Echo society guides ultrasound contrast use

Ultrasound contrast agents took a hit on the chin a year ago when the FDA decided to issue a black-box label for them warning physicians of potentially fatal reactions. The black-box labeling of the echocardiography agents was imposed after more than 100 cases of serious cardiopulmonary reactions and at least four deaths from cardiac arrest were reported during their administration.

In spring, the label was modified to focus on contraindications for patients with known or suspected right-to-left, bidirectional, or transient right-to-left cardiac shunts and hypersensitivity to perflutren, the main ingredient of the microsphere agents. Intra-arterial injection remains banned.

Use of the agents is down dramatically since the FDA warning, according to Arlington Medical Resources. The Philadelphia market research firm reported in August that use of these agents declined in the second quarter of 2008 to 22% of the level two years earlier. AMR attributed the drop to the FDA's black-box warning, which may still be holding physicians back from using the agents, according to the American Society of Echocardiography.

Now the ASE has stepped in with a guide that outlines why, when, and how these contrast agents -- one from Lantheus Medical Imaging, the other from GE Healthcare -- should be used. Based on expert consensus opinion and evidence-based research, The American Society of Echocardiography consensus statement on the clinical applications of ultrasonic contrast agents in echocardiography also describes the role of staff involved in the administration of these agents and the methods they should use.

Published in the November 2008 issue of the Journal of the American Society of Echocardiography, the statement outlines the proven benefits of the agents and reviews specific contraindications, including intracardiac shunts and known hypersensitivity.

While acknowledging the FDA black-box warning initiated in 2007 and revised in 2008, the consensus statement concludes that contrast enhancement is an essential part of modern, quality-driven echocardiography laboratories inside and outside the hospital where both resting and stress echo testing are done.

"Ultrasound contrast agents have an established role in clinical diagnosis, patient management, and clinical research," said Dr. Sharon Mulvagh, a lead author of the ASE statement. "Contrast agents can provide the clear images needed to diagnose life-threatening heart conditions that may not be otherwise visible."

Beyond the obvious benefits of being able to see clearly heart structures in patients who image poorly, most commonly due to intervening fat and lung tissues, unique benefits include triage of patients with chest pain in the emergency department, bedside assessment of ICU patients, and qualitative and quantitative evaluation of the heart chambers of patients being considered for implantation of medical devices or heart transplantation.

The ASE statement notes that ultrasound contrast agents are cost-effective when used in an appropriate and efficient manner, as they can convert a technically difficult, nondiagnostic stress echocardiogram into an accurate diagnostic study, thereby avoiding further testing and improving efficiency.

For more information from the Diagnostic Imaging archives:

Contrast-enhanced ultrasound diagnoses small renal lesionsContrast-enhanced ultrasound shows vascular details of liver nodulesContrast-enhanced ultrasound proves nearly as accurate as CT for assessing abdominal trauma in children