Filling pressures in Fontan revisited: Comparison between pulmonary artery wedge, ventricular end-diastolic, and left atrial pressures in adults

Background Pulmonary artery wedge pressure (PAWP) has been shown to correlate better with left atrial pressure (LAP) than ventricular end-diastolic pressure (VEDP) in acquired heart disease. The correlation between VEDP and PAWP and their performance as surrogates for LAP in Fontan patients is unknown. Methods Offline single-beat simultaneous measurement of PAWP and VEDP was performed in 50 adult Fontan patients and non-simultaneous hemodynamic data abstracted for calculation of pulmonary vascular resistance (PVR). For the evaluation of PAWP and VEDP as surrogates for LAP, 14 fenestrated adult Fontan patients were included. Results Mean age was 34.2 ± 10 years and 54% of patients were female. Tricuspid atresia and double inlet left ventricle were the most common congenital defects (44% and 20%, respectively). Simultaneous mean VEDP was 10.8 ± 4.6 mm Hg and mean PAWP was 11 ± 4.6 mm Hg; the PAWP-VEDP correlation was 0.91 (p < 0.001). Using non-simultaneous data, right-sided (mean difference 0.6 WU·m², 95% CI 0.2–1.0; p = 0.005) and left-sided (mean difference 0.5 WU·m², 95% CI 0.1–0.9; p = 0.02) PVRs were significantly higher when PAWP rather than VEDP was used. In fenestrated patients, LAP-right PAWP and LAP-left PAWP correlations were 0.97 and 0.95 (p < 0.0001 for both), respectively, whereas the correlation between LAP-VEDP was 0.76 (p = 0.007). Conclusions PAWP and VEDP correlate reasonably well in adult Fontan patients but PAWP is a better surrogate for LAP. The use of VEDP instead of PAWP appears to significantly underestimate PVR in these patients.