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

Background: 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.

Methods: 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.

Results: 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).

Conclusions: 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.