Surveillance of adults with congenital heart disease: Current guidelines and actual clinical practice.

BACKGROUND AND AIM: Congenital heart disease (CHD) is the most common birth defect with prevalence of 0.8%. Thanks to tremendous progress in medical and surgical practice, nowadays, >90% of children survive into adulthood. Recently European Society of Cardiology (ESC), American College of Cardiology (ACC)/ American Heart Association (AHA) issued guidelines which offer diagnostic and therapeutic recommendations for the different defect categories. However, the type of technical exams and their frequency of follow-up may vary largely between clinicians and centres. We aimed to present an overview of available diagnostic modalities and describe current surveillance practices by cardiologists taking care of adults with CHD (ACHD). METHODS AND RESULTS: A questionnaire was used to assess the frequency cardiologists treating ACHD for at least one year administrated the most common diagnostic tests for ACHD. The most frequently employed diagnostic modalities were ECG and echocardiography for both mild and moderate/severe CHD. Sixty-seven percent of respondents reported that they routinely address psychosocial well-being. CONCLUSION: Differences exist between reported current clinical practice and published guidelines. This is particularly true for the care of patients with mild lesions. In addition, some differences exist between ESC and American guidelines, with more frequent surveillance suggested by the Americans.

Aorta pathology and pregnancy-related risks in adult congenital cardiac disease: does the aorta dilate during pregnancy?

Background: Aortic dilatation and pregnancy are major concerns in women with aortopathy (AOP). This single-centre retrospective analysis focuses on the evolution of aortic diameters during and after pregnancy in women with Marfan syndrome (MS), Turner syndrome (TS) and bicuspid aortic valve (BAV) aortopathy. Methods and results: Thirty-eight women who had one or more single pregnancies were included. The ascending aorta was measured during pregnancy and postpartum. During pregnancy, a significant increase of diameters of the sinus aortae (median 1.4 mm; [-1.3; 3.8]) and ascending aorta (median 2.1 mm; [0.0; 4.0]) was noted. Systemic hypertension gives dilation of the aorta, but it did not influence the overall trajectory during pregnancy. Conclusion: Significant aortic dilatation is noted during pregnancy in women with underlying AOP, even persisting in the long term. Pre-existing systemic hypertension is associated with larger aortic diameters prior to pregnancy. More research on a larger study population however is needed.

External Validation of a Risk Score Model for Predicting Major Clinical Events in Adults After Atrial Switch.

BACKGROUND: A risk model has been proposed to provide a patient individualized estimation of risk for major clinical events (heart failure events, ventricular arrhythmia, all-cause mortality) in patients with transposition of the great arteries and atrial switch surgery. We aimed to externally validate the model. METHODS AND RESULTS: A retrospective, multicentric, longitudinal cohort of 417 patients with transposition of the great arteries (median age, 24 years at baseline [interquartile range, 18-30]; 63% men) independent of the model development and internal validation cohort was studied. The performance of the prediction model in predicting risk at 5 years was assessed, and additional predictors of major clinical events were evaluated separately in our cohort. Twenty-five patients (5.9%) met the major clinical events end point within 5 years. Model validation showed good discrimination between high and low 5-year risk patients (Harrell C index of 0.73 [95% CI, 0.65-0.81]) but tended to overestimate this risk (calibration slope of 0.20 [95% CI, 0.03-0.36]). In our population, the strongest independent predictors of major clinical events were a history of heart failure and at least mild impairment of the subpulmonary left ventricle function. CONCLUSIONS: We reported the first external validation of a major clinical events risk model in a large cohort of adults with transposition of the great arteries. The model allows for distinguishing patients at low risk from those at intermediate to high risk. Previous episode of heart failure and subpulmonary left ventricle dysfunction appear to be key markers in the prognosis of patients. Further optimizing risk models are needed to individualize risk predictions in patients with transposition of the great arteries.

Participation in Competitive Sports by Patients With Congenital Heart Disease: AHA/ACC and EAPC/ESC/AEPC Guidelines Comparison.

Sports participation in patients with congenital heart disease is an evolving subject. The American Heart Association/American College of Cardiology released a set of guidelines that advise the type and level of sports participation based primarily on anatomical defects with secondary consideration given to hemodynamic effects. Recently, the European Association of Preventive Cardiology/European Society of Cardiology/Association for European Paediatric and Congenital Cardiology offered a contrasting approach to sports participation that is based on hemodynamic and electrophysiological profiles of each patient, regardless of anatomical consideration. These guidelines are drastically different in their approaches but do have some similarities. In this review, we compare both documents, focusing on the aim, population, classification of sports, and the methodology of making recommendations. This review aims to assist practicing cardiologists in integrating the available published data and recommendations when counseling patients for sports participation.

Anxiety and Depression in Adults With Congenital Heart Disease.

BACKGROUND: A comprehensive understanding of adult congenital heart disease outcomes must include psychological functioning. Our multisite study offered the opportunity to explore depression and anxiety symptoms within a global sample. OBJECTIVES: In this substudy of the APPROACH-IS (Assessment of Patterns of Patient-Reported Outcomes in Adults With Congenital Heart Disease-International Study), the authors we investigated the prevalence of elevated depression and anxiety symptoms, explored associated sociodemographic and medical factors, and examined how quality of life (QOL) and health status (HS) differ according to the degree of psychological symptoms. METHODS: Participants completed the Hospital Anxiety and Depression Scale, which includes subscales for symptoms of anxiety (HADS-A) and depression (HADS-D). Subscale scores of 8 or higher indicate clinically elevated symptoms and can be further categorized as mild, moderate, or severe. Participants also completed analogue scales on a scale of 0 to 100 for QOL and HS. Analysis of variance was performed to investigate whether QOL and HS differed by symptom category. RESULTS: Of 3,815 participants from 15 countries (age 34.8 ± 12.9 years; 52.7% female), 1,148 (30.1%) had elevated symptoms in one or both subscales: elevated HADS-A only (18.3%), elevated HADS-D only (2.9%), or elevations on both subscales (8.9%). Percentages varied among countries. Both QOL and HS decreased in accordance with increasing HADS-A and HADS-D symptom categories (P < 0.001). CONCLUSIONS: In this global sample of adults with congenital heart disease, almost one-third reported elevated symptoms of depression and/or anxiety, which in turn were associated with lower QOL and HS. We strongly advocate for the implementation of strategies to recognize and manage psychological distress in clinical settings. (Patient-Reported Outcomes in Adults With Congenital Heart Disease [APPROACH-IS]; NCT02150603).

Association of European Paediatric and Congenital Cardiology practical recommendations for surveillance and prevention of cardiac disease in childhood cancer survivors: the importance of physical activity and lifestyle changes From the Association of European Paediatric and Congenital Cardiology Working Group Sports Cardiology, Physical Activity and Prevention, Working Group Adult Congenital Heart Disease, Working Group Imaging and Working Group Heart Failure.

BACKGROUND: Childhood cancer survivors are at increased risk of developing cardiovascular diseases, presenting as the main causes of morbidity and mortality within this group. Besides the usual primary and secondary prevention in combination with screening during follow-up, the modifiable lifestyle factors of physical activity, nutrition, and body weight have not yet gained enough attention regarding potential cardiovascular risk reduction. OBJECTIVE: These practical recommendations aim to provide summarised information and practical implications to paediatricians and health professionals treating childhood cancer survivors to reduce the risk of cardiovascular late effects. METHODS: The content derives from either published guidelines or expert opinions from Association of European Paediatric and Congenital Cardiology working groups and is in accordance with current state-of-the-art. RESULTS: All usual methods of prevention and screening regarding the risk, monitoring, and treatment of occurring cardiovascular diseases are summarised. Additionally, modifiable lifestyle factors are explained, and clear practical implications are named. CONCLUSION: Modifiable lifestyle factors should definitely be considered as a cost-effective and complementary approach to already implemented follow-up care programs in cardio-oncology, which can be actively addressed by the survivors themselves. However, treating physicians are strongly encouraged to support survivors to develop and maintain a healthy lifestyle, including physical activity as one of the major influencing factors. This article summarises relevant background information and provides specific practical recommendations on how to advise survivors to increase their level of physical activity.

Biomarkers in transposition of the great arteries after arterial switch operation: A pilot trial with deep phenotyping.

INTRODUCTION: Transposition of the great arteries (TGA) is a cyanotic congenital heart defect for which the arterial switch operation (ASO) is the preferred surgical repair. This study wanted to investigate whether a panel of biomarkers could identify morphologic as well as hemodynamic changes obtained by cardiac magnetic resonance (CMR). METHODS: Forty-four adult patients were included. Blood samples were collected to measure a broad range of biomarkers (galectin-3, ST2, GDF-15, PINP, ICTP, PIIINP, IGF-1, NT-proBNP, and hs-Tn). CMR was performed at rest and during exercise to assess cardiac function and morphology. Explorative statistics were performed between biomarker levels and CMR findings. RESULTS: All patients were asymptomatic. While galectin-3, GDF-15, and NT-proBNP levels were within normal ranges, increased ST2, PINP, PIIINP, and ICTP levels were found in 20.5%, 34.1%, 45.5%, and 27.3% of patients, respectively. Moreover, 3 and 2 patients, respectively, showed elevated IGF-1 and hs-Tn levels. Although the ejection fraction of both ventricles was within normal limits, impaired cardiac reserve was found in 20 and 25% of patients for left and right ventricle, respectively. CMR revealed no evidence of diffuse interstitial fibrosis, while 4 patients showed focal ischemic scarring. However, no significant associations between serum biomarkers and CMR data could be detected. CONCLUSION: The results suggest that in asymptomatic ASO-repaired TGA patients serum level biomarkers are elevated and that this increase is not associated with morphological changes nor with a decreased cardiac reserve. Further study with larger sample sizes is required to draw conclusions with greater confidence.

Adult congenital heart disease training in Europe: current status, disparities and potential solutions.

OBJECTIVES: This study aimed to determine the status of training of adult congenital heart disease (ACHD) cardiologists in Europe. METHODS: A questionnaire was sent to ACHD cardiologists from 34 European countries. RESULTS: Representatives from 31 of 34 countries (91%) responded. ACHD cardiology was recognised by the respective ministry of Health in two countries (7%) as a subspecialty. Two countries (7%) have formally recognised ACHD training programmes, 15 (48%) have informal (neither accredited nor certified) training and 14 (45%) have very limited or no programme. Twenty-five countries (81%) described training ACHD doctors 'on the job'. The median number of ACHD centres per country was 4 (range 0-28), median number of ACHD surgical centres was 3 (0-26) and the median number of ACHD training centres was 2 (range 0-28). An established exit examination in ACHD was conducted in only one country (3%) and formal certification provided by two countries (7%). ACHD cardiologist number versus gross domestic product Pearson correlation coefficient=0.789 (p<0.001). CONCLUSION: Formal or accredited training in ACHD is rare among European countries. Many countries have very limited or no training and resort to 'train people on the job'. Few countries provide either an exit examination or certification. Efforts to harmonise training and establish standards in exit examination and certification may improve training and consequently promote the alignment of high-quality patient care.

Left atrial strain in patients after arterial switch operation for transposition of the great arteries.

BACKGROUND: Left atrial (LA) strain, comprising LA reservoir, conduit and contractile function could add mechanistic information of patients after arterial switch operation (ASO) for transposition of the great arteries (TGA). ASO patients might have abnormal ventriculoarterial coupling, which makes them vulnerable to left ventricle (LV) dysfunction and results in reduced exercise capacity. This explorative study aimed to evaluate the relation between LA strain, atrial size, ventricular function, and exercise data obtained by cardiopulmonary exercise testing (CPET). METHODS: In a cohort of 44 patients (71% male, mean age 25 ± 4 years) LA strain was measured using transthoracic speckle-tracking echocardiography. Further assessment involved standard echocardiography, CPET evaluation, and blood sampling. LA strain values were compared to normal values. Correlations were calculated. Regression analysis with all strain variables to the CPET data was performed. RESULTS: LA reservoir, conduit and contractile strain were normal in 30%, 89% and 50% of the patients, respectively. LA reservoir/contractile strain correlated to LV ejection fraction (ρ 0.310/-0.159, respectively) and LA reservoir/conduit strain correlated to the LA volume index (ρ 0.336/-0.357, respectively). None of the individual LA strain parameters were associated with the CPET variables. In multivariate regression analysis, LA contractile strain was significantly associated with the percentage of predicted maximal heart rate (ß - 2.555). CONCLUSIONS: These data suggest that in TGA patients after ASO repair LA strain is impaired and correlates with LA size and LV function. However, impaired LA strain wasn't associated with the standard CPET parameters. As such, clinical significance needs to be further unravelled.

Percutaneous embolization of pulmonary arteriovenous malformations in adult patient with Rendu-Osler-Weber: a case report.

Background: Hereditary haemorrhagic telangiectasia (HHT), or Rendu-Osler-Weber syndrome, is a rare genetic disorder characterized by the development of telangiectasias and arteriovenous malformations (AVMs) throughout the body. We present a case of percutaneous embolization of pulmonary AVMs in an adult patient. Case summary: A 26-year-old male patient with polycythaemia of unknown origin and a family history of secundum atrial septal defect underwent cardiac evaluation which revealed clubbing as a sign of peripheral cyanosis. Transthoracic echocardiography showed no intracardiac shunting, but further imaging revealed pulmonary AVMs in the lower lobe of the left lung. Magnetic resonance imaging of the brain detected vascular-ischaemic lesions, likely due to embolization through the pulmonary malformations. Right heart catheterization and pulmonary angiography confirmed the presence of large AVMs in the left lower pulmonary lobe. Percutaneous closure using Amplatzer devices was performed, followed by temporary anticoagulation therapy. Oxygen saturation improved and follow-up imaging confirmed successful closure of the AVMs. Genetic testing using whole exome sequencing identified a mutation in the ENG gene, confirming the diagnosis of HHT. Discussion: Our case highlights the importance of investigating both intra- and extracardiac shunting in patients with clinical features of right-to-left shunting. Arteriovenous malformations can serve as a pathway for paradoxical emboli, potentially leading to ischaemic brain events, and might cause pulmonary arterial hypertension. Screening for arteriovenous malformations in various organs and embolization of significant shunts are essential aspects of managing HHT. Genetic testing aids in confirming the diagnosis and guides family testing.

Collaterals in congenital heart disease: when and how to treat?

The development of collateral circulation is not that rare in patients with congenital heart defects. These collaterals can affect cardiovascular hemodynamics and cause systemic arterial desaturation, which arises the question whether these should be closed. To date, few if any reports have been published on the therapeutic management of collaterals in adult patients with congenital heart disease in heart failure (HF). The focus of this article is to provide a pragmatic approach in the assessment of collateral circulation of the patient with HF. By considering the underlying hemodynamics and overall effects of the collateral circulation, we aim to provide a practical tool useful in clinical decision making. The paper highlights mainly the systemic venous to systemic venous collaterals, systemic venous to pulmonary venous (or pulmonary venous atrium) collaterals, and pulmonary arterio-venous malformations. Systemic venous anomalies are frequent and reported in 20% to 40% of patients who underwent Glenn or Fontan procedure. A reduction in effective pulmonary blood flow, coupled with increasing oxygen demands with growth, as well as a pressure difference between the higher pressure caval venous system and lower pressure atria (so called decompressing collaterals) are potential causes of collateral formation. Whether angiogenesis de novo or reappearance of embryological venous channels is responsible for collateral formation remains to be elucidated.

Decreased cardiac reserve in asymptomatic patients after arterial switch operation for transposition of the great arteries.

BACKGROUND: Exercise capacity is impaired in patients after arterial switch operation (ASO) for complete transposition of the great arteries. Maximal oxygen consumption is related with outcome. OBJECTIVES: This study assessed ventricular function by advanced echocardiography and cardiac magnetic resonance (CMR) imaging at rest and during exercise, to determine exercise capacity in ASO patients, and to correlate exercise capacity with ventricular function as potential early marker of subclinical impairment. METHODS: Forty-four patients (71% male, mean age 25 ± 4 years - range 18-40 years) were included during routine clinical follow-up. Assessment involved physical examination, 12­lead ECG, echocardiography, and cardiopulmonary exercise test (CPET) (day 1). On day 2 CMR imaging at rest and during exercise was performed. Blood was sampled for biomarkers. RESULTS: All patients reported New York Heart Association class I, the overall cohort had an impaired exercise capacity (80 ± 14% of predicted peak oxygen consumption). Fragmented QRS was present in 27%. Exercise CMR showed that 20% of patients had abnormal contractile reserve (CR) of the left ventricle (LV) and 25% had reduced CR of the right ventricle (RV). CR LV and CR RV were significantly associated with impaired exercise capacity. Pathological patterns on myocardial delayed enhancement and hinge point fibrosis were detected. Biomarkers were normal. CONCLUSION: This study found that in some asymptomatic ASO patients electrical, LV and RV changes at rest, and signs of fibrosis are present. Maximal exercise capacity is impaired and seems to be linearly related to the CR of the LV and the RV. Therefore, exercise CMR might play a role in detecting subclinical deterioration of ASO patients.

Integrative Interpretation of Cardiopulmonary Exercise Tests for Cardiovascular Outcome Prediction: A Machine Learning Approach.

Integrative interpretation of cardiopulmonary exercise tests (CPETs) may improve assessment of cardiovascular (CV) risk. Here, we identified patient phenogroups based on CPET summary metrics and evaluated their predictive value for CV events. We included 2280 patients with diverse CV risk who underwent maximal CPET by cycle ergometry. Key CPET indices and information on incident CV events (median follow-up time: 5.3 years) were derived. Next, we applied unsupervised clustering by Gaussian Mixture modeling to subdivide the cohort into four male and four female phenogroups solely based on differences in CPET metrics. Ten of 18 CPET metrics were used for clustering as eight were removed due to high collinearity. In males and females, the phenogroups differed significantly in age, BMI, blood pressure, disease prevalence, medication intake and spirometry. In males, phenogroups 3 and 4 presented a significantly higher risk for incident CV events than phenogroup 1 (multivariable-adjusted hazard ratio: 1.51 and 2.19; p ≤ 0.048). In females, differences in the risk for future CV events between the phenogroups were not significant after adjustment for clinical covariables. Integrative CPET-based phenogrouping, thus, adequately stratified male patients according to CV risk. CPET phenomapping may facilitate comprehensive evaluation of CPET results and steer CV risk stratification and management.

Anesthetic management of patients with peripartum cardiomyopathy.

PURPOSE OF REVIEW: Cardiovascular disease is increasingly emerging as a cause of peripartum morbidity and mortality. Peripartum cardiomyopathy (PPCM) is defined as pregnancy-related heart failure with a reduced left ventricular ejection fraction <45%. PPCM develops in the peripartum phase and is not an aggravation of an existing prepregnancy cardiomyopathy. Anesthesiologists typically encounter these patients in the peripartum phase in a variety of settings and should be aware of this pathology and its implications for the perioperative management of parturients. RECENT FINDINGS: PPCM has been investigated increasingly over the last few years. Significant progress has been made in the assessment of global epidemiology, pathophysiological mechanisms, genetics and treatment. SUMMARY: Although PPCM is an overall rare pathology, patients can potentially be encountered by any anesthesiologist in many different settings. Therefore, it is important to be aware of this disease and understand the basic implications for anesthetic management. Severe cases often require early referral to specialized centers for advanced hemodynamic monitoring and pharmacological or mechanical circulatory support.

Exercise in patients with repaired tetralogy of Fallot: a systematic review and meta-analysis.

OBJECTIVE: Children and adults with repaired tetralogy of Fallot (rTOF) have an impaired exercise capacity, a less active lifestyle and an increased long-term risk of adverse outcomes compared with healthy peers. This study aimed to summarise the current evidence for the effectiveness and safety of exercise training interventions in patients with rTOF. METHODS: PubMed/MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, Scopus and reference lists of relevant articles were searched for prospective studies published by November 2021. Random-effects meta-analysis and descriptive synthesis were performed to assess the effectiveness and safety of exercise training in patients with rTOF. RESULTS: Of the 9677 citations identified, 12 articles were included that reported on 10 unique studies and covered 208 patients with rTOF (range of mean/median age: 7.4-43.3 years). All studies implemented 2 to 7 aerobic or respiratory training sessions per week with durations ranging from 6 to 26 weeks. Meta-analysis of the included randomised controlled trials showed that exercise training was associated with a significant improvement in peak VO2 (pooled mean difference: +3.1 mL/min/kg; 95% CI: 0.76 to 5.36 mL/min/kg, p=0.019). Cardiac imaging studies revealed no subclinical adverse remodelling after the exercise interventions. No serious adverse events including arrhythmias were reported in these studies. CONCLUSION: Current evidence suggests that exercise training can improve exercise capacity in patients with rTOF with a low risk for adverse events. Exercise prescription may be a safe and effective tool to help improving outcomes in patients with rTOF. PROSPERO REGISTRATION NUMBER: CRD42021292809.

Cardiovascular Complications of Down Syndrome: Scoping Review and Expert Consensus.

Cardiovascular disease is a leading cause of morbidity and mortality in individuals with Down syndrome. Congenital heart disease is the most common cardiovascular condition in this group, present in up to 50% of people with Down syndrome and contributing to poor outcomes. Additional factors contributing to cardiovascular outcomes include pulmonary hypertension; coexistent pulmonary, endocrine, and metabolic diseases; and risk factors for atherosclerotic disease. Moreover, disparities in the cardiovascular care of people with Down syndrome compared with the general population, which vary across different geographies and health care systems, further contribute to cardiovascular mortality; this issue is often overlooked by the wider medical community. This review focuses on the diagnosis, prevalence, and management of cardiovascular disease encountered in people with Down syndrome and summarizes available evidence in 10 key areas relating to Down syndrome and cardiac disease, from prenatal diagnosis to disparities in care in areas of differing resource availability. All specialists and nonspecialist clinicians providing care for people with Down syndrome should be aware of best clinical practice in all aspects of care of this distinct population.

Short-term Prognostic Value of Heart Failure Diagnosis in a Contemporary Cohort of Patients With Adult Congenital Heart Disease.

BACKGROUND: Heart failure (HF) is the primary cause of premature death in adult congenital heart disease (ACHD). This study aimed to describe the impact of a HF diagnosis on short-term prognosis and to investigate the added prognostic value of an HF diagnosis to the ACHD Anatomic and Physiologic classification (ACHD-AP). METHODS: This study included 3995 patients followed in a tertiary care centre (last follow-up after January 1, 2010). Survival curves were plotted, and predictors of the primary end point (death, heart transplantation, or ventricular assist device [VAD]) were identified with the use of Cox proportional hazard models and compared with the use of Harrell's C-statistic. RESULTS: Mean age at baseline was 35.7 ± 13.3 years. The prevalence of ACHD-HF was 6.4%. During a median follow-up of 3.1 years (IQR 2.1-3.6 years), 27.3% of ACHD-HF patients reached the primary end point, compared with 1.4% of ACHD patients without HF. Event-free survivals were 78.3%, 61.9%, and 57.5% at 1, 3, and 5 years in ACHD-HF patients, compared with 99.3%, 98.3%, and 98.0% in ACHD patients without HF (P < 0.001). An HF diagnosis (HR 6.9, 95% CI 4.3-11.2) and the physiologic classification (HR 2.6, 95% CI 1.9-3.7) were independently associated with the primary end point. The addition of HF to the ACHD-AP classification yielded a Harrell's C-index of 0.8631, providing a significant improvement over the ACHD-AP classification alone (P = 0.0003). CONCLUSIONS: The risk of mortality, transplantation, or VAD is increased in ACHD-HF patients. An HF diagnosis appears to be a valuable prognostic marker in addition to the ACHD-AP classification.

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.