title: The Index of Microcirculatory Resistance Postpercutaneous Coronary Intervention Predicts Left Ventricular Recovery in Patients With Thrombolyzed ST-Segment Elevation Myocardial Infarction.
abstract: BACKGROUND
  The index of microcirculatory resistance (IMR), an invasive measure of microvascular function, has been shown to correlate with clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI). The aim of this study is to evaluate the predictive value of IMR on left ventricular recovery in patients undergoing a pharmacoinvasive strategy for STEMI.
  
  
  METHODS
  The index of microcirculatory resistance was assessed following percutaneous coronary intervention (PCI) in 31 patients with STEMI who were initially managed with thrombolysis. Other markers of microvascular function such as coronary flow reserve (CFR), TIMI flow grade, corrected TIMI frame count (cTFC), and ST-segment resolution were also recorded. All indices were evaluated against measures of left ventricular function and recovery 3 months postindex event.
  
  
  RESULTS
  The IMR correlated with left ventricular function, as assessed by wall motion score and ejection fraction at 3-month follow-up (r = 0.652, P = 0.005; r = -0.452, P = 0.011, respectively). The traditional methods of assessing microvascular function, such as CFR, TIMI flow grade, cTFC, and ST-segment resolution did not correlate with wall motion score and ejection fraction at 3 months. Post-PCI IMR was significantly lower in those patients with left ventricular recovery at 3 months (18 U vs 39 U, P < 0.001). The optimal cut-off value for post-PCI IMR and left ventricular recovery was 32 U. In patients in whom the IMR was greater than 32 U, the percent change in ejection fraction was significantly lower than in those patients in whom the IMR was less than 32 U (2 ± 11 vs 12 ± 8, P = 0.012).
  
  
  CONCLUSIONS
  In patients presenting with STEMI initially managed with thrombolysis and subsequently undergoing PCI, IMR correlates with measures of left ventricular function and has the potential to predict left ventricular recovery at 3 months.
authors.affiliation: Department of Cardiology, St Vincent's Hospital, Fitzroy, Victoria, Australia.|Department of Cardiology, Golden Jubilee National Hospital, Glasgow, United Kingdom.
authors.forename: Sonny
authors.initials: S
authors.lastname: Palmer
authors.affiliation: Department of Cardiology, St Vincent's Hospital, Fitzroy, Victoria, Australia.
authors.forename: Jamie
authors.initials: J
authors.lastname: Layland
authors.affiliation: Department of Cardiology, St Vincent's Hospital, Fitzroy, Victoria, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Carrick
authors.affiliation: Department of Cardiology, St Vincent's Hospital, Fitzroy, Victoria, Australia.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Williams
authors.affiliation: Department of Cardiology, St Vincent's Hospital, Fitzroy, Victoria, Australia.|Department of Cardiology, Golden Jubilee National Hospital, Glasgow, United Kingdom.
authors.forename: Christopher
authors.initials: C
authors.lastname: Judkins
authors.affiliation: Department of Cardiology, St Vincent's Hospital, Fitzroy, Victoria, Australia.
authors.forename: Fei Fei
authors.initials: FF
authors.lastname: Gong
authors.affiliation: Department of Cardiology, St Vincent's Hospital, Fitzroy, Victoria, Australia.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Burns
authors.affiliation: Department of Cardiology, St Vincent's Hospital, Fitzroy, Victoria, Australia.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Whitbourn
authors.affiliation: Department of Cardiology, St Vincent's Hospital, Fitzroy, Victoria, Australia.
authors.forename: Andrew I
authors.initials: AI
authors.lastname: MacIsaac
authors.affiliation: Department of Cardiology, St Vincent's Hospital, Fitzroy, Victoria, Australia.|Department of Cardiology, Golden Jubilee National Hospital, Glasgow, United Kingdom.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Wilson
mesh_terms: D000368:Aged; D015415:Biomarkers; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology* / Q000601:surgery; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects / Q000379:methods*; D010865:Pilot Projects; D015912:Thrombolytic Therapy / Q000379:methods; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D015415:Biomarkers