Targeted Neonatal Echocardiography-Guided Therapy in Vein of Galen Aneurysmal Malformation: A Report of Two Cases with a Review of Physiology and Approach to Management

Guidelines and Recommendations for Targeted Neonatal Echocardiography and Cardiac Point-of-Care Ultrasound in the Neonatal Intensive Care Unit: An Update from the American Society of Echocardiography

Targeted neonatal echocardiography (TNE) involves the use of comprehensive echocardiography to appraise cardiovascular physiology and neonatal hemodynamics to enhance diagnostic and therapeutic precision in the neonatal intensive care unit. Since the last publication of guidelines for TNE in 2011, the field has matured through the development of formalized neonatal hemodynamics fellowships, clinical programs, and the expansion of scientific knowledge to further enhance clinical care. The most common indications for TNE include adjudication of hemodynamic significance of a patent ductus arteriosus, evaluation of acute and chronic pulmonary hypertension, evaluation of right and left ventricular systolic and/or diastolic function, and screening for pericardial effusions and/or malpositioned central catheters. Neonatal cardiac point-of-care ultrasound (cPOCUS) is a limited cardiovascular evaluation which may include line tip evaluation, identification of pericardial effusion and differentiation of hypovolemia from severe impairment in myocardial contractility in the hemodynamically unstable neonate. This document is the product of an American Society of Echocardiography task force composed of representatives from neonatology-hemodynamics, pediatric cardiology, pediatric cardiac sonography, and neonatology-cPOCUS. This document provides (1) guidance on the purpose and rationale for both TNE and cPOCUS, (2) an overview of the components of a standard TNE and cPOCUS evaluation, (3) disease and/or clinical scenario-based indications for TNE, (4) training and competency-based evaluative requirements for both TNE and cPOCUS, and (5) components of quality assurance. The writing group would like to acknowledge the contributions of Dr. Regan Giesinger who sadly passed during the final revisions phase of these guidelines. Her contributions to the field of neonatal hemodynamics were immense.

Aortic Steal Correlates with Acute Organ Dysfunction and Short-Term Outcomes in Neonates with Vein of Galen Malformation

INTRODUCTION

Vein of Galen aneurysmal malformation (VGAM) is a rare, congenital cerebrovascular malformation with high morbidity and mortality. Parameters to foresee clinical progression and allow individualized parent counseling are lacking. The aim of this study was to evaluate aortic steal measured by Doppler ultrasound as a prognostic parameter in these neonates.

METHODS

A retrospective monocentric analysis of cardiac ultrasound exams before embolization in neonates with VGAM was conducted. Percentage of aortic steal measured by time-averaged maximum velocity above and below the zero flow baseline by pulsed Doppler ultrasound at the preductal aortic isthmus was calculated. Association of aortic steal with parameters of acute organ dysfunction (Bicêtre neonatal evaluation score [BNES], neonatal multiple organ dysfunction score [NeoMODS]) and mortality and determination of correlation between aortic steal and cerebral damage on initial and follow-up cerebral magnetic resonance imaging (cMRI) were evaluated.

RESULTS

Twelve neonates were included, of which 3 died. Per 10 percentage point increase of aortic steal, BNES decreased by 1.64 (95% confidence interval [CI]: 1.28-2.0) points and the maximum observed NeoMODS increased by 1.25 (CI: 0.94-1.57) points. The odds for mortality increased by 2.3 (CI: 1.14-13.67) per 10 percentage point increase of aortic steal. There was a correlation between aortic steal and cerebral damage at baseline (white matter ρ [rho] = 0.34, gray matter ρ = 0.81) and follow-up (white matter ρ = 0.80, gray matter ρ = 0.72).

CONCLUSION

The degree of aortic steal in neonates with VGAM was highly associated with the severity of organ dysfunction, disease progression on cMRI, and mortality.

Point-of-care ultrasound (POCUS) protocol for systematic assessment of the crashing neonate-expert consensus statement of the international crashing neonate working group

Sudden unexpected clinical deterioration or cardiorespiratory instability is common in neonates and is often referred as a "crashing" neonate. The established resuscitation guidelines provide an excellent framework to stabilize and evaluate these infants, but it is primarily based upon clinical assessment only. However, clinical assessment in sick neonates is limited in identifying underlying pathophysiology. The Crashing Neonate Protocol (CNP), utilizing point-of-care ultrasound (POCUS), is specifically designed for use in neonatal emergencies. It can be applied both in term and pre-term neonates in the neonatal intensive care unit (NICU). The proposed protocol involves a stepwise systematic assessment with basic ultrasound views which can be easily learnt and reproduced with focused structured training on the use of portable ultrasonography (similar to the FAST and BLUE protocols in adult clinical practice). We conducted a literature review of the evidence-based use of POCUS in neonatal practice. We then applied stepwise voting process with a modified DELPHI strategy (electronic voting) utilizing an international expert group to prioritize recommendations. We also conducted an international survey among a group of neonatologists practicing POCUS. The lead expert authors identified a specific list of recommendations to be included in the proposed CNP. This protocol involves pre-defined steps focused on identifying the underlying etiology of clinical instability and assessing the response to intervention.Conclusion: To conclude, the newly proposed POCUS-based CNP should be used as an adjunct to the current recommendations for neonatal resuscitation and not replace them, especially in infants unresponsive to standard resuscitation steps, or where the underlying cause of deterioration remains unclear. What is known? • Point-of-care ultrasound (POCUS) is helpful in evaluation of the underlying pathophysiologic mechanisms in sick infants. What is new? • The Crashing Neonate Protocol (CNP) is proposed as an adjunct to the current recommendations for neonatal resuscitation, with pre-defined steps focused on gaining information regarding the underlying pathophysiology in unexplained "crashing" neonates. • The proposed CNP can help in targeting specific and early therapy based upon the underlying pathophysiology, and it allows assessment of the response to intervention(s) in a timely fashion.

Use of Point-of-Care Ultrasonography in the NICU for Diagnostic and Procedural Purposes

Point-of-care ultrasonography (POCUS) refers to the use of portable imaging performed by the provider clinician at the bedside for diagnostic, therapeutic, and procedural purposes. POCUS could be considered an extension of the physical examination but not a substitute for diagnostic imaging. Use of POCUS in emergency situations can be lifesaving in the NICU if performed in a timely fashion for cardiac tamponade, pleural effusions, pneumothorax, etc, with potential for enhancing quality of care and improving outcomes.

In the past 2 decades, POCUS has gained significant acceptance in clinical medicine in many parts of the world and in many subspecialties. Formal accredited training and certification programs are available for neonatology trainees as well as for many other subspecialties in Canada, Australia, and New Zealand. Although no formal training program or certification is available to neonatologists in Europe, POCUS is widely available to providers in NICUs. A formal institutional POCUS fellowship is now available in Canada. In the United States, many clinicians have the skills to perform POCUS and have incorporated it in their daily clinical practice. However, appropriate equipment remains limited, and many barriers exist to POCUS program implementation.

Recently, the first international evidence-based POCUS guidelines for use in neonatology and pediatric critical care were published. Considering the potential benefits, a recent national survey of neonatologists confirmed that the majority of clinicians were inclined to adopt POCUS in their clinical practice if the barriers could be resolved.

This technical report describes many potential POCUS applications in the NICU for diagnostic and procedural purposes.

Management of cardiac dysfunction in neonates with pulmonary hypertension and the role of the ductus arteriosus

Pulmonary hypertension in the neonate is associated with cardiopulmonary disturbances and neurodevelopment morbidity. The patent ductus arteriosus is a persistent fetal shunt that can be pathologic vs supportive in the setting of neonatal pulmonary hypertension. Understanding the underlying pathophysiology of pulmonary hypertension and the cardiopulmonary effects of various phenotypes can guide management in this vulnerable population. In this narrative, we will summarize the physiologic principles of pulmonary hypertension, the impact of the patent ductus arteriosus on various phenotypes, and the utility of serial targeted neonatal echocardiography to individualize clinical assessment and management.

A vasoactive inotropic score predicts the severity of compromised systemic circulation and mortality in preterm infants

OBJECTIVE

To validate the vasoactive inotropic score as a predictor of the severity of compromised systemic circulation and mortality in preterm infants.

METHODS

A retrospective study was conducted on preterm infants with Compromised systemic circulation [hypotension±lactic acidosis±oliguria] who received a cardiovascular support, we calculated the vasoactive inotropic score (VIS) and cumulative exposure to cardiovascular medications over time (VISct). Receiver operator curve was constructed to predict the primary outcome which was death & refractory hypotension.

RESULTS

VIS had an area under the curve of 0.73 (95% CI 0.85-0.98, p <  0.001). A VIS cut off of 25 has sensitivity and specificity of 66% and 92%, and positive and negative predictive values of 78.5% and 83%, respectively.

CONCLUSION

High VIS predicts the severity of Compromised systemic circulation and mortality rate in preterm infants.

A new physiologic-based integrated algorithm in the management of neonatal hemodynamic instability

Physiologic-based management of hemodynamic instability is proven to guide the logical selection of cardiovascular support and shorten the time to clinical recovery compared to an empiric approach that ignores the heterogeneity of the hemodynamic instability related mechanisms. In this report, we classified neonatal hemodynamic instability, circulatory shock, and degree of compensation into five physiologic categories, based on different phenotypes of blood pressure (BP), other clinical parameters, echocardiography markers, and oxygen indices. This approach is focused on hemodynamic instability in infants with normal cardiac anatomy.Conclusion: The management of hemodynamic instability is challenging due to the complexity of the pathophysiology; integrating different monitoring techniques is essential to understand the underlying pathophysiologic mechanisms and formulate a physiologic-based medical recommendation and approach. What is Known: • Physiologic-based assessment of hemodynamics leads to targeted and pathophysiologic-based medical recommendations. What is New: • Hemodynamic instability in neonates can be categorized according to the underlying mechanism into five main categories, based on blood pressure phenotypes, systemic vascular resistance, and myocardial performance. • The new classification helps with the targeted management and logical selection of cardiovascular support.

Effects of inhaled nitric oxide (iNO) in pulmonary hypertension secondary to arteriovenous malformations: a retrospective cohort study from the European iNO registry

This study aims to assess the effects of inhaled nitric oxide (iNO) on oxygenation in the management of pulmonary hypertension (PH) secondary to arteriovenous malformations (AVMs) in neonates. This is a matched retrospective cohort study from January 1, 2013, to December 31, 2017. The European inhaled nitric oxide registry from 43 neonatal and pediatric ICUs in 13 countries across Europe was used to extract data. The target population was neonates treated with iNO for the management of PH. The cases (PH secondary to AVMs treated with iNO) were matched (1:4 ratio) to controls (PH without AVMs treated with iNO). The main outcome measure was the absolute change of oxygenation index (OI) from baseline to 60 min after starting iNO in cases and controls. The primary outcome of our study was that the mean absolute change in OI from baseline to after 60 min was higher among cases 10.7 (14), than in controls 6 (22.5), and was not statistically different between the groups. The secondary outcome variable - death before discharge - was found to be significantly higher in cases (55%) than in controls (8%). All the other variables for secondary outcome measures remained statistically insignificant.   Conclusion: Infants with PH secondary to AVMs treated with iNO did not respond differently compared to those presented with PH without AVMs treated with iNO. Right ventricular dysfunction on echocardiography was higher in cases than controls (cases: 66.7% and controls: 28.6%) but was not statistically significant. What is Known: • Arterioenous malformation (AVM) is a well-known cause of persistent pulmonary hypertension in newborns. Inhaled nitric oxide (iNO) is most commonly used as first-line therapy for pulmonary hypertension in newborns. • Around 40-50% of vein of Galen malformations (VOGMs) are found to have congestive heart failure in the neonatal period. What is New: • Neonates may present with an isolated PH of the newborn as the main feature of the VOGMs. A large proportion of cases with AVMs have been associated with right ventricular cardiac dysfunction.  • Results from one of the largest database registries in the world for iNO have been used to answer our research question.

Targeted neonatal echocardiography-guided therapy pre-embolisation for congenital hepatic vascular malformation: inhaled nitric oxide to prevent paradoxical embolisation to the systemic circulation

Arteriovenous malformations may present with significant haemodynamic compromise in the neonatal period, typically with high output cardiac failure that may be accompanied by hypoxia and right ventricular dysfunction. Targeted neonatal echocardiography performed by trained neonatologists provides an enhanced physiology-based approach that can guide treatment and minimise complications. We present a case of a large hepatic vascular malformation whose therapy was guided by targeted neonatal echocardiography to prevent paradoxical embolisation of procedural glue to the systemic circulation.

Perioperative management of arteriovenous malformation guided by integrated evaluation of hemodynamics

We aimed to demonstrate the value of monitoring infants with arteriovenous malformation (AVM) during endovascular embolization with integrated evaluation of hemodynamics (IEH) and guiding decisions according to the underlying pathophysiology. This is a retrospective analysis of the perioperative hemodynamics data for 2 complex cases of AVM transferred to Khaula Hospital in Oman for interventional management. We described the value of novel physiological insights gained from comprehensive IEH and provided a systematic approach to the perioperative management. Postoperative targeted neonatal echo (TNE) was used to guide the weaning of the cardiovascular medications within 24 h. Both cases showed significant right ventricle (RV) volume overload before surgery. Narrowing of the pulse pressure (PP) during or after endovascular embolization was used as a marker of compromised systemic blood flow in real time followed by an assessment by TNE to guide the appropriate therapy.Conclusion: Integrated evaluation of hemodynamics is helpful to guide perioperative physiologic-based management of AVM. What is Known: • The preoperative management of hemodynamic compromise due to AVM has been described in many articles. • Perioperative management of AVM and related hemodynamics is a challenge to the intensive care team. What is New: • Integrated evaluation of hemodynamics is a comprehensive assessment and helpful in understanding the underlying physiologic changes during intervention with AVM. • This integrated evaluation can lead to physiologic-based medical recommendation with subsequent improvement.

Updates on Management for Acute and Chronic Phenotypes of Neonatal Pulmonary Hypertension

Neonatal pulmonary hypertension is a heterogeneous disease in term and preterm neonates. It is characterized by persistent increase of pulmonary artery pressures after birth (acute) or an increase in pulmonary artery pressures after approximately 4 weeks of age (chronic); both phenotypes result in exposure of the right ventricle to sustained high afterload. In-depth clinical assessment plus echocardiographic measures evaluating pulmonary blood flow, pulmonary vascular resistance, pulmonary capillary wedge pressure, and myocardial contractility are needed to determine the cause and provide individualized targeted therapies. This article summarizes the causes, risk factors, hemodynamic assessment, and management of neonatal pulmonary hypertension.