David A. Hehir

Nutrition algorithms for infants with hypoplastic left heart syndrome; birth through the first interstage period.

Failure to thrive is common in infants with hypoplastic left heart syndrome and its variants and those with poor growth may be at risk for worse surgical and neurodevelopmental outcomes. The etiology of growth failure in this population is multifactorial and complex, but may be impacted by nutritional intervention. There are no consensus guidelines outlining best practices for nutritional monitoring and intervention in this group of infants. The Feeding Work Group of the National Pediatric Cardiology Quality Improvement Collaborative performed a literature review and assessment of best nutrition practices from centers participating in the collaborative in order to provide nutritional recommendations and levels of evidence for those caring for infants with single ventricle physiology.

Improving interstage survival after Norwood operation: outcomes from 10 years of home monitoring.

OBJECTIVE Infants who undergo Norwood stage 1 palliation (S1P) continue with high-risk circulation until stage 2 palliation (S2P). Routine care during the interstage period is associated with 10% to 20% mortality. This report illustrates the sustained reduction of interstage mortality over 10 years associated with use of home monitoring. METHODS Daily monitoring of oxygen saturation and weight was done for all patients discharged to home after S1P. Notification of the care team occurred for oxygen saturation<75% or >90%, weight gain<20 g over 3 days, weight loss>30 g, or intake<100 cc/kg/d. Breach of these criteria marked an interstage event. Interstage outcomes are reported. Patient characteristics and perioperative variables were compared between patients with and without interstage events. RESULTS Over 10 years, 157 patients were discharged after S1P with home monitoring. Interstage survival was 98%. Breach of home criteria occurred in 59% (93 out of 157), with violation of oxygen saturation<75% the most common event. Patient characteristics, operative data, and early postoperative morbidity did not differ between patients with and without events. CONCLUSIONS Home monitoring after S1P is associated with excellent interstage survival. Although a breach of monitoring criteria occurred in more than half of patients, our analysis failed to identify independent predictors of interstage events. Analysis of variables predicting mortality could not be assessed due to the low frequency of death in this cohort. Failure to identify specific variables for interstage events suggests that home monitoring, as part of an interstage surveillance program, should be applied to all S1P hospital survivors.

Feeding, growth, nutrition, and optimal interstage surveillance for infants with hypoplastic left heart syndrome.

Improvement in operative survival of patients with hypoplastic left heart syndrome has led to increasing emphasis on prevention of interstage mortality. Many centres have improved interstage results through programmes of home monitoring following discharge after the Norwood (Stage 1) operation. Experience with heightened interstage surveillance has identified failure to thrive during infancy as a modifiable risk factor for this population, one that has been linked to concerning outcomes at subsequent palliative surgeries. Ensuring normal growth as an infant has thus become a priority of management of patients with functionally univentricular hearts. Herein, we review the existing evidence for best practices in interstage surveillance and optimal nutrition in infants with functionally univentricular hearts. In addition, we highlight data presented at HeartWeek 2011, from Cardiology 2011, the 15th Annual Update on Pediatric and Congenital Cardiovascular Disease, and the 11th Annual International Symposium on Congenital Heart Disease.

Effect of feeding modality on interstage growth after stage I palliation: A report from the National Pediatric Cardiology Quality Improvement Collaborative

OBJECTIVES Achieving adequate growth after stage 1 palliation for children with single-ventricle heart defects often requires supplemental nutrition through enteral tubes. Significant practice variability exists between centers in the choice of feeding tube. The impact of feeding modality on the growth of patients with a single ventricle after stage 1 palliation was examined using the multiinstitutional National Pediatric Cardiology Quality Improvement Collaborative data registry. METHODS Characteristics of patients were compared by feeding modality, defined as oral only, nasogastric tube only, oral and nasogastric tube, gastrostomy tube only, and oral and gastrostomy tube. The impact of feeding modality on change in weight for age z-score during the interstage period, from stage 1 palliation discharge to stage 2 palliation, was evaluated by multivariable linear regression, adjusting for important patient characteristics and postoperative morbidities. RESULTS In this cohort of 465 patients, all groups demonstrated improved weight for age z-score during the interstage period with a mean increase of 0.3±0.8. In multivariable analysis, feeding modality was not associated with differences in the change in weight for age z-score during the interstage period (P=.72). Risk factors for poor growth were a diagnosis of hypoplastic left heart syndrome (P=.003), vocal cord injury (P=.007), and lower target caloric goal at discharge (P=.001). CONCLUSIONS In this large multicenter cohort, interstage growth improved for all groups and did not differ by feeding modality. With appropriate caloric goals and interstage monitoring, adequate growth may be achieved regardless of feeding modality and therefore local comfort and complication risk should dictate feeding modality.

Longitudinal Assessment of Growth in Hypoplastic Left Heart Syndrome: Results From the Single Ventricle Reconstruction Trial

Background We sought to characterize growth between birth and age 3 years in infants with hypoplastic left heart syndrome who underwent the Norwood procedure. Methods and Results We performed a secondary analysis using the Single Ventricle Reconstruction Trial database after excluding patients <37 weeks gestation (N=498). We determined length‐for‐age z score (LAZ) and weight‐for‐age z score (WAZ) at birth and age 3 years and change in WAZ over 4 clinically relevant time periods. We identified correlates of change in WAZ and LAZ using multivariable linear regression with bootstrapping. Mean WAZ and LAZ were below average relative to the general population at birth (P<0.001, P=0.05, respectively) and age 3 years (P<0.001 each). The largest decrease in WAZ occurred between birth and Norwood discharge; the greatest gain occurred between stage II and 14 months. At age 3 years, WAZ and LAZ were <−2 in 6% and 18%, respectively. Factors associated with change in WAZ differed among time periods. Shunt type was associated with change in WAZ only in the Norwood discharge to stage II period; subjects with a Blalock‐Taussig shunt had a greater decline in WAZ than those with a right ventricle‐pulmonary artery shunt (P=0.002). Conclusions WAZ changed over time and the predictors of change in WAZ varied among time periods. By age 3 years, subjects remained small and three times as many children were short as were underweight (>2 SD below normal). Failure to find consistent risk factors supports the strategy of tailoring nutritional therapies to patient‐ and stage‐specific targets. Clinical Trial Registration URL: http://clinicaltrials.gov/. Unique identifier: NCT00115934.

Recovery of vocal fold immobility following isolated patent ductus arteriosus ligation

OBJECTIVE Identify laryngoscopic and functional outcomes of infants with vocal fold immobility (VFI) following patent ductus arteriosus (PDA) ligation and identify predictors of recovery. METHODS Retrospective review of patients with VFI following PDA ligation from 2001 to 2012 at a single institution. Inclusion criteria were: (1) PDA ligation as only cardiac surgical procedure; (2) left VFI documented by laryngoscopy; (3) minimum follow up 120 days, with at least 2 laryngoscopies performed. Resolution of VFI was determined at follow-up laryngoscopy. Univariate logistic regression models were used to identify variables associated with VFI recovery. RESULTS 66 subjects were included with median follow up of 3.0 (± 2.1) years. The mean gestational age was 24.5 ± 1.4 weeks, mean birth weight 673 ± 167 g, and mean age at procedure was 18.6 ± 14.3 days. Patients presented with respiratory symptoms (39%), dysphonia (78%) and dysphagia (55%). Resolution of VFI was observed in 2/66 (3%) patients. Recovery was documented at 20 days and 11 months respectively. Respiratory symptoms, dysphagia, and dysphonia persisted at last follow up in 11%, 47%, and 20% of patients. CONCLUSIONS VFI associated with ligation of the ductus arteriosus has a low rate of recovery. Clinical symptoms frequently persist, and as such regular follow-up by otolaryngologists to mitigate morbidity is indicated.

Single-ventricle infant home monitoring programs: outcomes and impact.

Purpose of review Patients with single-ventricle, shunt-dependent physiology are at increased risk for interstage death due to the inherent instability of parallel circulation. Enhanced surveillance and early identification of deteriorating physiology via interstage home monitoring result in significant reduction in mortality. These programs are an important focus of improving outcomes for patients with single-ventricle heart disease. Recent findings In the multi-institutional Pediatric Heart Network Single-Ventricle Reconstruction Trial, interstage mortality was 12%, highlighting the continued opportunity to improve on this metric. A number of single-center series have demonstrated significant benefit of interstage monitoring on survival and growth. The focus on interstage monitoring by the National Pediatric Cardiology Quality Improvement Collaborative of the Joint Council on Congenital Heart Disease should improve our understanding of patients at greatest risk and help establish best practices for interstage care. In addition, a number of pilot projects utilizing newer communication technologies seek to improve the connection between program and patient. Summary Interstage home monitoring programs are a model of collaborative care that improves outcomes. Continued research in this area will refine the elements of home monitoring programs and continue to guide improved results. In addition, this model may serve as a template for the care of other populations of medically complex infants.

Changes in cerebral oxygen saturation correlate with S100B in infants undergoing cardiac surgery with cardiopulmonary bypass.

Objectives: The relationship of cerebral saturation measured by near-infrared spectroscopy with serum biomarker of brain injury S100B was investigated in infants undergoing cardiac surgery with cardiopulmonary bypass. Design: Prospective cohort study. Setting: Single-center children’s hospital. Patients: Forty infants between 1 and 12 months old weighing greater than or equal to 4 kg with congenital heart disease undergoing cardiac surgery with cardiopulmonary bypass were enrolled. Interventions: None. Measurements and Main Results: Serum S100B was measured at eight time points over 72 hours using enzyme-linked immunosorbent assay. Physiologic data including arterial, cerebral, and somatic regional oxygen saturations measured by near-infrared spectroscopy were synchronously recorded at 1-minute intervals from anesthesia induction through 72 postoperative hours. The arterial-cerebral oxygen saturation difference was calculated as the difference between arterial saturation and cerebral regional saturation. Thirty-eight patients, 5.4 ± 2.5 months old, were included in the analysis; two were excluded due to the use of postoperative extracorporeal membrane oxygenation. Seventeen patients (44.7%) had preoperative cyanosis. S100B increased during cardiopulmonary bypass in all patients, from a median preoperative baseline of mean ± SE: 0.055 ± 0.038 to a peak of 0.610 ± 0.038 ng/mL, p less than 0.0001. Patients without preoperative cyanosis had a higher S100B peak at the end of cardiopulmonary bypass. Although the absolute cerebral regional saturation on cardiopulmonary bypass was not associated with S100B elevation, patients who had arterial-cerebral oxygen saturation difference greater than 50 at any time during cardiopulmonary bypass had a higher S100B peak (mean ± SE: 1.053 ± 0.080 vs 0.504 ± 0.039 ng/mL; p < 0.0001). Conclusions: A wide cerebral arteriovenous difference measured by near-infrared spectroscopy during cardiopulmonary bypass is associated with increased serum S100B in the perioperative period and may be a modifiable risk factor for neurological injury.

Superior cavopulmonary anastomosis timing and outcomes in infants with single ventricle

OBJECTIVES We sought to identify factors associated with the timing and surgical outcomes of the superior cavopulmonary anastomosis. METHODS The Pediatric Heart Networks Infant Single Ventricle trial database identified participants who underwent superior cavopulmonary anastomosis. Factors potentially associated with age at superior cavopulmonary anastomosis, length of stay and death by 14 months of age were evaluated. Factors included subject demographics, cardiac anatomy, measures from neonatal hospitalization and pre-superior cavopulmonary anastomosis visit, adverse events, echocardiographic variables, intraoperative variables, superior cavopulmonary anastomosis type, and number of concurrent cardiac surgical procedures. Age at superior cavopulmonary anastomosis was analyzed using Cox proportional hazards regression. Natural log length of stay was analyzed by multiple linear regression. RESULTS Superior cavopulmonary anastomosis was performed in 193 subjects at 5.2 months of age (interquartile range, 4.2, 6.2) and weight of 5.9 kg (interquartile range, 5.3, 6.6). The median length of stay was 7 days (interquartile range, 6, 10). There were 3 deaths and 1 transplant during the superior cavopulmonary anastomosis hospitalization, and 3 deaths and 3 transplants between discharge and 14 months of age. Age at superior cavopulmonary anastomosis was associated with center and interstage adverse events. A longer length of stay was associated with younger age and greater case complexity. Superior cavopulmonary anastomosis type, valve regurgitation, ventricular ejection fraction, and ventricular end-diastolic pressure were not independently associated with age at superior cavopulmonary anastomosis or the length of stay. CONCLUSIONS Greater case complexity and more frequent interstage adverse events are associated with an earlier age at superior cavopulmonary anastomosis. Significant variation in age at superior cavopulmonary anastomosis among centers, independent of subject factors, highlights a lack of consensus regarding the optimal timing. Factors associated with length of stay could offer insights for improving presuperior cavopulmonary anastomosis care and surgical outcome.

Hemodynamic Profile of Acute Kidney Injury Following the Fontan Procedure: Impact of Renal Perfusion Pressure:

Background: Acute kidney injury (AKI) is common following cardiopulmonary bypass. Fontan completion may result in systemic venous hypertension and low cardiac output, reducing renal perfusion pressure (RPP) and further increasing the risk of AKI. We investigated the incidence and risk factors for post-Fontan AKI. Methods: Single-center retrospective study of children undergoing Fontan completion from 2005 to 2012. Demographic and hemodynamic variables were assessed for association with AKI. Subgroup analysis was performed on patients with high-grade AKI (creatinine increase of ≥2.0 × baseline). Vital sign data were collected hourly for the first postoperative day. Results: A total of 186 patients underwent Fontan at 3.1 (2.5-3.8) years of age and 13.5 kg (12.2-15.1). Acute kidney injury occurred in 97 (52%) patients, with high-grade AKI in 52 (28%). Univariate analysis identified reduced RPP in patients with AKI compared to those without AKI, 50 (45-56) mm Hg versus 58 (54-61) mm Hg (P < .0001), due to lower mean arterial blood pressure, 63 (60-69) versus 70 (66-73) mm Hg (P < .0001), and higher central venous pressure, 14 (12-16) versus 13 (11-14) mm Hg, (p < .0001). Multivariable logistic regression and classification tree analyses further identified elements of RPP as significant predictors of AKI, especially high-grade AKI. Postoperative intubation was linked to AKI development. Patients with AKI had decreased postoperative urine output with increased colloid requirements, duration of chest tube insertion, and hospital length of stay. Conclusion: Acute kidney injury occurs frequently following the Fontan procedure. Associated factors include reduced RPP, high colloid requirements, and postoperative intubation. Targeted hemodynamic interventions may serve to reduce the incidence of post-Fontan AKI.