Invasive hemodynamic assessment of the effect of sildenafil treatment after Fontan operation

There is no pumping subpulmonary ventricle in patients with univentricular hemodynamics after Fontan type physiological correction of complex congenital heart defects (CHD). Hence the blood fl ow to the lungs is passive and depends on central venous pressure (CVP) and pulmonary vascular resistance (PVR) to provide adequate fi lling of the single ventricle. The increase in PVR leads to a reduction in ventricular fi lling and cardiac output, resulting in failure of the Fontan circulation (the so-called failing Fontan). Purpose. Invasive assessment of the hemodynamic effect of sildenafi l treatment in children with single ventricle Fontan circulation. Material and Methods. Twenty-six children (12 girls, 14 boys) with completed stages of Fontan type surgery in whom a selective pulmonary vasodilator (sildenafi l) has been administered during the follow-up have been investigated. An open-label, non-randomized, prospective invasive study of the hemodynamic effect of sildenafi l treatment in patients with completed Fontan surgery stages was performed. Results. A signifi cant decrease in the cavopulmonary pressure (from 16.58 ± 1.88 mm Hg to 13.80 ± 2.20 mm Hg; p < 0.001) and the pulmonary vascular resistance (from 2.02 ± 0.72 WU to 1.42 ± 0.41 WU; p = 0.001), increase of the pulmonary/systemic blood fl ow ratio (from 0.71 ± 0.21 to 0.83 ± 0.18; p < 0.05), as well as increase in the systemic oxygen saturation (from 85.65 ± 7.48% to 90.72 ± 4.53%; p = 0.005) were found. No signifi cant difference in hemodynamic parameters related to the ventricular morphology and the type of previous palliation was found. The only exception was the pulmonary blood fl ow after sildenafi l treatment,  which was signifi cantly higher in children with а previous systemic to pulmonary shunt compared to children with а previous banding (p < 0.05). Conclusion. Our study showed signifi cant benefi cial changes in the main hemodynamic parameters after sildenafi l treatment. The pharmacological modulation of the pulmonary vascular status is an important component of the treatment of patients with Fontan circulation.