Intermediate-term mortality and cardiac transplantation in infants with single-ventricle lesions: risk factors and their interaction with shunt type

Impact of low birth weight on staged single-ventricle palliation

BACKGROUND

To assess the impact of low birth weight on early and late outcomes after staged palliation for single ventricle.

METHODS

Patients after stage 1 palliation for single ventricle in our institution were retrospectively included and divided into two weight groups: 2.5 kg or less (low birth weight) and more than 2.5 kg. The impact of low birth weight on mortality and on the progression to further palliation stages (bidirectional Glenn, stage 2, and total cavopulmonary connection, stage 3) was assessed.

RESULTS

A total of 452 patients were included. Patients with low birth weight (n = 37, 8 %) had more frequently associated prematurity and extracardiac anomalies. Early and inter-stage mortality after stage 1 was higher in patients with low birth weight, so that less of these patients reached the next palliation stage (57 % vs. 77 %, p = 0.01, and 38 % vs. 56 %, p = 0.05, for stage 2 and stage 3, respectively). After 5 years, overall survival was inferior in patients with low birth weight (48 % vs. 73 %, p < 0.001). Survival conditioned by stage 2 palliation was inferior in patients with low birth weight compared to the reference group (76 % vs. 89 % after 5 years, p = 0.04). Low birth weight was a risk factor for death in most patients' subgroups, inclusive those with restricted pulmonary blood flow after a systemic-to-pulmonary shunt procedure.

CONCLUSIONS

During staged palliation of single-ventricle physiology, low birth weight has a detrimental impact on survival extending to beyond stage 2. This study calls for increased vigilance of these patients beyond the first interstage.

Optimal Shunt Type for Norwood Procedure: Predicted Adverse Impact of Discordant Surgical Approach

BACKGROUND

The Single Ventricle Reconstruction (SVR) trial compared survival after Norwood procedure with either modified Blalock Taussig shunt (MBTS) or right ventricle pulmonary artery shunt (RVPAS).

METHODS

Data from all 549 participants in the SVR trial were used to develop the MBTS TFSA algorithms, which predict the transplantation-free survival advantage (TFSA) after MBTS vs RVPAS at 1 and 6 years after Norwood procedure. Linear regression analysis of the MBTS TFSA values was performed to identify factors related to more optimal outcomes with MBTS at each timepoint. The impact of discordant management (ie, predicted shunt type did not equal the one actually received) on outcomes and the extent of inconsistencies between predictions were evaluated.

RESULTS

The MBTS TFSA algorithm favored MBTS over RVPAS for only 6.2% of participants at 1 year and for 27.0% at 6 years. In terms of both 1- and 6-year outcomes, MBTS was favored with younger age at Norwood procedure and pre-Norwood intubation, while RVPAS was favored with younger gestational age and metrics indicating larger right ventricle size in the parasternal echocardiographic views. Other predictors were timepoint-specific. MBTS TFSA based allocation could have led to an absolute risk reduction in heart transplantation and mortality of 8.0% at 1 year and 16.8% at 6 years, mostly by preventing discordant MBTS management. Notably, separate predictions from the 1-year and 6-year algorithms produced discordant predictions for 136 participants (24.8%).

CONCLUSIONS

The incorporation of data-derived patient-specific factors for selection of shunt type for the Norwood procedure may produce more optimal transplantation free survival. These precision medicine algorithms require prospective validation.

Childhood Opportunity and Acute Interstage Outcomes: A National Pediatric Cardiology Quality Improvement Collaborative Analysis

BACKGROUND

The interstage period after discharge from stage 1 palliation carries high morbidity and mortality. The impact of social determinants of health on interstage outcomes is not well characterized. We assessed the relationship between childhood opportunity and acute interstage outcomes.

METHODS

Infants discharged home after stage 1 palliation in the National Pediatric Quality Improvement Collaborative Phase II registry (2016-2022) were retrospectively reviewed. Zip code-level Childhood Opportunity Index (COI), a composite metric of 29 indicators across education, health and environment, and socioeconomic domains, was used to classify patients into 5 COI levels. Acute interstage outcomes included death or transplant listing, unplanned readmission, intensive care unit admission, unplanned catheterization, and reoperation. The association between COI level and acute interstage outcomes was assessed using logistic regression with sequential adjustment for potential confounders.

RESULTS

The analysis cohort included 1837 patients from 69 centers. Birth weight (P<0.001) and proximity to a surgical center at birth (P=0.02) increased with COI level. Stage 1 length of stay decreased (P=0.001), and exclusive oral feeding rate at discharge increased (P<0.001), with higher COI level. More than 98% of patients in all COI levels were enrolled in home monitoring. Death or transplant listing occurred in 101 (5%) patients with unplanned readmission in 987 (53%), intensive care unit admission in 448 (24%), catheterization in 345 (19%), and reoperation in 83 (5%). There was no difference in the incidence or time to occurrence of any acute interstage outcome among COI levels in unadjusted or adjusted analysis. There was no interaction between race and ethnicity and childhood opportunity in acute interstage outcomes.

CONCLUSIONS

Zip code COI level is associated with differences in preoperative risk factors and stage 1 palliation hospitalization characteristics. Acute interstage outcomes, although common across the spectrum of childhood opportunity, are not associated with COI level in an era of highly prevalent home monitoring programs. The role of home monitoring in mitigating disparities during the interstage period merits further investigation.

Morphology of the native ascending aorta after the Norwood procedure for aortic atresia: impact on survival and right ventricular dysfunction

OBJECTIVES

Our goal was to evaluate the impact of variable morphology of the native ascending aorta after the Norwood I procedure in patients with hypoplastic left heart syndrome/aortic atresia on long-term survival and systemic right ventricular dysfunction.

METHODS

Of 151 survivors of the Norwood procedure for hypoplastic left heart syndrome/aortic atresia at our institution between January 2001 and December 2020, we included patients with available and measurable aortograms prior to stage II palliation. The diameter of the native ascending aorta, the length of the native ascending aorta and the angle between the native ascending aorta and the proximal pulmonary artery were measured. We investigated the impact of these morphologic parameters on mortality and on right ventricular dysfunction (defined as at least moderate).

RESULTS

Angiograms were available for 78 patients. The median diameter of the native ascending aorta was 3.2 mm (2.6-3.7), the median length of the native ascending aorta was 15.4 mm (13.3-17.9) and the median angle between the native ascending aorta and the proximal pulmonary artery was 44° (35°-51°). During the median follow-up of 6.5 years, 8 (10%) patients died and systemic right ventricular dysfunction occurred in 19 patients (24%). No significant association between aortic morphology and mortality could be detected. Right ventricular function was negatively affected by a larger angle between the native ascending aorta and the proximal pulmonary artery [odds ratio 1.07 (1.01-1.14), P = 0.02].

CONCLUSIONS

In survivors of the Norwood procedure for hypoplastic left heart syndrome/aortic atresia with available angiograms, no significant association between native aortic morphology and mortality could be demonstrated after stage II palliation, within the scope of this limited study. A larger anastomosis angle between the native ascending aorta and the proximal pulmonary artery emerged as a risk factor for right ventricular dysfunction.

Long-term impact of anatomic subtype in hypoplastic left heart syndrome after Fontan completion

BACKGROUND

Aortic atresia (AA)/mitral stenosis (MS) is a well-known risk factor for survival after Norwood; however, the effect of anatomical subtypes in those who survive surgical palliation is unknown.

METHODS

We performed a retrospective single-center study of patients with classic hypoplastic left heart syndrome (HLHS) who underwent Fontan at our center between August 1989 and July 2017. Clinical outcomes, as well as ventricular and atrioventricular-valve (AVV) function, were determined for each patient, and the effects of HLHS subtype were estimated using multivariable statistical analyses.

RESULTS

We included 418 patients with HLHS (AA/mitral atresia [MA] 153, AA/MS 100, aortic stenosis [AS]/MS 154, and AS/MA 11). The median follow-up period was 8.6 (interquartile range, 2.9-15.8) years. Overall transplant-free survival, cumulative incidence of AVV failure, and ventricular failure, which were defined by moderate dysfunction or greater or the necessity of surgical interventions, were 70.1%, 35.9%, and 17.9% at 20 years, respectively. Of the 3 major subtypes, AA/MS was associated with lower survival rate (AA/MA 74.6% vs AS/MS 79.1% vs AA/MS 56.1% at 17 years, P = .04). The subanalysis between AA/MA and AA/MS revealed AA/MS tended to have a greater rate of ventricular failure without a significant difference of AVV failure (AA/MA 11.2% vs AA/MS 26.2% at 17 years, P = .053).

CONCLUSIONS

The survival risk of the anatomic subtype AA/MS persisted long term after Fontan completion and was likely due to a greater rate of single ventricle rather than AVV failure. These findings suggest that the abnormal pressure overload condition of the hypoplastic left ventricle created by AA/MS has a detrimental effect on single right ventricle function.

Socioeconomic Influences on Outcomes Following Congenital Heart Disease Surgery

Associations between social determinants of health (SDOH) and adverse outcomes for children with congenital heart disease (CHD) are starting to be recognized; however, such links remain understudied. We examined the relationship between community-level material deprivation on mortality, readmission, and length of stay (LOS) for children undergoing surgery for CHD. We performed a retrospective cohort study of patients who underwent cardiac surgery at our institution from 2015 to 2018. A community-level deprivation index (DI), a marker of community material deprivation, was generated to contextualize the lived experience of children with CHD. Generalized mixed-effects models were used to assess links between the DI and outcomes of mortality, readmission, and LOS following cardiac surgery. The DI and components were scaled to provide mean differences for a one standard deviation (SD) increase in deprivation. We identified 1,187 unique patients with surgical admissions. The median LOS was 11 days, with an overall mortality rate of 4.6% and readmission rate of 7.6%. The DI ranged from 0.08 to 0.85 with a mean of 0.37 (SD 0.12). The DI was associated with increased LOS for patients with more complex heart disease (STAT 3, 4, and 5), which persisted after adjusting for factors that could prolong LOS (all p < 0.05). The DI approached but did not meet a significant association with mortality (p = 0.0528); it was not associated with readmission (p = 0.36). Community-level deprivation is associated with increased LOS for patients undergoing cardiac surgery. Future work to identify the specific health-related social needs contributing to LOS and identify targets for intervention is needed.

Treatment of hypoplastic left heart syndrome: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

This meta-analysis aimed to consolidate existing data from randomised controlled trials on hypoplastic left heart syndrome.

METHODS

Hypoplastic left heart syndrome specific randomised controlled trials published between January 2005 and September 2021 in MEDLINE, EMBASE, and Cochrane databases were included. Regardless of clinical outcomes, we included all randomised controlled trials about hypoplastic left heart syndrome and categorised them according to their results. Two reviewers independently assessed for eligibility, relevance, and data extraction. The primary outcome was mortality after Norwood surgery. Study quality and heterogeneity were assessed. A random-effects model was used for analysis.

RESULTS

Of the 33 included randomised controlled trials, 21 compared right ventricle-to-pulmonary artery shunt and modified Blalock-Taussig-Thomas shunt during the Norwood procedure, and 12 regarded medication, surgical strategy, cardiopulmonary bypass tactics, and ICU management. Survival rates up to 1 year were superior in the right ventricle-to-pulmonary artery shunt group; this difference began to disappear at 3 years and remained unchanged until 6 years. The right ventricle-to-pulmonary artery shunt group had a significantly higher reintervention rate from the interstage to the 6-year follow-up period. Right ventricular function was better in the modified Blalock-Taussig-Thomas shunt group 1-3 years after the Norwood procedure, but its superiority diminished in the 6-year follow-up. Randomised controlled trials regarding medical treatment, surgical strategy during cardiopulmonary bypass, and ICU management yielded insignificant results.

CONCLUSIONS

Although right ventricle-to-pulmonary artery shunt appeared to be superior in the early period, the two shunts applied during the Norwood procedure demonstrated comparable long-term prognosis despite high reintervention rates in right ventricle-to-pulmonary artery shunt due to pulmonary artery stenosis. For medical/perioperative management of hypoplastic left heart syndrome, further randomised controlled trials are needed to deliver specific evidence-based recommendations.

Social Determinants of Health Including Child Opportunity Index Leading to Gaps in Care for Patients With Significant Congenital Heart Disease

BACKGROUND

Gaps in care (GIC) are common for patients with congenital heart disease (CHD) and can lead to worsening clinical status, unplanned hospitalization, and mortality. Understanding of how social determinants of health (SDOH) contribute to GIC in CHD is incomplete. We hypothesize that SDOH, including Child Opportunity Index (COI), are associated with GIC in patients with significant CHD.

METHODS AND RESULTS

A total of 8554 patients followed at a regional specialty pediatric hospital with moderate to severe CHD seen in cardiology clinic between January 2013 and December 2015 were retrospectively reviewed. SDOH factors including race, ethnicity, language, and COI calculated based on home address and zip code were analyzed. GIC of >3.25 years were identified in 32% (2709) of patients. GIC were associated with ages 14 to 29 years (P<0.001), Black race or Hispanic ethnicity (P<0.001), living ≥150 miles from the hospital (P=0.017), public health insurance (P<0.001), a maternal education level of high school or less (P<0.001), and a low COI (P<0.001). Multivariable analysis showed that GIC were associated with age ≥14 years, Black race or Hispanic ethnicity, documenting <3 caregivers as contacts, mother's education level being high school or less, a very low/low COI, and insurance status (C statistic 0.66).

CONCLUSIONS

One-third of patients followed in a regional referral center with significant CHD experienced a substantial GIC (>3.25 years). Several SDOH, including a low COI, were associated with GIC. Hospitals should adopt formal GIC improvement programs focusing on SDOH to improve continuity of care and ultimately overall outcomes for patients with CHD.

Association Between Remote Monitoring and Interstage Morbidity and Death in Patients With Single-Ventricle Heart Disease Across Socioeconomic Groups

BACKGROUND

Despite improvements in survival over time, the mortality rate for infants with single-ventricle heart disease remains high. Infants of low socioeconomic status (SES) are particularly vulnerable. We sought to determine whether use of a novel remote monitoring program, the Cardiac High Acuity Monitoring Program, mitigates differences in outcomes by SES.

METHODS AND RESULTS

Within the Cardiac High Acuity Monitoring Program, we identified 610 infants across 11 centers from 2014 to 2021. All enrolled families had access to a mobile application allowing for near-instantaneous transfer of patient information to the care team. Patients were divided into SES tertiles on the basis of 6 variables relating to SES. Hierarchical logistic regression, adjusted for potential confounding characteristics, was used to determine the association between SES and death or transplant listing during the interstage period. Of 610 infants, 39 (6.4%) died or were listed for transplant. In unadjusted analysis, the rate of reaching the primary outcome between SES tertiles was similar (P=0.24). Even after multivariable adjustment, the odds of death or transplant listing were no different for those in the middle (odds ratio, 1.7 [95% CI, 0.73-3.94) or highest (odds ratio, 0.997 [95% CI, 0.30, 3.36]) SES tertile compared with patients in the lowest (overall P value 0.4).

CONCLUSIONS

In a large multicenter cohort of infants with single-ventricle heart disease enrolled in a digital remote monitoring program during the interstage period, we found no difference in outcomes based on SES. Our study suggests that this novel technology could help mitigate differences in outcomes for this fragile population of patients.

Neighborhood Social Vulnerability and Interstage Weight Gain: Evaluating the Role of a Home Monitoring Program

Background Poor interstage weight gain is a risk factor for adverse outcomes in infants with hypoplastic left heart syndrome. We sought to examine the association of neighborhood social vulnerability and interstage weight gain and determine if this association is modified by enrollment in our institution's Infant Single Ventricle Management and Monitoring Program (ISVMP). Methods and Results We performed a retrospective single-center study of infants with hypoplastic left heart syndrome before (2007-2010) and after (2011-2020) introduction of the ISVMP. The primary outcome was interstage weight gain, and the secondary outcome was interstage growth failure. Multivariable linear and logistic regression models were used to examine the association between the Social Vulnerability Index and the outcomes. We introduced an interaction term into the models to test for effect modification by the ISVMP. We evaluated 217 ISVMP infants and 111 pre-ISVMP historical controls. The Social Vulnerability Index was associated with interstage growth failure (P=0.001); however, enrollment in the ISVMP strongly attenuated this association (P=0.04). Pre-ISVMP, as well as high- and middle-vulnerability infants gained 4 g/d less and were significantly more likely to experience growth failure than low-vulnerability infants (high versus low: adjusted odds ratio [aOR], 12.5 [95% CI, 2.5-62.2]; middle versus low: aOR, 7.8 [95% CI, 2.0-31.2]). After the introduction of the ISVMP, outcomes did not differ by Social Vulnerability Index tertile. Infants with middle and high Social Vulnerability Index scores who were enrolled in the ISVMP gained 4 g/d and 2 g/d more, respectively, than pre-ISVMP controls. Conclusions In infants with hypoplastic left heart syndrome, high social vulnerability is a risk factor for poor interstage weight gain. However, enrollment in the ISVMP significantly reduces growth disparities.

Neighborhood socioeconomic status and length of stay after congenital heart disease surgery

Background and Objectives

Socioeconomic factors are associated with health outcomes and can affect postoperative length of stay after congenital heart disease (CHD) surgery. The hypothesis of this study is that patients from neighborhoods with a disadvantaged socioeconomic status (SES) have a prolonged length of hospital stay after CHD surgery.

Methods

Pre- and postoperative data were collected on patients who underwent CHD surgery at the University of Maryland Medical Center between 2011 and 2019. A neighborhood SES score was calculated for each patient using data from the United States Census Bureau and patients were grouped by high vs. low SES neighborhoods. The difference of patient length of stay (LOS) from the Society for Thoracic Surgeons median LOS for that surgery was the primary outcome measure. Linear regression was performed to examine the association between the difference from the median LOS and SES, as well as other third variables.

Results

The difference from the median LOS was -4.8 vs. -2.2 days in high vs. low SES groups (p = 0.003). SES category was a significant predictor of LOS in unadjusted and adjusted regression analyses. There was a significant interaction between Norwood operation and SES-patients with a low neighborhood SES who underwent Norwood operation had a longer LOS, but there was no difference in LOS by SES in patients who underwent other operations.

Conclusions

Neighborhood SES is a significant predictor of the LOS after congenital heart disease surgery. This effect was seen primarily in patients undergoing Norwood operation.

Hypoplastic Left Heart Syndrome: A Review

Hypoplastic left heart syndrome is a rare and poorly understood congenital disorder featuring a univentricular myocardium, invariably resulting in early childhood death if left untreated. The process to palliate this congenital cardiomyopathy is of high complexity and may include invasive interventions in the first week of life. The preferred treatment strategy involves a staged correction with 3 surgical procedures at different points in time. The Norwood procedure is usually performed within the first weeks of life and aims to increase systemic circulation and relieve pulmonary vascular pressure. This procedure is followed by the bidirectional Glenn and the Fontan procedures in later life, which offer to decrease stress in the ventricular chamber. The prognosis of children with this disease has greatly improved in the past decades; however, it is still largely driven by multiple modifiable and nonmodifiable variables. Novel and clever alternatives have been proposed to improve the survival and neurodevelopment of these patients, although they are not used as standard of care in all centers. The neurodevelopmental outcomes among these patients have received particular attention in the last decade in light to improve this very limiting associated comorbidity that compromises quality of life.

Impact of Neighborhood Socioeconomic Status on Outcomes Following First-Stage Palliation of Single Ventricle Heart Disease

Background The impact of neighborhood socioeconomic status (SES) on outcomes following first-stage palliation of single ventricle heart disease remains incompletely characterized. Methods and Results This was a single-center, retrospective review of consecutive patients who underwent the Norwood procedure from January 1, 1997 to November 11, 2017. Outcomes of interest included in-hospital (early) mortality or transplant, postoperative hospital length-of-stay, inpatient cost, and postdischarge (late) mortality or transplant. The primary exposure was neighborhood SES, assessed using a composite score derived from 6 US census-block group measures related to wealth, income, education, and occupation. Associations between SES and outcomes were assessed using logistic regression, generalized linear, or Cox proportional hazards models, adjusting for baseline patient-related risk factors. Of 478 patients, there were 62 (13.0%) early deaths or transplants. Among 416 transplant-free survivors at hospital discharge, median postoperative hospital length-of-stay and cost were 24 (interquartile range, 15-43) days and $295 000 (interquartile range, $193 000-$563 000), respectively. There were 97 (23.3%) late deaths or transplants. On multivariable analysis, patients in the lowest SES tertile had greater risk of early mortality or transplant (odds ratio [OR], 4.3 [95% CI, 2.0-9.4; P<0.001]), had longer hospitalizations (coefficient 0.4 [95% CI, 0.2-0.5; P<0.001]), incurred higher costs (coefficient 0.5 [95% CI, 0.3-0.7; P<0.001]), and had greater risk of late mortality or transplant (hazard ratio, 2.2 [95% CI, 1.3-3.7; P=0.004]), compared with those in the highest tertile. The risk of late mortality was partially attenuated with successful completion of home monitoring programs. Conclusions Lower neighborhood SES is associated with worse transplant-free survival following the Norwood operation. This risk persists throughout the first decade of life and may be mitigated with successful completion of interstage surveillance programs.

Impact of Extracardiac Anomalies on Mortality and Morbidity in Staged Single Ventricle Palliation

BACKGROUND

This study was intended to determine the impact of extracardiac anomalies on outcomes in patients with functional single ventricle who underwent staged palliation.

METHODS

We reviewed medical records of patients who underwent first-stage palliation at our center between 2001 and 2020. The prevalence and type of extracardiac anomalies were evaluated, and their impact on outcomes during staged palliation was analyzed.

RESULTS

Among 602 patients who underwent first-stage palliation, 81 (14%) patients had associated with extracardiac anomalies. They were more frequently associated with prematurity (P = .03) and low birth weight below 2.5 kg (P < .01). Mortality between first-stage palliation and stage II was similar in patients with and without extracardiac anomalies (24.7% vs 17.1%, P = .10). However, mortality between stage II and stage III was significantly higher in patients with extracardiac anomalies compared with those without (22.2% vs 12.5%, P = .02). Mortality after stage III was also higher in patients with extracardiac anomalies compared with those without (4.9% vs 1.5%, P = .04). In the subgroup analysis of 81 patients with extracardiac anomalies, renal anomalies were identified as a significant risk factor for mortality (P = .03, hazard ratio 2.44).

CONCLUSIONS

The incidence of extracardiac anomalies in this study was 14%, and patients with extracardiac anomalies were highly associated with prematurity and low birth weight. Presence of extracardiac anomalies was associated with higher mortality between stage II and stage III palliation and after stage III phase, but not before stage II. Among extracardiac anomalies, renal anomalies were identified as a risk factor for mortality.

Cumulative comorbid conditions influence mortality risk after staged palliation for hypoplastic left heart syndrome and variants

OBJECTIVE

Prematurity, low birth weight, genetic syndromes, extracardiac conditions, and secondary cardiac lesions are considered high-risk conditions associated with mortality after stage 1 palliation. We report the impact of these conditions on outcomes from a prospective multicenter improvement collaborative.

METHODS

The National Pediatric Cardiology Quality Improvement Collaborative Phase II registry was queried. Comorbid conditions were categorized and quantified to determine the cumulative burden of high-risk diagnoses on survival to the first birthday. Logistic regression was applied to evaluate factors associated with mortality.

RESULTS

Of the 1421 participants, 40% (575) had at least 1 high-risk condition. The aggregate high-risk group had lower survival to the first birthday compared with standard risk (76.2% vs 88.1%, P < .001). Presence of a single high-risk diagnosis was not associated with reduced survival to the first birthday (odds ratio, 0.71; confidence interval, 0.49-1.02, P = .066). Incremental increases in high-risk diagnoses were associated with reduced survival to first birthday (odds ratio, 0.23; confidence interval, 0.15-0.36, P < .001) for 2 and 0.17 (confidence interval, 0.10-0.30, P < .001) for 3 to 5 high-risk diagnoses. Additional analysis that included prestage 1 palliation characteristics and stage 1 palliation perioperative variables identified multiple high-risk diagnoses, poststage 1 palliation extracorporeal membrane oxygenation support (odds ratio, 0.14; confidence interval, 0.10-0.22, P < .001), and cardiac reoperation (odds ratio, 0.66; confidence interval, 0.45-0.98, P = .037) to be associated with reduced survival odds to the first birthday.

CONCLUSIONS

The presence of 1 high-risk diagnostic category was not associated with decreased survival at 1 year. Cumulative diagnoses across multiple high-risk diagnostic categories were associated with decreased odds of survival. Further patient accrual is needed to evaluate the impact of specific comorbid conditions within the broader high-risk categories.

Preterm Birth Is Associated With Adverse Cardiac Remodeling and Worse Outcomes in Patients With a Functional Single Right Ventricle

OBJECTIVE

To assess the effects of preterm birth on cardiac structure and function and transplant-free survival in patients with hypoplastic left heart syndrome and associated anomalies throughout the staged palliation process.

STUDY DESIGN

Data from the Single Ventricle Reconstruction trial were used to assess the impact of prematurity on echocardiographic measures at birth, Norwood, Stage II, and 14 months in 549 patients with a single functional right ventricle. Medical history was recorded once a year using medical records or telephone interviews. Cox regression models were applied to analyze transplant-free survival to age 6 years. Causal mediation analysis was performed to estimate the mediating effect of birth weight within this relationship.

RESULTS

Of the 549 participants, 64 (11.7%) were born preterm. Preterm-born participants had lower indexed right ventricle end-diastolic volumes at birth but higher volumes than term-born participants by age 14 months. Preterm-born participants had an increased risk of death or heart transplantation from birth to age 6 years, with an almost linear increase in the observed risk as gestational age decreased below 37 weeks. Of the total effect of preterm birth on transplant-free survival, 27.3% (95% CI 2.5-59.0%) was mediated through birth weight.

CONCLUSIONS

Preterm birth is associated with adverse right ventricle remodeling and worse transplant-free survival throughout the palliation process, in part independently of low birth weight. Further investigation into this vulnerable group may allow development of strategies that mitigate the impact of prematurity on outcomes in patients with hypoplastic left heart syndrome.

Is native aortic valvuloplasty at time of Norwood operation in infants with hypoplastic left heart syndrome and aortic stenosis safe?

In hypoplastic left heart syndrome, the size and function of the left ventricle vary and are dependent on the patency of the aortic valve. A patent native aortic valve, permitting left ventricular ejection, can augment cardiac output. We performed a retrospective chart review of patients with hypoplastic left heart syndrome and a stenotic aortic valve who underwent native aortic valvuloplasty at the time of Norwood and found that none of the eight patients identified had clinically significant aortic insufficiency. This case series suggests that surgical aortic valvuloplasty at Norwood is associated with aortic valve patency/augmented systemic cardiac output without the development of clinically significant aortic regurgitation at intermediate follow-up in a limited cohort.

High-Risk Anatomic Subsets in Hypoplastic Left Heart Syndrome

Despite overall improvements in outcomes for patients with hypoplastic left heart syndrome, there remain anatomic features that can place these patients at higher risk throughout their treatment course. These include severe preoperative obstruction to pulmonary venous return, restrictive atrial septum, coronary fistulae, severe tricuspid regurgitation, smaller ascending aorta diameter (especially if <2 mm), and poor ventricular function. The risk of traditional staged palliation has led to the development of alternative strategies for such patients. To further improve the outcomes, we must continue to diligently examine and study anatomic details in HLHS patients.

Cumulative In-Hospital Costs Associated With Single-Ventricle Palliation

Background

In the SVR (Single Ventricle Reconstruction) Trial, 1-year survival in recipients of right ventricle to pulmonary artery shunts (RVPAS) was superior to that in those receiving modified Blalock-Taussig-Thomas shunts (MBTTS), but not in subsequent follow-up. Cost analysis is an expedient means of evaluating value and morbidity.

Objectives

The purpose of this study was to evaluate differences in cumulative hospital costs between RVPAS and MBTTS.

Methods

Clinical data from SVR and costs from Pediatric Health Information Systems database were combined. Cumulative hospital costs and cost-per-day-alive were compared serially at 1, 3, and 5 years between RVPAS and MBTTS. Potential associations between patient-level factors and cost were explored with multivariable models.

Results

In total, 303 participants (55% of the SVR cohort) from 9 of 15 sites were studied (48% MBTTS). Observed total costs at 1 year were lower for MBTTS ($701,260 ± 442,081) than those for RVPAS ($804,062 ± 615,068), a difference that was not statistically significant (P = 0.10). Total costs were also not significantly different at 3 and 5 years (P = 0.21 and 0.32). Similarly, cost-per-day-alive did not differ significantly for either group at 1, 3, and 5 years (all P > 0.05). In analyses of transplant-free survivors, total costs and cost-per-day-alive were higher for RVPAS at 1 year (P = 0.05 for both) but not at 3 and 5 years (P > 0.05 for all). In multivariable models, aortic atresia and prematurity were associated with increased cost-per-day-alive across follow-up (P < 0.05).

Conclusions

Total costs do not differ significantly between MBTTS and RVPAS. The magnitude of longitudinal costs underscores the importance of efforts to improve outcomes in this vulnerable population.

Distance from home to birth hospital, transfer, and mortality in neonates with hypoplastic left heart syndrome in California

BACKGROUND

Prior studies report a lower risk of mortality among neonates with hypoplastic left heart syndrome (HLHS) who are born at a cardiac surgical center, but many neonates with HLHS are born elsewhere and transferred for repair. We investigated the associations between the distance from maternal home to birth hospital, the need for transfer after birth, sociodemographic factors, and mortality in infants with HLHS in California from 2006 to 2011.

METHODS

We used linked data from two statewide databases to identify neonates for this study. Three groups were included in the analysis: "lived close/not transferred," "lived close/transferred," and "lived far/not transferred." We defined "lived close" versus "lived far" as 11 miles, the median distance from maternal residence to birth hospital. Log-binomial regression models were used to identify the association between sociodemographic variables, distance to birth hospital and transfer. Cox proportional hazards models were used to identify the association between mortality and distance to birth hospital and transfer. Models were adjusted for sociodemographic variables.

RESULTS

Infants in the lived close/not transferred and the lived close/transferred groups (vs. the lived far/not transferred group) were more likely to live in census tracts above the 75th percentile for poverty with relative risks 1.94 (95% confidence interval [CI] 1.41-2.68) and 1.21 (95% CI 1.05-1.40), respectively. Neonatal mortality was higher among the lived close/not transferred group compared with the lived far/not transferred group (hazard ratio 1.77, 95% CI 1.17-2.67).

CONCLUSIONS

Infants born to mothers experiencing poverty were more likely to be born close to home. Infants with HLHS who were born close to home and not transferred to a cardiac center had a higher risk of neonatal mortality than infants who were delivered far from home and not transferred. Future studies should identify the barriers to delivery at a cardiac center for mothers experiencing poverty.

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.

Impact of Left Ventricular Morphology on Adverse Outcomes Following Stage 1 Palliation for Hypoplastic Left Heart Syndrome: 20 Years of National Data From Sweden

Background

Hypoplastic left heart syndrome is associated with significant morbidity and mortality. We aimed to assess the influence of left ventricular morphology and choice of shunt on adverse outcome in patients with hypoplastic left heart syndrome and stage 1 palliation.

Methods and Results

This was a retrospective analysis of patients with hypoplastic left heart syndrome with stage 1 palliation between 1999 and 2018 in Sweden. Patients (n=167) were grouped based on the anatomic subtypes aortic‐mitral atresia, aortic atresia‐mitral stenosis (AA‐MS), and aortic‐mitral stenosis. The left ventricular phenotypes including globular left ventricle (Glob‐LV), miniaturized and slit‐like left ventricle (LV), and the incidence of major adverse events (MAEs) including mortality were assessed. The overall mortality and MAEs were 31% and 41%, respectively. AA‐MS (35%) was associated with both mortality (all other subtypes versus AA‐MS: interstage‐I: hazard ratio [HR], 2.7; P =0.006; overall: HR, 2.2; P =0.005) and MAEs (HR, 2.4; P =0.0009). Glob‐LV (57%), noticed in all patients with AA‐MS, 61% of patients with aortic stenosis‐mitral stenosis, and 19% of patients with aortic atresia‐mitral atresia, was associated with both mortality (all other left ventricular phenotypes versus Glob‐LV: interstage‐I: HR, 4.5; P =0.004; overall: HR, 3.4; P =0.0007) and MAEs (HR, 2.7; P =0.0007). There was no difference in mortality and MAEs between patients with AA‐MS and without AA‐MS with Glob‐LV ( P >0.15). Patients with AA‐MS (35%) or Glob‐LV (38%) palliated with a Blalock‐Taussig shunt had higher overall mortality compared with those palliated with Sano shunts, irrespective of the stage 1 palliation year (AA‐MS: HR, 2.6; P =0.04; Glob‐ LV: HR, 2.1; P =0.03).

Conclusions

Glob‐LV and AA‐MS are independent morphological risk factors for adverse short‐ and long‐ term outcome, especially if a Blalock‐Taussig shunt is used as part of stage 1 palliation. These findings are important for the clinical management of patients with hypoplastic left heart syndrome.

Global longitudinal strain analysis of the singe right ventricle: leveling the playing field

BACKGROUND

All available echocardiographic methods to assess single, systemic right ventricle (sRV) systolic function have limitations. Subjective grading is prone to bias and varies among readers. Quantitative methods that require significant manual input, such as fractional area change (FAC), are often not reproducible. The aim of this study is to determine whether global longitudinal strain (GLS) is more reproducible than FAC and subjective grading in sRV patients among individual readers and across different levels of experience.

METHODS

Clinically indicated echocardiograms for 40 patients with functional systemic right ventricles were assessed by 5 readers with varying reading experience: one sonographer, one cardiology fellow, and three attending cardiologists at different career stages. All readers were blinded to patient data and other reader responses. Each reader reviewed the same images for subjective grade (scale 1-8, normal to severely depressed), RV end-diastolic and end-systolic area measurements, and longitudinal strain analysis. A repeat analysis was performed under identical conditions after at least 2 weeks on all 40 patients. Inter- and intra-reader reproducibility was assessed with intraclass correlation coefficient (ICC). Correlations between responses were assessed with Spearman's correlation coefficient.

RESULTS

The subjective method had fair to good reproducibility (ICC 0.7, interquartile range (IQR) 0.60,0.72) while the FAC method was poor (ICC 0.46, IQR 0.39,0.51) between readers. Reproducibility for GLS was excellent (ICC 0.88, IQR 0.88,0.89). Intra-reader reproducibility was excellent by subjective grading (ICC 0.85, IQR 0.73,0.88), poor by FAC (ICC = 0.63, IQR 0.35,0.66) and excellent by GLS (ICC 0.93, IQR 0.88,0.96). Attending-level readers were more consistent with their subjective grading, while all readers were excellent with GLS.

CONCLUSION

GLS is more reproducible than conventional methods at assessing sRV systolic function between readers with different levels of experience. For most readers it was more consistent than their own subjective grade of RV function. Laboratories staffed by multiple readers are likely to be more consistent in grading systemic RV systolic function using GLS.

Socioeconomic Impact on Outcomes During the First Year of Life of Patients with Single Ventricle Heart Disease: An Analysis of the National Pediatric Cardiology Quality Improvement Collaborative Registry

Socioeconomic status (SES) affects a range of health outcomes but has not been extensively explored in the single ventricle population. We investigate the impact of community-level deprivation on morbidity and mortality for infants with single ventricle heart disease in the first year of life. Retrospective cohort analysis of infants enrolled in the National Pediatric Cardiology Improvement Collaborative who underwent staged single ventricle palliation examining mortality and length of stay (LOS) using a community-level deprivation index (DI). 974 patients met inclusion criteria. Overall mortality was 20.5%, with 15.7% of deaths occurring between the first and second palliations. After adjusting for clinical risk factors, the DI was associated with death (log relative hazard [Formula: see text] = 8.92, p = 0.030) and death or transplant (log relative hazard [Formula: see text] = 8.62, p = 0.035) in a non-linear fashion, impacting those near the mean DI. Deprivation was associated with LOS following the first surgical palliation (S1P) (p = 0.031) and overall hospitalization during the first year of life (p = 0.018). For every 0.1 increase in the DI, LOS following S1P increased by 3.35 days (95% confidence interval 0.31-6.38) and total hospitalized days by 5.08 days (95% CI 0.88-9.27). Community deprivation is associated with mortality and LOS for patients with single ventricle congenital heart disease. While patients near the mean DI had a higher hazard of one year mortality compared to those at the extremes of the DI, LOS and DI were linearly associated, demonstrating the complex nature of SES factors.

Increasing Use of the Right Ventricle to Pulmonary Artery Shunt for Stage 1 Palliation

BACKGROUND

Stage 1 palliation of hypoplastic left heart syndrome entails use of the Norwood operation with either a modified Blalock-Taussig shunt or a right ventricle-to-pulmonary artery shunt, or the Hybrid procedure. Utilization trends and factors influencing palliation selection remain unclear. We aimed to evaluate these questions and to compare outcomes between types of stage 1 palliation.

METHODS

The National Pediatric Cardiology Quality Improvement Collaborative phase 1 (6/2008-8/2016) and phase 2 (8/2016-9/2019) databases were used. Procedure type was assessed by operation year. Baseline characteristics and annual hospital volume were evaluated. Post-surgical admission duration and outcomes were compared.

RESULTS

3,497 patients were included, 30.8% with modified Blalock-Taussig shunt, 59.7% with right-ventricle-to-pulmonary-artery shunt, and 9.5% with Hybrid. Use of the right-ventricle-to-pulmonary-artery shunt increased over time (p=0.02). This increase was similar among all hospital volumes. Higher hospital volume (OR 1.2 [95% CI 1.1-1.4], p=0.003), male sex (OR 1.3 [95% CI 1.1-1.6], p=0.01), and isolated cardiac disease (OR 1.33 [95% CI 1.01-1.55], p=0.05) were associated with relatively higher likelihoods of a modified Blalock-Taussig shunt. Mortality/transplant rates before stage 2 palliation were higher with the modified Blalock-Taussig shunt than the right-ventricle-to-pulmonary-artery shunt (12.3% vs 9.6%, p=0.03).

CONCLUSIONS

In stage one palliation, use of right-ventricle-to-pulmonary-artery shunts has increased over time, use of modified Blalock-Taussig shunts has decreased, and use of Hybrids was unchanged. The modified Blalock-Taussig shunt has a higher likelihood of use in higher volume centers, males, and less complex patients, but is associated with longer hospitalizations and lower transplant-free survival to stage 2 palliation.

The Outcome of Post-cardiotomy Extracorporeal Membrane Oxygenation in Neonates and Pediatric Patients: A Systematic Review and Meta-Analysis

OBJECTIVE

Post-cardiotomy extracorporeal membrane oxygenation (PC-ECMO) is a known rescue therapy for neonates and pediatric patients who failed to wean from cardiopulmonary bypass (CPB) or who deteriorate in intensive care unit (ICU) due to various reasons such as low cardiac output syndrome (LCOS), cardiac arrest and respiratory failure. We conducted a systematic review and meta-analysis to assess the survival in neonates and pediatric patients who require PC-ECMO and sought the difference in survivals by each indication for PC-ECMO.

DESIGN

Systematic review and meta-analysis.

SETTING

Multi-institutional analysis.

PARTICIPANTS

Neonates and pediatric patients who requires PC- ECMO.

INTERVENTIONS

ECMO after open-heart surgery.

RESULTS

Twenty-six studies were included in the analysis with a total of 186,648 patients and the proportion of the population who underwent PC-ECMO was 2.5% (2,683 patients). The overall pooled proportion of survival in this population was 43.3% [95% Confidence interval (CI): 41.3-45.3%; I ²: 1%]. The survival by indications of PC-ECMO were 44.6% (95% CI: 42.6-46.6; I ²: 0%) for CPB weaning failure, 47.3% (95% CI: 39.9-54.7%; I ²: 5%) for LCOS, 37.6% (95% CI: 31.0-44.3%; I ²: 32%) for cardiac arrest and 47.7% (95% CI: 32.5-63.1%; I ²: 0%) for respiratory failure. Survival from PC-ECMO for single ventricle or biventricular physiology, was reported by 12 studies. The risk ratio (RR) was 0.74 for survival in patients with single ventricle physiology (95% CI: 0.63-0.86; I ²: 40%, P < 0.001). Eight studies reported on the survival after PC-ECMO for genetic conditions. The RR was 0.93 for survival in patients with genetic condition (95% CI: 0.52-1.65; I ²: 65%, P = 0.812).

CONCLUSIONS

PC-ECMO is an effective modality to support neonates and pediatric patients in case of failed CPB weaning and deterioration in ICU. Even though ECMO seems to improve survival, mortality and morbidity remain high, especially in neonates and pediatric patients with single ventricle physiology. Most genetic conditions alone should not be considered a contraindication to ECMO support, further studies are needed to determine which genetic abnormalities are associated with favorable outcome.

Influence of Shunt Type on Survival and Right Heart Function after the Norwood Procedure for Aortic Atresia

The study objective was to compare the results after Norwood procedure between modified Blalock-Taussig shunt (MBTS) and right ventricle-to-pulmonary artery conduit (RVPAC) according to Sano in patients with hypoplastic left heart syndrome (HLHS) and aortic atresia (AA). A total of 146 neonates with HLHS and AA who underwent the Norwood procedure at our institution between 2001 and 2020 were divided into 2 groups according to shunt type (MBTS or RVPAC). Survival after the Norwood procedure was compared between the groups. Longitudinal right ventricular and tricuspid valve function in each group were evaluated using cubic splines method. RVPAC was performed in 103 patients and MBTS in 43 according to surgeon preference. There were no differences in the 30-day mortality rates (16.5% vs 16.3%, P  = 0.973). Survival at 0.5, 1 and 3 years was 79.6%, 74.6%, and 68.9% in RVPAC and 66.8%, 64.3%, and 58.5% in MBTS (P  =  0.293). Among 23 patients undergoing tricuspid valve procedure, different mechanisms of tricuspid regurgitation were observed between the groups. Longitudinal analysis revealed greater prevalence of late right ventricular dysfunction in RVPAC patients. In 77 patients who completed Fontan procedure, the postoperative N-terminal pro B-type natriuretic peptide value was significantly higher in RVPAC vs MBTS (554 vs 276 ng/L, P  =  0.007). No survival advantage of RVPAC over MBTS was observed in neonates with HLHS and AA undergoing the Norwood procedure. Longitudinal analysis demonstrated a greater prevalence of right ventricular dysfunction and higher N-terminal pro B-type natriuretic peptide values during late follow-up in patients with RVPAC.

Post-operative Renal Failure, Shunt Type and Mortality after Norwood Palliation

BACKGROUND

The Single Ventricle Reconstruction (SVR) trial demonstrated increased risk of death or heart transplant one year post-Norwood in subjects randomized to Blalock-Taussig shunts (mBTS) compared to right ventricle-to-pulmonary artery (RV-PA) shunts. We used the SVR public use database to evaluate incidence and risk factors for post-operative renal failure and relationships between renal failure, shunt type and outcomes post-Norwood.

METHODS

Post-operative renal failure was defined a-priori as a 3-fold rise in creatinine from baseline, or dialysis use, within 7 days of Norwood. We used multivariate logistic regression to evaluate risk factors for post-operative renal failure and Cox hazard regression to determine the association between post-operative renal failure and one-year post-Norwood mortality.

RESULTS

Overall, post-operative renal failure occurred in 8.4% (46/544) with risk factors including receipt of a mBTS (aOR 3.3, p=0.02), low center volume (aOR 2.7, p=0.005), presence of ≥2 pre-op complications (aOR 4.0, p<0.001), low birth weight (aOR 3.2, p=0.002), post-operative heart block (aOR 8.5, p=0.001), and delayed sternal closure (aOR 5.3, p=0.026). Renal failure was an independent risk factor for one-year mortality (aHR 1.9, p=0.019). Assessing interaction by shunt type, mortality risk associated with renal failure was greatest in the RV-PA shunt group (aHR 3.3 versus RV-PA shunt without renal failure, p=0.001), but was also increased in the mBTS group (aHR 1.9, p=0.03).

CONCLUSIONS

Post-operative renal failure is common after Norwood and is independently associated with mortality. Although renal failure is more common after mBTS, the highest mortality risk with renal failure occurs after RV-PA shunt.

Preoperative risk factors influencing inter-stage mortality after the Norwood procedure

OBJECTIVES

With improvements in early survival after the stage I palliation (S1P) Norwood procedure for hypoplastic left heart syndrome (HLHS) and its variants, inter-stage death accounts for an increasing proportion of mortality. Our aim was to identify the risk factors for inter-stage mortality.

METHODS

The records of 322 neonates with HLHS or a variant who underwent the Norwood procedure at our centre between 2001 and 2019 were retrospectively analysed.

RESULTS

The diagnoses included 271 neonates with HLHS (84%) and 51 with variants (16%). Aortic atresia was observed in 138 (43%) patients, mitral atresia in 91 (28%), extracardiac anomalies in 42 (13%) and genetic disorder in 14 (4%). The median age and weight of the patients at the S1P Norwood procedure were 9 (interquartile range: 7-12) days and 3.2 (2.9-3.5) kg, respectively. The median cardiopulmonary bypass time was 137 (107-163) min. Modified Blalock-Taussig shunts were used in 159 (49%) and unvalved right ventricle-to-pulmonary artery shunts in 163 (51%) patients. The number of inter-stage deaths was as follows: between S1P and stage II palliation (S2P), 61 including 38 early (<30 days) and 23 late (>30 days) deaths, and between S2P and stage III palliation, 32 deaths. Low birth weight (<2.5 kg) (odds ratio 4.37, P = 0.020) and restrictive atrial septum (odds ratio 2.97, P = 0.013) were identified as risks for early mortality. Low birth weight [hazard ratio (HR) 0.99/g, P = 0.002] was a risk for inter-stage mortality between S1P and S2P. Extracardiac anomalies (HR 4.75, P = 0.049) and significant pre-S1P atrioventricular valve regurgitation (HR: 7.72, P = 0.016) were risks for inter-stage mortality between S2P and stage III palliation. Other anatomical variables including aortic atresia, anatomical subtypes and the diameter of the ascending aorta nor shunt type were not identified as risk factors for mortality during any inter-stage period.

CONCLUSIONS

The risk factors for inter-stage attrition after the Norwood procedure were different between each stage. Preoperative factors, including birth weight, restrictive atrial septum and extracardiac anomalies, adversely affected the inter-stage mortality.

Patch augmentation of small ascending aorta during stage I procedure reduces the risk of morbidity and mortality

OBJECTIVES

Hypoplastic left heart syndrome (HLHS) with aortic atresia (AA) patients are prone to coronary insufficiency due to a small ascending aorta. Prophylactic patch augmentation of the small ascending aorta during the stage I procedure (S1P) may reduce the risk of coronary insufficiency as marked by ventricular dysfunction, need for extracorporeal membrane oxygenator (ECMO) support or mortality.

METHODS

Retrospective analysis of patients with HLHS with AA who underwent an S1P was completed. Baseline ascending aorta size, right ventricular (RV) function and outcome variables of transplant-free survival, ECMO support after the stage 1 operation and RV function at the time of the bidirectional Glenn and latest follow-up were collected.

RESULTS

Between January 2010 and April 2020, 11 patients underwent prophylactic ascending aorta augmentation at the time of the S1P as a planned portion of the procedure. A total of 125 patients underwent S1P during this period as a comparison. Overall survival was 100% for the augmented group and 74% for the control group (P = 0.66). A composite end point of transplant-free survival, no post-S1P ECMO and less than moderate RV dysfunction was created. At the time of BDG, this composite end point was 100% for the augmented group and 61.8% for the control group (P = 0.008) and at most recent follow-up was 100% for the augmented group and 59.3% for control (P = 0.007). Eight patients required a rescue procedure for the clinical evidence of coronary insufficiency following S1P that included ascending aorta patch augmentation or stent placement. When comparing these rescue versus prophylactic ascending aortic augmentations, there were also differences in the composite outcome 100% for augmented and 60% for rescue (P = 0.009) and at the time of most recent follow-up 100% for augmented and 50% for rescue (P = 0.029).

CONCLUSIONS

Prophylactic patch augmentation of the ascending aorta in HLHS patients with AA may reduce the risk of mortality, ECMO and reduced RV function. Patients not initially undergoing augmentation but then requiring a rescue procedure have particularly poor outcomes. Patch augmentation for smaller ascending aortic diameters should be considered and further clinical experience may help delineate aorta diameter threshold for augmentation.

Comparison of shunt types in the neonatal Norwood procedure for single ventricle

OBJECTIVES

The ideal shunt for pulmonary blood flow, modified Blalock-Taussig shunt (MBTS) or right ventricular-pulmonary artery conduit (RVPAC) is yet to be determined. This study aimed to evaluate outcomes after the Norwood procedure according to the type of shunt.

METHODS

A total of 322 neonates with hypoplastic left heart syndrome and related anomalies who underwent the Norwood procedure at our institution between 2001 and 2019 were divided into MBTS and RVPAC groups and the outcomes after the Norwood procedure were compared between the groups with respect to mortality after each staged procedure.

RESULTS

We identified 322 consequent patients who underwent neonatal Norwood procedure for hypoplastic left heart syndrome (271 patients, 84.2%) and its variant (51 patients, 15.8%). RVPAC was performed in 163 (50.6%) patients and MBTS was performed in 159 (49.4%). There were no differences in the rate of early death (11.0% vs 12.6%, P = 0.69) or late death (7.4% vs 6.9%, P = 0.87) between the 2 groups after the Norwood procedure, and no significant difference in the number of patients who reached bidirectional cavopulmonary shunt (77.9% vs 76.1%, P = 0.69), and there was no difference in mortality after bidirectional cavopulmonary shunt (12.3% vs 7.5%, P = 0.15) or Fontan completion rate (54.0% vs 52.2%, P = 0.42) between the 2 groups. Survival at 0.5, 1, 3 and 6 years after the Norwood procedure was 81.0%, 73.8%, 67.9% and 67.0% in patients with RVPAC and 77.1%, 73.3%, 69.1% and 67.9% in patients with MBTS. There was no significant difference in the survival between the 2 groups during the median follow-up of 2.6 (interquartile ranges: 0.3-8.4, maximal 18.8) years (P = 0.97).

CONCLUSIONS

In neonates undergoing the Norwood procedure, our available data of maximal 18.8 years follow-up showed no significant difference in early mortality, inter-stage attritions, or overall survival, between MBTS and RVPAC.

Periscopic technique in Norwood operation is associated with better preservation of early ventricular function

Objective

Although the right ventricle (RV) to pulmonary artery conduit in stage 1 Norwood operation results in improved interstage survival, the long-term effects of the ventriculotomy used in the traditional technique remain a concern. The periscopic technique (PT) of RV to pulmonary artery conduit placement has been described as an alternative technique to minimize RV injury. A retrospective study was performed to compare the effects of traditional technique and PT on ventricular function following Norwood operation.

Methods

A retrospective study of all patients who underwent Norwood operation from 2012 to 2019 was performed. Patients with baseline RV dysfunction and significant tricuspid valve regurgitation were excluded. Prestage 2 echocardiograms were reviewed by a blinded experienced imager for quantification of RV function (sinus and infundibular RV fractional area change) as well as for regional conduit site wall dysfunction (normal or abnormal, including hypokinesia, akinesia, or dyskinesia). Wilcoxon rank-sum tests were used to assess differences in RV infundibular and RV sinus ejection fraction and the Fisher exact test was used to assess differences in regional wall dysfunction.

Results

Twenty-two patients met inclusion criteria. Eight underwent traditional technique and 14 underwent PT. Median infundibular RV fractional area change was 49% and 37% (P = .02) and sinus RV fractional area change was 50% and 41% for PT and traditional technique (P = .007) respectively. Similarly qualitative regional RV wall function was better preserved in PT (P = .002).

Conclusions

The PT for RV to pulmonary artery conduit in Norwood operation results in better preservation of early RV global and regional systolic function. Whether or not this benefit translates to improved clinical outcome still needs to be studied.

Social determinants of health and outcomes for children and adults with congenital heart disease: a systematic review

BACKGROUND

Social determinants of health (SDH) can substantially impact health outcomes. A systematic review, however, has never been conducted on associations of SDH with congenital heart disease (CHD) outcomes. The aim, therefore, was to conduct such a systematic review.

METHODS

Seven databases were searched through May 2020 to identify articles on SDH associations with CHD. SDH examined included poverty, uninsurance, housing instability, parental educational attainment, immigration status, food insecurity, and transportation barriers. Studies were independently selected and coded by two researchers based on the PICO statement.

RESULTS

The search generated 3992 citations; 88 were included in the final database. SDH were significantly associated with a lower likelihood of fetal CHD diagnosis, higher CHD incidence and prevalence, increased infant mortality, adverse post-surgical outcomes (including hospital readmission and death), decreased healthcare access (including missed appointments, no shows, and loss to follow-up), impaired neurodevelopmental outcomes (including IQ and school performance) and quality of life, and adverse outcomes for adults with CHD (including endocarditis, hospitalization, and death).

CONCLUSIONS

SDH are associated with a wide range of adverse outcomes for fetuses, children, and adults with CHD. SDH screening and referral to appropriate services has the potential to improve outcomes for CHD patients across the lifespan.

IMPACT

Social determinants of health (SDH) are associated with a wide range of adverse outcomes for fetuses, children, and adults with congenital heart disease (CHD). This is the first systematic review (to our knowledge) on associations of SDH with congenital heart disease CHD outcomes. SDH screening and referral to appropriate services has the potential to improve outcomes for CHD patients across the lifespan.

Attrition between the superior cavopulmonary connection and the Fontan procedure in hypoplastic left heart syndrome

OBJECTIVE

We investigated the incidence and predictors of failure to undergo the Fontan in children with hypoplastic left heart syndrome who survived superior cavopulmonary connection.

METHODS

The cohort consists of all patients with hypoplastic left heart syndrome who survived to hospital discharge after superior cavopulmonary connection between 1988 and 2017. The primary outcome was attrition, which was defined as death, nonsuitability for the Fontan, or cardiac transplantation before the Fontan. Subjects were excluded if they were awaiting the Fontan, were lost to follow-up, or underwent biventricular repair. The study period was divided into 4 eras based on changes in operative or medical management. Attrition was estimated with 95% confidence intervals, and predictors were identified using adjusted, logistic regression models.

RESULTS

Of the 856 hospital survivors after superior cavopulmonary connection, 52 died, 7 were deemed unsuitable for Fontan, and 12 underwent or were awaiting heart transplant. Overall attrition was 8.3% (71/856). Attrition rate did not change significantly across eras. A best-fitting multiple logistic regression model was used, adjusting for superior cavopulmonary connection year and other influential covariates: right ventricle to pulmonary artery shunt at Norwood (P < .01), total support time at superior cavopulmonary connection (P < .01), atrioventricular valve reconstruction at superior cavopulmonary connection (P = .02), performance of other procedures at superior cavopulmonary connection (P = .01), and length of stay after superior cavopulmonary connection (P < .01).

CONCLUSIONS

In this study spanning more than 3 decades, 8.3% of children with hypoplastic left heart syndrome failed to undergo the Fontan after superior cavopulmonary connection. This attrition rate has not decreased over 30 years. Use of a right ventricle to pulmonary artery shunt at the Norwood procedure was associated with increased attrition.

Global Leadership in Paediatric and Congenital Cardiac Care: "Using data to improve outcomes - an interview with Jennifer S. Li, MD, MHS"

Dr. Jennifer Li is the focus of our second in a planned series of interviews in Cardiology in the Young entitled, "Global Leadership in Paediatric and Congenital Cardiac Care". Dr. Li was born in Boston, Massachusetts, United States of America, and moved to Indianapolis, Indiana where she completed her secondary education. She then attended Stanford University, majoring in Chemistry and English and graduating with distinction in 1983. Dr. Li then attended Duke University School of Medicine, graduating in 1987. She then completed her internship at Children's Hospital of Philadelphia in 1987-1989, returning to Duke University Medical Center to complete both her residency in general paediatrics in 1989-1990 followed by her fellowship in paediatric cardiology in 1990-1993. She would later complete her Master's Degree in Health Sciences at Duke University in 2005.Dr. Li has spent her entire career as a paediatric cardiologist at Duke University Medical Center, where she was appointed a Professor of Pediatrics and Professor of Medicine in 2008 and has held the position as Beverly C. Morgan Endowed Professor of Pediatrics since 2012. She has served as the Chief of Paediatric Cardiology at Duke University Medical Center since 2006. She also was the Director of Paediatric Research at Duke Clinical Research Institute from 2001-2015. Dr. Li has played an instrumental role in evaluating the safety and efficacy of drugs in children, as well as in analysing and linking large multicentric databases to evaluate the outcomes, quality, and cost of paediatric and congenital cardiac care. Dr. Li has received funding from the National Institute of Health of the United States of America, as well as from industry and foundation grants. This article presents our interview with Dr. Li, an interview that covers her experience collaborating with governmental organizations and industry in the pursuit of common interests to design clinical drug trials, link and analyse large, multicentric databases, and improve paediatric health care.

Standardization of the Perioperative Management for Neonates Undergoing the Norwood Operation for Hypoplastic Left Heart Syndrome and Related Heart Defects

OBJECTIVES

In-hospital complications after the Norwood operation for single ventricle heart defects account for the majority of morbidity and mortality. Inpatient care variation occurs within and across centers. This multidisciplinary quality improvement project standardized perioperative management in a large referral center.

DESIGN

Quality improvement project.

SETTING

High volume cardiac center, tertiary care children's hospital.

PATIENTS

Neonates undergoing Norwood operation.

INTERVENTIONS

The quality improvement team developed and implemented a clinical guideline (preoperative admission to 48 hr after surgery). The composite process metric, Guideline Adherence Score, contained 13 recommendations in the guideline that reflected consistent care for all patients.

MEASUREMENTS AND MAIN RESULTS

One-hundred two consecutive neonates who underwent Norwood operation (January 1, 2013, to July 12, 2016) before guideline implementation were compared with 50 consecutive neonates after guideline implementation (July 13, 2016, to May 4, 2018). No preguideline operations met the goal Guideline Adherence Score. In the first 6 months after guideline implementation, 10 of 12 operations achieved goal Guideline Adherence Score and continued through implementation, reaching 100% for the last 10 operations. Statistical process control analysis demonstrated less variability and decreased hours of postoperative mechanical ventilation and cardiac ICU length of stay during implementation. There were no statistically significant differences in major hospital complications or in 30-day mortality. A higher percentage of patients were extubated by postoperative day 2 after guideline implementation (67% [30/47] vs 41% [41/99], respectively; p = 0.01). Of these patients, reintubation within 72 hours of extubation significantly decreased after guideline implementation (0% [0/30] vs 17% [7/41] patients, respectively; p = 0.02).

CONCLUSIONS

This initiative successfully implemented a standardized perioperative care guideline for neonates undergoing the Norwood operation at a large center. Positive statistical process control centerline shifts in Guideline Adherence Score, length of postoperative mechanical ventilation, and cardiac ICU length of stay were demonstrated. A higher percentage were successfully extubated by postoperative day 2. Establishment of standard processes can lead to best practices to decrease major adverse events.

Choice of shunt type for the Norwood I procedure: does it make a difference?

OBJECTIVES

This study aimed to compare pulmonary artery (PA) growth between patients who received a right ventricle-to-PA (RV-PA) shunt and those who received a modified Blalock-Taussig shunt (mBTS).

METHODS

All consecutive patients with hypoplastic left heart syndrome who underwent the Norwood I procedure between 2001 and 2017 were included in the study. Pre-stage 2 angiograms were analysed to measure the size of the PA. The Nakata index was calculated to estimate PA growth. The ratio of the right PA to left PA cross-sectional area (RPA/LPA) was used to calculate the difference in growth between the 2 branches. Study end points were shunt failure, shunt-related mortality and growth of the PAs.

RESULTS

A total of 223 patients with hypoplastic left heart syndrome (RV-PA group = 137, mBTS group = 86) underwent the Norwood I procedure, and 186 patients (RV-PA n = 116, mBTS n = 70) achieved the stage 2 procedure. PA growth was better in patients with mBTS (Nakata index: RV-PA = 282, mBTS = 315 mm2/m2, P = 0.021). LPA growth was worse compared to RPA growth in both groups (RPA/LPA: RV-PA = 1.21, mBTS = 1.29, P = 1.0). Patients with RV-PA shunts experienced more frequent shunt stenosis compared to patients with mBTS (26 vs 2, P < 0.010). Freedom from shunt failure was 83.3 ± 3.2% and 94 ± 2% at 6 months in the RV-PA and mBTS groups, respectively (P = 0.003).

CONCLUSIONS

PA growth is significantly better in patients who received an mBTS. Moreover, patients with an RV-PA shunt more frequently experienced shunt failure due to shunt stenosis. However, survival after the NW procedure is not shunt dependent and growth of the LPA is less pronounced than RPA, regardless of the shunt type.

Evolution of care pathways for babies with hypoplastic left heart syndrome: integrating mechanistic and clinical process investigation, standardization, and collaborative study

Since initial descriptions of staged palliation for hypoplastic left heart syndrome (HLHS) in the 1980’s, much has been learned about the pathophysiology of the single ventricle circulation. New therapies that leverage systems biology and clinical derivatives have been developed. While in-hospital mortality and morbidity for babies with HLHS have continued to improve, there remains a long (and daresay winding) road ahead to achieve ideal outcomes. Important variation in even these abbreviated in-hospital metrics persists among institutions and currently utilized prediction models explain only a small amount of this variation. Moreover, long-term survival and neurodevelopmental health for patients with HLHS are infrequently reported and remain suboptimal despite improved in-hospital outcomes. This focused review will describe the evolution of national outcomes for HLHS over time and the potential factors motivating improved time-related mortality. Emerging modifiable risk-factors that hold promise in terms of moving the needle for long-term success, including social determinants of health and the delineation of genetic profiles, will be discussed. Specifically, this review will integrate contemporary data based on the first murine HLHS models that suggest a genetically elicited modular phenotype with environmental factors known to impact the initial durability of surgical therapies. A comprehensive approach to the management of HLHS, which leverages both proactive transplantation and hybrid palliation, in addition to traditional Norwood palliation, will be emphasized to extend and match management to the complete spectrum of patient risk-profiles. Finally, we will explore the critical role that national collaboratives and quality reporting initiatives have played in improving outcomes and shifting the focus to more meaningful long-term survival and neurodevelopment.

Impact of Initial Shunt Type on Echocardiographic Indices in Children After Single Right Ventricle Palliations

Background Heart size and function in children with single right ventricle (RV) anomalies may be influenced by shunt type at the Norwood procedure. We sought to identify shunt-related differences during early childhood after staged surgical palliations using echocardiography. Methods We compared echocardiographic indices of RV, neoaortic, and tricuspid valve size and function at 14 months, pre-Fontan, and 6 years in 241 subjects randomized to a Norwood procedure using either the modified Blalock-Taussig shunt or RV-to-pulmonary-artery shunt. Results At 6 years, the shunt groups did not differ significantly in any measure except for increased indexed neoaortic area in the modified Blalock-Taussig shunt. RV ejection fraction improved between pre-Fontan and 6 years in the RV-to-pulmonary artery shunt group but was stable in the modified Blalock-Taussig shunt group. For the entire cohort, RV diastolic and systolic size and functional indices were improved at 6 years compared with earlier measurements, and indexed tricuspid and neoaortic annular area decreased from 14 months to 6 years. The prevalence of ≥moderate tricuspid and neoaortic regurgitation was uncommon and did not vary by group or time period. Diminished RV ejection fraction at the 14-month study was predictive of late death/transplant; the hazard of late death/transplant when RV ejection fraction was <40% was tripled (hazard ratio, 3.18; 95% CI, 1.41-7.17). Conclusions By 6 years after staged palliation, shunt type has not impacted RV size and function, and RV and valvar size and function show beneficial remodeling. Poor RV systolic function at 14 months predicts worse late survival independent of the initial shunt type. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT00115934.

Galectin-3 as a Predictor of Long-term Survival After Isolated Coronary Artery Bypass Grafting Surgery

BACKGROUND

Galectin-3 (Gal-3) is a well-established biomarker of adverse clinical outcomes, but its prognostic value for long-term survival after cardiac surgery is not well understood. Elevated levels of Gal-3 have been found to be remarkably associated with higher risk of death in both acute decompensated and chronic heart failure populations. Its prognostic value for long-term survival after cardiac surgery is not known.

METHODS

A sample of patients contributing to the Northern New England Cardiovascular Disease Study Group Cardiac Surgery Registry from 2004 to 2007 were enrolled in a prospective biomarker cohort (N = 1690). Preoperative Gal-3 levels were measured and categorized by quartile. We used Kaplan-Meier survival analysis and Cox regression models, adjusting for variables in The Society of Thoracic Surgeons Collaboration on the Comparative Effectiveness of Revascularization Strategy probability calculator to evaluate the association between elevated Gal-3 levels and survival to 6 years.

RESULTS

Preoperative Gal-3 levels ranged from 1.72 to 28.89 ng/mL (mean, 8.96 ng/mL; median, 8.06 ng/mL; interquartile range, 5.42-11.08 ng/mL). Crude survival decreased by increasing quartile. After adjustment, serum levels of Gal-3 in the highest quartile of the cohort were associated with significantly decreased survival compared with the lowest quartile (hazard ratio [HR] 2.22; 95% confidence interval [CI], 1.40-3.54; P = .001). No decrease in survival was found for the middle quartiles (HR 1.36; 95% CI, 0.87-2.12; P = .177).

CONCLUSIONS

A substantial association was found between elevated preoperative Gal-3 levels and risk of mortality after isolated coronary artery bypass grafting surgery. An assessment of the relationship between preoperative serum biomarkers and long-term survival can be used for risk stratification or estimating postsurgical prognosis.

Socio-economic inequalities in mortality in children with congenital heart disease: A systematic review and meta-analysis

BACKGROUND

The impact of socio-economic status (SES) on congenital heart disease (CHD)-related mortality in children is not well established.

OBJECTIVES

We aimed to systematically review and appraise the existing evidence on the association between SES (including poverty, parental education, health insurance, and income) and mortality among children with CHD.

DATA SOURCES

Seven electronic databases (Medline, Embase, Scopus, PsycINFO, CINAHL, ProQuest Natural, and Biological Science Collections), reference lists, citations, and key journals were searched.

STUDY SELECTION AND DATA EXTRACTION

We included articles reporting original research on the association between SES and mortality in children with CHD if they were full papers published in the English language and regardless of (a) timing of mortality; (b) individual or area-based measures of SES; (c) CHD subtype; (d) age at ascertainment; (e) study period examined. Screening for eligibility, data extraction, and quality appraisal were performed in duplicate.

SYNTHESIS

Meta-analyses were performed to estimate pooled ORs for in-hospital mortality according to health insurance status.

RESULTS

Of 1388 identified articles, 28 met the inclusion criteria. Increased area-based poverty was associated with increased odds/risk of postoperative (n = 1), neonatal (n = 1), post-discharge (n = 1), infant (n = 1), and long-term mortality (n = 2). Higher parental education was associated with decreased odds/risk of neonatal (n = 1) and infant mortality (n = 5), but not with long-term mortality (n = 1). A meta-analysis of four US articles showed increased unadjusted odds of in-hospital mortality in those with government/public versus private health insurance (OR 1.40, 95% CI 1.24, 1.56). The association between area-based income and CHD-related mortality was conflicting, with three of eight articles reporting significant associations.

CONCLUSION

This systematic review provides evidence that children of lower SES are at increased risk of CHD-related mortality. As these children are over-represented in the CHD population, interventions targeting socio-economic inequalities could have a large impact on improving CHD survival.

Gestational Age, Birth Weight, and Outcomes Six Years After the Norwood Procedure

BACKGROUND

Preterm delivery and low birth weight (LBW) are generally associated with worse outcomes in hypoplastic left heart syndrome (HLHS), but an individual preterm or small neonate may do well. We sought to explore the interactions between gestational age, birth weight, and birth weight for gestational age with intermediate outcomes in HLHS.

METHODS

We analyzed survival, growth, neurodevelopment, length of stay, and complications to age 6 years in subjects with HLHS from the Single Ventricle Reconstruction trial. Univariate and multivariable survival and regression analyses examined the effects and interactions of LBW (<2500 g), weight for gestational age, and gestational age category.

RESULTS

Early-term delivery (n = 234) was more common than term (n = 219) delivery. Small for gestational age (SGA) was present in 41% of subjects, but only 14% had LBW. Preterm, compared with term, delivery was associated with an increased risk of death or transplant at age 6 years (all: hazard ratio = 2.58, confidence interval = 1.43-4.67; Norwood survivors: hazard ratio = 1.96, confidence interval = 1.10-3.49) independent of LBW and weight for gestational age. Preterm delivery, early-term delivery, LBW, and SGA were each associated with lower weight at 6 years. Neurodevelopmental outcomes were worst in the LBW cohort.

CONCLUSIONS

Preterm delivery in HLHS was associated with worse survival, even beyond Norwood hospitalization. LBW, SGA, and early-term delivery were associated with worse growth but not survival. LBW was associated with worse neurodevelopment, despite similar length of stay and complications. These data suggest that preterm birth and LBW (although often concomitant) are not equivalent, impacting clinical outcomes through mechanisms independent of perioperative course complexity.

Factors Associated With Interstage Mortality Following Neonatal Single Ventricle Palliation

Background:

Several advances have led to improved hospital survival following neonatal palliation (NP) of single ventricle (SV) anomalies. Nonetheless, a number of patients continue to suffer from interstage mortality (ISM) prior to subsequent Glenn. We aim to study patients’ characteristics and anatomic, surgical, and clinical details associated with ISM.

Methods:

A total of 453 SV neonates survived to hospital discharge following NP. Competing risk analysis modeled events after NP (Glenn, transplantation, or death) and examined variables associated with ISM.

Results:

Competing risk analysis showed that one year following NP, 10% of patients had died, 87% had progressed to Glenn, 1% had received heart transplantation, and 2% were alive without subsequent surgery. On multivariable analysis, factors associated with ISM were as follows: weight ≤2.5 kg (hazard ratio, HR = 2.4 [1.2-4.6], P = .013), premature birth ≤36 weeks (HR = 2.0 [1.0-4.0], P = .05), genetic syndromes (HR = 3.2 [1.7-6.1], P < .001), unplanned cardiac reoperation (HR = 2.1 [1.0-4.4], P = .05), and prolonged intensive care unit (ICU) stay >30 days following NP (HR = 2.5 [1.4-4.5], P < .001). Palliative surgery type (shunt, Norwood, band) was not associated with ISM, although aortopulmonary shunt circulation after Norwood was (HR = 5.4 [1.5-19.2] P = .01). Of interest, underlying SV anatomy was not associated with ISM (HR = 1.1 [0.6-2.2], P = .749).

Conclusions:

In our series, ISM following NP occurred in 10% of hospital survivors. As opposed to hospital death, underlying SV anomaly was not associated with ISM. Conversely, several patient factors (prematurity, low weight, and genetic syndromes) and clinical factors (unplanned reoperation and prolonged ICU stay following NP) were associated with ISM. Vigilant outpatient management that is individualized to specific clinical and social needs, taking into account all associated factors, is warranted to improve survival in high-risk patients.

The Impact of the Left Ventricle on Right Ventricular Function and Clinical Outcomes in Infants with Single-Right Ventricle Anomalies up to 14 Months of Age

BACKGROUND

Children with single-right ventricle anomalies such as hypoplastic left heart syndrome (HLHS) have left ventricles of variable size and function. The impact of the left ventricle on the performance of the right ventricle and on survival remains unclear. The aim of this study was to identify whether left ventricular (LV) size and function influence right ventricular (RV) function and clinical outcome after staged palliation for single-right ventricle anomalies.

METHODS

In the Single Ventricle Reconstruction trial, echocardiography-derived measures of LV size and function were compared with measures of RV systolic and diastolic function, tricuspid regurgitation, and outcomes (death and/or heart transplantation) at baseline (preoperatively), early after Norwood palliation, before stage 2 palliation, and at 14 months of age.

RESULTS

Of the 522 subjects who met the study inclusion criteria, 381 (73%) had measurable left ventricles. The HLHS subtype of aortic atresia/mitral atresia was significantly less likely to have a measurable left ventricle (41%) compared with the other HLHS subtypes: aortic stenosis/mitral stenosis (100%), aortic atresia/mitral stenosis (96%), and those without HLHS (83%). RV end-diastolic and end-systolic volumes were significantly larger, while diastolic indices suggested better diastolic properties in those subjects with no left ventricles compared with those with measurable left ventricles. However, RV ejection fraction was not different on the basis of LV size and function after staged palliation. Moreover, there was no difference in transplantation-free survival to Norwood discharge, through the interstage period, or at 14 months of age between those subjects who had measurable left ventricles compared with those who did not.

CONCLUSIONS

LV size varies by anatomic subtype in infants with single-right ventricle anomalies. Although indices of RV size and diastolic function were influenced by the presence of a left ventricle, there was no difference in RV systolic function or transplantation-free survival on the basis of LV measures.