Background and Objectives Although survival of patients with the hypoplastic left heart syndrome treated by staged surgical palliation has improved, hemodynamic data after fenestrated Fontan operation and after fenestration closure have not been reported in this patient population. We sought to describe the hemodynamic status of these patients at cardiac catheterization performed for the purpose of fenestration closure and to compare these data with data from contemporary patients with other forms of univentricular heart.

Methods and Results Hemodynamic responses to fenestration closure during cardiac catheterization were reviewed in 40 consecutive patients, including 20 with the hypoplastic left heart syndrome and 20 with other forms of univentricular heart defects. Hemodynamics before fenestration closure (arterial saturation and pressure, Fontan baffle saturation and pressure, pulmonary capillary wedge pressure, systemic arteriovenous oxygen content difference, and right-to-left shunt fraction) were nearly identical between the two groups. Significant (p < 0.05) changes after fenestration closure included increases in arterial saturation (9%), mean arterial pressure (3 mm Hg), and baffle pressure (1 mm Hg) and arteriovenous oxygen content difference (18 ml/L), with near elimination of right-to-left shunting. Cardiac output decreased by 21% and systemic oxygen transport by 13%, with no differences between the two patient groups. Mean baffle pressures were <17 mm Hg in 32 patients (80%).

Conclusions Hemodynamics after fenestrated Fontan operation and responses to fenestration closure in patients with the hypoplastic left heart syndrome were remarkably similar to that in patients with other univentricular heart defects. (Am Heart J 1998;136:302-6.)