title: Value of adenosine infusion for infarct size determination using real-time myocardial contrast echocardiography.
abstract: BACKGROUND
  Myocardial contrast echocardiography has been used for determination of infarct size (IS) in experimental models. However, with intermittent harmonic imaging, IS seems to be underestimated immediately after reperfusion due to areas with preserved, yet dysfunctional, microvasculature. The use of exogenous vasodilators showed to be useful to unmask these infarcted areas with depressed coronary flow reserve. This study was undertaken to assess the value of adenosine for IS determination in an open-chest canine model of coronary occlusion and reperfusion, using real-time myocardial contrast echocardiography (RTMCE).
  
  
  METHODS
  Nine dogs underwent 180 minutes of coronary occlusion followed by reperfusion. PESDA (Perfluorocarbon-Exposed Sonicated Dextrose Albumin) was used as contrast agent. IS was determined by RTMCE before and during adenosine infusion at a rate of 140 mcg.Kg(-1).min(-1). Post-mortem necrotic area was determined by triphenyl-tetrazolium chloride (TTC) staining.
  
  
  RESULTS
  IS determined by RTMCE was 1.98 +/- 1.30 cm2 and increased to 2.58 +/- 1.53 cm2 during adenosine infusion (p = 0.004), with good correlation between measurements (r = 0.91; p < 0.01). The necrotic area determined by TTC was 2.29 +/- 1.36 cm2 and showed no significant difference with IS determined by RTMCE before or during hyperemia. A slight better correlation between RTMCE and TTC measurements was observed during adenosine (r = 0.99; p < 0.001) then before it (r = 0.92; p = 0.0013).
  
  
  CONCLUSIONS
  RTMCE can accurately determine IS in immediate period after acute myocardial infarction. Adenosine infusion results in a slight better detection of actual size of myocardial damage.
authors.affiliation: Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil. pmmdourado@terra.com.br
authors.forename: Paulo Magno Martins
authors.initials: PM
authors.lastname: Dourado
authors.forename: Jeane Mike
authors.initials: JM
authors.lastname: Tsutsui
authors.forename: Antonio Carlos Palandri
authors.initials: AC
authors.lastname: Chagas
authors.forename: João César Nunes
authors.initials: JC
authors.lastname: Sbano
authors.forename: Vera Demarchi
authors.initials: VD
authors.lastname: Aiello
authors.forename: Protásio Lemos da
authors.initials: PL
authors.lastname: Luz
authors.forename: Wilson
authors.initials: W
authors.lastname: Mathias
authors.forename: Jose A F
authors.initials: JA
authors.lastname: Ramires
mesh_terms: D000241:Adenosine / Q000008:administration & dosage*; D000818:Animals; D003199:Computer Systems; D004285:Dogs; D004452:Echocardiography / Q000379:methods*; D007089:Image Enhancement / Q000379:methods*; D007262:Infusions, Intravenous; D009203:Myocardial Infarction / Q000145:classification / Q000000981:diagnostic imaging*; D009206:Myocardium; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014665:Vasodilator Agents / Q000008:administration & dosage
chemical_list: D014665:Vasodilator Agents; D000241:Adenosine