The optimal age at Fontan procedure and the ‘ticking clock’ theory: do we have an answer?

Abstract

We read with interest the article by Pace Napoleone et al. [1]. The title of their report and their conclusion may, however, mislead the medical community to believe that the age at Fontan operation should be postponed to the latest possible date. The data on which they base their argument is the finding that the shortand midterm outcomes of their patients operated before and after the age of 7 were similar. In the present era, early outcomes after Fontan surgery have become so good that they are unlikely to show any disparities between patient subgroups. In a 2001 study of Fontan procedures performed in children and adults, differences in late outcomes only became noticeable after 15 years of follow-up [2]. There is a general consensus that we will observe a continuous attrition of the population of Fontan patients, but the factors contributing to this attrition are still largely unknown. The proponents of the ‘ticking clock theory’ advocate that any Fontan circulation will have a limited lifetime and that, therefore, the Fontan procedure should be postponed to the latest possible age. This theory has been solely based on the assumption that the long-term perspectives of Fontan patients are poor. This assumption, however, has been proven to be inaccurate in the present era [3]. This present report comes at a time when two recent investigations have shed new light on the impact of age at operation on outcomes after Fontan surgery [4,5]. Both have shown that the exercise capacity early after Fontan was improved if the surgery was performed at a younger age. In one of the few reports of serial exercise studies in Fontan patients, published in the same journal, it was observed that all patients see a progressive decline in their exercise capacity, but more importantly, the decrease in exercise capacity was accelerated if the Fontan surgery was performed in adolescents and adults rather than in children [4]. In a serial angiographic study comparing Fontan surgery before and after the age of 3 years, it was demonstrated that the cardiac index was preserved if Fontan surgery took place before 3 years of age, and progressively deteriorated if performed at a later age [5]. The exact reasons for these results are still unclear and need confirmation, but they bring, for the first time, objective evidence that delaying Fontan surgery may be deleterious. Nonetheless, it remains our practice to avoid Fontan surgery before the age of 3 years, because we are reluctant to perform implantation of an extra-cardiac conduit smaller than 18 mm in diameter. We thank the authors for demonstrating that later age at Fontan surgery is no longer a risk factor for early adverse outcomes. However, based on the present evidence, it does not seem that the medical community should be encouraged to postpone Fontan surgery, because it may adversely affect patients’ long-term outcomes.