title: Microvascular resistance of the culprit coronary artery in acute ST-elevation myocardial infarction.
abstract: Failed myocardial reperfusion is common and prognostically important after acute ST-elevation myocardial infarction (STEMI). The purpose of this study was to investigate coronary flow reserve (CFR), a measure of vasodilator capacity, and the index of microvascular resistance (IMR; mmHg × s) in the culprit artery of STEMI survivors.
  
  
  
  IMR (n= 288) and CFR (n= 283; mean age [SD], 60 [12] years) were measured acutely using guide wire-based thermodilution. Cardiac MRI disclosed left ventricular pathology, function, and volumes at 2 days (n= 281) and 6 months after STEMI (n= 264). All-cause death or first heart failure hospitalization was independently adjudicated (median follow-up 845 days).
  
  
  
  Myocardial hemorrhage and microvascular obstruction occurred in 89 (42%) and 114 (54%) patients with evaluable T2*-MRI maps. IMR and CFR were associated with microvascular pathology (none vs. microvascular obstruction only vs. microvascular obstruction and myocardial hemorrhage) (median [interquartile range], IMR: 17 [12.0-33.0] vs. 17 [13.0-39.0] vs. 37 [21.0-63.0],P< 0.001; CFR: 1.7 [1.4-2.5] vs. 1.5 [1.1-1.8] vs. 1.4 [1.0-1.8],P< 0.001), whereas thrombolysis in myocardial infarction blush grade was not. IMR was a multivariable associate of changes in left ventricular end-diastolic volume (regression coefficient [95% CI] 0.13 [0.01, 0.24];P= 0.036), whereas CFR was not (P= 0.160). IMR (5 units) was a multivariable associate of all-cause death or heart failure hospitalization (n= 30 events; hazard ratio [95% CI], 1.09 [1.04, 1.14];P< 0.001), whereas CFR (P= 0.124) and thrombolysis in myocardial infarction blush grade (P= 0.613) were not. IMR had similar prognostic value for these outcomes as <50% ST-segment resolution on the ECG.
  
  
  
  IMR is more closely associated with microvascular pathology, left ventricular remodeling, and health outcomes than the angiogram or CFR.
  
  
  
  NCT02072850.
  
  
  
  A British Heart Foundation Project Grant (PG/11/2/28474), the National Health Service, the Chief Scientist Office, a Scottish Funding Council Senior Fellowship, a British Heart Foundation Intermediate Fellowship (FS/12/62/29889), and a nonfinancial research agreement with Siemens Healthcare.
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom.|West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Carrick
authors.affiliation: Robertson Centre for Biostatistics, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Caroline
authors.initials: C
authors.lastname: Haig
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom.|West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom.
authors.forename: Jaclyn
authors.initials: J
authors.lastname: Carberry
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom.|West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom.
authors.forename: Vannesa Teng Yue
authors.initials: VTY
authors.lastname: May
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom.|West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: McCartney
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Paul
authors.initials: P
authors.lastname: Welsh
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Nadeem
authors.initials: N
authors.lastname: Ahmed
authors.affiliation: West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom.
authors.forename: Margaret
authors.initials: M
authors.lastname: McEntegart
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom.|West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Petrie
authors.affiliation: West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom.
authors.forename: Hany
authors.initials: H
authors.lastname: Eteiba
authors.affiliation: West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom.
authors.forename: Mitchell
authors.initials: M
authors.lastname: Lindsay
authors.affiliation: West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom.
authors.forename: Stuart
authors.initials: S
authors.lastname: Hood
authors.affiliation: West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom.
authors.forename: Stuart
authors.initials: S
authors.lastname: Watkins
authors.affiliation: West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Mahrous
authors.affiliation: West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom.
authors.forename: Samuli Mo
authors.initials: SM
authors.lastname: Rauhalammi
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Ify
authors.initials: I
authors.lastname: Mordi
authors.affiliation: Robertson Centre for Biostatistics, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Ian
authors.initials: I
authors.lastname: Ford
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Radjenovic
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Naveed
authors.initials: N
authors.lastname: Sattar
authors.affiliation: West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom.
authors.forename: Keith G
authors.initials: KG
authors.lastname: Oldroyd
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom.|West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom.
authors.forename: Colin
authors.initials: C
authors.lastname: Berry
mesh_terms: D000368:Aged; D003331:Coronary Vessels / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology*; D000072657:ST Elevation Myocardial Infarction / Q000503:physiopathology*