Exercise Capacity, NT-proBNP, and Exercise Hemodynamics in Adults Post-Fontan

Cardiopulmonary exercise testing (CPET) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurement are frequently performed in adults post-Fontan, but their correlations with exercise invasive hemodynamics are poorly understood. Moreover, whether exercise cardiac catheterization provides incremental prognostic information is unknown.

The authors sought to correlate resting and exercise Fontan pressures (FP) and pulmonary artery wedge pressure (PAWP) with peak oxygen consumption (VO₂) on CPET, NT-proBNP, and clinical outcomes.

This was a retrospective cohort of 50 adults (age ≥18 years) post-Fontan undergoing supine exercise venous catheterization between 2018 and 2022.

Median age was 31.5 years (IQR: 23.7-36.5 years). Ventricular ejection fraction was 48.5% ± 13.0%. Exercise FP and PAWP were related to peak VO₂ and ln NT-proBNP levels. Patients with peak VO₂ <50% predicted had higher exercise FP (30.0 ± 6.8 mm Hg vs 19 mm Hg [IQR: 16-24 mm Hg]; P < 0.001) and PAWP (25.9 ± 6.3 mm Hg vs 15.1 ± 7.0 mm Hg; P <0.001) compared with those with more preserved exercise capacity. Exercise FP (30.0 ± 7.1 mm Hg vs 23.2 ± 7.2 mm Hg; P = 0.003) and PAWP (25.1 ± 6.7 mm Hg vs 18.8 ± 7.9 mm Hg; P = 0.006) were higher in those with NT-proBNP levels ≥300 pg/mL. During a follow-up of 0.9 years (IQR: 0.6-2.9 years), exercise FP and PAWP remained independently associated with a composite of death, cardiac transplantation, or hospitalization due to heart failure/refractory arrhythmias after adjusting for confounders.

In adults post-Fontan, resting and exercise FP and PAWP were inversely related to exercise capacity on noninvasive CPET, and exercise hemodynamics were directly related to NT-proBNP levels. Exercise FP and PAWP were independently associated with clinical outcomes and might be more sensitive than resting values to predict clinical outcomes.