title: Influence of preinfarction angina and coronary collateral blood flow on the efficacy of remote ischaemic conditioning in patients with ST segment elevation myocardial infarction: post hoc subgroup analysis of a randomised controlled trial.
abstract: Remote ischaemic conditioning (RIC) confers cardioprotection in patients with ST segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI). We investigated whether preinfarction angina and coronary collateral blood flow (CCBF) to the infarct-related artery modify the efficacy of RIC.
  
  
  
  Post hoc subgroup analysis of a randomised controlled trial.
  
  
  
  A total of 139 patients with STEMI randomised to treatment with pPCI or RIC+pPCI.
  
  
  
  RIC was performed prior to pPCI as four cycles of 5 min upper arm ischaemia and reperfusion with a blood pressure cuff.
  
  
  
  Myocardial salvage index (MSI) assessed by single-photon emission computerised tomography. We evaluated the efficacy of RIC in subgroups of patients with or without preinfarction angina or CCBF.
  
  
  
  Of 139 patients included in the study, 109 had available data for preinfarction angina status and 54 had preinfarction angina. Among 83 patients with Thrombolysis In Myocardial Infarction flow 0/1 on arrival, 43 had CCBF. Overall, RIC+pPCI increased median MSI compared with pPCI alone (0.75 vs 0.56, p=0.045). Mean MSI did not differ between patients with and without preinfarction angina in either the pPCI alone (0.58 and 0.57; 95% CI -0.17 to 0.19, p=0.94) or the RIC+pPCI group (0.66 and 0.69; 95% CI -0.18 to 0.10, p=0.58). Mean MSI did not differ between patients with and without CCBF in the pPCI alone group (0.51 and 0.55; 95% CI -0.20 to 0.13, p=0.64), but was increased in patients with CCBF versus without CCBF in the RIC+pPCI group (0.75 vs 0.58; 95% CI 0.03 to 0.31, p=0.02; effect modification from CCBF on the effect of RIC on MSI, p=0.06).
  
  
  
  Preinfarction angina did not modify the efficacy of RIC in patients with STEMI undergoing pPCI. CCBF to the infarct-related artery seems to be of importance for the cardioprotective efficacy of RIC.
  
  
  
  NCT00435266, Post-results.
authors.affiliation: Department of Cardiology, Aarhus University Hospital Skejby, Aarhus, Denmark.|Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors.forename: Kasper
authors.initials: K
authors.lastname: Pryds
authors.affiliation: Department of Internal Medicine, Hospital Unit West, Herning, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Bøttcher
authors.affiliation: Department of Cardiology, Aarhus University Hospital Skejby, Aarhus, Denmark.|Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors.forename: Astrid Drivsholm
authors.initials: AD
authors.lastname: Sloth
authors.affiliation: Department of Cardiology, Aarhus University Hospital Skejby, Aarhus, Denmark.
authors.forename: Kim
authors.initials: K
authors.lastname: Munk
authors.affiliation: Department of Cardiology, Aarhus University Hospital Skejby, Aarhus, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Rahbek Schmidt
authors.affiliation: Department of Cardiology, Aarhus University Hospital Skejby, Aarhus, Denmark.
authors.forename: Hans Erik
authors.initials: HE
authors.lastname: Bøtker
mesh_terms: D000368:Aged; D000789:Angina, Unstable / Q000000981:diagnostic imaging / Q000453:epidemiology*; D003097:Collateral Circulation / Q000502:physiology*; D003326:Coronary Circulation / Q000502:physiology; D003718:Denmark; D005260:Female; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015428:Myocardial Reperfusion Injury / Q000000981:diagnostic imaging / Q000503:physiopathology*; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects*; D000072657:ST Elevation Myocardial Infarction / Q000503:physiopathology* / Q000601:surgery; D012720:Severity of Illness Index; D015899:Tomography, Emission-Computed, Single-Photon; D016896:Treatment Outcome