ABSTRACT
OBJECTIVES: The study sought to prospectively compare patient outcome after stress real-time myocardial contrast echocardiography (RTMCE) versus conventional stress echo (CSE), where contrast is used to optimize wall motion (WM) analysis. BACKGROUND: Myocardial perfusion imaging with RTMCE may improve the detection of coronary artery disease (CAD), and predict patient outcome. METHODS: Patients with intermediate to high pre-test probability referred for dobutamine or exercise stress echocardiography were prospectively randomized to either RTMCE or CSE. Definity contrast was used for CSE only when endocardial border delineation was inadequate (63% of studies). Studies were interpreted by either an experienced contrast reviewer (R1; n = 1257), or 4 Level 3 echocardiographers (R2) with basic contrast training (n = 806). Death, nonfatal myocardial infarction (MI), and revascularizations were recorded at follow-up. RESULTS: Follow-up was available in 2,014 patients (median 2.6 years). Mean age was 59 ± 13 years (53% women). An abnormal RTMCE was more frequently observed than an abnormal CSE (p < 0.001), and more frequently resulted in revascularization (p = 0.004). Resting WM abnormalities were also more frequently seen with RTMCE (p < 0.01), and were an independent predictor of death/nonfatal MI (p = 0.005) for RTMCE, but not CSE. The predictive value of a positive study, whether with CSE or RTMCE, was significant for both R1 and R2 reviewers in predicting the combined endpoint, but R1 was better than R2 at predicting patients at risk for death or nonfatal MI. CONCLUSIONS: Perfusion imaging with RTMCE improves the detection of CAD during stress echocardiography, and identifies those more likely to undergo revascularization following an abnormal study.
Subject(s)
Echocardiography/methods , Exercise Test/methods , Myocardium/pathology , Aged , Angiography/methods , Contrast Media/pharmacology , Disease-Free Survival , Female , Hemodynamics , Humans , Image Processing, Computer-Assisted/methods , Male , Middle Aged , Movement , Probability , Prospective Studies , Treatment OutcomeABSTRACT
BACKGROUND: Although retrospective studies have suggested that myocardial perfusion and wall motion analysis with real-time myocardial contrast echocardiography (RTMCE) improves the detection of coronary artery disease (CAD) during dobutamine or exercise stress echocardiography, a prospective randomized comparison with conventional stress echocardiography that did not use RTMCE has not been performed. METHODS: A total of 1,776 patients with preserved resting left ventricular wall motion undergoing dobutamine or exercise stress echocardiography for suspicion of CAD were randomized to either non-RTMCE, for which contrast was used only for the approved indication of enhancing left ventricular opacification, or RTMCE, for which contrast infusion was used in all cases to examine both wall motion and myocardial perfusion. Comparisons in test positivity, and positive predictive value in those subsequently referred for quantitative coronary angiography, were performed. RESULTS: Patients randomized to RTMCE had significantly higher test positivity (22% for RTMCE vs 15% with non-RTMCE, P = .0002). The increased test positivity occurred without a difference in positive predictive value in predicting >50% diameter stenoses by quantitative coronary angiography (67% for non-RTMCE, 73% for RTMCE). The mechanism for increased detection of CAD with RTMCE was mostly due to the detection of subendocardial wall thickening abnormalities that would have gone undetected when examining transmural wall thickening. CONCLUSIONS: RTMCE improves the detection of CAD during dobutamine and exercise stress echocardiography, mainly by the detection of subendocardial ischemia.