title: Coronary microembolization causes long-term detrimental effects on regional left ventricular function.
abstract: OBJECTIVE
  To investigate whether coronary microemboli have long-term effects on left ventricular (LV) function in an experimental model. Furthermore, to determine if first-pass perfusion and late gadolinium enhancement (LGE) patterns differs between small- and large-sized microemboli.
  
  
  METHODS
  Six pigs underwent left anterior descending (LAD)-coronary microembolization with small-sized (40-120 μm, n ∼ 250 000) microemboli using a combined x-ray and MRI-system. MR-images before, one hour after and 7-8 weeks after microembolization were obtained. Results were compared to MRI obtained by large-sized (100-300 μm, n ∼ 7200) microemboli.
  
  
  RESULTS
  Cine MRI showed an acute drop in ejection fraction (from 49.5 ± 2.6% to 32.5 ± 2.8) that substantially recovered at 7-8 weeks (47.5 ± 3.2%). Regional LV-function assessed as circumferential, longitudinal and radial strain declined in both microinfarcts and remote regions followed by partial recovery at 7-8 weeks. The decline in LV function and the severe perfusion deficit from the small microemboli was similar to the large microemboli at one hour. There was a significant recovery in perfusion at 7-8 weeks in the microinfarcts. LGE demonstrated the microinfarcts at 7-8 weeks but not at one hour and the microinfarcts were confirmed by histopathology.
  
  
  CONCLUSIONS
  Microembolization causes long-term, regional LV dysfunction and this study confirmed the need of a comprehensive MRI-protocol for the detection of microinfarcts. These findings suggest that even small microemboli (40-120 μm in diameter), which may escape the distal protective devices influence cardiac function.
authors.affiliation: Department of Clinical Physiology, Lund University, Skåne University Hospital, Lund, Sweden. Marcus.carlsson@med.lu.se
authors.forename: Marcus
authors.initials: M
authors.lastname: Carlsson
authors.forename: Robert
authors.initials: R
authors.lastname: Jablonowski
authors.forename: Alastair J
authors.initials: AJ
authors.lastname: Martin
authors.forename: Philip C
authors.initials: PC
authors.lastname: Ursell
authors.forename: Maythem
authors.initials: M
authors.lastname: Saeed
mesh_terms: D000818:Animals; D003331:Coronary Vessels; D004617:Embolism / Q000150:complications* / Q000503:physiopathology; D019786:Gadolinium DTPA; D007089:Image Enhancement; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods; D008863:Microspheres; D009203:Myocardial Infarction / Q000503:physiopathology*; D055414:Myocardial Perfusion Imaging; D013552:Swine; D018487:Ventricular Dysfunction, Left / Q000209:etiology* / Q000503:physiopathology
chemical_list: D019786:Gadolinium DTPA