Exercise capacity and mid-term survival in patients with tricuspid atresia and complex congenital cardiac malformations after modified Fontan-operation.

OBJECTIVE Continued follow-up of the Fontan population group is mandatory in order to evaluate the best approach for long term treatment. We studied exercise capacity and survival in patients with either right atrial to right ventricular (Fontan-Bjoerk, RA-RV) anastomosis or right atrial to pulmonary artery (RA-PA) connection. METHODS Between January 1980 and December 1995 Fontan-Bjoerk modifications were performed in 73 patients with tricuspid atresia. A RA-PA anastomosis (performed either with direct atrio-pulmonary connection or with a lateral tunnel of autologous atrial tissue) was used in 118 patients with single ventricle or complex cardiac malformations. Using bicycle ergospirometry and impedance cardiography standard variables of exercise testing were measured in 15 patients with RA-RV and in 18 patients with RA-PA connection. A group of 23 healthy pupils served as controls. RESULTS Follow-up was complete for 97.9% (n = 187) of all operated patients. Survival (% mean +/- SEM) at 5, 10 and 15 years was 89.3 +/- 3.6, 76.8 +/- 0.6 and 63.6 +/- 10.5 for RA-RV connection and 80.2 +/- 4.0, 75.3 +/- 4.5 and 64.6 +/- 10.7 for RA-PA connection (P = 0.12) respectively. Exercise capacity was tested after a median time of 6.0 (0.8-19.8) years after Fontan operation in RA-RV and of 7.8 (4.3-18.2) years in RA-PA patients. Total work load was equal in the two Fontan groups, but it was below normal. Heart rate, respiratory rate, oxygen uptake and ventilatory equivalent for oxygen were not different between the two Fontan groups. Cardiac index and stroke volume index were consistently lower at anaerobic threshold and at maximal exercise in RA-PA patients compared with controls. CONCLUSION Survival analysis between RA-RV and RA-PA Fontan connection failed to demonstrate a better outcome for patients with either Fontan modification. Although there was a tendency for RA-RV connection to adapt cardiac output more efficient to exercise compared with RA-PA patients, total work load and ventilatory equivalent was not significantly different between the two Fontan modifications. We conclude, that by incorporation of a residual subpulmonary ventricular chamber within the Fontan circulation no additional benefit for exercise capacity could be observed.