title: β-blockers and volatile anesthetics may attenuate cardioprotection by remote preconditioning in adult cardiac surgery: a meta-analysis of 15 randomized trials.
abstract: OBJECTIVE
  Clinical trials on cardioprotection by remote ischemic preconditioning (RIPC) for adult patients undergoing cardiac surgery revealed mixed results. Previous meta-analyses have been conducted and found marked heterogeneity among studies. The aim of this meta-analysis was to evaluate the factors affecting cardioprotection by remote preconditioning in adult cardiac surgery.
  
  
  METHODS
  A meta-analysis of randomized controlled trials.
  
  
  METHODS
  University hospitals.
  
  
  METHODS
  Adult subjects undergoing cardiac surgery.
  
  
  METHODS
  RIPC.
  
  
  RESULTS
  Fifteen trials with a total of 1,155 study patients reporting postoperative myocardial biomarker (CK-MB or troponin) levels were identified from PubMed, Embase, and the Cochrane Library (up to July 2012). Compared with controls, RIPC significantly reduced postoperative biomarkers of myocardial injury (standardized mean difference = -0.31, p = 0.041; heterogeneity test: I(2) = 83.5%). This effect seemed more significant in valve surgery (standardized mean difference = -0.74, p = 0.002) than in coronary artery surgery (standardized mean difference = -0.23; p = 0.17). Univariate meta-regression analyses suggested that the major sources of significant heterogeneity were β-blockers (%) (coefficient = 0.0161, p = 0.022, adjusted R(2) = 0.37) and volatile anesthetics (coefficient = 0.6617, p = 0.065, adjusted R(2) = 0.22). These results were further confirmed in multivariate regression and subgroup analyses.
  
  
  CONCLUSIONS
  Available data from this meta-analysis further confirmed the cardioprotection conferred by RIPC in adult cardiac surgery. Moreover, the cardioprotective effect may be attenuated when combined with β-blockers or volatile anesthetics.
authors.affiliation: State Key Laboratory of Cardiovascular Medicine, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Chenghui
authors.initials: C
authors.lastname: Zhou
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Yuntai
authors.initials: Y
authors.lastname: Yao
authors.forename: Shan
authors.initials: S
authors.lastname: Zhou
authors.forename: Nengxin
authors.initials: N
authors.lastname: Fang
authors.forename: Weipeng
authors.initials: W
authors.lastname: Wang
authors.forename: Lihuan
authors.initials: L
authors.lastname: Li
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D018685:Anesthetics, Inhalation / Q000627:therapeutic use*; D015906:Angioplasty, Balloon, Coronary; D015415:Biomarkers / Q000032:analysis; D006348:Cardiac Surgical Procedures / Q000379:methods* / Q000401:mortality; D002316:Cardiotonic Agents; D002648:Child; D016001:Confidence Intervals; D001026:Coronary Artery Bypass; D052279:Creatine Kinase, MB Form / Q000097:blood; D003627:Data Interpretation, Statistical; D023381:Endpoint Determination; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D011184:Postoperative Period; D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D014336:Troponin / Q000097:blood
chemical_list: D000319:Adrenergic beta-Antagonists; D018685:Anesthetics, Inhalation; D015415:Biomarkers; D002316:Cardiotonic Agents; D014336:Troponin; D052279:Creatine Kinase, MB Form