Fontan Patients With a Systemic Left Ventricle Have Greater Exercise Capacity Than Those With a Systemic Right Ventricle: A Systematic Review and Meta-analysis
Bibliographic record
Abstract
Abstract Intro: Cardiopulmonary exercise testing (CPET) has emerged as a useful metric to track the health of the Fontan patients. There is clinical utility in understanding the role of ventricular morphology, as this could influence how CPET results are interpreted in Fontan patients. This systematic review and meta-analysis aimed to assess the CPET capacity of left ventricle (LV) over right ventricle (RV) morphology among Fontan patients. Methods: PubMed, Embase, and Cochrane were searched from inception to October 2024. Inclusion criteria were 1) interventional and observational studies, 2) presence of Fontan circuit, 3) CPET via treadmill or cycle ergometer, and 4) separation of outcomes of interest by systemic ventricle. Outcomes of interest were VO2 max, O2 pulse, VE/VCO2 slope, VO2 at anaerobic threshold (VAT), and maximum heart rate. The quality of studies was assessed using the Newcastle-Ottawa scale. Measure of effects were reported as standardized mean difference (SMD) or weighted mean difference (MD) where applicable along with 95% confidence interval (CI). Meta analysis was performed using a random-effects DerSimonian-Laird model. Results: A total of 20 out of 1368 studies met criteria. This included 50% retrospective cohort studies, 35% cross-sectional, 10% randomized control trials, and 5% pre-experimental design with 1,473 total participants (59.4% male, 57.7% systemic left/mixed ventricles, 30% treadmill). Patients with morphologic left/mixed versus right ventricles showed a significantly greater VO2 max of 0.40 (95% CI 0.20, 0.9; n=17; I2=51%) and O2 pulse of 0.29 (0.10, 0.49; n=6; I2=6%) as well as a significantly lower VE/VCO2 slope by -3.14 (-5.06, -1.23; n=8; I2=66%). There was an increase in VAT by 0.12 (-0.03, 0.27; N=9; I2=0%) and max HR by 7.63 bpm (-0.95, 16.20; N=7; I2=78%) in LV compared to RV, however these did not achieve statistical significance. Conclusions: These results demonstrate that Fontan patients with a systemic left ventricle have superior exercise capacity and stroke volume with less dead space ventilation as compared to those with a systemic right ventricle given the greater VO2 max and O2 pulse with a decreased VE/VCO2 slope. Limitations to this analysis include the exclusion of abstract-only data and an inability to include data from studies reporting no difference between ventricles but without corresponding data, which likely biased these results away from the null. Time from Fontan procedure was also unable to be evaluated. These findings support the need for further research into the clinical differences between Fontan patients with a systemic left versus right ventricle.
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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 | 0.008 | 0.023 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.014 | 0.034 |
| Bibliometrics | 0.006 | 0.007 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 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".