Abstract 4147741: The Effect of Anemia on the Mechanisms of Exercise Intolerance in Adults with HFpEF
Bibliographic record
Abstract
Introduction: Anemia (males: [Hb] <13.5 g/dL, females: <12 g/dL) is common in heart failure with preserved ejection fraction (HFpEF) and associated with exercise intolerance. The hemodynamic effect of anemia and the mechanism by which anemia impairs exercise capacity in patients with HFpEF are unclear. We investigated the effects of anemia on exercise hemodynamics and oxygen transport and utilization (VO 2 ) during a cardiopulmonary exercise test (CPET) and single leg knee extension exercise (SLKE) in patients with HFpEF. Methods: Patients with HFpEF (n=57) classified as non-anemic (n=33, 67% female, age: 70±7 y, BMI: 39.3±5.8 kg/m 2 , [Hb]: 13.7±1.5 g/dL) or anemic (63% female, age: 71±7 y, BMI: 34.7±5.9 kg/m 2 , [Hb]: 11.2±0.9 g/dL) completed CPET on a seated upright cycle ergometer. A subgroup (n=20 non-anemic; 14 anemic) also completed SLKE to exhaustion. During CPET we measured VO 2 (indirect calorimetry), arterio-venous O 2 difference (Δa-vO 2 ; arterial and right heart catheters) and cardiac output (Qc; Direct Fick). During SLKE we measured femoral artery blood flow (LBF; Doppler ultrasound), Δa-vO 2 (pulse oximetry and femoral venous catheter) and leg VO 2 . We also measured total hemoglobin mass (tHbmass; carbon monoxide rebreathing) and plasma volume. Data were compared via independent samples t-tests. Results: The anemic group had lower relative tHbmass (g/kg lean mass; Figure 1A) compared to non-anemic, with no difference in plasma volume (Figure 1B). Peak VO 2 during CPET was similar between groups (non-anemic: 1.32±0.39 vs anemic: 1.24±0.44 L/min, P =0.269), but the anemic group had a higher Q c -VO 2 slope (Figure 1C&D) and a lower Δa-vO 2 (non-anemic: 12.6±1.8; anemic: 10.7±1.4 mL/dL, P <0.001). During SLKE, no difference was detected in peak leg VO 2 , LBF, Δa-vO 2 , or diffusive capacity (all, P >0.175); however, the anemic group had a significantly greater LBF-VO 2 slope (Figure 1D). Conclusion: Patients with HFpEF and anemia present with a hyperdynamic circulation during exercise despite similar peak VO 2 to non-anemic peers. [Hb] modifies the coupling of oxygen delivery and demand and may be a key mechanism responsible for hyperdynamic circulatory responses to exercise in patients with HFpEF and anemia.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| 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".