Revisiting the Effect of Udenafil on Exercise Performance in Patients With Fontan Circulation: Results of a Post Hoc Analysis of the FUEL Trial
Bibliographic record
Abstract
Background In the FUEL (Fontan Udenafil Exercise Longitudinal) trial, a positive treatment effect was identified for outcomes at the ventilatory anaerobic threshold but not for the primary outcome, oxygen consumption (V o 2 ) at peak exercise. This disparate response may be explained by the physiologic challenge of improving peak V o 2 in participants with near‐normal baseline exercise performance. Methods Participants were divided into subgroups by baseline predicted peak V o 2 (<80% versus ≥80%). Treatment effect was evaluated in those with a baseline peak V o 2 <80% predicted and linear regression was performed to examine the interaction between subgroup and response to therapy for the primary and secondary outcomes. Results Of the 379 participants with paired exercise data, 302 (80%) had a baseline peak V o 2 <80% predicted. In this subgroup, the primary outcome of peak V o 2 improved significantly after 6 months of udenafil treatment, when compared with placebo (0.23±4.17 mL/kg per min versus −0.90±3.74 mL/kg per min; P =0.021). Secondary outcome measures, including V o 2 at ventilatory anaerobic threshold ( P =0.023), work at ventilatory anaerobic threshold ( P =0.032), and the myocardial performance index ( P =0.007) were all significantly improved as well. A significant interaction was found between exercise subgroups and response to udenafil for peak V o 2 ( P =0.036) but not for other outcomes. Conclusions In this post hoc subgroup analysis, after exclusion of patients with Fontan circulation with near‐normal baseline peak V o 2 , a positive treatment effect of udenafil was identified for the primary outcome of peak V o 2 . The interaction between baseline peak V o 2 and treatment may have influenced the outcome of the FUEL trial. Registration URL: https://clinicaltrials.gov ; Unique identifier: NCT0274115.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.006 | 0.008 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.005 | 0.004 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".