title: A tool for predicting the outcome of reperfusion in ST-elevation myocardial infarction using age, thrombotic burden and index of microcirculatory resistance (ATI score).
abstract: OBJECTIVE
  Restoration of effective myocardial reperfusion by primary percutaneous coronary intervention (PPCI) in patients with ST-elevation myocardial infarction is difficult to predict. A method to assess the likelihood of a suboptimal response to conventional pharmacomechanical therapies could be beneficial. We aimed to derive and validate a scoring system that can be used acutely at the time of coronary reopening to predict the likelihood of downstream microvascular impairment in patients with STEMI.
  
  
  RESULTS
  A score estimating the risk of post-procedural microvascular injury defined by an index of microcirculatory resistance (IMR) >40 was initially derived in a cohort of 85 STEMI patients (derivation cohort). This score was then tested and validated in three further cohorts of patients (retrospective [30 patients], prospective [42 patients] and external [29 patients]). The ATI score (age [>50=1]; pre-stenting IMR [>40 and <100=1; ≥100=2]; thrombus score [4=1; 5=3]) was highly predictive of a post-stenting IMR >40 in all four cohorts (AUC: 0.87; p<0.001-derivation cohort, 0.84; p=0.002-retrospective cohort, 0.92; p<0.001-prospective cohort and 0.81; p=0.006-external cohort). In the whole population, an ATI score ≥4 presented a 95.1% risk of final IMR >40, while no cases of final IMR >40 occurred in the presence of an ATI score <2.
  
  
  CONCLUSIONS
  The ATI score appears to be a promising tool capable of identifying patients during PPCI who are at the highest risk of coronary microvascular impairment following revascularisation. This procedural risk stratification has a number of potential research and clinical applications and warrants further investigation.
authors.affiliation: Oxford University Hospitals, Oxford, United Kingdom.
authors.forename: Giovanni Luigi
authors.initials: GL
authors.lastname: De Maria
authors.forename: Gregor
authors.initials: G
authors.lastname: Fahrni
authors.forename: Mohammad
authors.initials: M
authors.lastname: Alkhalil
authors.forename: Florim
authors.initials: F
authors.lastname: Cuculi
authors.forename: Sam
authors.initials: S
authors.lastname: Dawkins
authors.forename: Mathias
authors.initials: M
authors.lastname: Wolfrum
authors.forename: Robin P
authors.initials: RP
authors.lastname: Choudhury
authors.forename: John C
authors.initials: JC
authors.lastname: Forfar
authors.forename: Bernard D
authors.initials: BD
authors.lastname: Prendergast
authors.forename: Tuncay
authors.initials: T
authors.lastname: Yetgin
authors.forename: Robert Jan
authors.initials: RJ
authors.lastname: van Geuns
authors.forename: Matteo
authors.initials: M
authors.lastname: Tebaldi
authors.forename: Keith M
authors.initials: KM
authors.lastname: Channon
authors.forename: Rajesh K
authors.initials: RK
authors.lastname: Kharbanda
authors.forename: Peter M
authors.initials: PM
authors.lastname: Rothwell
authors.forename: Marco
authors.initials: M
authors.lastname: Valgimigli
authors.forename: Adrian P
authors.initials: AP
authors.lastname: Banning
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D015425:Myocardial Reperfusion / Q000379:methods; D011446:Prospective Studies; D012189:Retrospective Studies; D000072657:ST Elevation Myocardial Infarction / Q000150:complications / Q000175:diagnosis* / Q000628:therapy*; D013927:Thrombosis / Q000150:complications*; D016896:Treatment Outcome; D014655:Vascular Resistance / Q000502:physiology*; D055815:Young Adult