Abstract 4364619: Performance of the ACTION Screening Criteria in Identifying Fontan Patients at Risk for Adverse Outcomes: A Single-Center Case-Control Study

Background: While Fontan palliation offers improved long-term survival for patients with single ventricle congenital heart disease, many eventually develop Fontan circulatory failure. The Advanced Cardiac Therapies Improving Outcomes Network (ACTION) published consensus-based screening criteria to guide timely referral for advanced heart failure care. However, the performance of these criteria in identifying high-risk patients remains unexplored. Objective: To evaluate the performance of the ACTION referral criteria in identifying Fontan patients at risk for death or heart transplantation. Methods: This is a retrospective, single-center, case-control study of patients after Fontan palliation between 2000 and 2023. Cases were defined as patients who died or required heart transplantation or VAD support. Controls were matched 2:1 or 3:1 based on the year of Fontan surgery[MOU1] . Clinical data were reviewed to assess whether patients met one or more of the ACTION screening criteria. Results: We identified 53 Fontan failure cases and matched them with 151 controls. All cases met at least one ACTION criterion, compared to only 35.8% of controls. Patients with adverse outcomes were significantly more likely to meet criteria across all major domains, including ventricular dysfunction, Fontan pathway abnormalities, lymphatic complications, and extracardiac organ dysfunction. A full performance of ACTION criterion for Fontan failure is presented in Table 1. The sensitivity and negative predictive value of the ACTION screening tool were 100%, with area under the curve (AUC) of 0.82, suggesting strong performance as a screening tool intended to identify patients at risk. For each of the 4 listed ACTION criteria subdomains, the AUCs were similarly good, except for the extracardiac domain, which had a much lower AUC of 0.57. Conclusion: The ACTION screening criteria demonstrated a good performance in identifying Fontan patients at risk for adverse outcomes. These findings provide the first objective evidence supporting the clinical utility of this expert consensus-based tool and highlight its potential value in guiding timely referral to advanced heart failure care. Prospective multi-center validation is warranted.