title: Microvascular obstruction in the right ventricle in reperfused anterior myocardial infarction. Macroscopic and pathologic evidence in a swine model.
abstract: BACKGROUND
  Data on right ventricular (RV) involvement in anterior myocardial infarction are scarce. The presence of RV microvascular obstruction (MVO) in this context has not been analyzed yet. The aim of the present study was to characterize the presence of MVO in the RV in a controlled experimental swine model of reperfused anterior myocardial infarction.
  
  
  METHODS
  Left anterior descending (LAD) artery-perfused area (thioflavin-S staining after selective infusion in LAD artery), infarct size (lack of triphenyltetrazolium-chloride staining) and MVO (lack of thioflavin-S staining in the core of the infarcted area) in the RV were studied. A quantitative (% of the ventricular volume) and semiquantitative (number of segments involved) analysis was carried out both in the RV and LV in a 90-min left anterior descending balloon occlusion and 3-day reperfusion model in swine (n=15).
  
  
  RESULTS
  RV infarction and RV MVO (>1 segment) were detected in 9 (60%) and 6 (40%) cases respectively. Mean LAD-perfused area, infarct size and MVO in the RV were 33.8 ± 13%, 13.53 ± 11.7% and 3.4 ± 4.5%. Haematoxylin and eosin stains and electron microscopy of the RV-MVO areas demonstrated generalized cardiomyocyte necrosis and inflammatory infiltration along with patched hemorrhagic areas. Ex-vivo nuclear magnetic resonance (T2 sequences) microimaging of RV-MVO showed, in comparison with remote non-infarcted territories, marked hypointense zones (corresponding to necrosis, inflammation and hemorrhage) in the core of hyperintense regions (corresponding to edema).
  
  
  CONCLUSIONS
  In reperfused anterior myocardial infarction, MVO is frequently present in the RV. It is associated with severe histologic repercussion on the RV wall. Nuclear magnetic resonance appears as a promising technique for the noninvasive detection of this phenomenon. Further studies are warranted to evaluate the pathophysiological and clinical implications.
authors.affiliation: Department of Cardiology, Hospital Clinico Universitario, INCLIVA, University of Valencia, Spain.
authors.forename: Clara
authors.initials: C
authors.lastname: Bonanad
authors.forename: Amparo
authors.initials: A
authors.lastname: Ruiz-Sauri
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Forteza
authors.forename: Fabian
authors.initials: F
authors.lastname: Chaustre
authors.forename: Gema
authors.initials: G
authors.lastname: Minana
authors.forename: Cristina
authors.initials: C
authors.lastname: Gomez
authors.forename: Ana
authors.initials: A
authors.lastname: Diaz
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Noguera
authors.forename: Elena
authors.initials: E
authors.lastname: de Dios
authors.forename: Julio
authors.initials: J
authors.lastname: Nunez
authors.forename: Luis
authors.initials: L
authors.lastname: Mainar
authors.forename: Juan
authors.initials: J
authors.lastname: Sanchis
authors.forename: Jose M
authors.initials: JM
authors.lastname: Morales
authors.forename: Daniel
authors.initials: D
authors.lastname: Monleon
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Chorro
authors.forename: Vicente
authors.initials: V
authors.lastname: Bodi
mesh_terms: D000818:Animals; D003331:Coronary Vessels / Q000473:pathology*; D005260:Female; D006352:Heart Ventricles / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D055806:Microvessels / Q000473:pathology*; D009203:Myocardial Infarction / Q000473:pathology*; D013552:Swine
keywords: 2,3,5-triphenyltetrazolium chloride; LAD; LV; MVO; Microvascular obstruction; RV; SEM; ST-segment elevation myocardial infarction; STEMI; Scanning electron microscopy; T-S; TEM; TTZ; Transmission electron microscopy; left anterior descending; left ventricle; microvascular obstruction; myocardial infarction; right ventricle; thioflavin-S