Changes in venous return parameters associated with univentricular Fontan circulations

Department of Cardiovascular and Pediatric Cardiac Surgery and Experimental Surgical Laboratory, Marie Lannelongue Hospital, Paris-Sud University, 92350 Le Plessis Robinson, France To clarify the physiology of venous return (Q vr ) in Fontan circulations, venous return conductance ( G vr ) and mean circulatory filling pressure (P mcf ) were determined in pentobarbital sodium-anesthetized pigs. Relationships between Q vr and right (biventricular, n = 8) or left (Fontan, n = 8) filling pressures are described by straight lines with significant correlation coefficients. Estimated P mcf values were correlated with observed P mcf values in either circulations ( P 0.02). G vr was smaller in Fontan than in biventricular circulations (4.51 ± 0.36 vs. 7.83 ± 0.69 ml · min 1 · kg 1 · mmHg 1 , P = 0.002) and inversely correlated with pulmonary vascular resistances in Fontan circulations ( P = 0.01). Estimated P mcf (20.5 ± 1.4 vs. 11.1 ± 0.9 mmHg, P = 0.001) and observed P mcf (21.8 ± 1.3 vs. 10.6 ± 0.8 mmHg, P