title: Assessment of collateralized myocardium with Cardiac Magnetic Resonance (CMR): transmural extent of infarction but not angiographic collateral vessel filling determines regional function and perfusion in collateral-dependent myocardium.
abstract: BACKGROUND
  Angiographic collateral vessel filling is limited to evaluate collateral-dependent myocardium. We hypothesize, that quantitative assessment of regional myocardial function, perfusion and viability with Cardiac Magnetic Resonance (CMR) adds complementary information to angiography of collateralized myocardium.
  
  
  METHODS
  CMR was performed in 30 patients with one chronic occluded coronary artery and no further flow limiting stenosis to assess transmural extend of infarction (TEI), resting perfusion and perfusion during adenosine-induced hyperemia and regional wall thickening (RWT) in collateral-dependent and antegradely-perfused myocardium. Collateral vessels were evaluated by angiography and the Rentrop grade (0-3).
  
  
  RESULTS
  In 15 patients with < 50% TEI in collateral-dependent myocardium resting perfusion (1.08+/-0.22 ml/min/g), hyperemia (2.21+/-0.73 ml/min/g) and RWT (4.0+/-2.6 mm) were similar to antegradely-perfused myocardium (rest 1.14+/-0.20 and hyperemia 2.46+/-0.82 ml/min/g, RWT 4.3+/-1.7 mm). In 15 patients with > or = 50% TEI in collateral-dependent myocardium resting perfusion and hyperemia as well as RWT were significantly lower (rest 0.84+/-0.19, p<0.001 and hyperemia 1.34+/-0.43 ml/min/g, p<0.001; RWT 1.0+/-1.0 mm, p<0.0001) compared to antegradely-perfused myocardium. There was an inverse correlation between TEI and resting or hyperemic perfusion or RWT. In contrary, resting perfusion and hyperemia as well as RWT in collateral-dependent myocardium were not different between patients with good (2-3) compared to patients with poor Rentrop grade (0-1). There was no correlation between TEI and Rentrop grade.
  
  
  CONCLUSIONS
  Function and perfusion in collateral-dependent myocardium are preserved, if transmural extent of infarction is limited (< 50%). This is independent of their angiographic collateral vessel filling. Thus, CMR adds complementary information to angiographic standard assessment of collateral vessels.
authors.affiliation: Department of Medicine, University of Munich, Germany. olaf.muehling@med.uni-muenchen.de
authors.forename: Olaf
authors.initials: O
authors.lastname: Muehling
authors.forename: Michael
authors.initials: M
authors.lastname: Jerosch-Herold
authors.forename: Clemens
authors.initials: C
authors.lastname: Cyran
authors.forename: Armin
authors.initials: A
authors.lastname: Huber
authors.forename: Stefan
authors.initials: S
authors.lastname: Schoenberg
authors.forename: Maximilian
authors.initials: M
authors.lastname: Reiser
authors.forename: Gerhard
authors.initials: G
authors.lastname: Steinbeck
authors.forename: Michael
authors.initials: M
authors.lastname: Nabauer
mesh_terms: D000368:Aged; D003097:Collateral Circulation / Q000502:physiology*; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000502:physiology*; D023921:Coronary Stenosis / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology*; D013318:Stroke Volume / Q000502:physiology; D020257:Ventricular Remodeling