Development of an Uncomplex Multimodal Score that Accurately Classifies Late Fontan Failure

Background: Despite the tremendous success of the Fontan operation in allowing patients with complex univentricular heart disease to survive into adulthood, it is a palliative procedure and patients eventually experience late failure of the Fontan circulation. Clinical presentation and hemodynamic phenotypes of Fontan failure, however, may vary widely. While several parameters were identified as risk factors for late Fontan failure, a feasible tool to classify and grade Fontan failure is lacking. We explored the possibility of developing a score based to classify Fontan failure.

Method: We performed a retrospective study in our cohort of adult Fontan patients (n = 198, median follow-up after Fontan procedure = 20.3 [IQR: 15.6–24.3] years), identifying those with clinical Fontan failure (n = 52, 26.3%). Numerous parameters were recorded and differences between patients with and without Fontan failure were analyzed. We composed a Fontan failure score ultimately containing 15 hemodynamic, echocardiographic, laboratory, and clinical parameters associated with Fontan failure and assessed its accuracy to discriminate between patients with and without late Fontan failure.

Results: Late failure occurred at a median of 18.2 [IQR: 9.1–21.1] years after Fontan completion. Mortality associated with Fontan failure was considerable (25/52, 48.1%) with freedom of death/transplantation/take-down of 64% at 5 and 36% at 10 years after onset of failure, respectively. Patients with Fontan failure had a significantly higher median Fontan failure score compared with nonfailing Fontan patients (8 points [IQR: 5–10] vs. 2 points [IQR: 1–5], p < 0.001). The score accurately classifies Fontan failure as assessed with receiver operating characteristic analysis. Area under the curve of the Fontan failure score was 0.963 [95% CI: 0.921; 0.985, p < 0.001] to discriminate failure.

Conclusion: We have developed an uncomplex yet remarkably accurate score to classify Fontan failure in adult Fontan patients. The score is comprised of several clinical, hemodynamic, echocardiographic, and laboratory parameters usually collected during routine follow-up examinations which makes it a feasible means to assess Fontan patients for failure. Prospective validation and most likely refinement and calibration of the score in larger and preferably multi-institutional cohorts is required to assess its potential to reflect Fontan failure severity and predict the risk of Fontan failure and late mortality.

Publication History

Article published online:
12 February 2022