Improving the Care of Our Youngest Patients: Strategies Aimed at Prenatal Cardiac Diagnosis and Management

Approximately 3.95 million births occur every year in the United States.¹ The preponderance of these are considered “normal pregnancies” from the perspective of lack of suspicion of a birth defect based upon routine assessment of the pregnant woman. Nevertheless, approximately 8 out of every 1,000 of these pregnancies² (yielding 31,600 U.S. births in 2012) will be complicated by the presence of congenital heart disease, with additional births at risk for “acquired” fetal cardiac perturbation due to toxic exposure, maternal disease, infections, and extracardiac fetal anomalies adversely affecting cardiac function. The pediatric cardiologist, maternal fetal medicine specialist, and the specialized radiologist are able to detect the vast majority of these conditions; however, this opportunity only arises if suspicion exists. In this case the pregnant woman is referred for evaluation once a concern is raised at the routine obstetrical visit or the screening ultrasound. While we have the technology and skills to manage these pregnancies which quickly transition from straightforward to complex, we can do so only if the patient comes to our attention.

In 2011 all 50 states and the District of Columbia required screening for 54 or more of the core conditions recommended by the American College of Medical Genetics.^3,4 These include hypothyroidism (1:3,600 births), phenylketonuria (1:15,000 births), congenital adrenal hyperplasia (1:25,000 births), galactosemia (1:60,000 births), and many more. All of these are treatable disorders, and a requirement exists that state labs performing these tests are certified to a minimum quality standard. Would we accept a false negative rate of 50% from these labs? The answer should be the same for fetal cardiac disease, eminently treatable, present at rates that exceed that of most if not all of the conditions currently screened for, and potentially resulting in significant morbidity and mortality if undetected. We are making headway: either by consensus agreement by birthing hospitals and providers, or by state mandate pulse oximetry screening for critical congenital heart disease is slowly making its way across the country.⁵ We can do more: An organized strategy for early detection should include not only early postnatal detection, but also improved prenatal surveillance. French specialized centers where every pregnant woman can receive screening for fetal birth defects including congenital and acquired cardiac disease is but one example. These multidisciplinary prenatal diagnosis centers have a proven track record of improving detection rates of congenital heart disease.⁶

And herein lays the crux of the problem. While the vast majority of pregnant women in this country receive a screening obstetrical ultrasound at between 18 and 22 weeks gestation (and many women receive multiple studies), the overall ability to identify features concerning for fetal cardiac disease remains unacceptable low. Many fetal cardiac programs report a prenatal detection rate greater than 50% for the fetus with critical cardiac disease, defined as those conditions requiring intervention prior to neonatal discharge. The prenatal detection rate for conditions requiring surgical intervention before the age of one year, but not within the critical newborn period is much poorer, and taken together most U.S. centers report an overall detection rate for these two groups of children of less than 50%. To what do we attribute this low detection rate? As expected the answer is multifactorial, and includes the following: (a) insufficient obstetrical and radiologic training of physicians and technicians in the identification of fetal cardiac disease, (b) outdated equipment, (c) limited understanding of which pregnancies are at risk, (d) time pressure to complete studies expeditiously, (e) maternal conditions that reduce visualization of cardiac structures, and (f) cardiac problems amenable to diagnosis by only the most experienced imagers. While we might find comfort in implicating this last reason, in fact this accounts for but a small fraction of those cardiac diagnoses requiring surgery or catheterization-based intervention in the first year of life.

With this background, the scientific statement entitled “Diagnosis and Treatment of Fetal Cardiac Disease” authored by Donofrio et al⁷ is an important next step in achieving improved fetal cardiac care. Aimed primarily for the audience of care providers who are providing these high-level consultations, this statement provides standard of care recommendations covering a broad spectrum of topics. Included are the basics of referral indications and timing for the acquisition of the optimal fetal cardiac assessment, methodologies for embarking upon a complete anatomic and functional survey of the fetal heart, and equipment and personnel requirements. A thorough review of the techniques for the assessment of fetal cardiac function covers every aspect of this important topic such that the fetal cardiac imager can apply these methodologies to their practice. The extracardiac implications of a cardiac diagnosis are explored, including the associated anatomic birth defects associated with specific cardiac diagnoses as well as insight into when to refer for genetic evaluation based upon the congenital cardiac defect or functional disturbance identified. Additionally, this scientific statement delves into our field’s state of the art, exploring new frontiers of imaging such as fetal strain, 3-D echocardiographic imaging techniques, fetal Doppler tissue imaging, and fetal cardiac MRI.

In addition to the anatomic and functional assessment of the fetal heart, a detailed overview of the diagnosis and treatment of fetal rhythm disorders is given careful consideration. All of the common as well as rare arrhythmias and conduction disorders are reviewed, and their management is discussed in detail. In the same vein, treatment of specific cardiac lesions is discussed from the perspective of fetal interventional strategies (predominantly catheterization-based techniques), procedural indications and the associated procedural outcomes. While it will be the rare cardiologist who is intimately involved in such procedures, a working knowledge of when to consider referral to a specialized fetal cardiac interventional center is certainly worthwhile. Finally, the authors embark upon a careful review of the peripartum period from the perspective of delivery timing, the logistics of the delivery site, neonatal transitional management and immediate postnatal strategies to optimize outcome.

A major strength of this scientific statement is the composition of the Committee, who span the gamut of specialists in fetal cardiac imaging, providers of prenatal cardiac care, and those who expertly care for the newborn with cardiac disease. As stated by the authors, “… and now the goal has become to understand the fetus as a patient, knowing that the fetal circulation is different than the postnatal circulation, that structural disease may progress in utero, and that cardiac function and stability of the cardiovascular system plays an important role in fetal wellness.” This approach has resulted in a document which not only ensures that every aspect of fetal cardiac disease diagnosis and management is covered in detail, but possibly just as importantly incorporates a review of strategies for the expert provision of prenatal counseling as well as the management of parental stress. While there are some who remain wary of the data demonstrating that the prenatal diagnosis of critical congenital heart disease alters postnatal survival, none can question the benefit elicited by parents when they have accurate information with which they can prepare.⁸

The authors provide a user-friendly summary which includes the following:

• Indications for fetal cardiac referral
• Standard (and specialized) fetal echocardiographic imaging guidelines
• Advancing imaging techniques for use in specific situations
• Fetal pharmacologic and procedural cardiac interventions
• Management in the delivery room and neonatal transition

In summary, this scientific statement provides comprehensive insight into all aspects of the contemporary management of the fetal heart. It is a document that will serve as a resource to all who care for our youngest patients with cardiac disease.