Simultaneous evaluation of perfusion by myocardial contrast echocardiography is incrementally beneficial beyond wall motion analysis only: results from a real-world stress echocardiography service

Abstract

Purpose: The diagnostic accuracy of myocardial contrast echocardiography (MCE), performed during stress echocardiography (SE), for evaluation of known or suspected coronary artery disease (CAD), has been proven in research studies. However, the feasibility and value of MCE incorporated into a real-world clinical SE service are unknown. This prospective study thus aimed to determine the clinical role of MCE. Methods: All patients had been referred for SE on clinical grounds. We performed MCE during SE, using a continuous infusion of Sonovue contrast, in patients undergoing pharmacological stress and those performing exercise in whom we suspected a high workload or target heart rate may not be attained. We documented clinical and SE variables and value of MCE to the reporting cardiologist, pre-defined as: incremental benefit over wall motion (WM), more confidence with WM, no benefit over WM or uninterpretable MCE images. All studies were analysed by the performing cardiologist and an expert. We examined agreement between WM and MCE data and angiography findings, where significant CAD was defined as ≥50% stenosis. Results: Over 21months, 220 patients underwent MCE by 8 operators. Mean age was 66yrs & 74% were men. MCE demonstrated excellent feasibility, with diagnostic images in 94% studies. Mean contrast use was 2.8 vials/study. MCE provided incremental benefit over WM analysis in 56 (25%) cases, gave more confidence with WM in 49 (22%) cases, had no added value over WM in 102 (47%) cases and was uninterpretable in 13 (6%) cases. Of the 60 patients with confirmed CAD at angiography, MCE detected more patients with LAD disease compared to WM only (65% vs. 53%, p 0.02) and a greater ischaemic burden than WM on a per-patient basis (median segments 5 [MCE] vs. 4 [WM], p <0.001) and in both the anterior (3 vs. 1 segments, p<0.001) and posterior (4 vs. 2 segments, p<0.001) coronary circulation. Multivessel disease (MVD – LAD + LCx/RCA disease) was correctly detected by MCE in 26/34 (76%) patients but only 19/34 (56%) patients by WM (p 0.02); in MVD patients, MCE also identified a significantly greater ischaemic burden than WM (7 vs. 5 segments, p<0.001) and, furthermore, identified LAD disease missed by WM in >50% MVD patients. Conclusion: MCE is feasible by multiple operators when incorporated into a clinical SE service. MCE data provides the reporting cardiologist with incremental benefit or greater confidence in a significant proportion of cases. MCE is more sensitive than WM for detecting flow-limiting LAD disease, correctly predicting presence of MVD and identifies a greater burden of ischaemia.