Early Diagnosis of Acute Coronary Syndrome Using Myocardial Contrast Echocardiography

Kang, Duk Hyun; Kang, Soo Jin; Kim, Young Hak; Hwang, Eun Sun; Song, Jong Min; Choi, Kee Joon; Hong, Myeong Ki; Song, Jae Kwan; Park, Seong Wook; Park, Seung Jung; Kim, You Ho

Abstract

BACKGROUND AND OBJECTIVES
Without typical electrocardiographic (ECG) changes, and the elevation of cardiac enzymes, the early identification of high risk chest pain patients remains a major challenge. We hypothesized that myocardial contrast echocardiography (MCE) was more sensitive than conventional echocardiography (Echo) for the identification of high risk patients.
SUBJECTS AND METHODS
We prospectively enrolled 75 consecutive patients (age ; 62+/-11 yrs, 34 men), presenting to the emergency room, with suspected cardiac chest pain at rest. The exclusion criteria for enrolment were : age <40 yrs, the presence of a Q wave or ST segment elevation, an initial troponin I level >1.5 ng/mL and a poor Echo window. Echo and MCE were performed to evaluate regional wall motion abnormalities (RWMA), and assess myocardial perfusion defects (PD), using a continuous infusion of PESDA during intermittent power Doppler harmonic imaging. The Echo and MCE studies were interpreted by different reviewers, blinded to the clinical data. We defined major adverse cardiac events (MACE) as mortality, myocardial infarction (MI) and severe ischemia requiring revascularization.
RESULTS
There were 35 MACE, including 12 MI, during hospitalization. No significant differences were found in the clinical characteristics between patients with, or without, MACE. A RWMA or a PD were seen in 18 (24%) and 27 (36%) of patients, respectively, and the sensitivity, specificity of RWMA were 46 and 95% for a MACE, and 59 and 86% for a MI. The sensitivity and specificity of a PD were 69 and 93% for MACE, and 88 and 79% for MI, respectively.
CONCLUSION
The assessment of a PD by MCE is clinically feasible, and a MCE can improve the sensitivity of Echo in identifying high risk chest pain patients.