Over the last decade, the field of targeted neonatal echocardiography (TNE) has matured greatly. Due to challenges with the clinical assessment of circulatory function in neonates, particularly those born preterm, neonatologists recognized a need for increased use of bedside echocardiography in neonatal intensive care units (NICUs). At Children’s Hospital of Orange County (CHOC), and other facilities, TNE allows neonatal clinicians to evaluate the hemodynamic phenotype and cardiac function of neonates without delay.
Dr. Wyman W. Lai, medical director of echocardiography at CHOC and clinical professor at the University of California, Irvine, as part of an international team from the American Society of Echocardiography, recently served as senior author of updated guidelines on the use of TNE and cardiac point-of-care ultrasound (cPOCUS) in the NICU. The updates reflect the growth that has occurred in the field since the original guidelines were published in 2011.
“The new guidelines lay out a three-tiered system of looking at the use of ultrasound in the NICU,” Dr. Lai says. “This includes cardiac point-of-care ultrasound, targeted neonatal echocardiogram and a more complete echocardiogram done from the vantage point of the cardiologist.”
Evolution of echocardiography in the NICU
Since the release of the first TNE guidelines in 2011, the importance of increased, comprehensive training for echocardiography in NICUs has further come to light.
“In many parts of the world, it often took too much time for a cardiologist to get to the NICU to get involved in care. This led to neonatologists picking up ultrasound machines, and the 2011 guidelines tried to standardize this use,” Dr. Lai says. “Now, neonatologists have really helped the field grow. Clinical trials have shown that ultrasound helps improve the outcomes of neonates, especially premature infants who are particularly prone to hemodynamic instability.”
The availability of TNE in NICUs may result in faster diagnosis and treatment of critical complications. In nearly 40% of cases, the use of TNE during hemodynamic consultation leads to the modification of cardiac management strategies, with this percentage jumping to more than 80% for life-threatening illnesses such as systemic hypotension and pulmonary hypertension.
These findings have led to the development of subspecialty fellowship training programs focused on neonatal hemodynamics, including a program at CHOC led by neonatologist Dr. Amir Ashrafi. Such programs include comprehensive training in TNE. As a result, the number of neonatologists who are skilled in TNE has increased exponentially.
The guidelines also give a framework for the use of cPOCUS, which provides a less comprehensive evaluation of cardiac function, life-threatening pericardial effusions and indwelling arterial or venous catheters.
Common indications for TNE
Neonatologists utilize TNE for neonates presenting with hemodynamic perturbation and who are not suspected to have major structural defects.
“If there is a suspicion or finding of a structural abnormality in the heart, then that patient and those studies are within the purview of the pediatric cardiologist,” Dr. Lai says.
The most common indications for TNE include:
- Adjudication of hemodynamically significant patent ductus arteriosus (PDA)
- Assessment of acute and chronic pulmonary hypertension
- Evaluation of left and right ventricular systolic and/or diastolic function
- Screening for pericardial effusions and/or malpositioned central lines
Neonatologists also use TNE to manage pharmacologic treatment and to prevent clinical instability after surgical ligation or transcatheter device closure. TNE can also help evaluate the severity of pulmonary vascular disease and may help stratify risk by identifying newborns at highest risk for mortality.
In some cases, neonatologists intersect with cardiologists in the diagnosis and management of neonates.
“Treatment of PDAs is an area where there is significant overlap between neonatologists and cardiologists,” Dr. Lai says. “Prior to intervention, there are multiple levels of medical treatment. When it moves beyond that to intervention, there’s another team of cardiologists that gets involved. At CHOC, we have a team of interventional cardiologists who perform transcatheter closures of PDA.”
The use of AI in echocardiography to detect PDA
Dr. Lai is leading an international group studying ways that artificial intelligence (AI) can be used in concert with echocardiography to ultimately improve outcomes for preterm infants. PDA is one of the most common congenital heart defects, yet also one of the most vexing for physicians treating premature neonates.
“The question of how to best treat PDA is one that has perplexed physicians for over 60 years now,” Dr. Lai says. “We still haven’t figured out the best way to treat these preterm babies. So, we’re looking at multiple clinical studies, as well as collaboration between groups and the employment of AI tools, to help answer this question.”
In a recent study, a team of researchers including Dr. Lai, Dr. Ashrafi and CHOC Chief Intelligence and Innovation Officer and pediatric cardiologist Dr. Anthony Chang used video clips of echocardiograms performed in the NICU to explore the efficacy of deep learning algorithms in the detection of PDA. The team developed a convolutional neural network (CNN) and used it to analyze 461 video clips from CHOC. The results, published in the journal Intelligence-Based Medicine in 2022, showed promise for the feasibility of PDA diagnosis within an edge-based AI framework.
Additional studies will focus on augmenting the echocardiogram dataset, classifying PDAs based on hemodynamic significance and size and creating new algorithmic approaches.
“It’s an exciting application of artificial intelligence using ultrasounds along with clinical data, which could eventually lead to having a more ready way of diagnosing structural heart disease,” Dr. Lai says. “Our goal is to ultimately provide better care for babies in the NICU with hemodynamic instability.”
CHOC Hospital was named one of the nation’s best children’s hospitals by U.S. News & World Report in its 2023-24 Best Children’s Hospitals rankings and ranked in the cardiology specialty.
