title: Utility of CMR Markers of Myocardial Injury in Predicting LV Functional Recovery: Results from PROTECTION AMI CMR Sub-study.
abstract: BACKGROUND
  Adverse left ventricular (LV) remodelling following acute ST-segment elevation myocardial infarction (STEMI) has prognostic importance. We aimed to predict 90-day left ventricular (LV) function following acute STEMI using variables from clinical presentation, biomarkers, and cardiovascular magnetic resonance imaging (CMR).
  
  
  METHODS
  Consecutive patients undergoing primary percutaneous coronary intervention for anterior STEMI as part of the Selective Inhibition of Delta-protein Kinase C for the Reduction of Infarct Size in Acute Myocardial Infarction (PROTECTION-AMI) trial were enrolled into the CMR sub-study at selected sites. CMR was performed at baseline (days 3 to 5) and 90 days and used to evaluate infarct size, myocardial salvage index, infarct heterogeneity, microvascular obstruction and global LV function. Biochemical markers including creatinine kinase area under the curve (CK AUC), peak CK, peak CK-myocardial band (CK-MB) and AUC, and troponin I were collected at specific time-points.
  
  
  RESULTS
  Ninety-six patients were enrolled in the CMR sub study and 85 completed the 90-day follow-up, across 24 centres worldwide. LV ejection fraction (EF) was 56% (46-63%) at baseline and 60% (49-67%) at 90 days (p<0.001). Infarct size had moderate inverse correlation with 90-day EF (Spearman's rho=-0.7, p < 0.001) and had the strongest correlation when compared to myocardial salvage index (Spearman's rho=0.5, p=0.001), infarct heterogeneity (Spearman's rho=-0.4, p=0.02 or microvascular obstruction (Spearman's rho=-0.4, p<0.001). All biochemical markers had similar moderate relationship to LVEF at 90 days (Spearman's rho -0.6 to -0.8, p=0.001). In a multivariable model, only baseline LVEF, CMR infarct size and infarct heterogeneity independently predicted 90-day LVEF.
  
  
  CONCLUSIONS
  This study reports findings of a combined CMR protocol (including myocardial oedema imaging) in a multi-centre, multi-vendor setting. We found infarct size, infarct heterogeneity and myocardial salvage index correlated favourably with 90-day LVEF, however only the former two were independently predictive.
authors.affiliation: Flinders University, Adelaide, SA, Australia; Cardiology Department, Flinders Medical Centre, Adelaide, SA Austrlaia; Cardiac Imaging Research Centre, South Australian Health and Medical Research Institute, Adelaide, SA, Australia. Electronic address: suchi.grover@health.sa.gov.au.
authors.forename: Suchi
authors.initials: S
authors.lastname: Grover
authors.affiliation: KAI Pharmaceuticals Inc, San Francisco, CAL, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Bell
authors.affiliation: Cleveland Clinic, Coordinating Center for Clinical Research (C5 Research), Cleveland, OH, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Lincoff
authors.affiliation: Flinders University, Adelaide, SA, Australia.
authors.forename: Lucas
authors.initials: L
authors.lastname: Jeorg
authors.affiliation: Flinders University, Adelaide, SA, Australia.
authors.forename: Per Lav
authors.initials: PL
authors.lastname: Madsen
authors.affiliation: KAI Pharmaceuticals Inc, San Francisco, CAL, USA.
authors.forename: Saling
authors.initials: S
authors.lastname: Huang
authors.affiliation: Flinders University, Adelaide, SA, Australia; Cardiac Imaging Research Centre, South Australian Health and Medical Research Institute, Adelaide, SA, Australia.
authors.forename: Sean
authors.initials: S
authors.lastname: Leow
authors.affiliation: Cardiology Department, Royal North Shore Hospital, Sydney, NSW, Australia.
authors.forename: Gemma
authors.initials: G
authors.lastname: Figtree
authors.affiliation: Flinders University, Adelaide, SA, Australia; Cardiac Imaging Research Centre, South Australian Health and Medical Research Institute, Adelaide, SA, Australia.
authors.forename: Adhiraj
authors.initials: A
authors.lastname: Chakrabarty
authors.affiliation: Flinders University, Adelaide, SA, Australia; Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, Canada.
authors.forename: Darryl P
authors.initials: DP
authors.lastname: Leong
authors.affiliation: Flinders Centre for Epidemiology and Biostatistics, Flinders University, Adelaide, SA, Australia.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Woodman
authors.affiliation: Flinders University, Adelaide, SA, Australia; Cardiology Department, Flinders Medical Centre, Adelaide, SA Austrlaia; Cardiac Imaging Research Centre, South Australian Health and Medical Research Institute, Adelaide, SA, Australia.
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Selvanayagam
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000503:physiopathology / Q000628:therapy; D009206:Myocardium / Q000378:metabolism*; D013318:Stroke Volume; D013997:Time Factors; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling
chemical_list: D015415:Biomarkers
keywords: Infarct heterogeneity; Infarct size; Left ventricular function; Myocardial salvage; ST elevation infarction