Although prior research has suggested a higher mortality risk in critically ill patients with the use of an ultrasound contrast agent (UCA) during echocardiography, a study published online Nov. 27 in the Journal of the American College of Cardiology: Cardiovascular Imaging found that UCA actually may be safer than no contrast at all.

In 2007, the FDA required labeling changes for UCAs after multiple reports of adverse reactions appeared to be related to the use of the agents. As a result, the FDA requested research to determine whether UCAs posed any risks to critically ill patients.

Investigators led by Michael L. Main, MD, of Saint Luke’s Mid America Heart Institute in Kansas City, Mo., compared death from any cause within 48 hours among critically ill patients (identified as those admitted to an intensive care unit or a critical care unit) who underwent echocardiography either with UCA or without contrast. They obtained discharge data from a nationwide hospital-based database and included critically ill adult patients discharged between 2002 and 2008 who underwent transthoracic echocardiography (TTE) either with UCA or without contrast.

There were 990,159 patients in the noncontrast (nTTE) group and 16,222 in the contrast (cTTE) group.

The 48-hour mortality risk was lower in the cTTE group than in the nTTE group (1.7 percent vs. 2.5 percent). These same patients also had a lower rate of in-hospital mortality (14.95 percent vs. 15.66 percent).

The authors noted that the reason for the association between UCAs and lower mortality in critically ill patients is not clear. Perhaps, they suggested, the contrast allowed for a more timely and accurate diagnosis, which led to more effective treatment.

Given that echocardiography is a treatment mainstay in seriously ill patients, the authors said their findings are “reassuring, given previous reports suggesting an association between cTTE and increased mortality in critically ill patients.”