Egbe AC; Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN.
Ali AE; Miranda WR; Connolly HM;Borlaug BA
Circulation. Heart failure [Circ Heart Fail] 2024 Dec 09, pp. e011981.
Date of Electronic Publication: 2024 Dec 09.
Background: Patients with Fontan palliation have reduced aerobic capacity because of impaired cardiac, pulmonary, and skeletal muscle function. However, the assessment of aerobic capacity in this population still relies on comparisons with people without cardiovascular disease rather than comparison with the expected aerobic capacity of other Fontan patients. The purpose of this study was to determine the expected aerobic capacity of adults with Fontan palliation.
Methods: Adults with Fontan palliation who underwent a cardiopulmonary exercise test at Mayo Clinic (2003-2023) were stratified into quartiles based on the predicted peak oxygen consumption (VO 2 ). We assessed the correlates of predicted peak VO 2 and the relationship between predicted peak VO 2 quartiles and cardiovascular outcomes (death/transplant).
Results: Of 323 patients (age, 29±9 years; 177 [55%] men), the median peak VO 2 was 19.1 (15.2-23.9) mL/kg per minute, and this corresponds to a predicted peak VO 2 of 51% (range, 19-88; interquartile range, 41-62). After multivariable adjustments, the correlates of predicted peak VO 2 were body mass index (β±SE, -2.61±0.95; 2.61% decrease in predicted peak VO 2 per 5 kg/m 2 increase in body mass index; P =0.009), systemic saturation (β±SE, 3.65±0.85; 3.65% increase in predicted peak VO 2 per 5% increase in oxygen saturation; P <0.001), and Fontan pressure (β±SE, -1.24±0.22; 1.24% decrease in predicted peak VO 2 per 1 mm Hg increase in Fontan pressures; P <0.001). There was a 47% increase in the risk for death/transplant from a higher predicted peak VO 2 quartile to the next lower quartile (adjusted hazard ratio, 1.47 [95% CI, 1.09-2.05]; P =0.01).
Conclusions: The results of the current study would help calibrate the interpretation of exercise test data in adults with Fontan palliation and improve risk stratification in this population. It also underscores the need to maintain normal Fontan hemodynamics and body weight, which are important determinants of aerobic capacity.