Relation of Fontan Baffle Stroke Volume to Fontan Failure and Lower Exercise Capacity in Patients With an Atriopulmonary Fontan

Fontan failure remains a significant problem, especially in patients with an atriopulmonary Fontan. Fontan baffle volume change during the cardiac cycle (Fontan baffle stroke volume) may affect outcomes in Fontan circulation. Assuming that increased Fontan baffle stroke volume is associated with increased energy loss in the baffle, we hypothesized that higher baffle stroke volume is associated with worse exercise capacity and increased incidence of Fontan failure. Patients from 6 centers with an atriopulmonary or lateral tunnel Fontan operation were included if they had a cardiac magnetic resonance (CMR) study and an adequate cardiopulmonary exercise test. Fontan baffle stroke volume was defined as the difference between maximum and minimum Fontan baffle volumes. Fontan failure was defined as death, listing for transplantation, heart failure symptoms requiring medications, or peak VO2 below 16 ml/kg/min. The study group consisted of 107 patients (median age 19 years, interquartile range, 14 to 29 years). Most patients (84%) had lateral tunnel procedure. During a median follow-up period of 6.8 [interquartile range: 3.2 to 8.8] years after the CMR, 25 (23%) patients had Fontan failure (7 deaths, 3 listed for transplantation, and 15 with heart failure symptoms). Predictors of Fontan failure on multivariable analysis were ventricular tachycardia, protein losing enteropathy, and additionally in atriopulmonary Fontan only, larger Fontan baffle stroke volume. Predictors of lower peak VO2 on multivariable analysis were older age at CMR and additionally in atriopulmonary Fontan only, larger Fontan baffle stroke volume. In conclusion, larger Fontan baffle stroke volume was independently associated with lower peak VO2 and Fontan failure in atriopulmonary Fontan

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