Fontan Operation clinical trials

Pulmonary Functions Test in Patients After Fontan Operation

Developed in the early 1970s, Fontan Operation has provided palliative care for patients with single ventricle physiology. Single ventricle is a rare subclass of the atrioventricular (AV) alignment abnormalities double inlet and common inlet ventricles (and rarely, straddling tricuspid valve), in which there is only one ventricular sinus [1]. Most patients present with symptoms of congestion , low cardiac output, and deep cyanosis immedietly after birth. Untreated, these heart anomalies are highly lethal. Neonatal heart transplantation is implacable because of shortage of donors. Fontan operation is a three staged palliative procedure: the single ventricle pumping blood to the systemic circulation , while blood flows laminarly to the lungs through direct anastomosis of the superior and inferior vena cavae (total cavo pulmonary connections), inevitably by-passing the right heart . This procedure has been shown to immediately correct the mixed venous blood dysfunction, providing treatment for the prominent signs of cyanosis. Along with its beneficial outcomes, Fontan circulation patients have been documented to have a variety of post-operative late complications. Of most substantial, increased systemic vascular resistance (mean of 10-15 mmHg higher) [2], systolic dysfunction as a result of decreased preload and increase afterload [3], and atrial arrhythmias [4]. With the advent of bypassing right-heart circulation with Fontan operation, the pulmonary vascular bed is exposed to a new atmosphere of blood flow. Instead of physiological pulsatile flow in normal circulation, the pulmonary vasculature is receiving slow velocity, laminar flow [5]. Patients post-Fontan operations have been documented to have restrictive-type pulmonary function, but still yet to be correlated with Fontan circulation or as a possible result of prior lung tissue injury from the pre/intra-operation high volume blood flow. Regardless, Fontan patients are described to have decreased pulmonary function. The purpose of this research effort is to document and analyze the pulmonary function of those patients post-Fontan operation. It is still unclear as to what the long-term effects of Fontan operation are towards the pulmonary vascular bed, leaving us questions about the effects on lung capacities, ventilation-perfusion efficiency, and oxygen saturation.