How Does Cross-sectional Imaging Impact the Management of Single Ventricle Patients After Stage II Palliation?

Background: In pediatric Single Ventricle (SV) patients after Stage II palliation (S2P), Computed Tomography with Angiography (CTA) and Cardiac Magnetic Resonance (CMR) imaging provide a more comprehensive assessment of cardiac anatomy and function compared to echocardiography. However, how cross-sectional imaging directly affects the clinical management and course of these patients has not been extensively studied.

Methods: With prior Institutional Board Review approval, we retrospectively reviewed the CTA/CMR imaging studies performed on SV patients who had undergone S2P between January 2010 to December 2019 at our institution. Patients were included if aged 5 years or less and with Glenn physiology at the time of the study. CTA/CMR studies were further analyzed if ordered by a pediatric cardiologist or cardiac intensivist taking care of the patient. Non-contrast CTs, studies performed on patients with biventricular circulation and Glenn anastomosis, or on Extracorporeal Membrane Oxygenation were further excluded.
CTA/CMR studies were independently analyzed, and patients’ medicals records were reviewed to determine Clinical Impact, which was defined as: major (if unique information provided by CTA/CMR significantly altered the patient’s clinical course), minor (CTA/CMR findings affected the clinical management without significantly changing the expected clinical course), and none (no significant information was provided considering the clinical indication and findings). In case of repeat studies on the same patient, more than one analysis for impact was conducted if the patient’s clinical course had significantly changed and/or a different and new abnormality had appeared in the interim.

Results: Patients’ characteristics are depicted in Table 1. Twenty-four patients met inclusion criteria; 15 (62.5%) were male. Most common underlying diagnosis was Hypoplastic Left Heart Syndrome (HLHS) in 14 cases (58%), and systemic ventricular morphology was of right ventricle in 18 cases (75%). Studies characteristics and statistical analysis are shown in Table 2. Twenty-two CTA and 8 CMR studies met inclusion criteria. Most common indication was Follow up after surgery/intervention in 7 cases (23%). Of note, 6 CMR studies were performed on stable HLHS patients while in the context of prior institutional research protocol (Research), with no specific clinical concern.
CTA/CMR imaging was associated with a major impact in 43% of cases, minor in 37% and none in 20%. Impact was higher with the use of CMR compared to CTA (major 50% vs 41%, p=0.011). Although Research studies were associated with a lower impact compared to all other indications (major 33% vs 45%; p=0.04), a major impact was observed in a third of cases. There were no statistically significant differences when analyzed by diagnosis, age or other clinical indications.

Conclusion: In SV patients after S2P, CTA/CMR imaging significantly impacts clinical decision-making and patient’s clinical course, especially when CMR is obtained. There could be a role for performing CMR in this population as surveillance only.