality, the maximum E-value confidence interval bound was 1.71, suggesting that these differences would disappear with an unmeasured confounder 1.71 times more associated with both the outcome and exposure (e.g., socioeconomic factors, environment, etc.) Our findings confirm previous literature demonstrating significant resource utilization among Norwood patients, particularly those undergoing ECMO use. Based on our E-value analysis, differences by hospital region and case volume can be explained by moderate unobserved confounding, rather than a reflection of the quality of care provided. Future analyses on surgical quality must account for unobserved factors to provide meaningful information for quality improvement.

Hypoplastic Left Heart Syndrome is not Associated with Worse Clinical or Neurodevelopmental Outcomes Than Other Cardiac Pathologies After the Norwood-Sano Operation.

There is evidence to suggest that patients undergoing a Norwood for non-HLHS anatomy may have lower mortality than classic HLHS, but differences in neurodevelopmental outcome have not been assessed. Our objective was to compare survival and neurodevelopmental outcome during the same surgical era in a large, well-described cohort. All subjects who underwent a Norwood-Sano operation between 2005 and 2014 were included. Follow-up clinical, neurological, and developmental data were obtained from the Western Canadian Complex Pediatric Therapies Follow-up Program database. Developmental outcomes were assessed at 2 years of age using the Bayley Scales of Infant and Toddler Development (Bayley-III). Survival was assessed using Kaplan-Meier analysis. Baseline characteristics, survival, and neurodevelopmental outcomes were compared between those with HLHS and those with non-HLHS anatomy (non-HLHS). The study comprised 126 infants (75 male), 87 of whom had HLHS. Five-year survival was the same for subjects with HLHS and those with non-HLHS (HLHS 71.8%, non-HLHS 76.9%; p = 0.592). Ninety-three patients underwent neurodevelopmental assessment including Bayley-III scores. The overall mean cognitive composite score was 91.5 (SD 14.6), language score was 86.6 (SD 16.7) and overall mean motor composite score was 85.8 (SD 14.5); being lower than the American normative population mean score of 100 (SD 15) for each (p-value for each comparison, <0.0001). None of the cognitive, language, or motor scores differed between those with HLHS and non-HLHS (all p > 0.05). In the generalized linear models, dominant right ventricle anatomy (present in 117 (93%) of patients) was predictive of lower language and motor scores. Comparative analysis of the HLHS and non-HLHS groups undergoing single ventricle palliation including a Norwood-Sano, during the same era, showed comparable 2-year survival and neurodevelopmental outcomes.

Outcome of Tricuspid Valve Plasty in Norwood Stage I Operation.

BACKGROUND: Significant tricuspid valve regurgitation (TR) is considered a poor prognosis factor for patients with hypoplastic left heart syndrome (HLHS). Performing a tricuspid valve plasty (TVP) during Norwood Stage I palliation (S1P) has rarely been reported. We report mid-term results of performing TVP during Norwood S1P. METHODS AND RESULTS: Between December 2004 and July 2013, 48 patients with HLHS or variants underwent Norwood S1P and of them 11 (23%) with TR of a moderate degree or above underwent TVP. The estimated 1- and 5-year survival rates for Norwood S1P were 61% and 54%, respectively. Among the 11 patients with TVP, there were 2 early deaths. Nine patients had a Stage II operation and 3 of them died late. Four patients completed a Fontan operation, and 2 were waiting. Using Cox regression analysis, lower body weight, presence of intact atrial septum, and preoperative cardiopulmonary resuscitation were factors associated with increased risk for death. Patients with significant TR and undergoing TVP during Norwood S1P had a similar survival curve to those without significant TR. CONCLUSIONS: Our results for TVP performed during Norwood S1P were encouraging. They suggested that aggressive TVP is warranted in Norwood S1P when primary heart transplantation is not available. Further study is required to determine if the strategy does improve the results for patients with HLHS and TR initially. (Circ J 2016; 80: 1362-1370).

Risk Factors for Interstage Mortality Following the Norwood Procedure: Impact of Sociodemographic Factors.

Interstage mortality remains significant for patients undergoing staged palliation for hypoplastic left heart syndrome and other related single right ventricle malformations (HLV). The purpose of this study was to identify factors related to demographics, socioeconomic position, and perioperative course associated with post-Norwood hospital discharge, pre-stage 2, interstage mortality (ISM). Medical record review was conducted for patients with HLV, born from 1/2000 to 7/2009 and discharged alive following the Norwood procedure. Sociodemographic and perioperative factors were reviewed. Patients were determined to have ISM if they died between Norwood procedure hospital discharge and stage 2 palliation. Univariable and multivariable logistic regressions were performed to identify risk factors associated with ISM. A total of 273 patients were included in the analysis; ISM occurred in 32 patients (12%). Multivariable analysis demonstrated that independent risk factors for interstage mortality included teen mothers [adjusted odds ratio (AOR) 6.6, 95% confidence interval (CI) 1.9-22.5], single adult caregivers (AOR 4.1, 95% CI 1.2-14.4), postoperative dysrhythmia (AOR 2.7, 95% CI 1.1-6.4), and longer ICU stay (AOR 2.7, 95% CI 1.2-6.1). Anatomic and surgical course variables were not associated with ISM in multivariable analysis. Patients with HLV are at increased risk of ISM if born to a teen mother, if they lived in a home with only one adult caregiver, suffered a postoperative dysrhythmia, or experienced a prolonged ICU stay. These risk factors are identifiable, and thus these infants may be targeted for interventions to reduce ISM.

Transplantation-free survival and interventions at 3 years in the single ventricle reconstruction trial.

BACKGROUND: In the Single Ventricle Reconstruction (SVR) trial, 1-year transplantation-free survival was better for the Norwood procedure with right ventricle-to-pulmonary artery shunt (RVPAS) compared with a modified Blalock-Taussig shunt (MBTS). At 3 years, we compared transplantation-free survival, echocardiographic right ventricular ejection fraction, and unplanned interventions in the treatment groups. METHODS AND RESULTS: Vital status and medical history were ascertained from annual medical records, death indexes, and phone interviews. The cohort included 549 patients randomized and treated in the SVR trial. Transplantation-free survival for the RVPAS versus MBTS groups did not differ at 3 years (67% versus 61%; P=0.15) or with all available follow-up of 4.8±1.1 years (log-rank P=0.14). Pre-Fontan right ventricular ejection fraction was lower in the RVPAS group than in the MBTS group (41.7±5.1% versus 44.7±6.0%; P=0.007), and right ventricular ejection fraction deteriorated in RVPAS (P=0.004) but not MBTS (P=0.40) subjects (pre-Fontan minus 14-month mean, -3.25±8.24% versus 0.99±8.80%; P=0.009). The RVPAS versus MBTS treatment effect had nonproportional hazards (P=0.004); the hazard ratio favored the RVPAS before 5 months (hazard ratio=0.63; 95% confidence interval, 0.45-0.88) but the MBTS beyond 1 year (hazard ratio=2.22; 95% confidence interval, 1.07-4.62). By 3 years, RVPAS subjects had a higher incidence of catheter interventions (P<0.001) with an increasing HR over time (P=0.005): <5 months, 1.14 (95% confidence interval, 0.81-1.60); from 5 months to 1 year, 1.94 (95% confidence interval, 1.02-3.69); and >1 year, 2.48 (95% confidence interval, 1.28-4.80). CONCLUSIONS: By 3 years, the Norwood procedure with RVPAS compared with MBTS was no longer associated with superior transplantation-free survival. Moreover, RVPAS subjects had slightly worse right ventricular ejection fraction and underwent more catheter interventions with increasing hazard ratio over time. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00115934.

Long-term progression and survival following Norwood Single Ventricle Reconstruction.

PURPOSE OF REVIEW: Much data exist concerning Norwood discharge mortality. Less is known about late survival. Examining the available data in light of the Single Ventricle Reconstruction trial is insightful as focus shifts toward long-term survival. RECENT FINDINGS: Data from 2000 to 2001 demonstrated approximately 40-50% 10-year survival, 30-40% or less between 10 and 15 years. The shape of the curves was characteristic; the majority of deaths within the first year, followed by a late constant phase. Publications from 2001 to 2005 suggested that various combinations of technical and perioperative modifications allowed hospital discharge survivals as high as 90-94%. As results matured (2005-2010) a consistent message was that, although the shape of the newer curves was similar (highest hazard in the first 1 year), higher hospital survival shifted the later phase to yield better long-term survival (70-85% between 5 and 10 years). Some emphasized right ventricle-based shunts as a 'cause' of improving results. Since 2010, the Single Ventricle Reconstruction trial has matured and has increasingly shifted opinion away from the right ventricle shunt as a 'cause' of improved results. The survival of the right ventricle shunt group is slightly higher at 3 years, but the 1-year statistical significance has been lost and the two groups converge. As the Single Ventricle Reconstruction study was based on the interaction between randomized shunt and survival, the secondary and other endpoint analyses must be cautiously considered. SUMMARY: The current English-language literature suggests a 60-80% 5-10 year survival expectation. The shape of the survival curve remains; the highest hazard remains the first year before a later, stable phase is reached. Rather than a 'magic bullet' theory surrounding one technique or practice, centers have differentially adopted various combinations to optimize Norwood survival. Optimizing interstage I survival is a challenge to further increase the percentage of patients reaching the late, stable phase.

Restrictive Atrial Septum Defect Becomes a Risk Factor for Norwood Palliation of Hypoplastic Left Heart Syndrome Only When It Is Combined with Mitral or Aortic Atresia.

BACKGROUND: Restrictive atrial septal defect (ASD) is described as risk factor for Norwood procedure because of elevated pulmonary resistance. We hypothesized that it invariably could not cause pulmonary hypertension, unless it was combined with mitral valve or aortic valve atresia. We investigated how restrictive ASD influenced survival of patients with hypoplastic left heart syndrome (HLHS) who underwent Norwood operation. PATIENTS AND METHODS: A total of 118 HLHS patients who underwent surgery between January 2005 and December 2012 were grouped into three groups. Group 1 included 31 patients with restrictive ASD combined with mitral or aortic atresia; Group 2 composed of 12 patients with restrictive ASD and mitral and aortic stenosis; Group 3 (n = 75) had no ASD restriction. Survival was determined for each group. Multivariate analysis was conducted to test risk factors for mortality. RESULTS: Mean follow-up was 26.3 ± 24.1 months. Survival was 78.7% ± 4.2% at 30-month interval and onward after Norwood procedure for the whole cohort; it was 43.8% ± 10.0%, 91.7% ± 8.0%, and 77.3% ± 5.0% for Group 1, 2, and 3, respectively. The difference was significant between Group 1 and Group 2 and 3: p < 0.001. Survival was similar for Group 2 and Group 3: p = 0.45. Combination of restrictive ASD and mitral or aortic atresia was found to be the sole risk factor for early and late mortality (odds ratio: 3.5, 95% confidence interval: 1.8-7.1, p < 0.001). CONCLUSION: Restrictive ASD only affects survival of HLHS patients following Norwood procedure if it is associated with mitral or aortic atresia.

Outcomes and hospital costs associated with the Norwood operation: beyond morbidity and mortality.

BACKGROUND: Although much is known about morbidity and mortality, there are limited data focussing on the financial aspect of the Norwood operation. Our objective is to characterise the hospitalisation and detail the hospital costs. METHODS: We retrospectively studied 86 newborns with hypoplastic left heart syndrome who underwent Norwood palliation between 2008 and 2012. Clinical and financial data were collected. Financial data have been reported for 2011-2012. RESULTS: At surgery, median age and weight of the patients were 4 days (range 1-13) and 3 kg (range 2-4.8), respectively. The median time from admission to surgery was 4 days (range 1-10), with the postoperative ICU stay and total length of stay at the hospital being 10 days (range 4-135) and 16 days (range 5-136), respectively. Discharge mortality was 14/86 (16%) patients. For patients operated on between 2011 and 2012 (n=40), median hospital costs, charges, and collections per patient were $117,021, $433,054, and $198,453, respectively, and mean hospital costs, charges, and collections per patient were $322,765, $1,109,500, and $511,271, respectively. A breakdown of total hospital costs (direct and indirect) by department showed that the top four areas of resource utilisation (excluding physician fees) were as follows: the cardiac ICU (35%), laboratory (12%), pharmacy (12%), and operating room (7%). Interestingly, point-of-care laboratory evaluations accounted for almost half of the laboratory total (5%). Extracorporeal membrane oxygenation, although only utilised in eight patients between 2011 and 2012, accounted for 7% of utilisation.General radiology only accounted for 2%, despite numerous radiographs. CONCLUSIONS: Limited data are available that detail the hospitalisation and costs associated with the Norwood operation. We hope that this analysis will identify areas for quality and value improvement from both system and patient perspectives.

Surgical palliation strategy does not affect interstage ventricular dysfunction or atrioventricular valve regurgitation in children with hypoplastic left heart syndrome and variants.

BACKGROUND: All 3 palliation strategies, Norwood, Sano, and Hybrid, currently used for hypoplastic left heart syndrome pose a risk of myocardial injury at different times and through different mechanisms. We sought to compare these strategies to understand longitudinal differences in interstage ventricular dysfunction and their subsequent impact on transplant-free survival and atrioventricular valve regurgitation (AVVR) as well as the relationship between adverse events and ventricular function. METHODS AND RESULTS: Serial echocardiographic reports and clinical data were reviewed for 138 children with hypoplastic left heart syndrome who underwent stage I surgical palliation (Sano: 11; Norwood: 73; Hybrid: 54) between 2004 and 2011. Stage II palliation was achieved in 92 (67%) patients (Sano: 7; Norwood: 51; Hybrid: 34). Interstage transplant-free survival, ventricular dysfunction, and AVVR were equivalent among palliation strategies. Patients with preserved ventricular function had a higher rate of transplant-free survival and freedom from AVVR, regardless of palliation strategy. Patients who had cardiac arrest, cardiopulmonary resuscitation, or extracorporeal membrane oxygenation (adverse events) experienced more transient and persistent ventricular dysfunction compared to those without adverse events. Surgical palliation strategies were not identified as risk factors for ventricular dysfunction or AVVR. CONCLUSIONS: Surgical palliation strategy does not affect mortality, interstage ventricular function, or interstage AVVR in children with hypoplastic left heart syndrome. Therefore, the different timing and mechanisms of myocardial injury among palliation strategies do not affect outcomes. Ventricular dysfunction adversely affects transplant-free survival and atrioventricular valve function. Adverse events are associated with the development of ventricular dysfunction. To improve outcomes, interstage treatment should focus on the preservation of ventricular function.

A systematic review of the impact of volume of surgery and specialization in Norwood procedure.

BACKGROUND: The volume-outcome relationship is supposed to be stronger in high risk, low volume procedures. The aim of this systematic review is to examine the available literature on the effects of hospital and surgeon volume, specialization and regionalization on the outcomes of the Norwood procedure. METHODS: A systematic literature search was performed in Medline, Embase, and the Cochrane Library. On the basis of titles and abstracts, articles of comparative studies were obtained in full-text in case of potential relevance and assessed for eligibility according to predefined inclusion criteria. All relevant data on study design, patient characteristics, hospital volume, surgeon volume and other institutional characteristics, as well as results were extracted in standardized tables. Study selection, data extraction and critical appraisal were carried out independently by two reviewers. RESULTS: We included 10 studies. All but one study had an observational design. The number of analyzed patients varied from 75 to 2555. Overall, the study quality was moderate with a huge number of items with an unclear risk of bias. All studies investigating hospital volume indicated a hospital volume-outcome relationship, most of them even having significant results. The results were very heterogeneous for surgeon volume. CONCLUSIONS: The volume-outcome relationship in the Norwood procedure can be supported. However, the magnitude of the volume effect is difficult to assess.

Efficacy of new pediatric extra-corporeal life support system (Endumo 2000) for postoperative management after Norwood operation.

This study aimed to assess the efficacy of a new pediatric extra-corporeal life support (ECLS) system (Endumo 2000, Heiwa Bussan, Tokyo, Japan) for postoperative management after the Norwood operation. Thirty-three consecutive patients with hypoplastic left heart syndrome or its variant undergoing the Norwood operation between August 2007 and December 2013 were divided into two groups according to available ECLS devices. Before November 2009, pediatric Emersave (TERUMO, Saitama, Japan) was employed as the ECLS device, and 14 patients were operated on during this period (Emersave era: 7 boys; 2.9 kg). After December 2009, Endumo 2000 was employed and 19 patients were operated on (Endumo era: 8 boys, 3.1 kg). The demographic characteristics of both groups showed no significant differences. ECLS was initiated in 7 of 14 patients (50%) during the Emersave era and 7 of 19 patients (37%) during the Endumo era (p = 0.45). Chest reentry for hemostasis during ECLS support was more frequently needed in patients supported by Emersave (5/7) than Endumo (1/7) (p = 0.03). The first ECLS circuit durability of Endumo was significantly longer than that of Emersave (p = 0.01). The survival at discharge rate in patients required ECLS was 0% (0/7) when supported by Emersave, but 57% (4/7) by Endumo (p = 0.02). As a result, the survival at discharge rate was 43% (6/14) in the Emersave era and 79% (14/19) in the Endumo era (p = 0.03). Longer durability and superior antithrombogenicity of the Endumo 2000 contributed to the improvement of surgical outcomes after the Norwood operation.

Clinical course and interstage monitoring after the Norwood and hybrid procedures for hypoplastic left heart syndrome.

Infants with hypoplastic left heart syndrome (HLHS) are at risk for interstage morbidity and mortality, especially between the first and second surgical stages after the Norwood and hybrid procedures. This study compared the morbidity and mortality of patients treated by either the Norwood or the hybrid procedure for HLHS between the first and second stages who were undergoing interstage monitoring. Between October 2008 and December 2011, 26 infants (14 boys) with HLHS (n = 16) and other univentricular heart malformations with aortic arch anomaly (n = 10) were scheduled for interstage monitoring after Norwood I (n = 12) and hybrid (n = 14) procedures. Three infants (11.5 %) died after first-stage palliation (one hybrid patient and two Norwood patients), and three infants (11.5 %) died after second-stage palliation (two hybrid patients and one Norwood patient) (p = 0.83), all after early second-stage surgery (<90 days). The Norwood I and hybrid procedures did not differ in terms of overall mortality (23 %) (three hybrid and three Norwood patients; p = 1.00). Seven infants (26.9 %) could not be discharged from the hospital due to hemodynamic instability and were referred for early second-stage surgery (<90 days). After the first stage, the invasive reevaluation rate before discharge was high (53.8 %), with cardiac catheterizations for 8 of 14 patients after the hybrid procedure and for 6 of 12 patients after the Norwood procedure (p = 0.69). A total of 11 reinterventions were performed (eight by catheter and three by surgery). Of the eight catheter reinterventions, five were performed for hybrid patients (p = 0.22). For 14 infants, 89 days (range 10-177 days) of interstage monitoring were scheduled. One infant (3.9 %) died during the interstage monitoring. The findings showed a breach of the physiologic criteria for interstage monitoring in seven infants (50 %) after 10 days (range 4-68 days) (five hybrid and two Norwood patients), leading to rehospitalization and catheterization for six patients (four hybrid and two Norwood patients), requiring interventions for two patients (patent arterial duct stent dilation, and atrial septal defect stenting, all for hybrid patients). Overall, three of the seven patients with red flag events of interstage monitoring were candidates for early second-stage surgery. In conclusion, morbidity among infants treated for HLHS remains high, either before or after hospital discharge, emphasizing the need of interstage monitoring programs. Despite retrograde aortic flow in infants with HLHS after the hybrid procedure, the mortality rate was comparable between the two groups. Mortality occurs after early second-stage surgery (<90 days).

Outcomes of the modified norwood procedure: hypoplastic left heart syndrome versus other single-ventricle malformations.

Recent studies have suggested that survival after the modified Norwood procedure is influenced by anatomy and is worse for patients with hypoplastic left heart syndrome (HLHS) than for patients with other forms of functional single ventricle. This study aimed to compare the outcomes of the modified Norwood procedure for these two groups at a single center. A retrospective chart review compared modified Norwood procedure outcomes between children with HLHS (n = 40) and children with other single-ventricle malformations (n = 19) from January 2002 to August 2012. The HLHS patients had a lower mean age (10.0 ± 13.2 days) at the time of operation than the non-HLHS patients (16.5 ± 18.5 days). The difference was not significant. The number of patients with a Sano modification was significantly higher in the HLHS group (HLHS 85 % vs non-HLHS 32 %; p < 0.001). The follow-up data did not differ between the groups (HLHS 3.6 ± 3.2 years vs non-HLHS 4.8 ± 3.3 years, nonsignificant difference). The overall operative survival was 85 %: 83 % for the patients with HLHS and 89 % for the patients with non-HLHS (nonsignificant difference). The Kaplan-Meier transplant-free survival estimate at 10 years was 73 % and did not differ between the HLHS patients (67 %) and the non-HLHS patients (84 %, nonsignificant difference). The timing of stages 2 and 3 palliation (bidirectional Glenn and external conduit Fontan) did not differ significantly (HLHS, 7.0 ± 2.8 months and 3.0 ± 0.5 years vs non-HLHS 6.1 ± 1.7 months and 2.8 ± 0.8 years). The two groups were similar with respect to the need for post-Norwood extracorporeal membrane oxygenation support, aortic arch reinterventions, atrioventricular valve repair, pulmonary artery reconstruction, pacemaker implantation, and progression to bidirectional Glenn and Fontan completion. The modified Norwood reconstruction provides good palliation for HLHS as well as other forms of functional single-ventricle anatomy. Survival, postoperative morbidity, and progression to Glenn and Fontan are not significantly different.

[Therapeutic results in children with hypoplastic left heart syndrome after Norwood procedure]. / Wyniki leczenia dzieci z zespolem niedorozwoju lewego serca po operacji metoda Norwooda.

UNLABELLED: Hypoplastic left heart syndrome (HLHS) encompasses hypoplasia or atresia of the left ventricle, stenotic or artretic aortic and mitral valves and hypoplasia of the ascending aorta. The aim of the 1-st stage operation called the modified Norwood procedure is reconstruction of the systemic flow, providing an adequate pulmonary flow and relieving interatrial restriction. The aim of the study was the analysis of treatment results after the Norwood operation in children hospitalized at Cardiology and Cardiac Surgery Departments in the period of 2009-2012. The material consisted of 65 children (42 males, 23 females). The following factors were analyzed: the age on admission, general condition, pre-operative clinical course. RESULTS: The mean age of children on admission was 4.4 ± 4.1 days and mean body weight--3.3 ± 0.5 kg. The general condition was good in the majority of patients (74%). The remaining children were found to have early symptoms of congestive heart failure (CHF). Cardiological and/or surgical interventions were necessary in 33 (50.8%) patients, among them three children required both procedures. In the majority of patients (n = 21, 32%), the main cause of intervention was re-coarctation of the neo-aortic isth- mus treated with balloon plasty and/ or stenting. In the early post-operative period, six children died due to CHF (n = 4) and infections (n = 2), while the remaining six children died due to various complications while waiting for the 2nd stage. CONCLUSIONS: Despite the progress in diagnosis and treatment of children with HLHS the mortality is still high.

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.

Outcome after extracorporeal membrane oxygenation therapy in Norwood patients before the bidirectional Glenn operation.

OBJECTIVES: Patients after the Norwood procedure are prone to postoperative instability. Extracorporeal membrane oxygenation (ECMO) can help to overcome short-term organ failure. This retrospective single-centre study examines ECMO weaning, hospital discharge and long-term survival after ECMO therapy between Norwood and bidirectional Glenn palliation as well as risk factors for mortality. METHODS: In our institution, over 450 Norwood procedures have been performed. Since the introduction of ECMO therapy, 306 Norwood operations took place between 2007 and 2022, involving ECMO in 59 cases before bidirectional Glenn. In 48.3% of cases, ECMO was initiated intraoperatively post-Norwood. Patient outcomes were tracked and mortality risk factors were analysed using uni- and multivariable testing. RESULTS: ECMO therapy after Norwood (median duration: 5 days; range 0-17 days) saw 31.0% installed under CPR. Weaning was achieved in 46 children (78.0%), with 55.9% discharged home after a median of 45 (36-66) days. Late death occurred in 3 patients after 27, 234 and 1541 days. Currently, 30 children are in a median 4.8 year (3.4-7.7) follow-up. At the time of inquiry, 1 patient awaits bidirectional Glenn, 6 are at stage II palliation, Fontan was completed in 22 and 1 was lost to follow-up post-Norwood. Risk factor analysis revealed dialysis (P < 0.001), cerebral lesions (P = 0.026), longer ECMO duration (P = 0.002), cardiac indication and lower body weight (P = 0.038) as mortality-increasing factors. The 10-year mortality probability after ECMO therapy was 48.5% (95% CI 36.5-62.9%). CONCLUSIONS: ECMO therapy in critically ill patients after the Norwood operation may significantly improve survival of a patient cohort otherwise forfeited and give the opportunity for successful future-stage operations.