Abstract
AIMS: Despite their universal predisposition, diagnosing diastolic dysfunction in patients post-Fontan palliation is challenging. Our aim was to compare exercise haemodynamics between adults post-Fontan and patients with heart failure with preserved ejection fraction (HFpEF) and non-cardiac dyspnoea (NCD). METHODS AND RESULTS: Twenty-four adults (age ≥18 years) post-Fontan palliation with resting and exercise pulmonary artery wedge pressure (PAWP) measured during supine biking were identified. Forty-eight patients with HFpEF and 48 with NCD diagnosed at catheterization were selected for comparison. Mean age for Fontan patients was 30.3 ± 7.5 years; median ventricular ejection fraction was 52.5% (45-55.8), being <50% in 37.5%. Resting PAWP among Fontan patients was 10.2 ± 3.5 mmHg (>12 mmHg in 25%); PAWP was lower in Fontan patients than in HFpEF but higher than NCD. During exercise, PAWP was lower in the Fontan group than HFpEF (22.5 mmHg [19.3-28] vs. 28.2 ± 6.3; p = 0.0006) but higher than NCD (11.2 ± 4.2, p ≤ 0.0001). However, there were no differences in ΔPAWP/ΔQs between Fontan and HFpEF patients (4.0 [2.1-7.3] vs. 2.7 [1.6-4.4]; p = 0.10) with the ratio being higher post-Fontan than in NCD (0.6 [0.2-1.2]; p < 0.0001). ΔPAWP/ΔQs remained similar between HFpEF and Fontan patients even when those with ejection fraction <50% were excluded (2.7 [1.6-4.4] vs. 2.7 [1.0-5.8]; p = 0.97). CONCLUSION: There were no differences in ΔPAWP/ΔQs ratios between post-Fontan and HFpEF patients, supporting markedly abnormal single ventricle compliance despite lower resting and exercise PAWP. Therefore, exercise invasive haemodynamics may represent a novel tool for the diagnosis of diastolic dysfunction in Fontan patients.