SAFETY OF A NEW TRANSPULMONARY ECHOCONTRAST AGENT (ALBUNEX(R)) IN REPEATED ECHOCARDIOGRAPHIC STUDIES IN PATIENTS

Background and hypothesis: Multiple contrast-enhanced echocardiographi c studies are to be expected in patients with cardiac ischemic disease , but the sonication process used to produce the echocontrast agent Al bunex(R) may result in new epitopes that could cause an immunogenic re sponse. Methods: Repeated exposures to intravenous Albunex over a peri od of time long enough to allow development of an eventual immune reac tion were performed in 12 patients while monitoring for lymphocyte tra nsformation, microsphere specific IgE and IgG antibodies, and systemic , pulmonary artery, capillary wedge, and right atrial pressures, as we ll as cardiac output, left ventricular fractional shortening, and bloo d gases. Results: No significant H-3-thymidine incorporation and thus no specific blastic transformation of the patients' lymphocytes were o bserved either for high or low Albunex concentrations, corresponding t o the expected hepatic and plasma concentrations of microspheres. No f ormation of microsphere-specific IgE and IgG antibodies was observed a fter the first or second Albunex exposure. Furthermore, no clinically significant hemodynamic or respiratory adverse reactions were observed in any patient. Conclusion: These results suggest that repeated expos ures to intravenous Albunex induce no adverse effect on the cellular a nd humoral immune systems and on left and right heart hemodynamics in patients.