Study of 99mTc-glucarate to Detect Acute Coronary Syndrome in Chest Pain Patients.

Acute coronary syndrome encompasses a range of coronary artery diseases, including unstable angina and both ST-segment elevation and non-ST-segment elevation myocardial infarction (MI). Differentiating ACS from noncardiac chest pain remains a challenge in the emergency department (ED). Myocardial perfusion imaging (MPI) for ischemia has been used to rule ACS in or out among chest pain patients with nondiagnostic ECGs upon presentation to the ED. Several studies have shown a high negative predictive value of MPI for ruling out acute ischemia in the emergency setting. Although myocardial imaging with perfusion agents provides important information for risk-stratifying stable post-ACS patients, this method is of limited value in patients with prior history of CAD, since these patients will often have abnormal resting perfusion patterns, thereby precluding the ability to differentiate old infarcts from new ischemic events. 99mTc-glucarate does not detect old MIs and thus should provide an improvement in specificity in the imaging of ACS patients with previous CAD. This study proposes to extend the evaluation of 99mTc-glucarate imaging by studying its ability to detect ACS in chest pain patients with no obvious signs of AMI but with known CAD, in the setting of the ED. Unlike MPI, 99mTc-glucarate imaging will not detect old MIs, thereby providing an advantage in specificity of the technique.