Novel Utilization of Ultrasound Enhancing Agents in Complex Congenital Heart Disease Following Superior Cavopulmonary Connection

Background: Children with single-ventricle congenital heart disease typically undergo a superior cavopulmonary connection (SCPC) as the second stage in their surgical palliation. Postoperatively, stenoses of the SCPC and branch pulmonary arteries can occur. If there are clinical concerns and echocardiography is insufficient for diagnosis, patients undergo invasive evaluation with exposure to radiation and anesthesia. The use of ultrasound enhancing agents (UEAs) to improve echocardiographic diagnostic capabilities has not previously been described in this population.

Methods: A single-center, retrospective case review was conducted of children who underwent echocardiography with UEA, following SCPC, from March 1, 2020, to April 15, 2022, at the Children's Hospital of Philadelphia. Twenty-two patients with hypoxemia or concern for obstruction following SCPC underwent UEA echocardiography. Extracted clinical data included patient demographics, echocardiographic images, angiography, surgical and transcatheter interventions, as well as available follow-up data.

Results: Six of the 22 UEA echocardiograms demonstrated stenosis or occlusion of either the SCPC or a pulmonary artery. All six patients underwent cardiac catheterization and five required intervention. Angioplasty was performed in each case with one requiring subsequent surgical revision. Sixteen of 22 UEA echocardiograms demonstrated no evidence of stenosis. Ten of these 16 patients improved, while six experienced persistent hypoxemia prompting referral for cardiac catheterization. Angiography confirmed the UEA echocardiographic findings (absence of stenosis) in four of these six patients. There were no adverse reactions related to UEA administration.

Conclusions: Echocardiography with UEAs is a valuable and safe adjunctive imaging modality following SCPC, particularly when two-dimensional and color imaging is limited. This novel application of UEAs in complex patients with congenital heart disease provides an "angiogram-like" image, better delineating vessel walls and improving assessment of postoperative obstruction. As experience with UEAs increases in the congenital heart disease population, there may be opportunities to decrease invasive and costly procedures, while expediting the care of patients in need of intervention.