Recommendations Endorsed for Contrast Agent Use in Cardiac Ultrasound Imaging

An American echocardiography society recently supported the use of contrast agents, used to enhance echocardiogram images, and provided a guide for physicians who may be hesitant to use the contrast agents following a 2007 U.S. Food and Drug administration (FDA) black box warning.

In a new statement, supported by expert consensus opinion, critical review, and evidence-based research, the American Society of Echocardiography (ASE; Morrisville, NC, USA; outlined why, when, and how the contrast agents should be used to enhance diagnosis, the role for each person in the lab, and methods to implement contrast in the lab. The statement, "The American Society of Echocardiography Consensus statement on the Clinical Applications of Ultrasonic Contrast Agents in Echocardiography," was published in the November 2008 issue of the Journal of the American Society of Echocardiography (JASE).

Cardiologists use echocardiograms (live, real-time ultrasound images of the beating heart) to evaluate the heart's performance, as well as the structures of the heart. The consensus statement confirmed that contrast enhancement is a fundamental part of modern, quality-driven echocardiography laboratories inside and outside the hospital where both resting and stress echo testing are performed.

"Ultrasound contrast agents have an established role in clinical diagnosis, patient management and clinical research," said Dr. Sharon Mulvagh, one of the lead authors of the document. "Contrast agents can provide sonographers and physicians the clear images they need to diagnose life-threatening heart conditions that may not be otherwise visible."

Acknowledging that the FDA black box warning initiated in 2007 and revised in 2008 may weigh heavily on concerned physicians, ASE outlined the proven benefits of contrast agents in its consensus statement, and reviewed the specific contraindications, which include significant intracardiac shunts, and known hypersensitivity. Beyond the obvious benefits of being able to clearly see heart structures in patients with poor images, most typically due to intervening fat and lung tissues, unique benefits include the following: (1) Contrast enhanced echocardiography in the emergency department can play a beneficial role in the triage of patients with chest pain through accurate, early diagnosis. (2) Contrast enhancement in technically difficult to image patients in the intensive care unit (ICU) can be used to provide bedside assessment of cardiac structure and function without having to resort to more invasive procedures (such as placing a probe into the esophagus and stomach). (3) The accuracy of contrast echocardiography has been validated for the qualitative and quantitative evaluation of the heart chambers, and should it be considered for patients in whom precise information is clinically required--such as patients under consideration for medical devices or potential heart transplant.

"Those in the medical field concerned about the safety of ultrasound contrast agents should consider the proven efficacy, the previously established safety of these compounds, and the potential risk of alternative procedures," said Dr. William A. Zoghbi, president of the American Society of Echocardiography. "Ultrasound contrast agents have been safely and effectively used in echocardiography studies performed in the echo lab, emergency department, ICU, interventional cardiology suite, and operating room."

ASE also noted that contrast agent use is cost-effective when used in an appropriate and efficient manner. Contrast echocardiography can convert a technically difficult, nondiagnostic stress echocardiogram into an accurate diagnostic study and avoid an unachievable, missed, or wrong diagnosis. This obviates the need for putting the patient through additional testing and improves efficiency, resulting in cost savings.

ASE advises the medical community that implementation of a contrast program requires a strong commitment to quality on the part of the medical director. Laboratories that have been successful in establishing contrast agent use have uniformly implemented a practice by which the sonographer, at the beginning of the study, identifies the need for the use of a contrast agent, on the basis of a standing order that clearly describes appropriate indications and addresses the relatively few contraindications.

The American Society of Echocardiography is a professional organization of physicians, cardiac sonographers, nurses, and scientists involved in echocardiography, the use of ultrasound to image the heart and cardiovascular system.

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American Society of Echocardiography