The effect of restrictive versus liberal transfusion strategies on longer-term outcomes after cardiac surgery: a systematic review and meta-analysis with trial sequential analysis.

PURPOSE: Blood transfusions are frequently administered in cardiac surgery. Despite a large number of published studies comparing a "restrictive" strategy with a "liberal" strategy, no clear consensus has emerged to guide blood transfusion practice in cardiac surgery patients. The purpose of this study was to identify, critically appraise, and summarize the evidence on the overall effect of restrictive transfusion strategies compared with liberal transfusion strategies on mortality, other clinical outcomes, and transfusion-related outcomes in adult patients undergoing cardiac surgery. SOURCE: We searched MEDLINE (OvidSP), EMBASE (OvidSP) and Cochrane CENTRAL (Wiley) from inception to 1 December 2017 and queried clinical trial registries and conference proceedings for randomized-controlled trials of liberal vs restrictive transfusion strategies in cardiac surgery. PRINCIPAL FINDINGS: From 7,908 citations, we included ten trials (9,101 patients) and eight companion publications. Overall, we found no significant difference in mortality between restrictive and liberal transfusion strategies (risk ratio [RR], 1.08; 95% confidence interval [CI], 0.76 to 1.54; I2 = 33%; seven trials; 8,661 patients). The use of a restrictive transfusion strategy did not appear to adversely impact any of the secondary clinical outcomes. As expected, the proportion of patients who received red blood cells (RBCs) in the restrictive group was significantly lower than in the liberal group (RR, 0.68; 95% CI, 0.64 to 0.73; I2 = 56%; 5 trials; 8,534 patients). Among transfused patients, a restrictive transfusion strategy was associated with fewer transfused RBC units per patient than a liberal transfusion strategy. CONCLUSIONS: In adult patients undergoing cardiac surgery, a restrictive transfusion strategy reduces RBC transfusion without impacting mortality rate or the incidence of other perioperative complications. Nevertheless, further large trials in subgroups of patients, potentially of differing age, are needed to establish firm evidence to guide transfusion in cardiac surgery. TRIAL REGISTRATION: PROSPERO (CRD42017071440); registered 20 April, 2018.

RéSUMé: OBJECTIF: Les transfusions sanguines sont fréquentes après une chirurgie cardiaque. Malgré le nombre important d'études publiées comparant une stratégie « restrictive ¼ à une stratégie « libérale ¼, aucun consensus clair n'est apparu pour guider la pratique de la transfusion sanguine chez les patients de chirurgie cardiaque. L'objectif de cette étude était d'identifier, d'évaluer de façon critique et de résumer les données probantes sur l'effet global des stratégies de transfusion restrictives comparativement aux stratégies libérales sur la mortalité, les autres devenirs cliniques, et les devenirs liés à la transfusion chez des patients adultes subissant une chirurgie cardiaque. SOURCE: Nous avons réalisé des recherches dans les bases de données MEDLINE (OvidSP), EMBASE (OvidSP) et Cochrane CENTRAL (Wiley) de leur création jusqu'au 1er décembre 2017 et avons exploré les registres d'études cliniques et les actes de conférence pour en tirer les études randomisées contrôlées évaluant des stratégies transfusionnelles restrictives vs libérales en chirurgie cardiaque. CONSTATATIONS PRINCIPALES: Sur 7908 citations, nous avons inclus dix études (9101 patients) et huit publications connexes. Globalement, nous n'avons observé aucune différence significative en matière de mortalité entre les stratégies transfusionnelles restrictives et libérales (risque relatif [RR], 1,08; intervalle de confiance [IC] 95 %, 0,76 à 1,54; I2 = 33 %; sept études; 8661 patients). Le recours à une stratégie de transfusion restrictive n'a semblé avoir aucun impact négatif sur quelque résultat clinique secondaire que ce soit. Comme anticipé, la proportion de patients ayant reçu des érythrocytes dans le groupe restrictif était significativement plus basse que dans le groupe libéral (RR, 0,68; IC 95 %, 0,64 à 0,73; I2 = 56 %; 7 études; 8534 patients). Parmi les patients transfusés, une stratégie de transfusion restrictive a été associée à un nombre moindre d'unités d'érythrocytes transfusées par patient que dans une stratégie transfusionnelle libérale. CONCLUSION: Dans une population de patients adultes subissant une chirurgie cardiaque, une stratégie transfusionnelle restrictive réduit la transfusion d'érythrocytes sans avoir d'impact sur le taux de mortalité ou sur l'incidence d'autres complications périopératoires. D'autres grandes études sur différents sous-groupes de patients, peut-être d'âges différents, sont toutefois nécessaires afin d'établir des données probantes concluantes pour guider les transfusions en chirurgie cardiaque. ENREGISTREMENT DE L'éTUDE: PROSPERO (CRD42017071440); enregistrée le 20 avril 2018.

Protocol for the electroencephalography guidance of anesthesia to alleviate geriatric syndromes (ENGAGES-Canada) study: A pragmatic, randomized clinical trial.

Background:  There is some evidence that electroencephalography guidance of general anesthesia can decrease postoperative delirium after non-cardiac surgery.  There is limited evidence in this regard for cardiac surgery.  A suppressed electroencephalogram pattern, occurring with deep anesthesia, is associated with increased incidence of postoperative delirium (POD) and death.  However, it is not yet clear whether this electroencephalographic pattern reflects an underlying vulnerability associated with increased incidence of delirium and mortality, or whether it is a modifiable risk factor for these adverse outcomes. Methods:  The Electroe ncephalography Guidance of Anesthesia to Alleviate Geriatric Syndromes ( ENGAGES-Canada) is an ongoing pragmatic 1200 patient trial at four Canadian sites.  The study compares the effect of two anesthetic management approaches on the incidence of POD after cardiac surgery.  One approach is based on current standard anesthetic practice and the other on electroencephalography guidance to reduce POD. In the guided arm, clinicians are encouraged to decrease anesthetic administration, primarily if there is electroencephalogram suppression and secondarily if the EEG index is lower than the manufacturers recommended value (bispectral index (BIS) or WAVcns below 40 or Patient State Index below 25).  The aim in the guided group is to administer the minimum concentration of anesthetic considered safe for individual patients.  The primary outcome of the study is the incidence of POD, detected using the confusion assessment method or the confusion assessment method for the intensive care unit; coupled with structured delirium chart review.  Secondary outcomes include unexpected intraoperative movement, awareness, length of intensive care unit and hospital stay, delirium severity and duration, quality of life, falls, and predictors and outcomes of perioperative distress and dissociation. Discussion:  The ENGAGES-Canada trial will help to clarify whether or not using the electroencephalogram to guide anesthetic administration during cardiac surgery decreases the incidence, severity, and duration of POD. Registration: ClinicalTrials.gov ( NCT02692300) 26/02/2016.

Ski drives an acute increase in MMP-9 gene expression and release in primary cardiac myofibroblasts.

Many etiologies of heart disease are characterized by expansion and remodeling of the cardiac extracellular matrix (ECM or matrix) which results in cardiac fibrosis. Cardiac fibrosis is mediated in cardiac fibroblasts by TGF-ß1 /R-Smad2/3 signaling. Matrix component proteins are synthesized by activated resident cardiac fibroblasts known as myofibroblasts (MFB). These events are causal to heart failure with diastolic dysfunction and reduced cardiac filling. We have shown that exogenous Ski, a TGF-ß1 /Smad repressor, localizes in the cellular nucleus and deactivates cardiac myofibroblasts. This deactivation is associated with reduction of myofibroblast marker protein expression in vitro, including alpha smooth muscle actin (α-SMA) and extracellular domain-A (ED-A) fibronectin. We hypothesize that Ski also acutely regulates MMP expression in cardiac MFB. While acute Ski overexpression in cardiac MFB in vitro was not associated with any change in intracellular MMP-9 protein expression versus LacZ-treated controls,exogenous Ski caused elevated MMP-9 mRNA expression and increased MMP-9 protein secretion versus controls. Zymographic analysis revealed increased MMP-9-specific gelatinase activity in myofibroblasts overexpressing Ski versus controls. Moreover, Ski expression was attended by reduced paxillin and focal adhesion kinase phosphorylation (FAK - Tyr 397) versus controls. As myofibroblasts are hypersecretory and less motile relative to fibroblasts, Ski's reduction of paxillin and FAK expression may reflect the relative deactivation of myofibroblasts. Thus, in addition to its known antifibrotic effects, Ski overexpression elevates expression and extracellular secretion/release of MMP-9 and thus may facilitate internal cytoskeletal remodeling as well as extracellular ECM components. Further, as acute TGF-ß1 treatment of primary cardiac MFB is known to cause rapid translocation of Ski to the nucleus, our data support an autoregulatory role for Ski in mediating cardiac ECM accumulation.

The Ski-Zeb2-Meox2 pathway provides a novel mechanism for regulation of the cardiac myofibroblast phenotype.

Cardiac fibrosis is linked to fibroblast-to-myofibroblast phenoconversion and proliferation but the mechanisms underlying this are poorly understood. Ski is a negative regulator of TGF-ß-Smad signaling in myofibroblasts, and might redirect the myofibroblast phenotype back to fibroblasts. Meox2 could alter TGF-ß-mediated cellular processes and is repressed by Zeb2. Here, we investigated whether Ski diminishes the myofibroblast phenotype by de-repressing Meox2 expression and function through repression of Zeb2 expression. We show that expression of Meox1 and Meox2 mRNA and Meox2 protein is reduced during phenoconversion of fibroblasts to myofibroblasts. Overexpression of Meox2 shifts the myofibroblasts into fibroblasts, whereas the Meox2 DNA-binding mutant has no effect on myofibroblast phenotype. Overexpression of Ski partially restores Meox2 mRNA expression levels to those in cardiac fibroblasts. Expression of Zeb2 increased during phenoconversion and Ski overexpression reduces Zeb2 expression in first-passage myofibroblasts. Furthermore, expression of Meox2 is decreased in scar following myocardial infarction, whereas Zeb2 protein expression increases in the infarct scar. Thus Ski modulates the cardiac myofibroblast phenotype and function through suppression of Zeb2 by upregulating the expression of Meox2. This cascade might regulate cardiac myofibroblast phenotype and presents therapeutic options for treatment of cardiac fibrosis.