Prenatal diagnosis and risk factors for preoperative death in neonates with single right ventricle and systemic outflow obstruction: screening data from the Pediatric Heart Network Single Ventricle Reconstruction Trial(∗)

OBJECTIVES

The purpose of this analysis was to assess preoperative risk factors before the first-stage Norwood procedure in infants with hypoplastic left heart syndrome and related single-ventricle lesions and to evaluate practice patterns in prenatal diagnosis, as well as the role of prenatal diagnosis in outcome.

METHODS

Data from all live births with morphologic single right ventricle and systemic outflow obstruction screened for the Pediatric Heart Network's Single Ventricle Reconstruction Trial were used to investigate prenatal diagnosis and preoperative risk factors. Demographics, gestational age, prenatal diagnosis status, presence of major extracardiac congenital abnormalities, and preoperative mortality rates were recorded.

RESULTS

Of 906 infants, 677 (75%) had prenatal diagnosis, 15% were preterm (<37 weeks' gestation), and 16% were low birth weight (<2500 g). Rates of prenatal diagnosis varied by study site (59% to 85%, P < .0001). Major extracardiac congenital abnormalities were less prevalent in those born after prenatal diagnosis (6% vs 10%, P = .03). There were 26 (3%) deaths before Norwood palliation; preoperative mortality did not differ by prenatal diagnosis status (P = .49). In multiple logistic regression models, preterm birth (P = .02), major extracardiac congenital abnormalities (P < .0001), and obstructed pulmonary venous return (P = .02) were independently associated with preoperative mortality.

CONCLUSIONS

Prenatal diagnosis occurred in 75%. Preoperative death was independently associated with preterm birth, obstructed pulmonary venous return, and major extracardiac congenital abnormalities. Adjusted for gestational age and the presence of obstructed pulmonary venous return, the estimated odds of preoperative mortality were 10 times greater for subjects with a major extracardiac congenital abnormality.

Hypoplastic left heart syndrome: from comfort care to long-term survival

The management of hypoplastic left heart syndrome (HLHS) has changed substantially over the past four decades. In the 1970s, children with HLHS could only be provided with supportive care. As a result, most of these unfortunate children died within the neonatal period. The advent of the Norwood procedure in the early 1980s has changed the prognosis for these children, and the majority now undergoing a series of three surgical stages that can support survival beyond the neonatal period and into early adulthood. This review will focus on the Norwood procedure and the other important innovations of the last half century that have improved our outlook toward children born with HLHS.

Feeding complications in hypoplastic left heart syndrome after the Norwood procedure: a systematic review of the literature

Gastrointestinal and feeding complications after the Norwood procedure in infants with hypoplastic left heart syndrome increases morbidity and mortality. These problems are the result of intraoperative challenges, shunt-dependent physiology, and the absence of best-practice guidelines. In response, a systematic review of feeding-related complications and management strategies was performed. A literature search from 1950 to March 2010 identified 21 primary research articles and 4 reviews. Dysphagia, necrotizing enterocolitis (NEC), and poor nutritional status are significant feeding-related complications. Three studies directly compared the modified Blalock-Taussig shunt with the right ventricle-to-pulmonary artery conduit (RV-PA). Patients palliated with either shunt had impaired mesenteric blood flow. Mortality did not differ between shunt types. Three studies demonstrated improved outcomes, e.g., increased survival, decreased incidence of NEC, and decreased median time to recommended daily allowance of calories, with a postoperative feeding algorithm. Two studies showed increased survival between stage I and II surgical palliation after implementation of a home-monitoring system consisting of daily weight and systemic oxygen saturation measurements. The RV-PA shunt does not significantly alter mortality or increase mesenteric blood flow. A postoperative feeding algorithm and a home-monitoring system may improve outcomes and decrease average hospital length of stay (LOS). Additional studies are needed to determine which interventions, as part of a standardized protocol, improve survival and decrease complications.

Identified mortality risk factors associated with presentation, initial hospitalisation, and interstage period for the Norwood operation in a multi-centre registry: a report from the national pediatric cardiology-quality improvement collaborative

INTRODUCTION

Despite improvements in care following Stage 1 palliation, interstage mortality remains substantial. The National Pediatric Cardiology-Quality Improvement Collaborative captures clinical process and outcome data on infants discharged into the interstage period after Stage 1. We sought to identify risk factors for interstage mortality using these data.

MATERIALS AND METHODS

Patients who reached Stage 2 palliation or died in the interstage were included. The analysis was considered exploratory and hypothesis generating. Kaplan-Meier survival analysis was used to screen for univariate predictors, and Cox multiple regression modelling was used to identify potential independent risk factors.

RESULTS

Data on 247 patients who met the criteria between June, 2008 and June, 2011 were collected from 33 surgical centres. There were 23 interstage mortalities (9%). The identified independent risk factors of interstage mortality with associated relative risk were: hypoplastic left heart syndrome with aortic stenosis and mitral atresia (relative risk = 13), anti-seizure medications at discharge (relative risk = 12.5), earlier gestational age (relative risk = 11.1), nasogastric or nasojejunal feeding (relative risk = 5.5), unscheduled readmissions (relative risk = 5.3), hypoplastic left heart syndrome with aortic atresia and mitral stenosis (relative risk = 5.2), fewer clinic visits with primary cardiologist identified (relative risk = 3.1), and fewer post-operative vasoactive medications (relative risk = 2.2).

CONCLUSION

Interstage mortality remains substantial, and there are multiple potential risk factors. Future efforts should focus on further exploration of each risk factor, with potential integration of the factors into surveillance schemes and clinical practice strategies.

Towards highly accelerated Cartesian time-resolved 3D flow cardiovascular magnetic resonance in the clinical setting

BACKGROUND

The clinical applicability of time-resolved 3D flow cardiovascular magnetic resonance (CMR) remains compromised by the long scan times associated with phase-contrast imaging. The present work demonstrates the applicability of 8-fold acceleration of Cartesian time-resolved 3D flow CMR in 10 volunteers and in 9 patients with different congenital heart diseases (CHD). It is demonstrated that accelerated 3D flow CMR data acquisition and image reconstruction using k-t PCA (principal component analysis) can be implemented into clinical workflow and results are sufficiently accurate relative to conventional 2D flow CMR to permit for comprehensive flow quantification in CHD patients.

METHODS

The fidelity of k-t PCA was first investigated on retrospectively undersampled data for different acceleration factors and compared to k-t SENSE and fully sampled reference data. Subsequently, k-t PCA with 8-fold nominal undersampling was applied on 10 healthy volunteers and 9 CHD patients on a clinical 1.5 T MR scanner. Quantitative flow validation was performed in vessels of interest on the 3D flow datasets and compared to 2D through-plane flow acquisitions. Particle trace analysis was used to qualitatively visualise flow patterns in patients.

RESULTS

Accelerated time-resolved 3D flow data were successfully acquired in all subjects with 8-fold nominal scan acceleration. Nominal scan times excluding navigator efficiency were on the order of 6 min and 7 min in patients and volunteers. Mean differences in stroke volume in selected vessels of interest were 2.5 ± 8.4 ml and 1.63 ± 4.8 ml in volunteers and patients, respectively. Qualitative flow pattern analysis in the time-resolved 3D dataset revealed valuable insights into hemodynamics including circular and helical patterns as well as flow distributions and origin in the Fontan circulation.

CONCLUSION

Highly accelerated time-resolved 3D flow using k-t PCA is readily applicable in clinical routine protocols of CHD patients. Nominal scan times of 6 min are well tolerated and allow for quantitative and qualitative flow assessment in all great vessels.

Preemptive gastrostomy tube placement after Norwood operation

OBJECTIVE

Because infants undergoing a Norwood operation have poor interstage weight gain, we hypothesized that preemptive gastrostomy tube (GT) placement would result in earlier discharge, improved growth, and higher survival to stage 2.

STUDY DESIGN

Records of 74 neonates who underwent a Norwood operation were reviewed until stage 2 palliation. The patients were divided into conventional (n = 43) and preemptive GT groups (n = 31). Data included demographics, cardiac surgery, feeding strategy, length of hospitalization, and mortality.

RESULTS

Transplant-free survival to stage 2 was significantly higher in the preemptive group, but there were no significant differences in survival to discharge after stage 1, length of hospitalization, and weight-for-age z-score at discharge and at stage 2 palliation. In the conventional group, 27 of 43 underwent GT placement, all via laparotomy, 23 with Nissen fundoplication. In the preemptive group, all underwent GT placement (21 laparoscopic, 10 laparotomy), 7 with Nissen fundoplication. A second gastric intervention was performed in 11 of 21 with laparoscopic GT (7 conversion to gastrojejunostomy tube, 4 Nissen fundoplication).

CONCLUSION

Preemptive GT placement is associated with improved survival to stage 2 after a Norwood operation but not with shorter hospitalization or better growth. A thorough gastrointestinal evaluation must be performed before GT placement to avoid additional surgery.

Hybrid Procedure for Neonates With Hypoplastic Left Heart Syndrome at High-Risk for Norwood: Midterm Outcomes

BACKGROUND

Hybrid procedure offers patients with severe congenital heart disease an alternative initial procedure to conventional surgical reconstruction. We report the midterm outcomes of a cohort of neonates who had a hybrid procedure for variants of hypoplastic left heart syndrome because they were at high risk for the Norwood procedure.

METHODS

Between December 2005 and January 2013, 41 neonates underwent bilateral pulmonary artery banding followed by ductal stenting by means of a sternotomy at a median age of 6 days (range, 2 to 18 days) and weight of 2.6 kg (range, 1.5 to 3.7 kg). Thirty-five patients had hypoplastic left heart syndrome, and 6 patients had critical aortic stenosis with hypoplastic left ventricle. Primary indications for the hybrid procedure were low birth weight in 17 patients, hypoplastic left ventricle with the possibility of later biventricular repair in 6 patients, intact or near-intact atrial septum in 5 patients, and poor patient condition in 13 patients. Echocardiographic, angiographic, operative, and clinical data were reviewed. Outcomes were summarized with descriptive statistics and risk factors for mortality identified.

RESULTS

All but 6 patients had an antenatal diagnosis, and 24 patients were from other congenital cardiac centers. Nine patients had perioperative balloon aortic valvuloplasty, 1 patient had fetal balloon aortic valvuloplasty, and 17 patients had intervention to their atrial septum (41.4%). There were 9 inpatient deaths (21.9%) and 4 interstage deaths (9.8%) after the hybrid procedure. Twenty-eight patients subsequently underwent either the Norwood procedure (11 patients), combined stage I and II (14 patients), or biventricular repair (3 patients). No patient had heart transplantation. Among the patients who had combined stage I and II as a second procedure after the hybrid procedure, there were 2 early deaths, 1 late death before the Fontan, and 1 late death after the Fontan completion after combined stage I and II. All patients who had subsequent Norwood procedure were midterm survivors. Three of the 4 patients who had biventricular repair were midterm survivors. Overall survival was 56.1% at a median follow-up of 32.0 months. By univariate analysis, patient factors, intact or near-intact atrial septum, and aortic atresia were associated with nonsurvival.

CONCLUSIONS

Hybrid procedure as an alternative to the Norwood procedure offers good midterm survival in patients deemed at high risk for neonatal reconstruction.

A genetic contribution to risk for postoperative junctional ectopic tachycardia in children undergoing surgery for congenital heart disease

BACKGROUND

Junctional ectopic tachycardia (JET) is a common arrhythmia complicating pediatric cardiac surgery, with many identifiable clinical risk factors but no genetic risk factors to date.

OBJECTIVE

To test the hypothesis that the angiotensin-converting enzyme insertion/deletion (ACE I/D) polymorphism associates with postoperative JET.

METHODS

DNA samples were collected from children undergoing the Norwood procedure; arterial switch operation; and repairs of Tetralogy of Fallot, balanced atrioventricular septal defect, and ventricular septal defect at a single center. The incidence of postoperative JET was associated with previously identified clinical risk factors and ACE I/D genotype.

RESULTS

Of the 174 children who underwent the above-mentioned surgeries, 21% developed JET. Postoperative JET developed in 31% of children with the D/D genotype but only in 16% of those with the I/I genotype or the I/D genotype (P = .02). Clinical predictors of JET were selected a priori and included age, inotrope score, cardiopulmonary bypass time, and cross-clamp time. Multivariable logistic regression identified a significant correlation between the D/D genotype and postoperative JET independent of these predictors (odds ratio = 2.4; 95% confidence interval, 1.04-5.34; P = .04). A gene-dose effect was apparent in the homogeneous subset of subjects with atrioventricular septal defect (58% JET in D/D subjects, 12% JET in I/D subjects, and 0% JET in I/I subjects; P <.01).

CONCLUSION

The common ACE deletion polymorphism is associated with a greater than 2-fold increase in the odds of developing JET in children undergoing surgical repair of atrioventricular septal defect, Tetralogy of Fallot, ventricular septal defect or the Norwood and arterial switch procedures. These findings may support the potential role of the renin-angiotensin-aldosterone system in the etiology of JET.

B-type natriuretic peptide levels predict outcomes in infants undergoing cardiac surgery in a lesion-dependent fashion

OBJECTIVE

B-type natriuretic peptide is used in the diagnosis, risk stratification, and management of adult patients with cardiac disease. However, its use in infants with congenital heart disease has been limited, particularly in the perioperative period. Our objective was to determine the alterations in perioperative B-type natriuretic peptide levels and their predictive value on postoperative outcomes, in infants undergoing congenital heart surgery.

METHODS

We prospectively enrolled 115 patients: 24 with univentricular heart disease undergoing a modified Norwood procedure, 11 with d-transposition of the great arteries, 55 with hemodynamically important left-to-right shunt, and 25 with tetralogy of Fallot undergoing primary repair. Clinical data and B-type natriuretic peptide samples were collected before and 2, 12, and 24 hours after cardiopulmonary bypass. Univariate analysis and multivariate linear regression analysis were performed.

RESULTS

The perioperative B-type natriuretic peptide levels were lesion specific. Patients with d-transposition of the great arteries and univentricular heart disease had high preoperative B-type natriuretic peptide levels that decreased postoperatively, and those with hemodynamically important left-to-right shunts and tetralogy of Fallot had lower preoperative levels that increased during the first 12 hours postoperatively. The patients with univentricular heart disease with an adverse outcome had a significantly greater 24-hour B-type natriuretic peptide level than those without (P < .05). Those with hemodynamically important left to right shunts and an adverse outcome had a greater 12-hour B-type natriuretic peptide level than those without (P < .05). A 12-hour postoperative/preoperative ratio greater than 45 was 100% sensitive and 82% specific for an adverse outcome in the patients with tetralogy of Fallot.

CONCLUSIONS

The perioperative changes in B-type natriuretic peptide levels and their ability to predict outcomes are lesion-specific. Characterization of these changes might be useful in caring for infants after congenital heart surgery.

Assessment of Growth 6 Years after the Norwood Procedure

At 6 years of age, patients with hypoplastic left heart syndrome had mean age-adjusted z-scores for weight and height below the normative population, and body mass index was similar to the normative population. Males had the greatest increase in z-scores for body mass index.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00115934.

Center Variability in Timing of Stage 2 Palliation and Association with Interstage Mortality: A Report from the National Pediatric Cardiology Quality Improvement Collaborative

For infants with single-ventricle lesions with aortic arch hypoplasia, the interstage period from discharge following stage 1 palliation (S1P) until stage 2 palliation (S2P) remains high risk. Significant variability among institutions exists around the timing of S2P. We sought to describe institutional variation in timing of S2P, determine the association between timing of S2P and interstage mortality, and determine the impact of earlier S2P on hospital morbidity and mortality. The National Pediatric Cardiology Quality Improvement Collaborative registry was queried. Centers were divided based on median age at S2P into early (n = 15) and late (n = 16) centers using a cutoff of 153 days. Groups were compared using Chi-squared or Wilcoxon rank-sum test. Multivariable logistic regression was used to determine risk factors for interstage mortality. The final cohort included 789 patients from 31 centers. There was intra- and inter-center variability in timing of S2P, with the median age by center ranging from 109 to 214 days. Late centers had a higher mortality (9.9 vs. 5.7 %, p = 0.03) than early centers. However, the event rate (late: 8.2 vs. early: 5.8 deaths per 10,000 interstage days) was not different by group (p = 0.26). Survival to hospital discharge and hospital length of stay following S2P were similar between groups. In conclusion, in a large multi-institution collaborative, the median age at S2P varies among centers. Although optimal timing of S2P remains unclear, centers performing early S2P did not experience worse S2P outcomes and experienced less interstage mortality.

Hypoplastic left heart syndrome: From bedside to bench and back

Hypoplastic Left Heart Syndrome (HLHS) is a complex Congenital Heart Disease (CHD) that was almost universally fatal until the advent of the Norwood operation in 1981. Children with HLHS who largely succumbed to the disease within the first year of life, are now surviving to adulthood. However, this survival is associated with multiple comorbidities and HLHS infants have a higher mortality rate as compared to other non-HLHS single ventricle patients. In this review we (a) discuss current clinical challenges associated in the care of HLHS patients, (b) explore the use of systems biology in understanding the molecular framework of this disease, (c) evaluate induced pluripotent stem cells as a translational model to understand molecular mechanisms and manipulate them to improve outcomes, and (d) investigate cell therapy, gene therapy, and tissue engineering as a potential tool to regenerate hypoplastic cardiac structures and improve outcomes.

Predictors of prolonged length of intensive care unit stay after stage I palliation: a report from the National Pediatric Cardiology Quality Improvement Collaborative

The objective of this study is to identify predictors of prolonged intensive care unit (ICU) length of stay (LOS) for single ventricle patients following Stage I palliation. We hypothesize that peri-operative factors contribute to prolonged ICU stay among children with hypoplastic left heart syndrome (HLHS) and its variants. In 2008, as a part of the Joint Council on Congenital Heart Disease initiative, the National Pediatric Cardiology-Quality Improvement Collaborative established a data registry for patients with HLHS and its variants undergoing staged palliation. Between July 2008 and August 2011, 33 sites across the United States submitted discharge data essential to this analysis. Data describing the patients, their procedures, and their hospital experience were entered. LOS estimates were generated. Prolonged LOS in the ICU was defined as stay greater than or equal to 26 days (i.e., 75th percentile). Statistical analyses were carried out to identify pre-operative, operative, and post-operative predictors of prolonged LOS in the ICU. The number of patients with complete discharge data was 303, and these subjects were included in the analysis. Univariate and multivariate analyses were performed. Multivariate analysis revealed that lower number of enrolled participants (e.g., 1-10) per site, the presence of pre-operative acidosis, increased circulatory arrest time, the occurrence of a central line infection, and the development of respiratory insufficiency requiring re-intubation were associated with prolonged LOS in the ICU. Prolonged LOS in the ICU following Stage I palliation in patients with HLHS and HLHS variant anatomy is associated with site enrollment, circulatory arrest time, pre-operative acidosis, and some post-operative complications, including central line infection and re-intubation. Further study of these associations may reveal strategies for reducing LOS in the ICU following the Norwood and Norwood-variant surgeries.

Results of a Feeding Protocol in Patients Undergoing the Hybrid Procedure

Neonates with single-ventricle physiology are at increased risk of developing gastrointestinal morbidities. Feeding protocols in this patient population have been shown to decrease feeding complications after the Norwood procedure, but no data exist to determine the effectiveness of a feeding protocol in patients undergoing the hybrid procedure. Goal of this study was to examine the impact of a standardized feeding protocol on the incidence of overall postoperative gastrointestinal morbidity after the hybrid procedure. Retrospective chart review was performed on neonates undergoing the hybrid procedure. Neonates were divided into two groups, pre-feeding protocol (pre-FP), which encompassed the years 2002-2008, and post-feeding protocol (post-FP), which encompassed the years 2011-2014. Preoperative, operative, and postoperative data were collected. T test or Fisher's exact test was used for analysis. p < 0.05 was considered significant. Seventy-three neonates were in the pre-FP and 52 neonates were in the post-FP. There were no significant differences between the pre-FP and the post-FP in cardiac diagnosis (62 HLHS, 11 other vs. 39 HLHS, 13 other, respectively). Pre-FP underwent hybrid procedure later than the post-FP (9.1 ± 5.8 vs. 5.7 ± 3.4 days, respectively, p < 0.01) and achieved full enteral feeds earlier than the post-FP (3.2 + 2.9 vs. 7.8 + 3.9 days, respectively, p < 0.01). The incidence of necrotizing enterocolitis was higher in the pre-FP versus post-FP [11.0 % (8/65) vs. 5.8 % (3/49), respectively, p = 0.36]. Though not significant, the incidence of necrotizing enterocolitis decreased by almost 50 % after initiating a feeding protocol in patients undergoing the hybrid procedure. This is consistent with previous studies showing beneficial results of a feeding protocol in this complex patient population.

Patient-Specific Multi-Scale Model Analysis of Hemodynamics Following the Hybrid Norwood Procedure for Hypoplastic Left Heart Syndrome: Effects of Reverse Blalock-Taussig Shunt Diameter

INTRODUCTION

The hybrid Norwood (HN) is a relatively new first stage palliative procedure for neonates with hypoplastic left heart syndrome, in which a sustainable uni-ventricular circulation is established in a less invasive manner than with the standard Norwood procedure. A computational multiscale model of the circulation following the HN procedure was used to obtain detailed hemodynamics. Implementation of a reverse-BT shunt (RBTS), a synthetic bypass from the main pulmonary to the innominate artery placed to counteract aortic arch stenosis, and its effects on local and global hemodynamics were studied.

METHODS

A post-op patient-derived anatomy of the HN procedure was utilized with varying degrees of distal arch obstruction, or stenosis, (nominal and 90% lumenal area reduction) and varying RBTS diameters (3.0, 3.5, 4.0 mm). A closed lumped parameter model (LPM) for the proximal and peripheral circulations was coupled to a 3D computational fluid dynamics (CFD) model in order to obtain converged flow fields for analysis.

RESULTS

CFD analyses of patient-derived anatomic configurations demonstrated consistent trends of vascular bed perfusion, vorticity, oscillatory shear index and wall shear stress levels. In the models with severe stenosis, implementation of the RBTS resulted in a restoration of arterial perfusion to near-nominal levels regardless of the shunt diameter. Shunt flow velocity, vorticity, and overall wall shear stress levels decreased with increasing shunt diameter, while shunt flow and systemic oxygen delivery increased with increased shunt diameter. In the absence of distal arch stenosis, large (4.0 mm) grafts may risk thrombosis due to low velocities and flow patterns.

CONCLUSION

Among the three graft sizes, the best option seems to be the 3.5 mm RBTS which provides a more organized flow similar to that of the 3.0 mm configuration with lower levels of wall shear stress. As such, in the setting of this study and for comparable HN physiologies our results suggest that: (1) the 4.0 mm shunt is a generous shunt diameter choice that may be problematic particularly when implemented prophylactically in the absence of stenosis, and (2) the 3.5 mm shunt may be a more suitable alternative since it exhibits more favorable hemodynamics at lower levels of wall shear stress.

Optimization of preoperative status in hypoplastic left heart syndrome with intact atrial septum by left atrial decompression and bilateral pulmonary artery bands

Hypoplastic left heart syndrome (HLHS) with intact (IAS) or highly restrictive atrial septum (RAS) has extremely poor outcomes largely related to pulmonary pathology. At birth, immediate left atrial (LA) decompression is required to remain viable, but there is a tradeoff between residual increase in LA pressure and pulmonary overcirculation, either of which exacerbates the pulmonary status. From August 2010 to April 2013, a retrospective chart review was performed on consecutive patients with a prenatal diagnosis of HLHS with IAS/RAS presenting to a single center. The management strategy was immediate LA decompression followed by placement of bilateral pulmonary artery bands (bPAB) and subsequent conventional Norwood procedure. Six patients were born with HLHS with IAS/RAS during this time period with this planned management strategy. Four patients underwent LA decompression and subsequently developed low cardiac output with pulmonary overcirculation. bPAB were used with improvement in cardiac output and pronounced diuresis. These patients all survived the Norwood and subsequent Glenn procedures and remain alive [median follow-up 2.2 years (range 11 months-2.7 years)]. Two patients did not survive with therapy being withdrawn before the Norwood procedure. It is hypothesized that a strategy of total LA decompression followed by bPAB maximizes preoperative systemic perfusion and minimizes ongoing injury to the pulmonary system. This may enhance patient candidacy for the Norwood procedure and long-term survival.

Patterns of Instability Associated With Endotracheal Suctioning in Infants With Single-Ventricle Physiology

BACKGROUND

In infants with single-ventricle physiology, endotracheal suctioning poses risks because of the instability between pulmonary and systemic blood flow.

OBJECTIVE

To examine processes and adverse events associated with endotracheal suctioning in the first 48 hours after 3 surgical procedures: the Norwood or Norwood-Sano procedure, pulmonary artery banding, and the modified Blalock-Taussig shunt.

METHODS

Prospective observational study in a pediatric intensive care unit.

RESULTS

Bedside nurses collected data from 211 episodes of endotracheal suctioning in 24 infants. Most (62%,130/211) suction episodes were unplanned; 38% (81/211) were planned. The most common reason for unplanned suctioning was arterial desaturation (48%, 62/130 episodes). The infants' oxygen saturation levels before suctioning ranged from 27% to 86%. Serious adverse events occurred in 9% (19/211) of suction episodes. In 8 (42%) of the episodes involving a serious adverse event, the patient received no additional intravenous bolus of analgesic or muscle relaxant before suctioning; in 8 episodes (42%), the patient received both an analgesic and a relaxant; in 3 episodes (16%), the patient received either an analgesic or a relaxant but not both. More adverse events occurred with open suctioning (68%, 13/19) than with closed suctioning (32%, 6/19). Most adverse events (68%, 13/19) occurred during the night shift.

CONCLUSIONS

Significant hemodynamic instability and adverse events occur during routine suctioning in infants with single-ventricle physiology after surgical palliation.

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.

Doppler flow patterns in the right ventricle-to-pulmonary artery shunt and neo-aorta in infants with single right ventricle anomalies: impact on outcome after initial staged palliations

BACKGROUND

A Pediatric Heart Network trial compared outcomes in infants with single right ventricle anomalies undergoing Norwood procedures randomized to modified Blalock-Taussig shunt (MBTS) or right ventricle-to-pulmonary artery shunt (RVPAS). Doppler patterns in the neo-aorta and RVPAS may characterize physiologic changes after staged palliations that affect outcomes and right ventricular (RV) function.

METHODS

Neo-aortic cardiac index (CI), retrograde fraction (RF) in the descending aorta and RVPAS conduit, RVPAS/neo-aortic systolic ejection time ratio, and systolic/diastolic (S/D) ratio were measured early after Norwood, before stage II palliation, and at 14 months. These parameters were compared with transplantation-free survival, length of hospital stay, and RV functional indices.

RESULTS

In 529 subjects (mean follow-up period, 3.0 ± 2.1 years), neo-aortic CI and descending aortic RF were significantly higher in the MBTS cohort after Norwood. The RVPAS RF averaged <25% at both interstage intervals. Higher pre-stage II descending aortic RF was correlated with lower RV ejection fraction (R = -0.24; P = .032) at 14 months for the MBTS cohort. Higher post-Norwood CI (5.6 vs 4.4 L/min/m(2), P = .04) and lower S/D ratio (1.40 vs 1.68, P = .01) were correlated with better interstage transplantation-free survival for the RVPAS cohort. No other Doppler flow patterns were correlated with outcomes.

CONCLUSIONS

After the Norwood procedure, infants tolerated significant descending aortic RF (MBTS) and conduit RF (RVPAS), with little correlation with clinical outcomes or RV function. Neo-aortic CI, ejection time, and S/D ratios also had limited correlations with outcomes or RV function, but higher post-Norwood neo-aortic CI and lower S/D ratio were correlated with better interstage survival in those with RVPAS.

Associations Between Day of Admission and Day of Surgery on Outcome and Resource Utilization in Infants With Hypoplastic Left Heart Syndrome Who Underwent Stage I Palliation (from the Single Ventricle Reconstruction Trial)

Newborns with hypoplastic left heart syndrome and other single right ventricular variants require substantial health care resources. Weekend acute care has been associated with worse outcomes and increased resource use in other populations but has not been studied in patients with single ventricle. Subjects of the Single Ventricle Reconstruction trial were classified by whether they had a weekend admission and by day of the week of Norwood procedure. The primary outcome was hospital length of stay (LOS); secondary outcomes included transplant-free survival, intensive care unit (ICU) LOS, and days of mechanical ventilation. The Student's t test with log transformation and the Wilcoxon rank-sum test were used to analyze associations. Admission day was categorized for 533 of 549 subjects (13% weekend). The day of the Norwood was Thursday/Friday in 39%. There was no difference in median hospital LOS, transplant-free survival, ICU LOS, or days ventilated for weekend versus non-weekend admissions. Day of the Norwood procedure was not associated with a difference in hospital LOS, transplant-free survival, ICU LOS, or days ventilated. Prenatally diagnosed infants born on the weekend had lower mean birth weight, younger gestational age, and were more likely to be intubated but did not have a difference in measured outcomes. In conclusion, in this cohort of patients with single right ventricle, neither weekend admission nor end-of-the-week Norwood procedure was associated with increased use of hospital resources or poorer outcomes. We speculate that the complex postoperative course following the Norwood procedure outweighs any impact that day of admission or operation may have on these outcomes.

Surgical strategy for severe aortic hypoplasia and aortic stenosis with ventricular septal defect and normal left ventricle

At our institution, the strategy for patients with bicuspid aortic valve, aortic valve stenosis (<5 mm), and aortic hypoplasia [hypoplastic aortic arch, coarctation of the aorta (CoA), or interrupted aortic arch (IAA)] with ventricular septal defects (VSDs) as well as normal left ventricular (LV) volume and mitral valve size consists of two parts. The Norwood operation is applied as the first palliation for this group of patients. Second, the decision whether the patients are to undergo the Rastelli operation or a univentricular repair is made depending on the size of the right ventricle after the Norwood operation. This study aimed to examine whether the aforementioned surgical strategy for this group of patients is adequate or not. Seven patients undergoing the Norwood operation as the first palliation for bicuspid aortic valve, aortic valve stenosis (<5 mm), and aortic hypoplasia with VSDs as well as normal LV volume and mitral valve size between February 2005 and March 2010 at Kitasato University Hospital and the Gunma Children's Medical Center were reviewed. Postoperative serum B-type natriuretic peptide (BNP) and central venous pressure (CVP) were measured in the patients undergoing the staged Norwood-Rastelli operation to assess whether the authors' right ventricular end-diastolic volume index (RVEDVI) cutoff (80 % of normal) is adequate. At this writing, all seven patients are alive after a mean follow-up period of 58.8 ± 17.8 months. They all had aortic valve stenosis of <5 mm and a bicuspid aortic valve. Four patients had a diagnosis of CoA with VSD, and three patients had IAA with VSD. Six patients underwent biventricular repair, and one patient had univentricular repair due to the small RVEDVI (74 % of normal). The patients with 80-90 % of normal RVEDVI had higher BNP and higher CVP than those with more than 90 % of normal RVEDVI after the Rastelli operation, whereas the patient undergoing the Fontan operation had a low BNP level. In conclusion, the described strategy for patients with severe aortic hypoplasia and aortic stenosis with VSD as well as normal LV and mitral valve size is reasonable.

Association Between Digoxin Use and Cardiac Function in Infants With Single-Ventricle Congenital Heart Disease During the Interstage Period

OBJECTIVES

To examine the association between digoxin use and cardiac function assessed by echocardiographic indices in infants with single-ventricle (SV) congenital heart disease (CHD) during the interstage period.

DESIGN

Retrospective cohort study.

SETTING

Fifteen North American hospitals.

PATIENTS

Infants discharged home following stage 1 palliation (S1P) and prior to stage 2 palliation (S2P). Infants with no post-S1P and pre-S2P echocardiograms were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 373 eligible infants who met inclusion criteria, 140 (37.5%) were discharged home on digoxin. In multivariable linear and logistic regressions, we found that compared with infants discharged home without digoxin, those discharged with digoxin had a smaller increase in end-systolic volume (β = -8.17 [95% CI, -15.59 to -0.74]; p = 0.03) and area (β = -1.27 [-2.45 to -0.09]; p = 0.04), as well as a smaller decrease in ejection fraction (β = 3.38 [0.47-6.29]; p = 0.02) and fractional area change (β = 2.27 [0.14-4.41]; p = 0.04) during the interstage period.

CONCLUSIONS

Digoxin may partially mitigate the expected decrease in cardiac function during the interstage period through its positive inotropic effects. Prospective clinical trials are needed to establish the pharmacokinetics, safety, and efficacy of digoxin use in SV CHD.

Decellularized vs Non-decellularized Allogeneic Pulmonary Artery Patches for Pulmonary Arterioplasty

We studied pulmonary artery size, reinterventions, and panel reactive antibodies in patients with single-ventricle physiology who underwent a pulmonary arterioplasty with decellularized (DAPAP) and non-decellularized allogeneic pulmonary artery patches (non-DAPAP). Retrospective review identified 59 patients with single-ventricle physiology who underwent pulmonary arterioplasty from 2008 to 2017: 28 patients underwent arterioplasty with DAPAP and 31 patients with non-DAPAP. Demographic and operative variables were similar between groups. Among patients who underwent a Norwood procedure, a right ventricle to pulmonary artery shunt was more commonly used in the DAPAP group (12/20, 60%) and a modified Blalock-Taussig shunt was more commonly used in the non-DAPAP group (17/22, 77%). On multivariable analysis, the use of DAPAP was associated with higher pre-Fontan angiography Z-scores in right (estimate = 0.17, standard error = 0.04, P = 0.0005) and left pulmonary arteries (estimate = 0.12, standard error = 0.05, P = 0.01). No areas of calcification, discrete coarctation, or pulmonary dilation were noted in any of the pulmonary arteries. On multivariable analysis, the use of DAPAP was associated with higher freedom from pulmonary artery reinterventions (Hazard ratio = 0.36, 95% confidence interval = 0.13-0.9, P = 0.04). The median value for Class I panel reactive antibodies was 0% (IQR 0, 4) in the DAPAP and 23% (IQR 14, 36) in the non-DAPAP group. The median value for Class II panel reactive antibodies was 15% (IQR 0, 17) in the DAPAP and 21% (IQR 10, 22) in the non-DAPAP group. Pulmonary arterioplasty with DAPAP was associated with higher pre-Fontan pulmonary artery Z-scores and higher freedom from pulmonary artery reinterventions.