Safety and Risk—Benefit Profile of Microbubble Contrast Agents in Echocardiography

Abstract

Ultrasound contrast agents capable of transpulmonary passage following intravenous injection have been commercially available since the 1990s. These agents are microbubbles, which are smaller than red blood cells and persist long enough (due to reduced rate of gas diffusion) to reach the left ventricle (LV). 1‐3 Ultrasound contrast agent applications included LV cavity opacification, enhancement of spectral Doppler signals, and evaluation of myocardial perfusion at rest or post-stress. 3 The commercially available second-generation ultrasound agents are approved by the US Food and Drug Administration (FDA) only for the enhancement of LV endocardial delineation in patients with baseline suboptimal examinations. 3 There are currently two commercially available ultrasound contrast agents in the US: Optison™ (perflutren proteintype A microspheres, GE Healthcare, Buckinghamshire, UK) and Definity® (perflutren lipid microspheres, Lantheus Medical Imaging, North Bellirica).