Looking beyond LVEF: cardiac and skeletal muscle function in long-term breast cancer survivors with normal versus reduced peak oxygen uptake
Notice bibliographique
Résumé
Abstract Background Peak oxygen uptake (VO2peak) is a marker of cardiovascular disease (CVD) and heart failure (HF) risk that is gaining interest in breast cancer survivors (BCS) treated with cardiotoxic therapy. However, the factors contributing to reduced VO2peak in this population remain unclear. Purpose To compare exercise magnetic resonance imaging (MRI) derived measures of cardiac and skeletal muscle function in BCS with normal (≥85% predicted) or reduced (<85% predicted) VO2peak. Methods 31 older (≥60 yrs) BCS previously treated (≥1 year) with cardiotoxic therapy (anthracycline chemotherapy and/or trastuzumab) without established CVD were recruited. VO2peak was measured from a maximal cardiopulmonary exercise test (cycle ergometer), and used to classify BCS into normal (≥85% predicted) or reduced VO2peak (<85% predicted) based on age, sex and height predicted values. Ventricular volumes, hemodynamics, and arterio-venous oxygen difference (a-vO2diff) was assessed with MRI at rest and during sub-maximal stepping exercise at ~60% of VO2peak. MRI-derived measures of peak calf muscle VO2peak (mVO2peak), blood flow and a-vO2diff (popliteal vein) were also assessed during an incremental to maximal plantar flexion exercise test. Groups were compared using analysis of covariance with adjustment for age. Results BCS with reduced VO2peak (n=18; 71±8% predicted) vs normal VO2peak (n=13; 99±13% predicted) were older (72±5 vs 67±3 yrs, P=0.004), tended to be leaner (BMI: 25.6±4.1 vs 28.3±5.6 kg/m2, P=0.14) and were evaluated a similar time post-treatment (15±6 vs 13±5 yrs, P=0.23). The reduced VO2peak group had markedly lower VO2peak (22.2±4.5 vs 17.3±3.6 mL/kg/min, P=0.002), despite similar peak respiratory exchange ratio (1.32±0.13 vs 1.30±0.13, P=0.56) and maximal heart rate (HR; 97±13 vs 101±10% predicted, P=0.40). At rest, both groups had comparable left-ventricular ejection fraction (LVEF; 59±5 vs 62±8%, P=0.30), but BCS with reduced VO2peak had smaller resting end-diastolic volume index (68±8 vs 77±15 mL/m2, P=0.033), and as a consequence, stroke volume index (SVi; 40±4 vs 47±6 mL/m2, P<0.001). During stepping exercise (Fig 1), BCS with reduced VO2peak had similar a-vO2diff (+0.3 mL/dL, P=0.75) but significantly decreased cardiac index (CI; -0.6 L/min/m2, P=0.031) secondary to decreased SVi (-7.3 mL/m2, P=0.035), as HR (-2 b/min, P=0.70) and LVEF (-1%, P=0.61) were comparable. In contrast, during small muscle mass exercise (Fig 2) there were no differences in calf mVO2peak (+2 mL/min, P=0.71), muscle blood flow (+5 mL/min, P=0.94) or a-vO2diff (+0.5 mL/dL, P=0.32). Conclusions Reduced VO2peak in long-term BCS is secondary to smaller ventricular size and blunted exercise cardiac augmentation, rather than impairments in skeletal muscle (at the small muscle level). This highlights the importance of further studies to evaluate the prognostic significance of reduced VO2peak for future CVD and HF events in BCS.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».