Detection of single-vessel coronary artery disease by dipyridamole stress echocardiography: no longer a problem?

We aimed to evaluate whether addition of myocardial contrast echocardiography (MCE) perfusion data improves the sensitivity of stress echocardiography for detection of single-vessel coronary artery disease (svCAD) and to compare the diagnostic value of MCE and single-photon emission computed tomography (SPECT) for detection of svCAD.

One hundred and three patients with suspected or known stable CAD underwent dipyridamole (0.84 mg kg(-1) intravenously over 4 min)-atropine (up to 1 mg intravenously) stress echocardiography combined with MCE. Wall motion abnormalities (WMA) and perfusion defects were assessed visually. Presence of CAD was detected by coronary angiography.

Single-vessel coronary artery disease defined as >or=70% stenosis was detected in 30% of patients, whereas 26% of patients had svCAD defined as >or=50% stenosis. Presence of inducible WMA had 35% and 26% sensitivity for detection of svCAD defined as >or=70% and >or=50% stenosis, respectively. Concomitant evaluation of MCE increased the sensitivity to 74% (P = 0.005) and 56% (P = 0.053), respectively, using any inducible abnormality (WMA or perfusion defects) as a criterion. Presence of any (inducible or fixed) WMA had 77% and 59% sensitivity for detection of svCAD defined as >or=70% and >or=50% stenosis, respectively. In case of such criterion for stress test positivity, the improvement in sensitivity provided by addition of MCE (to 94% and 78%, respectively) did not reach statistical significance.

Addition of MCE perfusion analysis during stress echocardiographical examination based on evaluation of inducible abnormalities improves the test sensitivity for detection of svCAD. This benefit is less apparent when fixed WMA and perfusion defects are incorporated into the stress test positivity criterion.