Pediatric echocardiography: applications and limitations

Regional Arch Measurements Differ Between Imaging Modalities in Infants With Aortic Coarctation

BACKGROUND

Aortic arch measurements provide a framework for surgical decision-making in neonatal aortic coarctation, specifically in the determination of approach for arch repair by lateral thoracotomy vs median sternotomy. The purpose of this study was to evaluate our experience with transthoracic echocardiography (TTE) and computed tomography angiography (CTA) in the preoperative evaluation of infants with aortic coarctation, specifically comparing arch dimensions as a function of imaging modality.

METHODS

Imaging data were reviewed for all infants undergoing surgical repair of aortic coarctation at our institution from 2012 to 2022. Infants with both TTE and CTA evaluations were included. Aortic measurements were compared at predefined anatomic regions including ascending aorta, proximal arch, distal arch, and isthmus.

RESULTS

During the study period, 372 infants underwent surgical coarctation repair; 72 (19.4%) infants had TTE and CTA arch evaluations preoperatively. Significant discrepancies between imaging modalities were defined by poor correlation coefficients and absolute measurement differences and were most prominent in the proximal aortic arch (R2 = 0.23 [-4.4 to 3.2 mm]) and isthmus regions (R2 = 0.11 [-4.2 to 1.7 mm]). Improved correlation was demonstrated in the ascending aorta (R2 = 0.63) and distal aortic arch (R2 = 0.54).

CONCLUSIONS

Significant variability exists between TTE- and CTA-derived aortic measurements in infants with coarctation, with proximal arch measurements demonstrating the poorest correlation. This anatomic location represents a commonly used arch region for the determination of approach for repair of neonatal aortic coarctation. Thus, these findings have important implications for current preoperative surgical decision-making paradigms and future prospective study to minimize the risk of residual or recurrent arch obstruction.

The Role of Echocardiography in Neonates and Pediatric Patients on Extracorporeal Membrane Oxygenation

Indications for extracorporeal membrane oxygenation (ECMO) and extracorporeal cardiopulmonary resuscitation (ECPR) are expanding, and echocardiography is a tool of utmost importance to assess safety, effectiveness and readiness for circuit initiation and separation. Echocardiography is key to anticipating complications and improving outcomes. Understanding the patient's as well as the ECMO circuit's anatomy and physiology is crucial prior to any ECMO echocardiographic evaluation. It is also vital to acknowledge that the utility of echocardiography in ECMO patients is not limited to the evaluation of cardiac function, and that clinical decisions should not be made exclusively upon echocardiographic findings. Though echocardiography has specific indications and applications, it also has limitations, characterized as: prior to and during cannulation, throughout the ECMO run, upon separation and after separation from the circuit. The use of specific and consistent echocardiographic protocols for patients on ECMO is recommended.