The effects of oral pulmonary vasodilator therapy on poor candidates for fenestration closure in patients with a fontan circulation

Background: The effect of pulmonary vasodilator therapy in non-pulsatile pulmonary circulation in single ventricle palliation (Fontan operation) is controversial. We evaluated the effect of chronic pulmonary vasodilator therapy on the hemodynamic findings during balloon occlusion of fenestration in Fontan patients who were identified as high risk for fenestration closure on a previous catheterization. Methods and results: Of 44 consecutive patients who underwent a fenestrated Fontan operation and attempted fenestration closure at catheterization, 8 were found to be unsuitable due to a decrease in cardiac index by more than 35%, or a significant increase in central venous pressure. All 8 patients were treated with pulmonary vasodilator therapy for at least 6 months prior to an additional attempt at closure. All repeated catheterizations for fenestration closure were successful. Comparison of hemodynamic parameters during balloon occlusion, prior to and under therapy, demonstrated a significantly smaller decrease in cardiac index [36% (15%) vs. 10% (5%), p = 0.008], a tendency to significant increase in pulmonary flow [3.2(1.2)vs. 2.5(1.2) Lit/min/m2, p = 0.1) while the PVRi was significantly lower too [2.6(0.2)vs. 1.45(0.45) Wui, p = 0.008]. Conclusion: Chronic oral pulmonary vasodilator therapy in fenestrated Fontan patients with a Fontan unsuitable for fenestration closure demonstrated significant hemodynamic benefit during catheterization and afforded subsequent fenestration closure.