Acute kidney injury in hypoplastic left heart syndrome patients following the comprehensive stage two palliation.

BACKGROUND: An alternative surgical approach for hypoplastic left heart syndrome is the Hybrid pathway, which delays the risk of acute kidney injury outside of the newborn period. We sought to determine the incidence, and associated morbidity, of acute kidney injury after the comprehensive stage 2 and the cumulative incidence after the first two operations in the Hybrid pathway. DESIGN: A single centre, retrospective study was conducted of hypoplastic left heart patients completing the second-stage palliation in the Hybrid pathway from 2009 to 2018. Acute kidney injury was defined utilising Kidney Diseases Improving Global Outcomes criteria. Perioperative and post-operative characteristics were analysed. RESULTS: Sixty-one patients were included in the study cohort. The incidence of acute kidney injury was 63.9%, with 36.1% developing severe injury. Cumulatively after the Hybrid Stage 1 and comprehensive stage 2 procedures, 69% developed acute kidney injury with 36% developing severe injury. The presence of post-operative acute kidney injury was not associated with an increase in 30-day mortality (acute kidney injury 7.7% versus none 9.1%; p = > 0.9). There was a significantly longer median duration of intubation among those with acute kidney injury (acute kidney injury 32 (8, 155) hours vs. no injury 9 (0, 94) hours; p = 0.018). CONCLUSIONS: Acute kidney injury after the comprehensive stage two procedure is common and accounts for most of the kidney injury in the first two operations of the Hybrid pathway. No difference in mortality was detected between those with acute kidney injury and those without, although there may be an increase in morbidity.

Preoperative versus postoperative survival in patients with univentricular heart: a nationwide, retrospective study of patients born in 1990-2015.

OBJECTIVES: Few data exist on mortality among patients with univentricular heart (UVH) before surgery. Our aim was to explore the results of intention to perform surgery by estimating preoperative vs postoperative survival in different UVH subgroups. DESIGN: Retrospective. SETTING: Tertiary centre for congenital cardiology and congenital heart surgery. PARTICIPANTS: All 595 Norwegian children with UVH born alive from 1990 to 2015, followed until 31 December 2020. RESULTS: One quarter (151/595; 25.4%) were not operated. Among these, only two survived, and 125/149 (83.9%) died within 1 month. Reasons for not operating were that surgery was not feasible in 31.1%, preoperative complications in 25.2%, general health issues in 23.2% and parental decision in 20.5%. In total, 327/595 (55.0%) died; 283/327 (86.5%) already died during the first 2 years of life. Preoperative survival varied widely among the UVH subgroups, ranging from 40/65 (61.5%) among patients with unbalanced atrioventricular septal defect to 39/42 (92.9%) among patients with double inlet left ventricle. Postoperative survival followed a similar pattern. Postoperative survival among patients with hypoplastic left heart syndrome (HLHS) improved significantly (5-year survival, 42.5% vs 75.3% among patients born in 1990-2002 vs 2003-2015; p<0.0001), but not among non-HLHS patients (65.7% vs 72.6%; p=0.22)-among whom several subgroups had a poor prognosis similar to HLHS. A total of 291/595 patients (48.9%) had Fontan surgery CONCLUSIONS: Surgery was refrained in one quarter of the patients, among whom almost all died shortly after birth. Long-term prognosis was largely determined during the first 2 years. There was a strong concordance between preoperative and postoperative survival. HLHS survival was improved, but non-HLHS survival did not change significantly. This study demonstrates the complications and outcomes encountering newborns with UVH at all major stages of preoperative and operative treatment.

Modeling of the Tricuspid Valve and Right Ventricle in Hypoplastic Left Heart Syndrome With a Fontan Circulation.

BACKGROUND: In hypoplastic left heart syndrome, tricuspid regurgitation (TR) is associated with circulatory failure and death. We hypothesized that the tricuspid valve (TV) structure of patients with hypoplastic left heart syndrome with a Fontan circulation and moderate or greater TR differs from those with mild or less TR, and that right ventricle volume is associated with TV structure and dysfunction. METHODS: TV of 100 patients with hypoplastic left heart syndrome and a Fontan circulation were modeled using transthoracic 3-dimensional echocardiograms and custom software in SlicerHeart. Associations of TV structure to TR grade and right ventricle function and volume were investigated. Shape parameterization and analysis was used to calculate the mean shape of the TV leaflets, their principal modes of variation, and to characterize associations of TV leaflet shape to TR. RESULTS: In univariate modeling, patients with moderate or greater TR had larger TV annular diameters and area, greater annular distance between the anteroseptal commissure and anteroposterior commissure, greater leaflet billow volume, and more laterally directed anterior papillary muscle angles compared to valves with mild or less TR (all P<0.001). In multivariate modeling greater total billow volume, lower anterior papillary muscle angle, and greater distance between the anteroposterior commissure and anteroseptal commissure were associated with moderate or greater TR (P<0.001, C statistic=0.85). Larger right ventricle volumes were associated with moderate or greater TR (P<0.001). TV shape analysis revealed structural features associated with TR, but also highly heterogeneous TV leaflet structure. CONCLUSIONS: Moderate or greater TR in patients with hypoplastic left heart syndrome with a Fontan circulation is associated with greater leaflet billow volume, a more laterally directed anterior papillary muscle angle, and greater annular distance between the anteroseptal commissure and anteroposterior commissure. However, there is significant heterogeneity of structure in the TV leaflets in regurgitant valves. Given this variability, an image-informed patient-specific approach to surgical planning may be needed to achieve optimal outcomes in this vulnerable and challenging population.

Evolution in the management of aorta to left ventricular tunnel in a national congenital cardiology centre.

An aorto-ventricular tunnel is a rare congenital cardiac defect, where a channel connects the lumen of the ascending aorta to the left or right ventricle. Four patients presented with an aorto-left ventricular tunnel over two decades at a median age of 8 months (range 0.1-10 months). Two patients (50%) had associated cardiac anomalies including hypoplastic left heart syndrome and left ventricular noncompaction/hypertrophic cardiomyopathy with aortic/pulmonary valve dysplasia in one patient each. Although traditionally surgical treatment has addressed this problem, management has evolved to transcatheter closure with excellent outcomes in appropriately selected patients at our national centre.

Norwood operation versus comprehensive stage II after bilateral pulmonary artery banding palliation for infants with critical left heart obstruction.

OBJECTIVE: To determine patient characteristics and outcomes after Norwood versus comprehensive stage II (COMPSII) for infants with critical left heart obstruction who had prior hybrid palliation (bilateral pulmonary artery banding ± ductal stent). METHODS: From 23 Congenital Heart Surgeons' Society institutions (2005-2020), 138 infants underwent hybrid palliation followed by either Norwood (n = 73, 53%) or COMPSII (n = 65). Baseline characteristics were compared between Norwood and COMPSII groups. Parametric hazard model with competing risk methodology was used to determine risk and factors associated with outcomes of Fontan, transplantation, or death. RESULTS: Infants who underwent Norwood versus COMPSII had a higher prevalence of prematurity (26% vs 14%, P = .08), lower birth weight (median 2.8 vs 3.2 kg, P < .01) and less frequent ductal stenting (37% vs 99%; P < .01). Norwood was performed at a median age of 44 days and median weight of 3.5 kg, versus COMPSII at 162 days and 6.0 kg (both P < .01). Median follow-up was 6.5 years. At 5 years after Norwood and COMPSII, respectively; 50% versus 68% had Fontan (P = .16), 3% versus 5% had transplantation (P = .70), 40% versus 15% died (P = .10), and 7% versus 11% are alive without transition, respectively. For factors associated with either mortality or Fontan, only preoperative mechanical ventilation occurred more frequently in the Norwood group. CONCLUSIONS: Higher prevalence of prematurity, lower birth weight, and other patient-related characteristics in the Norwood versus COMPSII groups may influence differences in outcomes that were not statistically significant for this limited risk-adjusted cohort. The clinical decision regarding Norwood versus COMPSII after initial hybrid palliation remains challenging.

Factors associated with morbidity, mortality, and hemodynamic failure after biventricular conversion in borderline hypoplastic left hearts.

OBJECTIVE: A subset of patients with borderline hypoplastic left heart may be candidates for single to biventricular conversion, but long-term morbidity and mortality persist. Prior studies have shown conflicting results regarding the association of preoperative diastolic dysfunction and outcome, and patient selection remains challenging. METHODS: Patients with borderline hypoplastic left heart undergoing biventricular conversion from 2005 to 2017 were included. Cox regression identified preoperative factors associated with a composite outcome of time to mortality, heart transplant, takedown to single ventricle circulation, or hemodynamic failure (defined as left ventricular end-diastolic pressure >20 mm Hg, mean pulmonary artery pressure >35 mm Hg, or pulmonary vascular resistance >6 international Woods units). RESULTS: Among 43 patients, 20 (46%) met the outcome, with a median time to outcome of 5.2 years. On univariate analysis, endocardial fibroelastosis, lower left ventricular end-diastolic volume/body surface area (when <50 mL/m2), lower left ventricular stroke volume/body surface area (when <32 mL/m2), and lower left:right ventricular stroke volume ratio (when <0.7) were associated with outcome; higher preoperative left ventricular end-diastolic pressure was not. Multivariable analysis demonstrated that endocardial fibroelastosis (hazard ratio, 5.1, 95% confidence interval, 1.5-22.7, P = .033) and left ventricular stroke volume/body surface area 28 mL/m2 or less (hazard ratio, 4.3, 95% confidence interval, 1.5-12.3, P = .006) were independently associated with a higher hazard of the outcome. Approximately all patients (86%) with endocardial fibroelastosis and left ventricular stroke volume/body surface area 28 mL/m2 or less met the outcome compared with 10% of those without endocardial fibroelastosis and with higher stroke volume/body surface area. CONCLUSIONS: History of endocardial fibroelastosis and smaller left ventricular stroke volume/body surface area are independent factors associated with adverse outcomes among patients with borderline hypoplastic left heart undergoing biventricular conversion. Normal preoperative left ventricular end-diastolic pressure is insufficient to reassure against diastolic dysfunction after biventricular conversion.

Fetal Diagnosis of Scimitar Syndrome in the Presence of Complex Congenital Heart Disease.

Fetal diagnosis of scimitar syndrome requires a high index of suspicion. We present two fetal cases of complex congenital heart disease associated with scimitar syndrome, one of them is diagnosed with scimitar syndrome in utero. We emphasize prenatal echocardiographic findings that may assist with arriving at the correct prenatal diagnosis. We also discuss potential challenges in suspecting the presence of scimitar syndrome in utero. The postnatal echocardiographic findings and course are described for both patients. We reviewed the available literature on prenatal diagnosis of scimitar syndrome in the presence of complex congenital heart disease. We describe a new association of VACTERL, imperforate anus, scimitar syndrome, and double-outlet right ventricle all on the same patient, as well as the first prenatal diagnosis of scimitar syndrome associated with hypoplastic left heart syndrome with restrictive atrial septum. Advanced imaging modalities such as a fetal lung Magnetic Resonance Imaging is suggested as a confirmatory test when scimitar syndrome is suspected in utero in the presence of complex congenital heart disease.

Cardiovascular intensive care unit variables inform need for feeding tube utilization in infants with hypoplastic left heart syndrome.

OBJECTIVE: Feeding strategies in infants with hypoplastic left heart syndrome (HLHS) following stage 1 palliation (S1P) include feeding tube utilization (FTU). Timely identification of infants who will fail oral feeding could mitigate morbidity in this vulnerable population. We aimed to develop a novel clinical risk prediction score for FTU. METHODS: This was a retrospective study of infants with HLHS admitted to the Boston Children's Hospital cardiovascular intensive care unit for S1P from 2009 to 2019. Infants discharged with feeding tubes were compared with those on full oral feeds. Variables from early (birth to surgery), mid (postsurgery to cardiovascular intensive care unit transfer), and late (inpatient transfer to discharge) hospitalization were analyzed in univariate and multivariable models. RESULTS: Of 180 infants, 66 (36.7%) discharged with a feeding tube. In univariate analyses, presence of a genetic disorder (early variable, odds ratio, 3.25; P = .014) and nearly all mid and late variables were associated with FTU. In the mid multivariable model, abnormal head imaging, ventilation duration, and vocal cord dysfunction were independent predictors of FTU (c-statistic 0.87). Addition of late variables minimally improved the model (c-statistic 0.91). A risk score (the HV2 score) for FTU was developed based on the mid multivariable model with high specificity (93%). CONCLUSIONS: Abnormal head imaging, duration of ventilation, and presence of vocal cord dysfunction were associated with FTU in infants with HLHS following S1P. The predictive HV2 risk score supports routine perioperative head imaging and vocal cord evaluation. Future application of the HV2 score may improve nutritional morbidity and hospital length of stay in this population.

Noonan syndrome associated with hypoplastic left heart syndrome.

Noonan syndrome is an inherited disorder caused by alterations in the RAS-MAPK pathway. There have been several identified genotype-phenotype associations made with respect to congenital cardiac lesions and Noonan syndrome variants, but limited data exist regarding single ventricle disease in this population. Here, we report two patients with PTPN11-related Noonan syndrome and hypoplastic left heart syndrome variants.

Predictors and Outcomes of Arrhythmia on Stage I Palliation of Single Ventricle Patients.

BACKGROUND: Arrhythmias are common in single ventricle patients though their effect on outcomes during stage I palliation (S1P) is unclear. OBJECTIVES: The authors sought to study associated risks for arrhythmia in patients undergoing S1P for single ventricle disease and evaluate the outcome of arrhythmias and their treatment strategies on survival. METHODS: Retrospective patient, surgical, medication, and arrhythmia data were obtained from the NPC-QIC (National Pediatric Cardiology Quality Improvement Collaborative) database. Bivariate analysis of variables associated with arrhythmias, as well as those associated with survival, was performed at the time of stage II palliation. Appropriate variables were included in multivariate modeling. RESULTS: Of the 2,048 patients included in the study, 36% had arrhythmia noted during their S1P hospitalization, with supraventricular tachycardia (12%) and focal atrial tachycardia (11%) the most common. At S1P discharge, 11% of patients were on an antiarrhythmic medication. Arrhythmias were associated with lower survival and increased hospital length of stay. Heterotaxy syndrome, younger age at S1P, male sex, and additional anomalies were associated with increased risk of arrhythmia in multivariable modeling (P ≤ 0.01). Arrhythmia and female sex were associated with increased mortality, whereas antiarrhythmic medication and digoxin use were associated with decreased mortality (P ≤ 0.003, model area under the curve = 0.79). The use of antiarrhythmic medications within the subcohort of arrhythmia patients was also associated with decreased risk of mortality (P < 0.0001; odds ratio: 2.0-7.2). CONCLUSIONS: Arrhythmias are common during admission for S1P and associated with poor outcomes. The use of antiarrhythmic medications may improve survival, though future studies are needed.

Prenatally diagnosed coronary artery abnormalities in hypoplastic left heart syndrome are associated with a higher probability of heart transplantation.

OBJECTIVE: Coronary artery abnormalities (CA) occur in patients with hypoplastic left heart syndrome (HLHS) and may be associated with higher mortality and heart transplantation (HT). We aimed to determine whether fetuses with HLHS and prenatal CA have a higher risk of death or HT. METHODS: We performed a retrospective review of fetal echocardiograms with HLHS from 2011 to 2018. We excluded fetuses with ventricular septal defects, elective termination, death in utero, planned postnatal non-intervention, or absent follow-up data. Presence or absence of CA was determined by review of serial fetal echocardiograms. Survival analysis was used to evaluate the relationship between prenatal CA and death or HT. RESULTS: Of 86 patients with fetal HLHS, 11 had prenatal diagnosis of CA. Of these, six required HT and five died (one after undergoing HT); only one remains alive without HT. Of those without prenatal CA (n = 75), 25 died and 7 underwent HT. Patients with prenatal diagnosis of HLHS and CA had a significantly increased likelihood of death or HT (p-value <0.05). CONCLUSION: Prenatal diagnosis of CA in our cohort of patients with HLHS was associated with increased risk of death or HT. These data have significance for prenatal counseling and postnatal management.

Evolving Approach in Hypoplastic Left Heart Syndrome With Restrictive and Intact Septum.

Background: Hypoplastic left heart syndrome (HLHS) with either intact atrial septum (IS) or highly restrictive interatrial communication (HRIC) is associated with poor survival. Immediate postpartum access to cardiac therapy and timely left atrial decompression (LAD) are paramount to a successful outcome. We describe herein our evolving approach to LAD and report interstage and longer-term results. Methods: We retrospectively identified neonates with HLHS IS/HRIC requiring LAD between 2005 and 2019. All babies had prenatal/postnatal echocardiography. Our LAD strategy evolved over time from attempt at transcatheter balloon atrial septostomy (BAS) to surgical septectomy with inflow occlusion, to hybrid trans-atrial stent implantation. Results: Twelve neonates required LAD at a median time of 14 (0.5-31) hours after birth. Five patients underwent BAS that proved successful in 2 cases. Of the 3 unsuccessful cases, 2 required extra-corporeal membrane oxygenation (ECMO) support and died subsequently; one underwent hybrid trans-atrial stent implantation. Of the remaining 7 patients, 3 underwent surgical septectomy with inflow-occlusion and 4 underwent hybrid trans-atrial stent implantations. Overall, 8 patients survived LAD and reached Norwood palliation. Three of the 8 required ECMO postoperatively. There was no hospital mortality after Norwood stage 1 palliation and interstage survival was 100%. Six patients successfully underwent Glenn shunt (superior cavopulmonary anastomosis) and 5 have completed total cavopulmonary connection. Conclusions: Our experience suggests that prompt postnatal LAD can be safely achieved with careful multidisciplinary planning and accurate antenatal diagnosis. In our hands, hybrid trans-atrial septal stent insertion appears to be a safe approach which combines the versatility of transcatheter techniques together with the effectiveness of surgical control.

Serial Assessment of Right Ventricular Deformation in Patients With Hypoplastic Left Heart Syndrome: A Cardiovascular Magnetic Resonance Feature Tracking Study.

Background As right ventricular dysfunction is a major cause of adverse outcome in patients with hypoplastic left heart syndrome, the aim was to assess right ventricular function and deformation after Fontan completion by performing 2-dimensional cardiovascular magnetic resonance feature tracking in serial cardiovascular magnetic resonance studies. Methods and Results Cardiovascular magnetic resonance examinations of 108 patients with hypoplastic left heart syndrome (female: 31) were analyzed. Short-axis cine images were used for right ventricular volumetry. Two-dimensional cardiovascular magnetic resonance feature tracking was performed using long-axis and short-axis cine images to measure myocardial global longitudinal, circumferential, and radial strain. All patients had at least 2 cardiovascular magnetic resonance examinations after Fontan completion and 41 patients had 3 examinations. Global strain values and right ventricular ejection fraction decreased from the first to the third examination with a significant decline in global longitudinal strain from the first examination to the second examination (median, first, and third quartile: -18.8%, [-20.5;-16.5] versus -16.9%, [-19.3;-14.7]) and from the first to the third examination in 41 patients (-18.6%, [-20.9;-15.7] versus -15.8%, [-18.7;-12.6]; P-values <0.004). Right ventricular ejection fraction decreased significantly from the first to the third examination (55.4%, [49.8;59.3] versus 50.2%, [45.0;55.9]; P<0.002) and from the second to the third examination (53.8%, [47.2;58.7] versus 50.2%, [45.0;55.9]; P<0.0002). Conclusions Serial assessment of cardiovascular magnetic resonance studies in patients with hypoplastic left heart syndrome after Fontan completion demonstrates a significant reduction in global strain values and right ventricular ejection fraction at follow-up. The significant reduction in global longitudinal strain between the first 2 examinations with non-significant changes in right ventricular ejection fraction suggest that global longitudinal strain measured by 2-dimensional cardiovascular magnetic resonance feature tracking might be a superior technique for the detection of changes in myocardial function.

Spontaneous thrombus formation in native aortic root in patients with hypoplastic left heart syndrome: clinical presentation, treatment, and outcomes.

We report a neonate who presented with spontaneous thrombus formation in the native aortic root after Norwood palliation for hypoplastic left heart syndrome. Thrombus formation led to myocardial ischaemia due to decreased coronary blood flow with electrocardiographic signs of ischaemia and elevated cardiac enzymes. Aggressive thrombolysis and anticoagulation therapy were major contributors to successful outcome.

Native Aortic Root Thrombosis in Single-Ventricle Patients with Native-to-Neoaortic Anastomoses.

In single-ventricle patients with native-to-neoaortic anastomoses, the native aortic root serves as a conduit to the coronary arteries. Thrombosis of the native aortic root has been described only in small, limited reports. We described our center's experience with this rare adverse event. All single-ventricle patients who underwent native-to-neoaortic anastomosis from 2002 to 2017 were compiled from institutional databases. Chart review identified cases of native aortic root thrombosis. Of 467 patients, there were 9 (2%) cases of native aortic root thrombosis; all had hypoplastic left heart syndrome. Timing of thrombosis varied and occurred following each stage of single-ventricle palliation. For treatment, 8 patients received systemic anticoagulation and one patient did not receive any treatment. One patient also underwent percutaneous thrombectomy. Three patients (33.3%) died during the follow-up period. Among survivors, 4/6 had right ventricular systolic function that was mildly depressed or worse at a median follow-up of 8.3 years (interquartile range 1.3-10.8). Native aortic root thrombosis is a rare complication occurring at various stages of single-ventricle palliation. In this series, 6 of 9 patients (66.6%) survived; however, ventricular function was often compromised. No risk factors were identified to focus preventative therapies.

Norwood procedure for hypoplastic left heart syndrome associated with valvular pulmonary stenosis.

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

Fetal case of rare association of hypoplastic left heart syndrome and absent atrial septum accompanied by mixed form of supracardiac total anomalous pulmonary venous connection.

Abnormal pulmonary venous flow patterns on fetal echocardiography and a nutmeg lung pattern on fetal magnetic resonance imaging are seen in patients with pulmonary venous stenosis. The association between these findings and the degree of pulmonary venous stenosis remains unknown. We report an extremely rare case of a fetus diagnosed with hypoplastic left heart syndrome complicated by an absent atrial septum and supracardiac total anomalous pulmonary venous connection with left pulmonary venous congestion. This case suggests that compared to non-pulsatile continuous pulmonary venous flow, the nutmeg lung pattern can only be observed with severe pulmonary congestion and advanced pulmonary lymphangiectasia.