Plasma volume status in patients after Fontan operation: Prognostic value and the associations with Fontan pathophysiology

Abstract

Background: Assessment of plasma volume status (PVS) is essential for the management of patients with heart failure (HF). We aimed to elucidate the clinical features of PVS in patients with Fontan circulation (FC). Methods: Plasma volume (PV) was measured via pulse dye densitometry (icg-PV) and compared with the calculated PV (c-PV) in 114 patients with FC and 32 with biventricular circulation (BVC). We derived the PVS (%) [{(c-PV－ideal-PV)/ideal-PV} ​× ​100] and elucidated its clinical associations in 275 consecutive patients with FC and 493 with BVC. Results: The c-PV correlated with the icg-PV in FC (r ​= ​0.70) and BVC (r ​= ​0.67) (p ​< ​0.0001 for each). Compared with BVC, FC exhibited contracted c-PV (37 ​± ​5 vs. 39 ​± ​4 ​mL/kg) and the PVS was lower (−4.7% ​± ​11.5% vs. −1.3% ​± ​9.8%), although the circulating blood volume (BV) was greater (69 ​± ​6 vs. 66 ​± ​5 ​mL/kg) (p ​< ​0.0001 for all). Increased PVS was independently associated with HF-associated hospitalization and all-cause mortality in both groups (p ​< ​0.05) with a cutoff value of 3.0% for FC. FC with PVS ≥3.0% (n ​= ​59) was characterized by low aortic pressure, high cardiac index, and large ventricular volume with a high prevalence of protein-losing enteropathy (p ​< ​0.05–0.0001). Conclusions: Compared with BVC, FC was associated with increased BV but contracted PV. Regarding Fontan, a higher PVS is associated with a phenotype of high output HF and higher risk of adverse outcomes.

Keywords

• Fontan
• Plasma volume status
• Heart failure
• Morbidity
• Mortality