Background Despite an ageing Fontan population, data on late outcomes are still scarce. Reported outcome measures and determinants vary greatly between studies making comprehensive appraisal of mortality hazard challenging.

Methods We conducted a systematic review to evaluate causes and factors associated with late mortality in patients with Fontan circulation. Late mortality was defined as mortality beyond the first postoperative year. Studies were included if they had ≥90 patients or ≥20 late mortalities and/or transplants. Studies with overlapping patients were rationalised to include only the most recent studies to avoid duplication.

Results From 28 studies, a total of 6707 patients with an average follow-up time of 8.23±5.42 years was identified. There were 1000 deaths. Causes of late death were reported in 697 cases. The five most common causes were heart/Fontan failure (22%), arrhythmia (16%), respiratory failure (15%), renal disease (12%) and thrombosis/bleeding (10%). Factors associated with late mortality were evaluated and classified into 9 categories.

Conclusions Causes and factors associated with late mortality after the Fontan operation are summarised in this study. The presented information will aid in identifying patients at highest risk for mortality and guide our risk stratification efforts in this patient population.