Imaging with real-time myocardial contrast echocardiography improved CAD detection

In a comparison of patient outcomes after two stress imaging approaches, stress real-time myocardial contrast echocardiography improved the detection of CAD during stress echocardiography over conventional stress echocardiography.

Researchers prospectively randomly assigned patients to stress real-time myocardial contrast echocardiography (RTMCE) or conventional stress echocardiography (CSE). All patients had intermediate to high pre-test probability and were referred for dobutamine or exercise stress echocardiography. Definity contrast was used in 63% of CSE studies only when endocardial border delineation was inadequate.

Follow-up data (median, 2.6 years) were available in 2,014 patients with a mean age of 59 years. Researchers more frequently observed an abnormal RTMCE compared with an abnormal CSE (P<.001). An abnormal RTMCE more frequently resulted in revascularization (P=.004). Resting wall motion abnormalities were also more frequently observed with RTMCE, and the abnormalities were an independent predictor of death and nonfatal MI (P=.005).

All studies were examined by an experienced contrast reviewer (n=1,257) or four level 3 echocardiographers with basic contrast training (n=806). The researchers also determined the effect of training experience on the predictive value of either stress imaging approach. For the combined endpoint of death/nonfatal MI/subsequent revascularization, studies read by reviewers of both levels had equivalent predictive value. Death or nonfatal MI after abnormal RTMCE or CSE studies were significantly higher when an experienced reviewer read a study as abnormal vs. normal; no difference was found with less-experienced reviewers.

The researchers concluded that “both RTMCE and CSE appear to be excellent at risk stratifying patients at intermediate risk for CAD. When performed properly, RTMCE identifies more patients with CAD and extensive ischemia, and those more likely to require revascularization.

“A resting wall motion abnormality detected with RTMCE is highly predictive of adverse outcomes, while it is not predictive of outcome with CSE. Therefore, although the prognostic values of RTMCE and CSE are similar when revascularization is considered as a time-dependent covariate, stress RTMCE should be the preferred technique for detecting those who may need revascularization, and RTMCE is better for detecting a resting wall motion abnormality that will impact outcome,” they wrote.

For more information:

Porter TR. J Am Coll Cardiol. 2013;61:2446-2455.

Disclosure: Porter reports receiving grant and/or equipment support from Astellas Pharma, General Electric Global Healthcare, Lantheus Medical Imaging and Philips Healthcare.