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.

Mortality and Heart Transplantation After Hybrid Palliation of Hypoplastic Left Heart Syndrome: A Systematic Review and Meta-Analysis.

BACKGROUND: Newborns with hypoplastic left heart syndrome (HLHS) who are considered at increased risk for death following Norwood/Sano surgery often undergo hybrid palliation (HP) as initial surgery. We aimed to compile the HP experience in HLHS and its variants and assess the rates of, and risk factors for, death and heart transplantation. METHODS: CINAHL, CINAHL PLUS, PubMed/MEDLINE, and SCOPUS were systematically searched for HP outcome studies of death or heart transplantation in HLHS between 1998 and 2022. Pooled incidence was estimated, and potential risk factors were identified using random-effects meta-analysis and reconstructed time-to-event data from Kaplan-Meier curves. RESULTS: Thirty-three publications were included in our review. Overall, of 1,162 patients 417 died and 57 underwent heart transplantation, resulting in a combined outcome of 40.7%, (474/1,162). There was a trend toward decreasing mortality risk across the stages of palliation. Pooled mortality between HP and comprehensive stage 2 palliation was 25%, after stage 2 up to Fontan palliation was 16%, and 6% post-Fontan. The incidence of death or heart transplantation was higher in high-risk patients-43% died and 10% received heart transplantation. CONCLUSION: Our systematic review and meta-analysis found high rates of death or heart transplantation in HP of HLHS patients between HP and Fontan surgeries. All patients should be closely followed during the initial interstage period, which is associated with the highest hazard. Prospective studies on appropriate patient selection, indications, and / or alternatives, as well as refining HP strategies for managing newborns with HLHS are needed to improve outcomes.

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.

Decreasing Interstage Mortality After the Norwood Procedure: A 30-Year Experience.

Background The superior cavo-pulmonary connection was introduced at our institution in 1988 for infants undergoing surgery for hypoplastic left heart syndrome. Patients with hypoplastic left heart syndrome remain at high risk for mortality in the time period between the Norwood procedure and the superior cavo-pulmonary connection. The primary objectives of this study were to compare interstage mortality across 4 eras and analyze factors that may impact interstage mortality. Methods and Results Patients with hypoplastic left heart syndrome who underwent the Norwood procedure, were discharged from the hospital, and were eligible for superior cavo-pulmonary connection between January 1, 1988, and December 31, 2017, were included. The study period was divided into 4 eras based on changes in operative or medical management. Mortality rates were estimated with 95% CIs. Adjusted and unadjusted logistic regression models were used to identify risk factors for mortality. There were 1111 patients who met the inclusion criteria. Overall, interstage mortality was 120/1111 (10.8%). Interstage mortality was significantly lower in era 4 relative to era 1 (4.6% versus 13.4%; P=0.02) during the time that age at the superior cavo-pulmonary connection was the lowest (135 days; P<0.01) and the interstage monitoring program was introduced. In addition, use of the right ventricle to pulmonary artery shunt was associated with decreased interstage mortality (P=0.02) and was more routinely practiced in era 4. Conclusions During this 30-year experience, the risk of interstage mortality decreased significantly in the most recent era. Factors that coincide with this finding include younger age at superior cavo-pulmonary connection, introduction of an interstage monitoring program, and increased use of the right ventricle to pulmonary artery shunt.

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.

Red Blood Cell Transfusion After Stage I Palliation Is Associated With Worse Clinical Outcomes.

Background Packed red blood cell transfusion may improve oxygen content in single-ventricle neonates, but its effect on clinical outcomes after Stage 1 palliation is unknown. Methods and Results Retrospective multicenter analysis of packed red blood cell transfusion exposures in neonates after Stage 1 palliation, excluding those with intraoperative mortality or need for extracorporeal membrane oxygenation. Transfusion practice variability was assessed, and multivariable regression used to identify transfusion risk factors. After propensity score adjustment for severity of illness, clinical outcomes were compared between transfused and nontransfused subjects. Of 396 subjects, 323 (82%) received 930 postoperative red blood cell transfusions. Packed red blood cell volume (median 9-42 mL/kg [P<0.0001]), donor exposures (1-2 [P<0.0001]), transfusion number (1-3 [P<0.0001]), and pretransfusion hemoglobin (12.1-13 g/dL, P=0.0049) varied between sites. Cyanosis (P=0.02), chest tube output (P=0.0003), and delayed sternal closure (P=0.0033) increased transfusion risk. Transfusion was associated with prolonged mechanical ventilation (6 [interquartile range 4, 12] versus 3 [1, 5] days, P=0.02) and intensive care unit stay (19 [12, 33] versus 9 [6, 19] days, P=0.016). When stratified by number of transfusions (0, 1, or >1), duration of mechanical ventilation (3 [1, 5] versus 4 [3, 6] versus 9 [5, 16] days [P<0.0001]) and intensive care unit stay (9 [6, 19] versus 13 [8, 25] versus 21 [13, 38] days [P<0.0001]) increased for those transfused more than once. Most subjects who died were transfused, though the association with mortality was not significant. Conclusions Packed red blood cell transfusion after Stage 1 palliation is common, and transfusion practice is variable. Transfusion is a significant predictor of longer intensive care unit stay and mechanical ventilation. Further studies to define evidence-based transfusion thresholds are warranted.

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.

Survival, Neurocognitive, and Functional Outcomes After Completion of Staged Surgical Palliation in a Cohort of Patients With Hypoplastic Left Heart Syndrome.

Background Management of patients with hypoplastic left heart syndrome has benefited from advancements in medical and surgical care. Outcomes have improved, although survival and long-term functional and cognitive deficits remain a concern. Methods and Results This is a cohort study of all consecutive patients with hypoplastic left heart syndrome undergoing surgical palliation at a single center. We aimed to examine demographic and perioperative factors from each surgical stage for their association with survival and neurocognitive outcomes. A total of 117 consecutive patients from 1996 to 2010 underwent surgical palliation. Seventy patients (60%) survived to the Fontan stage and 68 patients (58%) survived to undergo neurocognitive assessment at a mean (SD) age of 56.6 months (6.4 months). Full-scale, performance, and verbal intelligence quotient, as well as visual-motor integration mean (SD) scores were 86.7 (16.1), 86.3 (15.8), 88.8 (17.2), and 83.2 (14.8), respectively. On multivariable analysis, older age at Fontan, sepsis peri-Norwood, lowest arterial partial pressure of oxygen postbidirectional cavopulmonary anastomosis, and presence of neuromotor disability pre-Fontan were strongly associated with lower scores for all intelligence quotient domains. Older age at Fontan and sepsis peri-Norwood remained associated with lower scores for all intelligence quotient domains in a subgroup analysis excluding patients with disability pre-Fontan or with chromosomal abnormalities. Conclusions Older age at Fontan and sepsis are among independent predictors of poor neurocognitive outcomes for patients with hypoplastic left heart syndrome. Further studies are required to identify the appropriate age range for Fontan completion, balancing a lower risk of acute and long-term hemodynamic complications while optimizing long-term neurocognitive outcomes.

Evolution of the Norwood operation outcomes in patients with late presentation.

OBJECTIVES: We present the evolution of Norwood operation outcomes and practice pattern changes over 15 years from a single institution in Saudi Arabia. We intended to identify time trends in patient selection, procedural details, and outcome predictors over time. METHODS: Patients who underwent a Norwood operation (n = 145) between 2003 and 2018 with the use of a Blalock-Taussig shunt (BT group; n = 72), right ventricle to pulmonary artery shunt (Sano group; n = 66), or a primary cavopulmonary shunt (CPS group; n = 7) were included. The study outcomes were operative mortality, long-term survival, and multistate transition to CPS, Fontan, and death. RESULTS: Median age was 29 days. Predictors of operative mortality were lower weight (P = .026), and longer bypass time (P = .014), whereas age, and type of shunt were not. Predictors of improved long-term survival were greater weight at operation (P = .0016), later era (P = .006), and shorter bypass time (P = .001). The multistate model revealed that patients with lower weight were more likely to undergo Sano versus BT (P < .001), and if BT was chosen in such patients, they were more likely to die (P = .027). The likelihood of receiving Sano shunt was 3-fold greater in the recent era (P = .003). CONCLUSIONS: Improved outcomes of the Norwood operation are evident in the recent era and with Sano shunt, especially in patients of smaller weight. Late presentation or older age is not a contraindication to Norwood operation. The incorporation of a primary CPS at stage one operation is feasible in selected patients.

Development of a validated risk score for interstage death or transplant after stage I palliation for single-ventricle heart disease.

OBJECTIVE: To develop a risk score to predict mortality or transplant in the interstage period. BACKGROUND: The "interstage" period between the stage 1 and stage 2 palliation is a time of high morbidity and mortality for infants with single-ventricle congenital heart disease. METHODS: This was an analysis of patients with single-ventricle congenital heart disease requiring arch reconstruction who were enrolled in the National Pediatric Cardiology Quality Improvement Collaborative registry from 2008 to 2015. The primary composite endpoint was interstage mortality or transplant. Multivariable logistic regression and classification and regression tree analysis were performed on two-thirds of the patients ("learning cohort") to build a risk score for the composite endpoint, that was validated in the remaining patients ("validation cohort"). RESULTS: In the 2128 patients analyzed in the registry, the overall event rate was 9% (153 [7%] deaths, 42 [2%] transplants). In the learning cohort, factors independently associated with the composite endpoint were (1) type of Norwood; (2) postoperative ECMO; (3) discharge with Opiates; (4) No Digoxin at discharge; (5) postoperative Arch obstruction, (6) moderate-to-severe Tricuspid regurgitation without an oxygen requirement, and (7) Extra Oxygen required at discharge in patients with moderate-to-severe tricuspid regurgitation. This model was used to create a weighted risk score ("NEONATE" score; 0-76 points), with >75% accuracy in the learning and validation cohorts. In the validation cohort, the event rate in patients with a score >17 was nearly three times those with a score ≤17. CONCLUSIONS: We introduce a risk score that can be used post-stage 1 palliation to predict freedom from interstage mortality or transplant.

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.

Survival After Norwood Procedure in High-Risk Patients.

BACKGROUND: Multiple single-ventricle populations are noted to be at increased risk for mortality after the Norwood procedure. Preoperative risk factors include low birth weight, restrictive/intact atrial septum, obstructed pulmonary veins, ventricular dysfunction, and atrioventricular valve regurgitation. We report outcomes of the Norwood procedure in standard- and high-risk patients in the recent era. METHODS: All patients born with hypoplastic left heart syndrome between 2006 and 2016 who underwent a Norwood procedure at our institution were included. Patient data were retrospectively reviewed, and Kaplan-Meier analysis was used to evaluate survival between groups. RESULTS: The cohort included 177 patients. Fifty patients were determined high-risk preoperatively: low birth weight (n = 18), ventricular dysfunction/atrioventricular valve regurgitation (n = 13), intact or restrictive atrial septum/obstructed anomalous pulmonary venous return (n = 14), and multiple factors (n = 5). There were 2 (1.6%) deaths before Glenn in the standard-risk group, with a total of 10 (20%) from the high-risk groups (P < .0001). Survival at 1 year differed greatly between groups, with highest being standard risk at 89% and lowest in the intact septum/obstructed veins group at 54%. The difference between groups in long-term survival was significant (P < .001). CONCLUSIONS: Outcomes after the Norwood procedure have improved for standard-risk patients. Those with preoperative risk factors account for most of the early deaths after the Norwood procedure. This high-risk status does not resolve after Glenn, because longer-term survival continues to diverge from the standard-risk group.

Norwood Procedure-Difficulty in Weaning From Cardiopulmonary Bypass and Implications for Outcomes.

Difficulty weaning from cardiopulmonary bypass (CPB) or the need to return to CPB (collectively D-CPB) may occur after the Norwood procedure. We sought to evaluate the relationship between D-CBP and survival. This was a retrospective chart review of all patients undergoing a Norwood procedure at our institution during the interval 2005-2017. Primary outcome was survival for the Norwood procedure. Secondary outcomes included various measures of morbidity. Successful wean from CBP (S-CPB) was defined as no need to return to full-flow CPB during the initial definitive wean or after separation from CPB; otherwise, the classification was difficulty with wean (D-CBP). Successful rescue in the D-CPB group was defined as not requiring extracorporeal life support either in the operating room or within the first 3 postoperative days. Of the 196 patients in the cohort, 49 were D-CPB. Survival for S-CPB was 92.5% (136/147) vs 71.4% (35/49) for D-CPB (P = 0.001). Major morbidity occurred in 29.9% (44/147) in S-CPB vs 69.4% (34/49) in D-CPB (P < 0.001). With multivariable analysis, D-CPB was significantly associated with mortality (odds ratio = 8.09; confidence interval 2.72-24.05; P < 0.001). Successful rescue occurred in 30 of 49 patients in the D-CPB group and demonstrated survival similar to the S-CPB group. In the Norwood patient, D-CPB is an important intraoperative event and prognostic factor for mortality and morbidity. Successful rescue appears to ameliorate the impact of D-CPB on survival.

Competing risks analysis of time-to-event data for cardiovascular surgeons.

OBJECTIVES: The purpose of this article is to provide thoracic and cardiovascular surgeons with a practical step-by-step strategy to use in collaboration with a biostatistician for implementation of competing risks analysis when analyzing time-to-event data. Patients may have an outside event that precludes the event of interest. Traditional time-to-event analysis incorrectly assumes noninformative censoring in this scenario, which will lead to invalid results and conclusions. METHODS: The steps are (1) to determine whether competing risks analysis is needed, (2) to perform a nonparametric analysis, (3) to perform a model-based analysis, (4) to interpret the results, and (5) to compare to traditional survival analysis methods. We apply our approach to a hypothetical cardiovascular surgery example in determining the hazard of mortality after the stage 3 Fontan operation associated with prematurity among patients with hypoplastic left heart syndrome who had successful completion of Norwood stage 1 while incorporating mortality during the stage 2 bidirectional Glenn procedure as a competing risk. We apply nonparametric, semiparametric, and parametric methods. RESULTS: Although Cox regression establishes prematurity as a significant risk factor of mortality after stage 3 (hazard ratio, 1.26; 95% confidence interval, 1.06-1.50; P = .009), the competing risks analysis with the Fine-Gray model accounting for mortality after stage 2 determines that prematurity is not a significant predictor (hazard ratio, 1.07; 95% confidence interval, 0.90-1.27; P = .467). CONCLUSIONS: This article provides a practical step-by-step approach for making competing risks more accessible for cardiac surgeons collaborating with a biostatistician in analyzing and interpreting time-to-event data.

Trajectory of right ventricular indices is an early predictor of outcomes in hypoplastic left heart syndrome.

BACKGROUND: Children with hypoplastic left heart syndrome (HLHS) have risk for mortality and/or transplantation. Previous studies have associated right ventricular (RV) indices in a single echocardiogram with survival, but none have related serial measurements to outcomes. This study sought to determine whether the trajectory of RV indices in the first year of life was associated with transplant-free survival to stage 3 palliation (S3P). METHODS: HLHS patients at a single center who underwent stage 1 palliation (S1P) between 2000 and 2015 were reviewed. Echocardiographic indices of RV size and function were obtained before and following S1P and stage 2 palliation (S2P). The association between these indices and transplant-free survival to S3P was examined. RESULTS: There were 61 patients enrolled in the study with 51 undergoing S2P, 20 S3P, and 18 awaiting S3P. In the stage 1 perioperative period, indexed RV end-systolic area increased in patients who died or needed transplant following S2P, and changed little in those surviving to S3P (3.37 vs -0.04 cm2 /m2 , P = .017). Increased indexed RV end-systolic area was associated with worse transplant-free survival. (OR = 0.815, P = .042). In the interstage period, indexed RV end-diastolic area increased less in those surviving to S3P (3.6 vs 9.2, P = .03). CONCLUSION: Change in indexed RV end-systolic area through the stage 1 perioperative period was associated with transplant-free survival to S3P. Neither the prestage nor poststage 1 indexed RV end-systolic area was associated with transplant-free survival to S3P. Patients with death or transplant before S3P had a greater increase in indexed RV end-diastolic area during the interstage period. This suggests earlier serial changes in RV size which may provide prognostic information beyond RV indices in a single study.

Determinants of acute events leading to mortality after shunt procedure in univentricular palliation.

OBJECTIVE: The study objective was to identify determinants of adverse outcomes in patients undergoing univentricular palliation after the shunt procedure. METHODS: We performed a retrospective study of patients with univentricular lesions undergoing modified Blalock-Taussig shunt and central shunt placement, with or without concomitant Norwood/Damus-Kaye-Stansel procedures, between 2004 and 2014. RESULTS: Overall, 246 patients were included, with 150 patients undergoing concomitant Norwood/Damus-Kaye-Stansel procedure. The 30-day and in-hospital mortality were 7.3% and 14.6%, respectively. Progression to bidirectional cavopulmonary connection was achieved in 76% of patients. Acute events occurred in 66 patients (27%), with 42 having an acute event in the first 72 hours postoperatively. Of all in-hospital deaths, 75% had preceding acute events. On multivariable analysis, the risk factor for 30-day or in-hospital mortality was the incidence of an acute event (odds ratio [OR], 13.5; 95% confidence interval [CI], 5.51-36.4; P < .001). Postoperative pH was associated with fewer acute events (OR, 0.61 per 0.1 unit increase; 95% CI, 0.45-0.82; P = .002). Risk factors for shunt thrombosis associated with an acute event were increased postoperative hematocrit (OR, 2.12 per 0.1 unit increase; 95% CI, 1.01-4.58; P = .049) and 3.0-mm shunt size (OR, 3.78; 95% CI, 1.47-10.6; P = .007). Damus-Kaye-Stansel/Norwood procedure, shunt type, morphology, and extracardiac or genetic anomaly were not risk factors for mortality or acute events. CONCLUSIONS: More than one-fifth of patients shunted during univentricular palliation die before the second stage. The majority of these deaths are associated with acute events occurring early after surgery. Strategies to improve survival should focus on prevention and management of acute events.

Thirty years and 1663 consecutive Norwood procedures: Has survival plateaued?

OBJECTIVE: Hypoplastic left heart syndrome is one of the most common and challenging lesions requiring surgical intervention in the neonatal period. The Norwood procedure for hypoplastic left heart syndrome was first reported in 1983. The objective of this study was to describe early outcomes after the Norwood procedure at a single institution over 30 years. METHODS: This retrospective cohort study included all patients with hypoplastic left heart syndrome (and variants) who underwent the Norwood procedure between January 1984 and May 2014 at a single institution. The study period was divided into 6 eras: era 1, 1984 to 1988; era 2, 1989 to 1993; era 3, 1994 to 1998; era 4, 1999 to 2003; era 5, 2004 to 2008; and era 6, 2009 to 2014. The primary outcome was in-hospital mortality after the Norwood procedure. Binomial point estimates complete with 95% confidence intervals (CL0.95) were computed for the entire cohort and by era. RESULTS: During the study period, 1663 infants underwent the Norwood procedure. Overall in-hospital mortality was 25.9% (CL0.95, 23.8-28.0). Mortality by chronologic era was 40.4% (CL0.95, 34.9-45.9), 33.6% (CL0.95, 29.2-37.9), 28.7% (CL0.95, 22.8-34.6), 14.9% (CL0.95, 10.4-19.3), 11.2% (CL0.95, 7.4-15.0), and 15.7% (CL0.95, 10.3-21.1). Survival was improved in eras 4 to 6 compared with eras 1 to 3 (P all < .03). Anomalous pulmonary drainage, moderate to severe atrioventricular valve regurgitation, lower birth weight, earlier era, younger gestational age, genetic anomaly, preterm birth, race other than white or African-American, and lower weight at the Norwood procedure were associated with increased mortality. Mortality was greatest in patients with 3 or more risk factors. In the best-fitting multiple covariate model, anomalous pulmonary venous drainage, gestational age in weeks, genetic anomaly, and race other than white and African American were statistically significant contributors, after adjusting for era. CONCLUSIONS: Survival after the Norwood procedure has plateaued despite improvements in diagnosis, perioperative care, and surgical techniques. Nonmodifiable patient characteristics are important determinants of the risk of mortality.

Impact of Regional Cerebral Perfusion on Outcomes Among Neonates Undergoing Norwood Operation.

OBJECTIVES: To evaluate the impact of regional cerebral perfusion (RCP) during heart operation on outcomes in neonates undergoing Norwood operation. METHODS: We performed a retrospective cohort study using data from the Single Ventricle Reconstruction trial data set. The adjusted effect of RCP use on each outcome was studied using a penalized logistic regression model with bootstrap validation. RESULTS: Of 549 patients included in the study, 252 patients (45.9%) received RCP during their heart operation. In univariate comparisons, the majority of the baseline characteristics and preoperative risk factors were similar in the RCP and No RCP group. The total cardiopulmonary bypass (CPB) time and the total cross-clamp (CC) time were longer in the RCP group (RCP vs No RCP, median CPB time: 161 minutes vs 109 minutes; median CC time: 63 minutes vs 43 minutes). In adjusted models, the use of RCP was not associated with decreased mortality and/or need for heart transplant at hospital discharge (odds ratio [OR]: 0.73; 95% confidence interval [CI]: 0.43-1.25) or prolonged mechanical ventilation (OR: 1.20, 95% CI: 0.62-2.28) or prolonged hospital length of stay (OR: 1.30, 95% CI: 0.73-2.30). We demonstrated that use of RCP was associated with longer CPB times, increased use of ultrafiltration, and higher probability of open chest after Norwood operation. CONCLUSIONS: This study did not demonstrate any impact of RCP on in-hospital mortality and/or heart transplantation, prolonged mechanical ventilation, and prolonged hospital length of stay among neonates undergoing Norwood operation.