Impact of Phrenic Nerve Palsy on Late Fontan Circulation

Although adverse effects of phrenic nerve palsy (PNP) on early Fontan circulation have been reported, detailed late impact remains unclear.

Of 218 patients undergoing extracardiac total cavopulmonary connection between 1995 and 2008, 160 who all underwent cardiac catheter examination, spirometry, and exercise capacity testing 10 years after the operation were enrolled. The cohort was divided into 2 groups: with (N = 21) or without PNP (control group, N = 139). The patients with PNP were further divided into the recovered PNP group (n = 10) and the persistent PNP group (n = 11). All but 2 patients who developed PNP (90.9%) underwent diaphragmatic plication. There was no difference in hemodynamic indices at pre-Fontan evaluation among the three groups.

Ten years after the Fontan procedure, the averaged forced vital capacity was 81% ± 18% of predicted in the control group, 86% ± 17% in the recovered PNP group, and 56% ± 12% in the persistent PNP group (P < .001). Peak oxygen consumption was linearly correlated to the forced vital capacity (r = 0.222, P = .009). There was no significant difference in the peak oxygen consumption between groups. Significant veno-venous collaterals into the diaphragm from lower body to pulmonary vein(s) or atria more frequently developed in patients who underwent diaphragmatic plication compared with those who did not (P < .001).

Persistent PNP resulted in reduced forced vital capacity; however, its influence on exercise intolerance could not be identified. Diaphragmatic plication should be reserved for patients who experience clinically significant respiratory or hemodynamic sequelae of PNP.