PERIPHERAL INTRAVENOUS MYOCARDIAL CONTRAST ECHOCARDIOGRAPHY USING A 2-PERCENT DODECAFLUOROPENTANE EMULSION - IDENTIFICATION OF MYOCARDIAL RISK AREA AND INFARCT SIZE IN THE CANINE MODEL OF ISCHEMIA

Objectives. This study assessed the accuracy of 2% dodecafluoropentane (EchoGen), an intravenous echocardiographic contrast agent, in identi fying myocardial area at risk and infarct size in the canine model of myocardial ischemia. Background. Myocardial contrast echocardiography allows determination of myocardial area at risk and infarct size but r equires intracoronary injection in humans. The development of agents t hat can be delivered by peripheral intravenous injection could enable bedside myocardial contrast echocardiographic assessment of risk area, infarct size and reperfusion. Methods. Two protocols were used. Proto col 1 assessed the accuracy of myocardial contrast echocardiography us ing intravenous dodecafluoropentane in defining myocardial area at ris k and infarct size in the canine model of regional myocardial ischemia versus gross pathologic specimens stained with monastral blue to dete rmine area at risk and triphenyltetrazolium chloride to determine the area of necrosis. Protocol 2 assessed the effects of repeated injectio ns of dodecafluoropentane (0.5 ml/kg body weight, four doses 30 min ap art or eight doses 10 min apart) on myocardial blood flow and hemodyna mic variables. Results. Myocardial contrast echocardiography accuratel y defined area at risk and infarct size (r = 0.96 vs. triphenyltetrazo lium chloride). Myocardial blood how remained stable after multiple se rial injections of dodecafluoropentane. However, a significant increas e in pulmonary artery pressure and pulmonary vascular resistance, alon g with a decrease in arterial oxygen saturation and cardiac output, wa s seen in dogs that received eight injections at 10-min intervals, Con clusions. Myocardial contrast echocardiography using intravenous dodec afluoropentane accurately defined myocardial area at risk and infarct size. Hemodynamic variables and regional myocardial blood flows remain ed stable when dodecafluoropentane was injected at 30-min intervals fo r up to four doses; more frequent administration led to cardiopulmonar y deterioration. Dodecafluoropentane offers the potential for reliable , noninvasive assessment of reperfusion after therapeutic intervention s.