Cerebral And Cardiac Hemodynamics During Exercise Are Related To Cognitive Function In Heart Transplant Recipients
Bibliographic record
Abstract
Heart transplant recipients (HTR) have an impaired VO2max, maximal cardiac output and peripheral vascular function compared to healthy age-matched subjects. Previous studies showed a reduced cerebral oxygenation and perfusion (COP) during exercise in HTR, but the relationship of COP with cognitive function is not clear. We aimed to analyze differences and correlations among COP, maximal cardiac index (CImax), VO2peak and cognitive function between heart transplant recipients and age-matched healthy subjects. METHOD: Twelve stable HTR (55±11 years) and 12 age-matched healthy subjects (55±12 years) were recruited for this pilot trial. In HTR, the mean time after transplantation was 6.8±5.4 years. Left frontal COP (NIRS: Oxymon Mk III, Netherlands) and cardiac hemodynamics (impedance cardiography: PhysioFlow, France) were measured during a maximal cardiopulmonary ergocycle test (Oxycon Pro; CareFusion, Jaegger, Germany). Cognitive function was evaluated at rest by a complete neuropsychological test battery (13 different items) and raw composite score were calculated for 4 different domains: 1) working memory (WM); 2) processing speed (PS); 3) Executive function (EF); and 4) Verbal memory (VM). ANOVA was used to test groups’ differences and Pearson or Spearman correlations were used to evaluate the relationship between cognitive function, COP (oxyhemoglobin: O2Hb, total hemoglobin: THb, CImax and VO2peak). Statistical significance was p<0.05. RESULTS: VO2peak (p=0.0005), CImax (p=0.0112), EF (p=0.0148) and WM (p=0.0194) were lower in HTR vs. HS; and a tendency for lower O2Hb (p=0.0921), THb (p=0.0720) and VM (p=0.0728) was observed. VM was positively correlated with VO2peak (p=0.034) and CImax (p=0.006); and EF was negatively correlated with VO2peak (p= 0.0001) and CImax (p=0.005) (figure 1); and O2Hb had a tendency to be correlated to EF (p=0.071) and VM (p=0.085). CONCLUSION: Our preliminary results demonstrated that cognitive function, especially verbal memory and executive function were related to VO2peak and maximal cardiac index in heart transplant recipients. We also believe that reduced COP could be related to cognitive function in these subjects, but there is no enough power to confirm this hypothesis. Supported by:ÉPIC Foundation and CNPq.
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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) | 0.000 | 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 | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".