Early Impact of Fontan Operation on Enteric Protein Loss

Protein-losing enteropathy (PLE) is a challenging complication after a Fontan operation. Subclinical enteric protein loss may precede development of overt PLE. We evaluated the acute effects of Fontan circulation on enteric protein loss and mesenteric vascular resistance.

A prospective cohort study was performed evaluating enteric protein loss in children undergoing Fontan operations. Stool alpha-1 antitrypsin (A1AT) concentration was measured in the preoperative, early postoperative, and intermediate postoperative (3-9 months) periods. The intestinal circulation was characterized by Doppler-derived resistance indices of the superior mesenteric artery (SMA), and serum albumin and protein levels were obtained.

We enrolled 33 participants at a median age at operation of 3.0 years (interquartile range [IQR], 2.5-3.3 years). No clinical PLE was observed. Six of the 93 stool samples obtained had elevated A1AT levels (>54 mg/dL), with 2 abnormal samples at each of the 3 time points. Two of the 5 participants with elevated stool A1AT values had significant hemodynamic disturbances requiring intervention (junctional bradycardia or tricuspid stenosis). There was no difference in SMA resistance in the preoperative versus early postoperative periods (p = 0.9). Serum albumin levels were lower in the early postoperative period compared with the preoperative period (3.2 mg/dL [{IQR}, 2.9-3.5] versus 4.1 mg/dL; IQR, 3.4-4.5; p = 0.01) but did not correlate with abnormal stool A1AT concentration or SMA resistance indices.

The Fontan operation does not commonly result in acute development of increased enteric protein loss. However, increased enteric protein loss may occur in children before or after a Fontan operation, particularly when hemodynamic disturbances are present.