Transcatheter Fontan completion (TFC) offers a less invasive alternative to surgery, but no technique has achieved routine adoption.

A systematic review was conducted in accordance with PRISMA guidelines, including English-language TFC studies indexed in PubMed up to 01/12/2025. Records were screened by titles and abstracts, followed by full-text eligibility assessment. Data were extracted and synthesized. Methodological quality was classified as high, moderate, or low based on assessment of study design, outcome reporting, follow-up duration, and sample representativeness, with discrepancies resolved by consensus.

Six studies assessed Glenn-stage preconditioning strategies (extracardiac conduits (ECC) and intracardiac tunnels) for subsequent TFC in animal models. Eighteen studies reported outcomes in 115 patients: 94.8% underwent Glenn-stage preconditioning (96.3% with intracardiac tunnels using various techniques; 3.7% with ECCs), while 5.2% had subsequent stent-based TFC without preconditioning. Overall, TFC was attempted and completed in 85/115 (73.9%) patients aged 20 months–15 years, with minimum weights of 9–10 kg, without procedure-related deaths or major adverse events. Hospital stay was 1–6 days. Antithrombotic strategies varied. Follow-up in 80 patients (1 week–40 months) showed 5 (6.2%) catheter reinterventions, 1 surgical revision, 1 neurological event, and 1 unexplained midterm death. Study quality was heterogeneous: only 11% were high quality, and 61% reported complete outcomes, limiting generalizability.

TFC is feasible and safe. TFC without surgical preconditioning remains a recent and rare approach. Outcomes are encouraging, but limited to the midterm. Heterogeneous studies underscore the need for multicenter research to establish long-term efficacy and clinical role.