Background
The use of ultrasound enhancing agents (UEA) in echocardiography is a
technique that can be used to enhance endocardial border delineation in
studies with suboptimal left ventricular cavity visualization
[1-3]. There are two different types
of contrast agents that serve different purposes. The first one is
agitated saline contrast which is frequently utilized to identify small
right-to-left shunts such as patent foramen ovale or atrial septal
defect [4]. The other is a newer
technique consisting of microbubble contrast agents which traverse the
pulmonary vasculature and opacify the left ventricle (LV), allowing for
accurate endocardial border definition in patients with suboptimal
echocardiograms [1]. This allows for
improved sensitivities and specificities when comparing patients with
poor echocardiographic windows to those with well visualized windows
[3, 5].
In a large prospective study, patients with technically difficult
echocardiographic studies were evaluated to see how UEA effected
diagnosis and management. The percentage of uninterpretable studies
decreased from 11.7% to 0.3%. Moreover, further procedures were
avoided in 33% of patients and medical management was altered in 10%
[1]. By decreasing need for additional
procedures, use of UEA is cost effective. In terms of safety profile
with UEAs, back pain is the most common complaint followed by headache
and allergic reactions [6].
Application of UEAs have not been associated with significant extra cost
of time and manipulations because small bolus injections have been shown
to suffice for image quality [7].
Indeed, they have been shown to be cost-effective (4) and life-saving
[8].