Safety and efficacy of a new transpulmonary ultrasound contrast agent: Initial multicenter clinical results

Abstract

Myocardial contrast echocardiography has been found to be a safe and useful technique for evaluating relative changes in myocardial perfusion and delineating areas at risk. Although earlier contrast agents required direct delivery into the coronary arteries or aortic root, a new echocardiographic contrast agent, sonicated albumin microspheres (Albunex), has been found to cross the pulmonary circulation in experimental models.

To determine the safety and preliminary efficacy of intravenous injections of Albunex in humans, 71 patients at three independent medical institutions underwent two-dimensional echocardiographic examination before, during and after the administration of three intravenous doses of Albunex, ranging from 0.01 to 0.12 ml/kg body weight. All patients provided a complete history and underwent physical and neurologic examination and laboratory and electrocardiographic evaluation before the injections; all evaluations (except for the history) were repeated at 2 h and 3 days after the injections of Albunex. The efficacy of the injections was qualitatively assessed by two independent blinded observers using a grading system of 0 to + 3, with 0 indicating an absence of contrast effect and + 3 indicating full opacification of the cavities examined.

All injections were well tolerated and no serious side effects were noted in any of the patients. Irrespective of dose group, a cavity opadfication ≥ + 2 was seen in the right ventricle in 212 (88%) of 240 injections and in the left ventricle in 151 (63%) of 240 injections as judged by the independent observers. The degree of ventricular cavity opacification appeared to be dose and concentration related. In conclusion, this first multicenter clinical study of Albunex demonstrates that the contrast agent is safe when administered Intravenously and achieves significant transpulmonary passage in a majority of patients.