Background: Central venous pressure (CVP) provides the driving force for pulmonary blood flow in Fontan physiology, and it is dependent on pulmonary vascular resistance index (PVRI), ventricular filling pressure and venous compliance. The relationship between CVP and PVRI in the Fontan physiology has not been studied. We hypothesized that in the absence of a subpulmonary ventricle in the Fontan physiology, PVRI becomes the primary determinant of CVP and Fontan related clinical outcomes.
Methods: Retrospective review of adult Fontan patients and non-congenital heart disease patients (non-CHD) that underwent cardiac catheterization at Mayo Clinic Rochester, Minnesota,1990–2015. Fontan patients were matched to the non-CHD (2:1) by age at time of catheterization (±10 years) and body mass index (±2 kg/m2).
Results: There were 164 patients and 82 patients in the Fontan and non-CHD groups respectively. In comparison to the non-CHD group, the Fontan patients were younger (median age 36 vs 45 years, p<0.001), more likely to be on anticoagulation or antiplatelet therapy, and more likely to have atrial arrhythmia or cirrhosis. There was a good correlation between CVP and PVRI in the Fontan group (r=0.79, p<0.001) in contrast to the non-CHD group where CVP was independent of PVRI. There was a weak correlation between CVP and PAWP in the Fontan group (r=0.19, p=0.04). Elevated PVRI was an risk factor for FAD (protein losing enteropathy, cirrhosis, heart failure hospitalization, arrhythmia, thromboembolism) and FAD was assisted with death (odds ratio 8.2; 95% CI 6.6–10.1, p<0.001).
Conclusions: The current study demonstrates a direct correlation between CVP and PVRI in Fontan physiology. The data suggest that elevated CVP (systemic venous congestion), which is the primary factor in the pathogenesis of most FAD and death, may to a large extent, be driven by elevation in PVR.