Impact of preoperative treatment strategies on the early perioperative outcome in neonates with hypoplastic left heart syndrome

Ability of the Right Ventricle to Serve as a Systemic Ventricle in Response to the Volume Overload at the Neonatal Stage

BACKGROUND

In children with hypoplastic left heart syndrome (HLHS), volume overload (VO) is inevitable, and the right ventricle (RV) pumps blood into the systemic circulation. Understanding the molecular differences and their different responses to VO between the RV and left ventricle (LV) at the neonatal and highly plastic stages may improve the long-term management of children with HLHS.

METHODS AND RESULTS

A neonatal rat ventricular VO model was established by the creation of a fistula between the inferior vena cava and the abdominal aorta on postnatal day 1 (P1) and confirmed by echocardiographic and histopathological analyses. Transcriptomic analysis demonstrated that some of the major differences between a normal neonatal RV and LV were associated with the thyroid hormone and insulin signaling pathways. Under the influence of VO, the levels of insulin receptors and thyroid hormone receptors were significantly increased in the LV but decreased in the RV. The transcriptomic analysis also demonstrated that under the influence of VO, the top two common enriched pathways between the RV and LV were the insulin and thyroid hormone signaling pathways, whereas the RV-specific enriched pathways were primarily associated with lipid metabolism and arrhythmogenic right ventricular cardiomyopathy (ARVC); further, the LV-specific enriched pathways were primarily associated with nucleic acid metabolism and microRNAs in cancer.

CONCLUSIONS

Insulin and thyroid hormones may play critical roles in the differences between a neonatal RV and LV as well as their common responses to VO. Regarding the isolated responses to VO, the RV favors an ARVC change and the LV favors a reduction in microRNAs in cancer. The current study suggests that insulin, thyroid hormone, and cancer-associated microRNAs are potential therapeutic targets that should be explored by basic science studies to improve the function of the RV to match that of the LV.

Anesthesia for bilateral pulmonary banding as part of hybrid stage I approach palliating neonates with hypoplastic left heart syndrome

BACKGROUND

Neonatal management of patients with hypoplastic left heart syndrome and complex remains a challenging task, whereby the "hybrid" palliation is often reserved for high-risk patients as a "rescue" procedure.

AIM

This study documents the anesthetic challenges and potential complications associated with the Giessen hybrid stage I approach.

METHODS

The Giessen hybrid stage I approach is focused on surgical bilateral pulmonary artery banding. Retrospective perioperative data were analyzed. Contrary to a stable group A, inotropic treatment before surgery for treatment of postnatal shock classified patients as unstable (Group B). Clinical outcomes considered were inhospital mortality, duration of postoperative mechanical ventilation, postoperative time at the intensive care unit, perioperative vasoactive medication requirements, and red blood cell transfusion.

RESULTS

From June 1998 to December 2015, 185 patients were allocated to Group A (n = 165) and Group B (n = 20). The inhospital mortality was 2.2% with no difference between the groups. There was also no difference in the postoperative time on mechanical ventilation and the time in the intensive care unit. Vasoactive medication was more often required in Group B (100%) compared to Group A (19%). In Group B, more red blood cells were transfused 6.0 ± 8.3 vs 2.0 ± 5.8 mL/kg in Group A (P < .05, 95% CI 0.0 - 2.6).

CONCLUSION

Considering a learning curve, anesthesia for surgical bilateral pulmonary artery banding palliating patients with hypoplastic left heart syndrome and complex can safely be performed, independent from the preoperative clinical status.

Association between preoperative respiratory support and outcomes in paediatric cardiac surgery

BACKGROUND

Preoperative mechanical ventilation is associated with morbidity and mortality following CHD surgery, but prior studies lack a comprehensive analysis of how preoperative respiratory support mode and timing affects outcomes.

METHODS

We retrospectively collected data on children <18 years of age undergoing cardiac surgery at an academic tertiary care medical centre. Using multivariable regression, we examined the association between modes of preoperative respiratory support (nasal cannula, high-flow nasal cannula/noninvasive ventilation, or invasive mechanical ventilation), escalation of preoperative respiratory support, and invasive mechanical ventilation on the day of surgery for three outcomes: operative mortality, postoperative length of stay, and postoperative complications. We repeated our analysis in a subcohort of neonates.

RESULTS

A total of 701 children underwent 800 surgical procedures, and 40% received preoperative respiratory support. Among neonates, 243 patients underwent 253 surgical procedures, and 79% received preoperative respiratory support. In multivariable analysis, all modes of preoperative respiratory support, escalation in preoperative respiratory support, and invasive mechanical ventilation on the day of surgery were associated with increased odds of prolonged length of stay in children and neonates. Children (odds ratio = 3.69, 95% CI 1.2-11.4) and neonates (odds ratio = 8.97, 95% CI 1.31-61.14) on high-flow nasal cannula/noninvasive ventilation had increased odds of operative mortality compared to those on room air.

CONCLUSION

Preoperative respiratory support is associated with prolonged length of stay and mortality following CHD surgery. Knowing how preoperative respiratory support affects outcomes may help guide surgical timing, inform prognostic conversations, and improve risk stratification models.

Improved Outcomes in Management of Hypoplastic Left Heart Syndrome Associated With Congenital Diaphragmatic Hernia: an Algorithmic Approach

Hypoplastic left heart syndrome (HLHS) is the second most common congenital heart disease associated with congenital diaphragmatic hernia (CDH). The reported survival rate of neonates with CDH and HLHS is only 1%-5%. We review our experience with CDH and HLHS and compare our outcomes with published literature. Retrospective review of all neonates with CDH and HLHS at our institution over a 10-year period was performed. The morphology of cardiac and diaphragm defects, clinical course, treatment strategies, and outcomes were reviewed, and an algorithmic approach was proposed. Five patients with CDH and HLHS were treated between 2006 and 2016. All had mitral stenosis with aortic stenosis. Four patients had a left-sided Bochdalek diaphragmatic hernia and 1 patient had a large bilateral Morgagni hernia. Two (2/4) of the Bochdalek hernias were associated with significant pulmonary hypoplasia and required patch closure of the CDH; both were palliated with percutaneous ductal stents and both died. Three patients underwent primary Norwood operation followed by repair of less severe CDH defect. All 3 patients are currently well and have survived bidirectional Glenn anastomosis; one patient is well after Fontan operation. Successful palliation of neonates with HLHS and associated CDH is possible in the current era. Outcome is determined primarily by the severity of the CDH and the degree of associated pulmonary hypoplasia. An algorithmic team approach is helpful in management of this difficult group of patients.

"Baby Heart Project": the Italian project for accreditation and quality management in pediatric cardiology and cardiac surgery

Optimization of the relationship between the supply and the demand for medical services should ideally be taken into consideration for the planning within each national Health System. Although government national health organizations embrace this policy specifically, the contribution of expert committees (under the scientific societies' guarantee in any specific medical field) should be advocated for their capability to collect and analyze the data reported by the various national institutions. In addition, these committees have the competence to analyze the need for the resources necessary to the operation of these centers. The field of pediatric cardiology and cardiac surgery may represent a model of clinical governance of particular interest with regard to programming and to a definition of the quality standards that may be extended to highly specialized institutions and ideally to the entire Health System. The "Baby Heart Project," which represents a model of governance and clinical quality in the field of pediatric cardiology and cardiac surgery, was born from the spontaneous aggregation of a committee of experts, supported by duly appointed Italian Scientific Societies and guided by a national agency for accreditation. The ultimate aim is to standardize both procedures and results for future planning within the national Health System.

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.

Advances in pediatric cardiac intensive care

Pediatric cardiac critical care has made, and continues to make, significant strides in improving outcomes. It is a measure of these successes that much of the discussion in this article does not focus on the reduction of mortality, but rather on perioperative management strategies intended to improve neurologic outcomes. The care of children with critical cardiac disease will continue to rely on broad and collaborative efforts by specialists and primary care practitioners to build on this foundation of success.

Surgical considerations in the management of hypoplastic left heart syndrome

Hypoplastic left heart syndrome is a congenital heart defect characterized by hypoplasia of left heart structures. Over the past 3 decades, there have been advances in techniques and management in the care of these patients. We discuss shunt selection, operative strategies, transplantation, and outline various facets of management at the University of Florida. This is a review of the literature highlighting some of the technical aspects of the preoperative, operative, and postoperative care that are important in today's management of hypoplastic left heart syndrome.

Hypoplastic left heart syndrome: current considerations and expectations

In the recent era, no congenital heart defect has undergone a more dramatic change in diagnostic approach, management, and outcomes than hypoplastic left heart syndrome (HLHS). During this time, survival to the age of 5 years (including Fontan) has ranged from 50% to 69%, but current expectations are that 70% of newborns born today with HLHS may reach adulthood. Although the 3-stage treatment approach to HLHS is now well founded, there is significant variation among centers. In this white paper, we present the current state of the art in our understanding and treatment of HLHS during the stages of care: 1) pre-Stage I: fetal and neonatal assessment and management; 2) Stage I: perioperative care, interstage monitoring, and management strategies; 3) Stage II: surgeries; 4) Stage III: Fontan surgery; and 5) long-term follow-up. Issues surrounding the genetics of HLHS, developmental outcomes, and quality of life are addressed in addition to the many other considerations for caring for this group of complex patients.

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.

Outcomes and risk factors for mortality in premature neonates with critical congenital heart disease

We sought to describe contemporary outcomes and identify risk factors for hospital mortality in premature neonates with critical congenital heart disease who were referred for early intervention. Neonates who were born before 37 weeks' gestation with critical congenital heart disease and admitted to our institution from 2002 to 2008 were included in this retrospective cohort study. Critical congenital heart disease was defined as a defect requiring surgical or transcatheter cardiac intervention or a defect resulting in death within the first 28 days of life. Logistic regression analyses were performed to identify risk factors for mortality before hospital discharge. The study included 180 premature neonates, of whom 37 (21%) died during their initial hospitalization, including 6 (4%) before cardiac intervention and 31 (17%) after cardiac intervention. For the 174 patients undergoing cardiac intervention, independent risk factors for mortality were a 5 min Apgar score ≤ 7, need for preintervention mechanical ventilation, and Risk Adjustment in Congenital Heart Surgery category ≥ 4 or not assignable. Mortality for premature infants with critical congenital heart disease who are referred for early intervention remains high. Patients with lower Apgar scores who receive preintervention mechanical ventilation and undergo more complex procedures are at greatest risk.

Management of the postoperative pediatric cardiac surgical patient

OBJECTIVE

To review the salient aspects and latest advances in the management of the postoperative pediatric cardiac patient.

DATA SOURCE

A Medline-based literature source.

CONCLUSION

The practice of pediatric cardiac intensive care has evolved considerably over the last several years. These efforts are the result of a collaborative effort from all subspecialties involved in the care of pediatric patients with congenital heart disease. Discoveries and innovations that are representative of this effort include the extension of cerebral oximetry from the operating room into the critical care setting; mechanical circulatory devices designed for pediatric patients; and surgery in very low birth weight neonates. Advances such as these impact postoperative management and make the field of pediatric cardiac intensive care an exciting, demanding, and evolving discipline, necessitating the ongoing commitment of various disciplines to pursue a greater understanding of disease processes and how to best go about treating them.

Outcome of the Norwood operation in patients with hypoplastic left heart syndrome: a 12-year single-center survey

OBJECTIVE

Recent advances in perioperative care have led to a decrease in mortality of children with hypoplastic left heart syndrome undergoing the Norwood operation. This study aimed to evaluate the outcome of the Norwood operation in a single center over 12 years and to identify clinical and anatomic risk factors for adverse early and longer term outcome.

METHODS

Full data on all 157 patients treated between 1996 and 2007 were analyzed.

RESULTS

Thirty-day mortality of the Norwood operation decreased from 21% in the first 3 years to 2.5% in the last 3 years. The estimated exponentially weighted moving average of early mortality after 157 Norwood operations was 2.3%. Risk factors were an aberrant right subclavian artery, the use and duration of circulatory arrest, and the duration of total support time. The anatomic subgroup mitral stenosis/aortic atresia and female gender tended to show an increased early mortality. In the group of patients who required postoperative cardiopulmonary resuscitation, the ascending aorta was significantly smaller than in the remainder (3.03 +/- 1.05 vs 3.63 +/- 1.41 mm). Interstage mortality was 15% until the initiation of a home surveillance program in 2005, which has zeroed it so far. It was significantly higher in the mitral stenosis/aortic atresia subgroup and tended to be higher in patients who required cardiopulmonary resuscitation after the Norwood operation. The best actuarial survival was observed in the mitral atresia/aortic atresia subgroup.

CONCLUSION

The Norwood operation can now be performed with low mortality. Patients with mitral stenosis/aortic atresia still constitute the most challenging subgroup.

Near-infrared spectroscopy in neonates before palliation of hypoplastic left heart syndrome

BACKGROUND

Neonates with hypoplastic left heart syndrome have circulatory vulnerability that results in shock and high risk of mortality without intervention. High arterial saturation (SaO(2)) is often used as a proxy for inadequate systemic oxygen delivery and triggers the use of invasive therapies to restore circulatory balance. We hypothesized that preoperative use of near-infrared spectroscopy (NIRS) would reduce the need for invasive therapies, including controlled ventilation and inspired gas manipulation.

METHODS

A Human Research Review Board-approved retrospective review of patients who had stage 1 palliation from January 2000 to January 2006 was conducted. Preoperative patient characteristics, cardiorespiratory support, and monitored data were collected for all patients. Cerebral and somatic tissue oxyhemoglobin saturations were recorded for patients with preoperative NIRS monitoring.

RESULTS

The studied cohort included 92 patients, 47 without and 45 with preoperative NIRS. Patient characteristics were similar between groups. Differences were observed in preoperative respiratory support. Controlled ventilation was less common in the NIRS group (51% versus 79%, p = 0.005) as was the use of inspired nitrogen (16% versus 70%, p = 0.001). The NIRS patients had higher mean SaO(2) (92% versus 88%, p = 0.001). Age at surgery was similar between groups (5.7 +/- 3.2 versus 6.5 +/- 5.2 days, p = 0.3). Early survival was 96% in each group.

CONCLUSIONS

Near-infrared spectroscopy monitoring of patients with hypoplastic left heart syndrome awaiting palliation provides noninvasive assessment of oxygen delivery and simplified management, with reduced use of controlled ventilation and inspired gas. Higher SaO(2) in the NIRS group was not associated with impaired systemic oxygen delivery, and did not lead to earlier palliation or postoperative mortality.

The pediatric multiple organ dysfunction syndrome

OBJECTIVES

To review the epidemiology of pediatric multiple organ dysfunction syndrome (MODS) and summarize current concepts regarding the pathophysiology of shock, organ dysfunction, and nosocomial infections in this population.

DATA SOURCE

A MEDLINE-based literature search using the keywords MODS and child, without any restriction to the idiom.

MAIN RESULTS

Critically ill children may frequently develop multisystemic manifestations during the course of severe infections, multiple trauma, surgery for congenital heart defects, or transplantations. Descriptive scores to estimate the severity of pediatric MODS have been validated. Young age and chronic health conditions have also been recognized as important contributors to the development of MODS. Unbalanced inflammatory processes and activation of coagulation may lead to the development of capillary leak and acute respiratory distress syndrome. Neuroendocrine and metabolic responses may result in insufficient adaptive immune response and the development of nosocomial infections, which may further threaten host homeostasis.

CONCLUSIONS

Over the last 20 yrs, there has been an increasing knowledge on the epidemiology of pediatric MODS and on the physiologic mechanisms involved in the genesis of organ dysfunction. Nevertheless, further studies are needed to more clearly evaluate what is the long-term outcome of pediatric MODS.

Significant correlation of comprehensive Aristotle score with total cardiac output during the early postoperative period after the Norwood procedure

BACKGROUND

The comprehensive Aristotle score has been proposed as an individualized measure of the complexity of a given surgical procedure and has been reported to significantly correlate with postoperative morbidity and mortality after the Norwood procedure. An important factor leading to postoperative morbidity and mortality is low cardiac output. We studied the correlation between the comprehensive Aristotle score and cardiac output (CO) in infants after the Norwood procedure.

METHODS AND RESULTS

Respiratory mass spectrometry was used to continuously measure systemic oxygen consumption (VO(2)) in 22 infants for 72 hours postoperatively. Arterial, superior vena caval and pulmonary venous blood gases were measured at 2 to 4 hour intervals to calculate CO. The comprehensive Aristotle score was collected. Hospital mortality was 4.5%. The comprehensive Aristotle score ranged from 14.5 to 23.5 and negatively correlated with CO (P = 0.027). Among the patient-adjusted factors, myocardial dysfunction (n = 10), mechanical ventilation to treat cardiorespiratory failure (n = 9) and atrioventricular valve regurgitation (n = 4) (P = 0.01) negatively correlated with CO (P = 0.06 to 0.07). Aortic atresia (n = 9) was associated with a lower CO (P = 0.01) for the first 24 hours which linearly increased overtime (P = 0.0001). No correlation was found between CO and other factors (P > 0.3 for all).

CONCLUSIONS

Comprehensive Aristotle score significantly negatively correlates with CO after the Norwood procedure. A preoperative estimation of the comprehensive Aristotle score, particularly in association with myocardial dysfunction, mechanical ventilation to treat cardiorespiratory failure, atrioventricular valve regurgitation and aortic atresia may help to anticipate a high postoperative morbidity with low cardiac output syndrome.

Postoperative course in the cardiac intensive care unit following the first stage of Norwood reconstruction

The medical records of all patients born between 1 September, 2000, and 31 August, 2002, and undergoing the first stage of Norwood reconstruction, were retrospectively reviewed for details of the perioperative course. We found 99 consecutive patients who met the criterions for inclusion. Hospital mortality for the entire cohort was 15.2%, but was 7.3%, with 4 of 55 dying, in the setting of a "standard" risk profile, as opposed to 25.0% for those with a "high" risk profile, 11 of 44 patients dying in this group. Extracorporeal membrane oxygenation was utilized in 7 patients, with 6 deaths. Median postoperative length of stay in the hospital was 14 days, with a range from 2 to 85 days, and stay in the cardiac intensive care unit was 11 days, with a range from 2 to 85 days. Delayed sternal closure was performed in 18.2%, with a median of 1 day until closure, with a range from zero to 5 days. Excluding isolated delayed sternal closure, and cannulation and decannulation for extracorporeal support, 24 patients underwent 33 cardiothoracic reoperations, including exploration for bleeding in 12, diaphragmatic plication in 4; shunt revision in 4, and other procedures in 13. The median duration of total mechanical ventilation was 4.0 days, with a range from 0.7 to 80.5 days. Excluding those who died, the median total duration of mechanical ventilation was 3.8 days, with a range from 0.9 to 46.3 days. Reintubation for cardiorespiratory failure or upper airway obstruction was performed in 31 patients. Postoperative electroencephalographic and/or clinical seizures occurred in 13 patients, with 7 discharged on anti-convulsant medications. Postoperative renal failure, defined as a level of creatinine greater than 1.5 mg/dl, was present in 13 patients. Eleven had significant thrombocytopenia, with fewer than 20,000 platelets per microl, and injury to the vocal cords was identified in eight patients. Risk factors for longer length of stay included lower Apgar scores, preoperative intubation, early reoperations, reintubation and sepsis, but not weight at birth, genetic syndromes, the specific surgeon, or the duration of surgery. Although mortality rates after the first stage of reconstruction continue to fall, the course in the intensive care unit is remarkable for significant morbidity, especially involving the cardiac, pulmonary and central nervous systems. These patients utilize significant resources during the first hospitalization. Further studies are necessary to stratify the risks faced by patients with hypoplasia of the left heart in whom the first stage of Norwood reconstruction is planned, to determine methods to reduce perioperative morbidity, and to determine the long-term implications of short-term complications, such as diaphragmatic paresis, injury to the vocal cords, prolonged mechanical ventilation, and postoperative seizures.

Hybrid palliation in hypoplastic left heart syndrome

PURPOSE OF REVIEW

Despite progressive improvement in surgical results, hypoplastic left heart syndrome remains one of the congenital heart abnormalities with the greatest morbidity and mortality. Hybrid approaches to management, combining surgical and interventional catheterization procedures, have been introduced to minimize exposure to cardiopulmonary bypass, and improve outcomes for these high-risk infants.

RECENT FINDINGS

First-stage palliation of hypoplastic left heart syndrome has been performed as a hybrid procedure combining surgical pulmonary artery banding with catheterization stenting of the ductus arteriosus and balloon atrial septostomy, especially in high-risk patients. Additionally, several centers have performed second-stage palliation - bidirectional Glenn or hemi-Fontan procedures - in a manner that allows the subsequent 'Fontan' procedure to be completed in the catheterization laboratory with a covered stent.

SUMMARY

These innovative procedures offer the potential of an alternative management strategy for hypoplastic left heart syndrome. They have been applied to a very limited number of patients and long-term results are not available. Their role in management of hypoplastic left heart syndrome remains to be defined, especially as results of conventional surgical management continue to improve.