Preoperative small pulmonary artery did not affect the midterm results of Fontan operation

It was well discussed, in the primary Fontan era, that small pulmonary arterial size could affect the results immediately after the Fontan procedure. The objective of the present study is to determine whether this feature remains as a risk factor in the era of the staged Fontan completion and poses functional impediments in the longer terms.

Between June 1991 and November 2004, the staged Fontan completion was carried out subsequent to the bidirectional Glenn procedure in consecutive 57 patients with a preoperative pulmonary artery index less than 250 mm2/m2 (Group-S; minimum index 104 mm2/m2). Clinical data were reviewed retrospectively. As background and reference information, similar data were collected in another consecutive 64 patients with larger pulmonary arteries who underwent the staged Fontan completion during the same period (Group-L; maximum index 697 mm2/m2).

No patients died after the Fontan procedure in Group-S, while six early deaths in Group-L. No takedown of the Fontan circulation was carried out in either group. The latest catheterizations, at 2.8+/-2.7 years postoperatively, showed a pulmonary artery index significantly lower than the preoperative index (Group-S: 198+/-37-176+/-49 mm2/m2; P=0.0082, Group-L: 360+/-94-266+/-89 mm2/m2; P<0.0001). Hemodynamics in Group-S during the intermediate term were identical with those in Group-L in mean pulmonary arterial pressure (10+/-2 in Group-S and 10+/-3 mmHg in Group-L), mean atrial pressure for the systemic chambers (5+/-2 and 6+/-3 mmHg, respectively), mean transpulmonary gradient (5+/-2 and 4+/-2 mmHg, respectively), cardiac index (3.0+/-0.7 and 3.0+/-0.6l/min/m2, respectively), and arterial oxygen saturation (93+/-3% and 94+/-2%, respectively). Similarly, brain natriuretic peptides concentration in the serum (19.4+/-15.6 in Group-S and 28.3+/-37.2 pg/ml in Group-L) and peak oxygen consumption on exercise testing (24.8+/-4.5 and 24.0+/-6.3 ml/kg/min, respectively) were not inferior in Group-S to those in Group-L.

The outcome after the Fontan completion, including functional ones in the intermediate term, was acceptable in patients having a preoperative PA index smaller than 250 mm2/m2. Pulmonary artery index decreased still further postoperatively, but did not obviously militate against functional efficacy of the Fontan circulation.