Value of adenosine infusion for infarct size determination using real-time myocardial contrast echocardiography.
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.
Dourado
Paulo Magno Martins
PM
Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil. pmmdourado@terra.com.br
Tsutsui
Jeane Mike
JM
Chagas
Antonio Carlos Palandri
AC
Sbano
João César Nunes
JC
Aiello
Vera Demarchi
VD
Luz
Protásio Lemos da
PL
Mathias
Wilson
W
Ramires
Jose A F
JA
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
D014665:Vasodilator Agents; D000241:Adenosine