Abstract 737: The Prevalence of Severe Coronary Artery Disease in Patients With Adenosine-Induced ST-Segment Depression and Normal Myocardial Perfusion Imaging
Background: The significance of ischemic ECG changes during adenosine infusion in patients with normal myocardial perfusion imaging [MPI] is controversial. Early studies showed that patients with such findings are at increased risk for cardiovascular events, while more recent studies failed to confirm these reports. We sought to evaluate the prevalence of, and define the predictors for, severe coronary artery disease [CAD] in patients with ST-segment depression and normal MPI.
Methods: Results of all 3500 adenosine MPI studies performed at our institution between June 2005 and December 2008 were reviewed. Patients with adenosine-induced ST-segment depression and normal MPI were eligible for the study. Those with an abnormal baseline ECG, history of percutaneous coronary intervention [PCI], coronary artery bypass surgery [CABG], or follow-up of < 6 months were excluded. Clinical history, invasive coronary angiography results, and clinical follow-up were obtained from medical records or telephone interview. Cardiovascular mortality, myocardial infarction [MI], and coronary revascularization were included as cardiovascular events. Clinical variables of those with and without cardiovascular events were compared using Chi-Square analysis.
Results: Data for 69 patients, aged 67±9 years, including 60 women (87%), were analyzed. At their cardiologists’ discretion, coronary angiography was performed in 26 patients (38%). Ten (14%) patients underwent revascularization (1 CABG, 7 one-vessel PCI, 2 two-vessel PCI). There were no deaths or MI. Patients with cardiovascular events tended to have more cardiac risk factors than event-free patients, while the prevalence of diabetes mellitus was significantly higher in those who had cardiovascular events (60% vs. 22%; p = 0.0355).
Conclusions: In patients with adenosine-induced ST-segment depression and normal MPI, only a minority of those undergoing coronary angiography were found to have obstructive CAD, most of which involved only one vessel. In the presence of normal MPI, the specificity of ischemic ECG changes during adenosine infusion for the detection of obstructive CAD is poor. Such ECG findings do not seem to reflect the presence of severe CAD and balanced ischemia.