P2.B023: Accounting for Differences in Postoperative Hemodynamic Profiles Following External Pericardial Lateral Tunnel Fontan Surgery

Background: The external pericardial lateral tunnel Fontan (EPLTF) is a variant of the Fontan operation for single ventricle palliation that utilizes viable, autologous pericardium. Recent research has demonstrated growth of the EPLTF pathway with increasing physiologic demands of somatic growth. However, the performance of the EPLTF technique in achieving favorable postoperative hemodynamics remains unclear. Many of the complications seen in patients following Fontan surgery are directly related to high pressures in the systemic venous system, including conditions like congestive hepatopathy and protein-losing enteropathy. Hemodynamic parameters are thus a crucial metric in assessing postoperative morbidity. This study sought to examine hemodynamic outcomes in patients following EPLTF surgery, accounting for the influence of both pathway dimensions and various patient factors.

Methods: Retrospective review of 231 cardiac catheterization studies from 158 patients following EPLTF was conducted. Minimum and maximum diameters were measured in the anteroposterior and lateral views on catheterization images. These measurements were used to calculate minimum and maximum cross-sectional areas, with the maximum to minimum area ratio serving to indicate pathway uniformity. All measurements were indexed to body surface area. For the analysis, cases were separated into two groups based on hemodynamic criteria. Group 1 consisted of cases defined as having a favorable hemodynamic profile, with Fontan pressure ≤ 12 mmHg and cardiac index ≥ 3 L/min/m^2. Cases not meeting either of these criteria were defined as having an unfavorable hemodynamic profile and assigned to Group 2. The two groups were compared with respect to sex, race, socioeconomic status, BMI-for-age percentile, time interval from Fontan, dominant ventricle, minimum pathway area, maximum pathway area, and pathway uniformity using Pearson’s chi-square for qualitative variables and an independent sample t-test with Levene’s test for equality of variances for quantitative variables.

Results: Significant differences were found between the study groups with respect to BMI-for-age percentile (p = 0.011) and time interval from Fontan (p = 0.004). No significant differences were found with respect to sex (p = 0.366), race (p = 0.288), socioeconomic status (p = 0.849), dominant ventricle (0.977), minimum pathway area (p = 0.601), maximum pathway area (p = 0.587), or pathway uniformity (p = 0.684).

Conclusion: For patients undergoing EPLTF surgery, BMI-for-age percentile and time interval from Fontan correlate with less favorable postoperative hemodynamics. Surprisingly, the size and uniformity of the Fontan pathway did not appear to influence postoperative hemodynamics in the studied population. Postoperative management of Fontan patients has traditionally focused on optimizing pathway dimensions through the use of stents and other interventions. The findings of our study suggest that this approach may be of limited value from a hemodynamic perspective. Patients may benefit from more conservative management strategies that place an emphasis on long-term follow-up and metabolic health.