Arteriovenous fistula creation for hypoxia after single ventricle palliation: A single‐institution experience and literature review

Background: Hypoxia is a common and sometimes severe morbidity of single ven‐ tricle congenital heart disease (CHD). Creation of an arteriovenous fistula (AVF) is occasionally performed for patients after superior or total cavopulmonary connec‐ tion (SCPC or TCPC) in an attempt to improve oxygen saturations. Despite previ‐ ous reports, AVF creation is a rare palliation with inadequately defined benefits and risks. We sought to determine changes in peripheral oxygen saturation (SpO₂) and risk of adverse event after AVF creation in children with single ventricle CHD at our institution.
Methods: We conducted a retrospective chart review of patients with a history of single ventricle palliation and history of surgical AVF creation who were seen at our tertiary care center from 1996 to 2017.
Results: A total of seven patients were included in our study. SpO₂ for the overall co‐ hort did not significantly increase after AVF creation (pre‐AVF 79.1 ± 6.9%, post‐AVF 82.7 ± 6.0% [P = .23]). SpO₂ trended up for large shunts (>5 mm) (pre‐AVF 75.0 ± 7.6%, post‐AVF 84.0 ± 5.3% [P = .25]). SpO₂ did not improve for small shunts (≤5 mm) (pre‐ AVF 82.3 ± 6.5%, post‐AVF 81.0 ± 8.5% [P = .50]). The 12‐month overall and transplant‐ free survival were 85.7% and 71.4%, respectively. Freedom from AVF‐related compli‐ cation (cephalic edema, thrombotic occlusion) was 51.4% at 12 months.
Conclusion: Palliative AVF creation for patients with single ventricle CHD and hy‐ poxia does not universally improve SpO₂ and is prone to early complications. Despite a lack of durable benefit and known risks, AVF creation remains a reasonable pallia‐ tion for a subset of patients after SCPC who are not candidates for TCPC, or poten‐ tially as a bridge to heart transplantation.     

Catheter‐associated bloodstream infection incidence and outcomes in congenital cardiac surgery

Objective: Catheter‐associated bloodstream infections complicate and prolong hos‐ pitalizations. The incidence of catheter‐associated bloodstream infections in children undergoing congenital cardiac surgery has not been reported. This study sought to define the incidence of catheter‐associated bloodstream infections after congenital cardiac surgery in neonates and infants ≤12 months old and compare hospital out‐ comes and costs to those who underwent surgery and did not have a catheter‐associ‐ ated bloodstream infections.
Design: Retrospective review of hospital admissions between October 2013 and November 2015 for neonates and infants ≤12 months old at admission with ICD‐9 codes for congenital cardiac surgery from discharge data from Vizient Clinical Data Base/Resource Manager (formerly University HealthSystem Consortium), an ana‐ lytic platform for performance improvement. Hospitals were included if they had >100 congenital cardiac surgery admissions during the study period. Admissions were stratified by age at admission: Neonates (<1 month) and Infants (1‐12 months). Established database flags for catheter‐associated bloodstream infections were uti‐ lized. Length of stay, mortality, and direct costs were compared between admissions with and without catheter‐associated bloodstream infections using t test or χ², as appropriate.
Results: Catheter‐associated bloodstream infections incidence after congenital car‐ diac surgery was higher in Neonates than Infants (1.5 vs 0.8%, P = .024). Length of stay and direct costs were significantly higher for patients with catheter‐associated bloodstream infections in both groups. Mortality was higher in the Infant group with catheter‐associated bloodstream infections compared to those without catheter‐as‐ sociated bloodstream infections.
Conclusion: Neonates develop catheter‐associated bloodstream infections at nearly twice the rate of older infants. For those who develop infection, mortality is 2‐8‐fold greater and hospital costs are 4‐6‐fold higher, which further highlight the importance of catheter‐associated bloodstream infections prevention in this population.     

Direct postoperative protein S100B and NIRS monitoring in infants after pediatric cardiac surgery enrich early mortality assessment at the PICU

BackgroundNeuromonitoring using plasmatic biomarkers such as S100B and near-infrared spectroscopy (NIRS) represents a standard procedure for detecting cerebral damage after cardiac surgery. Their use in pediatric clinical assessment, however, is negligible.ObjectivesThe goal of this study was to evaluate the predictive role of S100B levels and cerebral oxygenation in postoperative pediatric cardiac patients for survival and potential cerebral injuries.MethodsA retrospective cohort study of infants after cardiac surgery. Primary outcome was survival until discharge. Intra/postoperative vital signs and laboratory data were measured and statistically analyzed.ResultsSeven out of 226 infants were non-survivors. Non-survivors had significantly lower cerebral saturation than survivors, as well as elevated S100B values at admission, associated with lower arterial pressure and higher serum lactate levels.ConclusionAlthough significant differences of S100B and crO₂ values between survivors and non-survivors were found, no critical thresholds could be established from the data. Nevertheless, changes from the norm in these parameters should raise awareness for critical clinical development.     

Ancillary referral patterns in infants after initial assessment in a cardiac developmental outcomes clinic

Objective: Neurodevelopmental impairment is common after surgery for congeni‐ tal heart disease (CHD) in infancy. While neurodevelopmental follow‐up of high‐risk patients has increased, the referral patterns for ancillary services following initial evaluation have not been reported. The aim of this study is to describe the rates and patterns of referral at the initial visit to our outcomes clinic of patients who under‐ went surgery for CHD during infancy.
Outcomes Measures: The Cardiac Developmental Outcomes Program clinic at Texas Children’s Hospital provides routine longitudinal follow‐up with developmental pedi‐ atricians and child psychologists for children who required surgery for CHD within the first 3 months of life. Demographic, diagnostic, and clinical data, including prior receipt of intervention and referral patterns at initial presentation, were abstracted from our database.
Results: Between April 2013 and May 2017, 244 infants under 12 months of age presented for initial evaluation at a mean age of 7 ± 1.3 months. At presentation, 31% (76/244) were referred for either therapeutic intervention (early intervention or pri‐ vate therapies), ancillary medical services, or both. Referral rates for low‐risk (STAT 1‐3) and high‐risk (STAT 4‐5) infants were similar (28 vs. 33%, P = .48). Referrals were more common in: Hispanic white infants (P = .012), infants with non‐cardiac congeni‐ tal anomalies (P = .001), history of gastrostomy tube placement (P < .001), and infants with prior therapy (P = .043). Infants of non‐English speaking parents were three times more likely to be referred (95% CI = 1.5, 6.4; P = .002).
Conclusion: At the time of presentation, nearly 1 in 3 infants required referral. Referral patterns did not vary by traditional risk stratification. Sociodemographic fac‐ tors and co‐morbid medical conditions increased the likelihood of referral. This sup‐ ports the need for routine follow‐up for all post‐surgical infants regardless of level of surgical complexity. Further research into the completion of referrals and long‐term referral patterns is needed.     

Systolic/diastolic ratio correlates with end diastolic pressures in pediatric patients with single right ventricles

Background: Increased ventricular end‐diastolic pressure (VEDP) is a known risk fac‐ tor for morbidity and mortality in patients with single right ventricle (RV) physiology. Previous studies have shown mixed results correlating echocardiographic measure‐ ments with catheter‐derived VEDP in this population. Goal of this study was to eval‐ uate if echocardiographic systolic/diastolic ratio (S/D) correlated with VEDP.
Methods: Patients with single RV physiology who underwent simultaneous echocar‐ diography and catheterization were evaluated. Systolic and diastolic durations were measured using tricuspid inflow durations from Doppler analysis to calculate the S/D ratio. VEDP was obtained from the catheterization report.
Results: Twenty‐seven studies were performed on patients with single RV physiol‐ ogy. Median age at time of catheterization was 11.4 months (range, 0‐132 months). Mean VEDP was 9.9 ± 4.5 mm Hg. S/D ratio was 1.8 ± 0.5. S/D ratio significantly correlated with VEDP (r = 0.63, P < .01). Optimum value of S/D ratio for discriminat‐ ing between patients with high (>10 mm Hg) vs low EDP was found to be 1.9. High S/D ratio had an area under the curve of 0.82 (0.65, 1.0), with 75% sensitivity and 89% specificity for predicting elevated VEDP.
Conclusion: In patients with single RV physiology, S/D significantly correlated with VEDP. S/D ratio is a simple technique that may be useful in both estimating and dis‐ criminating between high and low VEDP in this complex patient population.     

Body mass index in adults with congenital heart disease

Objective: To investigate the status of body mass index (BMI) in adult people with congenital heart disease (ACHD).
Methods: Five hundred thirty‐nine adults with CHD (53.8% men) were seen in the outpatient clinic from 2013 to 2015 and compared to a reference population (n = 1737). The severity of CHD was categorized as mild, moderate, and severe ac‐ cording to standard guidelines. Patients were categorized based on BMI as under‐ weight (<18.5), overweight (25‐30), or obese (>30). Echocardiography and magnetic resonance imaging were used to measure ventricular function while exercise capac‐ ity was estimated via cardiopulmonary exercise test.
Results: Adults with CHD had slightly lower BMI than the reference group (24.1 ± 4.3 vs 24.6 ± 4.3; P = .012). Men in the mild and severe group (23.9 ± 3.6; 23.3 ± 4.4 vs 25.1 ± 3.7; P = .007; P = .023) and women in the severe group (21.6 ± 3.3 vs 24.2 ± 4.7; P < .001) had lower BMI compared to the reference group. In the subgroups, men with ventricular septal defect, coarctation of aorta/ventricular septal defect and Fontan cir‐ culation and women with Fontan circulation had lower BMI than the reference group. Underweight was more prevalent in women with severe lesions compared to the refer‐ ence group (22.2% vs 3.8%; P < .001). BMI was associated with age and exercise ca‐ pacity in patients with mild and moderate lesions, while higher BMI was related to better ventricular function in women with Fontan circulation.
Conclusion: Underweight was more prevalent in ACHD patients with severe lesions. Special attention should be paid to the possible existence of underweight‐related comorbidities.     

Right thoracotomy for aortic valve replacement in the adolescents with bicuspid aortic valve

Background: In this study, we compared our experience about early and midterm follow‐up outcomes for right anterolateral minithoracotomy (RAMT) vs full sternot‐ omy (FS) in surgical aortic valve replacement (AVR) among adolescents with bicuspid aortic valve (BAV).
Methods: Patients were retrospectively enrolled from January 2008 to December 2017. Inclusion criteria were patients with BAV who had to undergo to AVR. They were divided in two groups: RAMT and FS. The choice of RAMT was based on indi‐ vidual surgeon’s preferences or when expressly requested by patient that was in‐ formed of nonconventional approach.
Results: We enrolled 61 patients, 23 in RAMT group and 38 in FS group. The mean age was 15.6 ± 1.7 years for RAMT group and 16.1 ± 1.5 years for FS group (P = .23). The RAMT group had a higher prevalence of female gender (P = .04). The patients in the RAMT group had longer cardiopulmonary bypass (115.2 ± 18.5 vs 102.2 ± 16.5 min; P = .006) and cross‐clamp time (78.6 ± 18.1 vs 74.3 ± 15.2 min; P = .01). No pa‐ tients required intraoperative conversion to FS. No differences were found in venti‐ lation times, postoperative intensive care unit (ICU), and hospital length of stay for both groups. Follow‐up echocardiograms were available for all patients at median of 5.2 years (range 0.5‐9.6 years, median 5.4 years for RAMT and 5.1 for FS) and no patient required reoperation for aortic prosthesis malfunction.
Conclusions: Our study shows that RAMT is safe and effective as FS. Although the RAMT operation takes slightly more operation time, it is not associated with major adverse effects.     

Efficiency of the home cardiac rehabilitation program for adults with complex congenital heart disease

Objective: We aimed to study the efficiency and safety of once‐a‐week outpatient rehabilitation followed by home program with tele‐monitoring in patients with com‐ plex cyanotic congenital heart disease.
Design: Prospective nonrandomized study.
Method: Patients who have been diagnosed either Eisenmenger’s syndrome or inop‐ erable complex cyanotic heart disease and able to attend 12‐week cardiac rehabilita‐ tion program were included. Training with treadmill walking and bicycling under supervision at cardiac rehabilitation unit once‐a‐week in the first 6 weeks followed by home‐based exercise program (bicycle and walking) with a target at 40%‐70% of maximum heart rate (HRmax) at pretraining peak exercise for another 6 weeks was performed in the intervention group. Video and telephone calls were scheduled for evaluation of compliance and complication. Data from cardiopulmonary exercise testing (CPET) on cycle ergometry including peak oxygen consumption (peakVO2), oxygen pulse (O2 pulse), ventilatory equivalent for carbon dioxide (VE/CO2 at an‐ aerobic threshold), constant work‐rate endurance time (CWRET) at 75% of peak VO2, and 6‐minute walk distance (6MWD) were compared between baseline and after training by paired t test.
Result: Of the 400 patients in our adult congenital heart disease clinic, 60 patients met the inclusion criteria. Eleven patients who could follow program regularly were assigned home program. There was a statistically significant improvement of CWRET, O₂ pulse, and 6MWD after finishing the program (P = .003, .039, and .001, respec‐ tively). The mean difference of 6MWD change in the home‐program group was sig‐ nificantly higher than in the control group (69.3 ± 47.9 meters vs. 4.1 ± 43.4 meters, P = .003). No serious adverse outcomes were reported during home training.
Conclusion: Once‐a‐week outpatient hospital‐based exercise program followed by supervised home‐based exercise program showed a significant benefit in improve‐ ment of exercise capacity in adults with complex cyanotic congenital heart disease without serious adverse outcomes.     

The clinical characteristics of coronary artery fistula anomalies in children and adults: A 24‐year experience

Objectives: The aim of our work is to investigate the clinical characteristics of coro‐ nary artery fistula (CAF) anomalies in South Vietnam.
Methods: This is a retrospective analysis of 119 patients with diagnosis of definite CAF between January 1992 and April 2016. The demographic, clinical, echocardio‐ graphic, and angiographic characteristics and management of CAF with short‐term outcomes are described.
Results: The median age was 15 years (range, 1‐79 years), with 49 male (41%) and 70 female (59%). There were 77 symptomatic patients (64.7%) and 91 patients (76.5%) who presented with a murmur. The electrocardiogram was abnormal in 45.4% and cardiac enlargement or increased pulmonary vasculature were seen in 76 patients (63.9%) on chest X‐ray. The sensitivity of echocardiography for CAF diagnosis was 79%. The source of the fistula was most often from the RCA (54%), most commonly to right atrium (34.5%) or right ventricle (31.1%). In comparison with surgery, tran‐ scatheter closure had a shorter hospital length of stay (5.4 ± 3.8 days vs 12.6 ± 6.5 days, P = .02) and better postprocedural left ventricular ejection fraction (67.9 ± 8.1% vs 62.9 ± 6.0%, P = .03).
Conclusion: The majority of fistula in this study originated from the RCA and termi‐ nated in the right atrium or the right ventricle. Transcatheter and surgical closure are both relatively safe and effective, with the potential for shortened length of hospital stay following transcatheter closure.     

Prolonged Tpeak‐Tend interval is a risk factor for sudden cardiac death in adults with congenital heart disease

Objective: Adult congenital heart disease (ACHD) patients are at risk of sudden cardiac death (SCD). However, methods for risk stratification are not yet well‐ defined. The T_peak‐T_end (TpTe) interval, a measure of dispersion of ventricular repolari‐ zation, is a risk factor for SCD in non‐ACHD patients. We aim to evaluate whether TpTe can be used in risk stratification for SCD in ACHD patients.
Design: From an international multicenter cohort of 25 790 ACHD patients, we iden‐ tified all SCD cases. Cases were matched to controls by age, gender, congenital de‐ fect, and (surgical) intervention.
Outcome Measures: TpTe was measured on a standard 12‐lead ECG. The maximum TpTe of all ECG leads (TpTe‐max), mean (TpTe‐mean), and TpTe dispersion (maximum minus minimum) were obtained. Odds ratios (OR) for SCD cases vs controls were calculated using conditional logistic regression analysis.
Results: ECGs were available for 147 cases (median age at death 33.5 years (quartiles 26.2, 48.7), 66% male) and 267 controls. The mean TpTe‐max was 97 ± 24 ms in cases vs 84 ± 17 ms in controls (P < .001); TpTe‐mean was 70 ± 16 vs 63 ± 10 ms (P < .001); and dispersion was 51 ± 22 ms vs 41 ± 16 ms (P = .02), respectively. Assessing each ECG lead separately, TpTe in lead aVR predicted SCD most accurately. TpTe in lead aVR was 71 ± 23 ms in cases vs 61 ± 13 ms in controls (P < .001). After adjusting for impaired ventricular function, heart failure symptoms, and prolonged QRS duration, the OR of SCD of TpTe in lead aVR at an optimal cutoff of 80 ms was 5.8 (95% CI 2.7‐12.4, P < .001).
Conclusions: The TpTe interval is associated with SCD in ACHD patients. Particularly, TpTe in lead aVR can be used as an independent risk factor for SCD in ACHD patients and may, therefore, add precision to current risk prediction models.     

Feeding methods for infants with single ventricle physiology are associated with length of stay during stage 2 surgery hospitalization

Background: Tube feedings are often needed to achieve the growth and nutrition goals associated with decreased morbidity and mortality in patients with single ventricle anat‐ omy. Variability in feeding method through the interstage period has been previously described, however, comparable information following stage 2 palliation is lacking.
Objectives: To identify types of feeding methods following stage 2 palliation and their influence on length of stay.
Design: Secondary analysis of the National Pediatric Cardiology Quality Improvement Collaborative registry was performed on 932 patients. Demographic data, medical characteristics, postoperative complications, type of feeding method, and length of stay for stage 2 palliation were analyzed.
Results: Type of feeding method remained relatively unchanged during hospitalization for stage 2 palliation. Gastrostomy tube fed only patients were the oldest at time of surgery (182.7 ± 57.7 days, P < .001) and had the lowest weight‐for‐age z scores at ad‐ mission (−1.6 ± 1.4, P < .001). Oral + gastrostomy tube groups had the longest median bypass times (172.5 minutes, P = .001) and longest length of stay (median 12 days, P < .001). Multivariable modeling revealed that feeding by tube only (P < .001), oral + tube feeding (P ≤ .001), reintubation (P < .001), and prolonged intubation (P < .001) were associated with increased length of stay. Neither age (P = .156) nor weight‐for‐age z score at admission (P = .066) was predictive of length of stay.
Conclusions: Feeding methods established at admission for stage 2 palliation are not likely to change by discharge. Length of stay is more likely to be impacted by tube feeding and intubation history than age or weight‐for‐age z score at admission. Better understanding for selection of feeding methods and their impact on patient out‐ comes is needed to develop evidence‐based guidelines to decrease variability in clini‐ cal practice patterns and provide appropriate counseling to caregivers.     

Can transcatheter PDA closure be performed in neonates ≤1000 grams? The Memphis experience

Objective: Advancements in transcatheter technology have now made it possible to safely close patent ductus arteriosus (PDA) in extremely low birth weight (ELBW) infants. The objective of this article is to describe our technique for transcatheter PDA closure (TCPC) in ELBW infants.
Design: The techniques employed are very specific to this population and are drasti‐ cally different when compared to the procedure performed in patients weighing >5 kg.
Setting: A multidisciplinary team approach should be taken to evaluate and manage ELBW infants in order to achieve success. It is important that specific techniques with venous‐only approach outlined in this article be followed to achieve optimal results with low risk of complications.
Patients: To date, in Memphis, 55 ELBW infants have had successful TCPC at a weight of ≤1000 g with minimal procedure‐related complications.
Interventions: It is important that specific techniques with venous‐only approach outlined in this article be followed to achieve optimal results with low risk of complications.
Outcome measures: This procedure entails a steep learning curve and should be lim‐ ited to specialized centers with expertise in these thanscatheter procedures.
Results: There has been 100% procedural success of performing TCPC in children ≤1000 g. There have been only two procedure‐related complications which hap‐ pened to the first two patients, ≤1000 g, that we performed TCPC on.
Conclusions: It is feasible and probably safe to perform TCPC in children ≤1000 g. The techniques described in this article represent our institutional experience and have helped us improve clinical outcomes in ELBW infants.     

Appropriateness of pediatric outpatient transthoracic echocardiogram orders following cessation of an active educational intervention

Objective: The educational intervention (EI) through the Pediatric Appropriate Use of Echocardiography (PAUSE) multicenter study resulted in improved appropriate‐ ness of transthoracic echocardiogram (TTE) orders at our center. The current study evaluated if this pattern persisted after cessation of EI and the potential physician characteristics influencing appropriateness.
Design: Outpatients (≤18 years old) seen for initial evaluation during the EI (July to October, 2015) and 6‐month post‐EI (May to August, 2016) phases were included. Comparison was made between TTE rates and appropriateness ratings during EI and post‐EI phase. Association between TTE rate and appropriateness with physician characteristics (age, experience, patient volume, and area of practice) was deter‐ mined using odds ratio.
Results: The study included 7781 patients (EI: N = 4016; post‐EI: N = 3765) seen by 31 physicians. Comparison of appropriateness ratings in a randomized sample (EI: N = 1270; post‐EI: N = 1325 patients) showed no significant differences between the two phases (appropriate: 75.2% vs 74.9%, P = .960; rarely appropriate 4.1% vs 6.5%, P = .065). Though there was significant variability among physicians for TTE order appropriateness (P = .044) and ordering rate (P < .001), none of their characteristics were associated with appropriateness and only a higher patient volume was associ‐ ated with decreased odds of TTE ordering (OR = 0.7).
Conclusion: The PAUSE study EI resulted in maintaining appropriate utilization of TTEs at our center for 6 months following its cessation. Though not statistically sig‐ nificant, there was a trend toward increase in the proportion of studies for indica‐ tions designated rarely appropriate (R). There was significant physician variability in TTE ordering and appropriateness during both phases. Development of EI to reduce physician variability and integration of EI with provider workflow may help sustain appropriate TTE utilization.     

A restrictive ventilatory pattern is common in patients with univentricular heart after Fontan palliation and associated with a reduced exercise capacity and quality of life

Aim: The Fontan circulation is highly dependent on ventilation, improving pulmonary blood flow and cardiac output. A reduced ventilatory function is reported in these patients. The extent of this impairment and its relation to exercise capacity and qual‐ ity of life is unknown and objective of this study.
Methods: This multicenter retrospective/cross‐sectional study included 232 patients (140 females, age 25.6 ± 10.8 years) after Fontan palliation (19.8% atrioventricular connection; 20.3% atriopulmonary connection; 59.9% total cavopulmonary connec‐ tion). Resting spirometry, cardiopulmonary exercise tests, and quality‐of‐life assess‐ ment (SF‐36 questionnaire) were performed between 2003 and 2015.
Results: Overall, mean forced expiratory volume in one second (FEV₁) was 74.7 ± 17.8%predicted (%pred). In 59.5% of the patients, FEV₁ was <80%pred., and all of these patients had FEV₁/forced vital capacity (FVC) > 80%, suggestive of a restric‐ tive ventilatory pattern. Reduced FEV₁ was associated with a reduced peakVO₂ of 67.0 ± 17.6%pred. (r = 0.43, P < .0001), even if analyzed together with possible con‐ founding factors (sex, BMI, age, years after palliation, number of interventions, sco‐ liosis, diaphragmatic paralysis). Synergistically to exercise capacity, FEV₁ was associated to quality of life in terms of physical component summary (r = 0.30, P = .002), physical functioning (r = 0.25, P = .008), bodily pain (r = 0.22, P = .02), and general health (r = 0.16, P = .024). Lower FEV₁ was associated with diaphragmatic paralysis (P = .001), scoliosis (P = .001), higher number of interventions (P = .002), and lower BMI (P = .01). No correlation was found to ventricular morphology, type of surgeries, or other perioperative/long‐term complications.
Conclusions: This study shows that the common restrictive ventilatory pattern in Fontan patients is associated with lower exercise capacity and quality of life. Risk factors are diaphragmatic paralysis, scoliosis, a high total number of interventions and low BMI.     

Exercise responses in children and adults with a Fontan circulation at simulated altitude

Background: Traveling to high altitude has become more popular. High‐altitude exposure causes hypobaric hypoxia. Exposure to acute high altitude, during air travel or mountain stays, seems to be safe for most patients with congenital heart disorders (CHD). Still, current guidelines for CHD patients express concerns regarding safety of altitude exposure for patients with a Fontan circulation. Therefore, investigating hemodynamic and pulmonary responses of acute high‐altitude exposure (±2500 m) at rest and during maximal exercise in patients with Fontan circulation can provide clarity in this dispute and may contribute to improvement of clinical counseling.
Methods: Twenty‐one Fontan patients with 21 age‐matched healthy controls, aged 8‐40 years, were enrolled in an observational study. Participants performed two car‐ diopulmonary exercise tests on a cycle ergometer with breath‐by‐breath respiratory gas analyses combined with noninvasive impedance cardiac output measurements: one at sea level (±6 m) and one at simulated high altitude (±2500 m), respectively.
Results: The effect of altitude exposure was different in rest for saturation (−2.3% vs −4.1%) between Fontan patients and healthy controls (P < .05). At peak exercise the effects of high altitude exposure was different on VO₂ (−5.1% vs 9.6%) and AvO₂‐diff (−0.3% vs −12.8%) between Fontan patients and healthy controls.
Conclusion: Although, acute high‐altitude exposure has a detrimental effect on exer‐ cise capacity, the impact on pulmonary and hemodynamic responses of high‐altitude exposure is comparable between Fontan patients and healthy controls.     

Circulating biomarkers of left ventricular hypertrophy in pediatric coarctation of the aorta

Objective: Patients undergoing surgical repair of aortic coarctation have a 50% risk of pathologic left ventricular remodeling (increased left ventricular mass or relative wall thickness). Endothelin 1, ST2, galectin 3, norepinephrine and B‐natriuretic pep‐ tide are biomarkers that have been associated with pathologic LV change in adult populations but their predictive value following pediatric coarctation repair are not known.
Hypothesis: Biomarker levels at coarctation repair will predict persistent left ven‐ tricular remodeling at 1‐year follow up.
Design: Prospective, cohort study of 27 patients’ age 2 days‐12 years with coarcta‐ tion of the aorta undergoing surgical repair. Echocardiograms were performed pre‐ operation, postoperation, and at 1‐year follow‐up. Plasma biomarker levels were measured at the peri‐operative time points. Association between biomarker concen‐ trations and echocardiographic parameters was assessed.
Results: Neither left ventricular mass index nor relative wall thickness varied from pre‐op to post‐op. At pre‐op, relative wall thickness was elevated in 52% and left ventricular mass index was elevated in 22%; at follow‐up, relative wall thickness was elevated in 13% and left ventricular mass index was elevated in 8%. Presence of re‐ sidual coarctation did not predict left ventricular remodeling (AUC 0.59; P > .05). Multivariable receiver operating characteristic curve combining pre‐op ST2 and en‐ dothelin 1 demonstrated significant predictive ability for late pathologic left ven‐ tricular remodeling (AUC 0.85; P = .02).
Conclusions: Persistent left ventricular hypertrophy and abnormal relative wall thick‐ ness at intermediate‐term follow‐up was rare compared to previous studies. A model combining pre‐op endothelin 1 and ST2 level demonstrated reasonable accuracy at predicting persistent abnormalities in this cohort. Larger studies will be needed to validate this finding and further explore the mechanism of persistent left ventricular remodeling in this population.     

Heart murmurs and echocardiography findings in the normal newborn nursery

Objective: To determine the clinical findings and management implications of echocardiograms performed on infants with murmurs in the nursery.
Design: Retrospective cohort study conducted from January 2008 through December 2015. Patients in the study were followed by chart review for up to 5 years. In addition, a survey of nursery providers was conducted in February 2016.
Setting: A single community hospital associated with a university.
Patients: All 26 573 infants who received care in the normal newborn nursery were eligible for inclusion in the study. Infants with echocardiograms were analyzed. The survey was sent by e‐mail to all 135 physicians who work in the nursery.
Outcome Measures: The primary outcomes include the specific findings on echocar‐ diogram and whether the findings required an acute change in management, outpa‐ tient follow up, or were incidental findings. The primary survey question was how physicians would manage an otherwise asymptomatic newborn with a heart murmur.
Results: Four hundred ninety‐nine infants had echocardiograms, and over the study period the utilization of echocardiography increased from 1.02% to 2.56% (P < .001) of all infants. Three hundred fifty‐four babies had echocardiography performed be‐ cause of a heart murmur. One hundred sixty‐three (46.0%) of these echocardiograms were normal and 160 (45.2%) had findings that did not require additional care. Twenty‐three neonates (6.5%) had echocardiographic findings that necessitated out‐ patient follow‐up and 8 neonates (2.3%) required neonatal intensive care due to the findings on their echocardiogram. In total, 14 infants (4%) would go on to require heart surgery or interventional cardiac catheterization. 63/135 (47%) physicians completed the survey, with wide variations in the management of newborns with heart murmurs.
Conclusions: The use of echocardiography in the normal newborn nursery has in‐ creased with time despite improved prenatal detection of heart disease and the use of pulse oximetry screening, and identifies significant heart disease in a small but important number of infants.     

Physiologic Limitation of Omega Exists in Patients after the Norwood Palliation and Is Underestimated by the Arterial Venous Oxygen Saturation Difference

Background. Survival after the Norwood palliation (NW) is dependent on maximizing systemic oxygen delivery. Omega (Ω) is used to express the excess of oxygen delivery to oxygen consumption. We hypothesized that an intrinsic deficiency in the ability to maximize the relationship between oxygen delivery (DO₂) and oxygen consumption (VO₂) is present in infants after NW and is underestimated by arterial venous oxygen saturation difference (a‐vO₂). Methods. Simultaneous arterial and systemic venous blood gas data were prospectively collected for the first 24 hours after surgery in 10 neonates after NW and 32 infants after biventricular repair (BV). Blood gas data were compared between groups. These data were compared with a group of 11 infants with hypoplastic left heart syndrome (HLHS) status post NW who were undergoing routine hemodynamic evaluation in the cardiac catheterization lab prior to a bidirectional Glenn operation (pre‐Glenn). Results. The mean systemic arterial oxygen saturation was 77% for NW, 83% for pre‐Glenn, and 97% for biventricular repair. NW group had a mean systemic venous oxygenation saturation (SvO₂) of 47% (range 12–67%) vs. 67% (range 29–84%) in the BV group (P = .001). Pre‐Glenn patients had a SvO₂ of 46 (not significant [NS] vs. NW, P = .001 vs. BV). In NW, a‐vO₂ mean was 32 (range 15–63) compared with mean 32 (range 16–71) in BV group (NS). Pre‐Glenn a‐vO₂ mean was 33.6 (NS vs. NW or BV). Ω for NW group was 2.6 (range 1.1–4.2) and 3.4 (1.4–6.25) in BV group (P = .001). Ω for pre‐Glenn was 2.5 (range 1.7–3.8) (NS vs. NW, P = .001 vs. BV). Conclusion. Omega is lower for patients in the immediate postoperative period after NW and prior to their bidirectional Glenn operation than in patients after biventricular repair. This places NW patients closer to the critical point of DO₂ and therefore at greater risk for hemodynamic compromise than BV patients. The a‐vO₂ difference underestimates this risk.