Peak Peripheral Venous Pressure-Oxygen Uptake Relationship During Exercise: A Tool for Assessing Veno-venous...

In patients with Fontan circulation, veno-venous collaterals (VVCs) are associated with complications such as cyanosis, ventricular overload, erythrocytosis, and paradoxical embolism. However, VVCs might play a compensatory role in the attenuation of central venous pressure elevation. In this study, we evaluated the effect of VVCs on Fontan circulation by analyzing the relationship between peak peripheral venous pressure (PPVP) and peak oxygen uptake (PVO₂) during exercise.

This single-centre cross-sectional study included 89 patients with Fontan circulation (31 with VVCs) who underwent cardiopulmonary exercise testing with upper-extremity peripheral venous pressure monitoring. PPVP and PVO₂ were measured, and multiple regression was performed to compare the relationship between PPVP and PVO₂ in patients with and without VVCs.

On the basis of the presence of VVCs, there was a statistically significant interaction between the PPVP and PVO₂ (P = 0.0116). Among patients with PVO₂ ≤ 31.05 mL/kg/min, the PPVP was lower in those with VVCs than in those without, suggestive of a buffering effect. Conversely, among patients with PVO₂ > 31.05 mL/kg/min, the PPVP was higher in those with VVCs than in those without, which indicates increased venous pressure during exercise.

PVO₂ might be an important indicator of VVC-related effects in patients with Fontan circulation. In patients with low PVO₂, VVCs might exert a buffering effect that attenuates central venous pressure elevation. Conversely, in patients with preserved PVO₂, VVCs might increase venous pressure overload during exertion, and potentially contribute to abdominal organ congestion.