The effect of additional pulmonary blood flow on timing of the total cavopulmonary connection

The staged Fontan procedure is used to palliate functionally univentricular hearts. The effect of additional pulmonary blood flow combined with a bidirectional cavopulmonary shunt in these patients remains a controversial subject.

This retrospective study included all 82 patients with a unilateral or bilateral bidirectional cavopulmonary shunt at our institution between April 1990 and July 2010. Patients with hypoplastic left heart syndrome were excluded. Two groups, based on the presence (n=57) or absence (n=25) of additional pulmonary blood flow after the bidirectional cavopulmonary shunt, were compared.

Patients with a bidirectional cavopulmonary shunt combined with additional pulmonary blood flow had higher arterial oxygen saturations postoperatively (86% [interquartile range, 85% to 90%] vs 82% [80% to 85%]; p=0.001) and had a longer median interval before the total cavopulmonary connection (3.42 [2.43 to 4.89] years vs 2.90 [2.08 to 3.32] years; p=0.06). At the total cavopulmonary connection, they were older (4.59 [3.88 to 6.49] years vs 3.94 [3.10 to 4.57] years; p=0.03) and had a larger median body surface area (0.73 [0.65 to 0.87] m2 vs 0.68 [0.59 to 0.73] m2; p=0.04).

Patients with a bidirectional cavopulmonary shunt and additional pulmonary blood flow have a longer interval before the total cavopulmonary connection without evident untoward effects. This may theoretically be advantageous for the pulmonary artery growth needed for a successful Fontan circulation. Furthermore, postponement of the final Fontan may ensure the insertion of a larger extracardiac conduit to avoid prosthesis-patient mismatch.