Association between the inferior vena cava collapsibility index and Fontan pressure in patients with Fontan physiology: a two-centre prospective pilot study

Abstract Introduction: Patients with functional single ventricle anatomy undergo staged surgical palliation in early childhood culminating in the Fontan procedure whereby the inferior vena cava is connected to the pulmonary artery. Fontan circulation inherently requires elevated central venous pressure to maintain adequate pulmonary blood flow; however, excessive elevation is associated with morbidity and mortality. In adults, a key component of echocardiographic evaluation is the use of a “sniff test” as a surrogate of downstream right atrial pressure. This technique has not yet been validated as a measure of pressure assessment in patients with Fontan circulation.