title: The size does not matter - the presence of microvascular obstruction but not its extent corresponds to larger infarct size in reperfused STEMI.
abstract: BACKGROUND
  Microvascular obstruction (MVO) is a cardiac magnetic resonance (CMR) marker of no-reflow in ST-segment elevation myocardial infarction (STEMI). It remains unresolved whether the infarct size corresponds only to the presence of MVO or also to its extent.
  
  
  METHODS
  The study included 53 patients with first STEMI (median age 61.5 years, 77% male) treated with percutaneous coronary intervention (PCI) who underwent CMR after median 5 days from PCI. Small MVO was defined as patchy, non-confluent spots of dark areas of absent contrast surrounded by late gadolinium enhancement (LGE). Large MVO was defined as confluent areas of MVO comprising a large amount of the infarct zone.
  
  
  RESULTS
  Microvascular obstruction was observed in 32 patients (60%) including 18 patients with small MVO (36%) and 14 patients with large MVO (24%). Patients with MVO were more likely to have TIMI 0/1 grade flow on initial angiogram, higher levels of necrotic markers, larger infarct size, larger left ventricular end-diastolic and end-systolic volume and lower ejection fraction in comparison to patients without MVO. These differences were not observed between patients with large and small MVO.
  
  
  CONCLUSIONS
  The presence of MVO but not its extent corresponds to larger infarct size in STEMI.
authors.affiliation: Department of Interventional Cardiology and Angiology, Institute of Cardiology, Warsaw, Poland. lmalek@ikard.pl
authors.forename: Łukasz A
authors.initials: ŁA
authors.lastname: Małek
authors.forename: Mateusz
authors.initials: M
authors.lastname: Śpiewak
authors.forename: Mariusz
authors.initials: M
authors.lastname: Kłopotowski
authors.forename: Jolanta
authors.initials: J
authors.lastname: Miśko
authors.forename: Witold
authors.initials: W
authors.lastname: Rużyłło
authors.forename: Adam
authors.initials: A
authors.lastname: Witkowski
mesh_terms: D000368:Aged; D003251:Constriction, Pathologic / Q000473:pathology; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D055806:Microvessels / Q000473:pathology*; D008875:Middle Aged; D009203:Myocardial Infarction / Q000473:pathology* / Q000601:surgery*; D062645:Percutaneous Coronary Intervention; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016896:Treatment Outcome