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Changes in venous return parameters associated with univentricular Fontan circulations.
L Macé1, P Dervanian, A Bourriez
1Department of Cardiovascular and Pediatric Cardiac Surgery and Experimental Surgical Laboratory, Marie Lannelongue Hospital, Paris-Sud University, 92350 Le Plessis Robinson, France. mace@ccml.com
American Journal of Physiology. Heart and Circulatory Physiology
|October 25, 2000
Summary
In Fontan circulation, higher pulmonary vascular resistance reduces venous return. However, volume loading increases filling pressure, maintaining systemic blood flow comparable to biventricular circulation.
Area of Science:
- Cardiovascular Physiology
- Pediatric Cardiology
Background:
- The Fontan circulation is a surgical procedure to manage single-ventricle congenital heart defects.
- Understanding venous return physiology is crucial for optimizing outcomes in Fontan patients.
Purpose of the Study:
- To investigate the determinants of venous return (Q(vr)) in Fontan circulations.
- To compare venous return conductance (G(vr)) and mean circulatory filling pressure (P(mcf)) between Fontan and biventricular circulations.
Main Methods:
- Utilized pentobarbital sodium-anesthetized pigs for hemodynamic measurements.
- Determined relationships between Q(vr) and filling pressures in biventricular and Fontan models.
- Assessed G(vr), P(mcf), and pulmonary vascular resistances.
Main Results:
- G(vr) was significantly lower in Fontan (4.51 ml.min⁻¹.kg⁻¹.mmHg⁻¹) versus biventricular circulations (7.83 ml.min⁻¹.kg⁻¹.mmHg⁻¹).
- P(mcf) was higher in Fontan (estimated: 20.5 mmHg, observed: 21.8 mmHg) compared to biventricular circulations (estimated: 11.1 mmHg, observed: 10.6 mmHg).
- Pulmonary vascular resistances were inversely correlated with G(vr) in Fontan circulations.
Conclusions:
- Pulmonary vascular resistances proportionally decrease G(vr) in Fontan circulations.
- Volume loading increases P(mcf) and the gradient for Q(vr), maintaining systemic blood flow at a biventricular level.