Does the External Pericardial Lateral Tunnel Fontan Pathway Enlarge to Accommodate Somatic Growth? A Preliminary Analysis.

Objectives: An ideal Fontan pathway should be capable of adapting to changes in circulatory demands. The external pericardial lateral tunnel Fontan (EPLTF) is constructed of viable, autologous tissue and may be capable of changing in size. We investigated the ability of the EPLTF to enlarge with increasing physiologic demands of somatic growth. Methods: Retrospective review of echocardiographic images for patients with a minimum of five years follow-up after EPLTF. Serial echocardiographic measurements of the EPLTF pathway were obtained at three distinct locations: the inferior vena cava junction with the EPLTF, midsection of the EPLTF, and cross-sectional area of the EPLTF visualized in a four-chamber view. Body surface area (BSA) was calculated at the time of each echocardiographic measurement. Changes in echocardiographic measurements over time were analyzed and compared with changes in BSA. Results: A total of 332 echocardiographic studies from 38 patients were reviewed. Significant enlargement of the EPLTF pathway is observed at the inferior vena caval junction (P < .001), midsection (P < .01), and cross-sectional area (P < .001). Repeated measures correlation between pathway measurements and BSA is highly significant (P < .001). Conclusions: The EPLTF pathway enlarges over time in correlation with increasing BSA. Further research is needed to define ideal pathway size, differentiate normal physiologic growth from pathologic enlargement, and correlate changes with clinical outcomes.