Nonobstructive ASD creation to qualify patients for the Fontan operation: effects on pulmonary hypertension due to restrictive left atrioventricular valve and interatrial communication.

Abstract

Pulmonary hypertension (PH) due to elevated left atrial pressure (LAp) caused by restrictive left atrioventricular valve and interatrial communication sometimes precludes patients with univentricular heart from undergoing the Fontan operation. We have created atrial septal defect (ASD) for such patients to reduce LAp and then pulmonary arterial pressure (PAp) and pulmonary vascular resistance (Rp) in an attempt to qualify the patients for the Fontan repair. This study was performed to clarify the efficacy and limitation of this approach. Twelve patients with PH (mean PAp > 20 mm Hg and/or Rp > 3.0 Wood's unit/m(2)) due to obstruction at the LA exit underwent ASD creation at the age of 4.0 +/- 4.0 (mean +/- SD) years. Follow-up catheterization 14.9 +/- 15.6 months after the ASD creation demonstrated marked reductions in mean LAp (from 21 +/- 5 to 8 +/- 2 mm Hg), mean PAp (from 39 +/- 13 to 17 +/- 4 mm Hg), and Rp (from 6.2 +/- 4.5 to 2.7 +/- 1.4 Wood's unit/m(2)) compared with those before the procedure (all P < 0.0001). Seven of the 12 patients (58%) qualified for the Fontan operation (mean PAp < 20 mm Hg, Rp < 3.0 Wood's unit/m(2), and Nakata's PA index > or = 250) after the ASD creation. Final surgical outcomes of the seven patients included successful Fontan operation in five and biventricular repair in two. Patients with severe PH [mean PAp > or = 45 mm Hg (n = 6) or Rp > or = 4.5 Wood's unit/m(2) (n = 5)] before the ASD creation qualified less frequently for the Fontan repair than those with mild PH [mean PAp < 45 mm Hg (n = 6; 17% vs. 100%; P = 0.008) or Rp < 4.5 Wood's unit/m(2) (n = 7; 20 vs. 86%; P = 0.045)]. Patients with PA banded after 6 months of age (n = 3) qualified less frequently for the Fontan operation than those banded before 6 months of age (n = 6; 0 vs. 83%; P = 0.048). These data suggest that ASD creation is an effective approach to qualify patients for the Fontan operation in the presence of restrictive left atrioventricular valve and interatrial obstruction, except those with longstanding severe PH following delayed PA banding.