Echocardiography ultrasound contrast agent not associated with increased mortality risk

Critically ill hospitalized patients undergoing echocardiography with an ultrasound contrast agent did not have an increased risk for mortality vs. those who did not receive the agent, study data indicated.

Using the largest hospital service-level database in the United States, the researchers identified adult patients undergoing in-patient echocardiography between January 2003 and October 2005 (n=2,588,722) and those who received perflutren protein-type A microspheres injectable suspension (n=22,499). Of the contrast echocardiography patients, 2,900 met the criteria for critical illness, which included HF, acute MI, arrhythmia, respiratory failure, pulmonary embolism, emphysema and pulmonary hypertension.

There were 167 deaths among critically ill patients, 38 of whom were from the contrast group and 129 from the control group (n=11,600). The contrast agent was not associated with an increase in same-day mortality (OR=1.18; 95% CI, 0.82-1.71). Before matching, contrast patients showed greater morbidity than noncontrast patients (Deyo-Charlson comorbidity score 2.45 vs. 2.25; P<.0001). After propensity score matching, which included variables for comorbidities, demographic factors, hospital-specific factors, level of care and mechanical ventilation status, the observable difference was reduced.

“Overall, there were no differences identified in same-day or next-day mortality in patients who received contrast at the time of echocardiography vs. patients who did not receive contrast,” the researchers concluded. “These results corroborate the established safety experience … as reflected in the published literature for ultrasound contrast agents.” – by Brian Ellis

Exuzides A. J Am Coll Cardiol Img. 2010;3:578-585.

Many patients exhibit poor acoustic windows (thus poor image quality for bedside echocardiograms) and are often too sick for transport to other imaging modalities such as MRI. Physicians need information related to cardiac function in order to make life-altering decisions. This is a situation in which ultrasound contrast may have marked utility, as it allows an assessment of the very information that physicians need to make these important decisions.

Several years ago, the FDA recommended against administering ultrasound contrast in this setting due to reports of adverse outcomes in critically ill patients of ultrasound contrast. Concern was raised by physicians performing these studies that this decision may have been premature, since it was not clear how the FDA accounted for adverse outcomes in critically ill patients independent of contrast administration. To this end, the physicians in this study have performed a retrospective review and provided information that supports the physicians' concerns. As shown, no differences were noted in outcomes in critically ill participants whether they did or did not receive contrast. Limitations to this type of data are that they are non-randomized; thus, one could argue they are not confirmatory or non-confirmatory. Nevertheless, they are what have been assembled to date, and raise the concern that the FDA decision may have been premature and require further study.

– W. Gregory Hundley, MD

Cardiology Today Section Editor

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