Safety and efficacy of LK565 - a new polymer ultrasound contrast agent

We tested a newly developed ultrasound contrast agent (LK565) from poly-asp artic acid (PAA; particle size 3 mum; particle content: air) in 15 healthy male probands (20-38 years) in doses of 10, 30 and 100 mg intravenously. On e day and immediately before the study a routine laboratory test, an ECG an d an EEG were performed. The EEG was continued through the complete time pe riod that the ultrasound contrast lasted, i.e., up to one hour after the in jection. All probands were followed clinically for 24 hours when the routin e laboratory and the ECG were repeated. All subjects tolerated the contrast agent well. There were no changes in ei ther the EEG or in the ECGs performed throughout the study. There were no s ignificant laboratory changes except for a small and transient increase in the neutrophil count in five probands receiving the highest dose. All injections with 10 mg led to a significant improvement in the color Dop pler signal. All injections with 30 and 100 mg led to a very strong echo co ntrast lasting for 5 to 12 minutes in the harmonic B-mode. Using the latter , fragments of intramyocardial coronaries could be visualized. The tested u ltrasound polymer contrast agent was safe, well tolerated and efficient in this acute study.