Effect of Anemia and Red Blood Cell Transfusion in Acute Myocardial Infarction.
Notice bibliographique
Résumé
Abstract Background: The optimal hemoglobin (Hb) in the setting of acute myocardial infarction (MI) is unknown. Anemia reduces the oxygen carrying capacity of blood and may theoretically exacerbate ischemia increasing myocardial injury. The benefit of transfusion to correct anemia in acute coronary syndromes is also controversial. The goal of this study was to determine the optimal Hb in the setting of acute MI and whether transfusion reduces myocardial injury and improves outcome. Experimental design: Ninety-two male Sprague-Dawley rats (170–190g) were divided into 8 groups: 1: Normal Hb, sham operation; 2: Normal Hb, MI; 3: Hb 80–90g/L, sham; 4: Hb 80–90g/L, MI; 5: Hb 70–80g/L, sham; 6: Hb 70–80g/L, MI; 7: Hb 80–90g/L, MI with transfusion to 100g/L; 8: Hb 80–90g/L, MI with transfusion to 120g/L. To determine the effect of blood transfusion, fresh blood was immediately transfused following MI. Induction of myocardial infarction was preformed by left coronary artery ligation. Sham-operated rats underwent the same surgical procedure without ligation. At 24 hours post-MI, rats were re-anaesthetized and hemodynamic measurements preformed. Area at risk and infarct size was measured by Evans blue and triphenyltetrazolium chloride, respectively. Results: In the normal Hb group (140–150g/L), survival following sham or MI surgery was 100%. Reduction of Hb to 80–90 and 70–80g/L significantly decreased survival post-MI to 42% and 47%, respectively. Survival was significantly improved after transfusion of fresh blood to raise the hemoglobin from 80–90g/L to 100g/L (P<0.05). However, there was no improvement in survival when Hb was raised by transfusion to 120g/L (P=NS). Twenty-four hours post-MI, the ischemic to non-ischemic left ventricle (LV) weight ratios were not significantly different between any groups indicating similar areas of myocardial ischemia among all groups (P=NS). However, the infarct size to area at risk ratios were significantly increased in both 70–80g/L and 80–90g/L groups compared to the normal Hb group (P<0.05). Transfusion from Hb 80–90g/L to 100g/L significantly decreased infarct size compared to the Hb 80–90g/L group (P<0.05). However, transfusion to Hb 120g/L resulted in a significantly larger infarct size compared to the Hb 100g/L transfused group (P<0.05). Cardiac function was determined at 24 hours post-MI. Heart rate, MAP, LVSP and LVEDP were not significantly different among all groups but anemic groups 80–90 and 70–80g/L showed a significant decrease in LV +dP/dtmax and −dP/dtmin in both sham and MI rats (P<0.01) with the most significant decrease noted in MI rats compared to sham operated rats (P<0.05). Blood transfusion post-MI from a Hb 80–90 to 100g/L significantly improved LV +dP/dtmax (P<0.05). Transfusion to Hb 120g/L did not result in any further improvement in cardiac function. Conclusions: In the setting of acute MI, anemia increased mortality and infarct size compared to non-anemic controls. At 24 hours post-MI, anemia also impaired cardiac function. Transfusion of anemic animals up to a Hb of 100g/L with fresh RBCs reduced mortality and infarct size and improved cardiac function. However, transfusion to a Hb of 120g/L did not demonstrate any additional benefit and was associated with larger infarcts.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 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 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 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 source (Gemma direct ou Codex distillé), 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 ».