title: Presence and extent of cardiac magnetic resonance microvascular obstruction in reperfused non-ST-elevated myocardial infarction and correlation with infarct size and myocardial enzyme release.
abstract: OBJECTIVE
  Microvascular obstruction (MO) is a factor of adverse outcome in patients with ST-elevated myocardial infarction (STEMI). We assessed the presence and extent of MO and its relationship with infarct size and left ventricular (LV) functional parameters after acute non-ST-elevated myocardial infarction (NSTEMI).
  
  
  METHODS
  Twenty-five patients with first acute NSTEMI underwent a cine and first-pass perfusion cardiac magnetic resonance (CMR) study, with late gadolinium enhancement imaging 72 h after myocardial infarction.
  
  
  RESULTS
  MO was detected in 32% of patients, and its extent comprised 0.5-3.1% of the total LV mass (mean 1.9 +/- 1.2%). Patients with MO had a significantly larger infarct size than patients without (14.1 +/- 5.9 vs. 5.3 +/- 4.1% LV mass; p < 0.001). There was no significant difference between both groups for the LV functional parameters and LV ejection fraction (58.5 +/- 6.8 vs. 62.6 +/- 9.6%; p = 0.29). Patients with MO showed a higher troponin I release (570 +/- 364 vs. 148 +/- 103 IU; p = 0.003) and a higher creatine kinase release (29,887 +/- 18,263 vs. 10,287 +/- 5,283 IU; p = 0.007).
  
  
  CONCLUSIONS
  In patients with acute NSTEMI, MO has a frequency similar to that observed in patients with STEMI and also correlates with the infarct extent. The prognostic significance on clinical outcome remains to be shown in this specific population.
authors.affiliation: Hôpital Cardiovasculaire Louis Pradel, Université de Lyon, Hospices Civils de Lyon, Lyon, France. nathan.mewton@chu-lyon.fr
authors.forename: N
authors.initials: N
authors.lastname: Mewton
authors.forename: E
authors.initials: E
authors.lastname: Bonnefoy
authors.forename: D
authors.initials: D
authors.lastname: Revel
authors.forename: M
authors.initials: M
authors.lastname: Ovize
authors.forename: G
authors.initials: G
authors.lastname: Kirkorian
authors.forename: P
authors.initials: P
authors.lastname: Croisille
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography; D003402:Creatine Kinase / Q000097:blood; D005260:Female; D005682:Gadolinium; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D055806:Microvessels / Q000473:pathology*; D008875:Middle Aged; D009203:Myocardial Infarction / Q000201:enzymology / Q000473:pathology* / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology*; D009336:Necrosis / Q000097:blood; D011446:Prospective Studies; D019210:Troponin I / Q000097:blood; D016277:Ventricular Function, Left
chemical_list: D019210:Troponin I; D005682:Gadolinium; D003402:Creatine Kinase