title: Remote ischemic conditioning reduces myocardial infarct size and edema in patients with ST-segment elevation myocardial infarction.
abstract: OBJECTIVE
  This study aimed to determine whether remote ischemic conditioning (RIC) initiated prior to primary percutaneous coronary intervention (PPCI) could reduce myocardial infarct (MI) size in patients presenting with ST-segment elevation myocardial infarction.
  
  
  BACKGROUND
  RIC, using transient limb ischemia and reperfusion, can protect the heart against acute ischemia-reperfusion injury. Whether RIC can reduce MI size, assessed by cardiac magnetic resonance (CMR), is unknown.
  
  
  METHODS
  We randomly assigned 197 ST-segment elevation myocardial infarction patients with TIMI (Thrombolysis In Myocardial Infarction) flow grade 0 to receive RIC (four 5-min cycles of upper arm cuff inflation/deflation) or control (uninflated cuff placed on upper arm for 40 min) protocols prior to PPCI. The primary study endpoint was MI size, measured by CMR in 83 subjects on days 3 to 6 after admission.
  
  
  RESULTS
  RIC reduced MI size by 27%, when compared with the MI size of control subjects (18.0 ± 10% [n = 40] vs. 24.5 ± 12.0% [n = 43]; p = 0.009). At 24 h, high-sensitivity troponin T was lower with RIC (2,296 ± 263 ng/l [n = 89] vs. 2,736 ± 325 ng/l [n = 84]; p = 0.037). RIC also reduced the extent of myocardial edema measured by T2-mapping CMR (28.5 ± 9.0% vs. 35.1 ± 10.0%; p = 0.003) and lowered mean T2 values (68.7 ± 5.8 ms vs. 73.1 ± 6.1 ms; p = 0.001), precluding the use of CMR edema imaging to correctly estimate the area at risk. Using CMR-independent coronary angiography jeopardy scores to estimate the area at risk, RIC, when compared with the control protocol, was found to significantly improve the myocardial salvage index (0.42 ± 0.29 vs. 0.28 ± 0.29; p = 0.03).
  
  
  CONCLUSIONS
  This randomized study demonstrated that in ST-segment elevation myocardial infarction patients treated by PPCI, RIC, initiated prior to PPCI, reduced MI size, increased myocardial salvage, and reduced myocardial edema.
authors.affiliation: The Hatter Cardiovascular Institute, Institute of Cardiovascular Science, National Institute of Health Research University College London Hospitals Biomedical Research Centre, University College London, London, United Kingdom; The Heart Hospital, London, United Kingdom.
authors.forename: Steven K
authors.initials: SK
authors.lastname: White
authors.affiliation: The Heart Hospital, London, United Kingdom.
authors.forename: Georg M
authors.initials: GM
authors.lastname: Frohlich
authors.affiliation: The Heart Hospital, London, United Kingdom.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Sado
authors.affiliation: The Heart Hospital, London, United Kingdom.
authors.forename: Viviana
authors.initials: V
authors.lastname: Maestrini
authors.affiliation: The Heart Hospital, London, United Kingdom.
authors.forename: Marianna
authors.initials: M
authors.lastname: Fontana
authors.affiliation: The Heart Hospital, London, United Kingdom.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Treibel
authors.affiliation: The Heart Hospital, London, United Kingdom.
authors.forename: Shana
authors.initials: S
authors.lastname: Tehrani
authors.affiliation: Department of Cardiology, University Hospital Southampton National Health Service Foundation Trust, Southampton, United Kingdom.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Flett
authors.affiliation: The Heart Hospital, London, United Kingdom.
authors.forename: Pascal
authors.initials: P
authors.lastname: Meier
authors.affiliation: London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Cono
authors.initials: C
authors.lastname: Ariti
authors.affiliation: The Essex Cardiothoracic Centre, Basildon University Hospital, Nethermayne, Basildon, Essex, United Kingdom.
authors.forename: John R
authors.initials: JR
authors.lastname: Davies
authors.affiliation: The Heart Hospital, London, United Kingdom.
authors.forename: James C
authors.initials: JC
authors.lastname: Moon
authors.affiliation: The Hatter Cardiovascular Institute, Institute of Cardiovascular Science, National Institute of Health Research University College London Hospitals Biomedical Research Centre, University College London, London, United Kingdom.
authors.forename: Derek M
authors.initials: DM
authors.lastname: Yellon
authors.affiliation: The Hatter Cardiovascular Institute, Institute of Cardiovascular Science, National Institute of Health Research University College London Hospitals Biomedical Research Centre, University College London, London, United Kingdom; The Heart Hospital, London, United Kingdom. Electronic address: d.hausenloy@ucl.ac.uk.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Hausenloy
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D017023:Coronary Angiography; D004489:Edema, Cardiac / Q000097:blood / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D004739:England; D005260:Female; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial / Q000009:adverse effects / Q000379:methods*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis / Q000628:therapy*; D009206:Myocardium / Q000473:pathology; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects; D011237:Predictive Value of Tests; D013997:Time Factors; D016896:Treatment Outcome; D020107:Troponin T / Q000097:blood; D034941:Upper Extremity / Q000098:blood supply*
chemical_list: D015415:Biomarkers; D020107:Troponin T
keywords: acute myocardial infarction; cardiovascular magnetic resonance; myocardial edema; primary percutaneous coronary intervention; remote ischemic conditioning; reperfusion injury