The Addition of Cardiac CT to Exercise Treadmill Testing in the Evaluation of Angina

The current outpatient evaluation for angina in low and intermediate risk patients typically starts with a functional assessment for coronary ischemia. Exercise treadmill testing is often selected as the initial diagnostic modality for coronary artery function. However, exercise treadmill testing is limited by its moderate sensitivity and specificity, often resulting in further cardiac resource utilization for patient risk stratification and reassurance. With the advent of coronary multislice computed tomography (MSCT) angiography, coronary artery anatomy can now be evaluated noninvasively. Despite its impressive performance characteristics, the role of coronary MSCT angiography in the outpatient evaluation of angina remains undefined. CT-EXTRA compares the impact on patient safety and downstream resource utilization of a novel initial diagnostic strategy employing the addition of coronary MSCT angiography to exercise treadmill testing with a standard diagnostic strategy of exercise treadmill testing for the ambulatory evaluation of low-intermediate risk patients with possible angina. The study is a single center, prospective, non-blinded, randomized clinical trial. Men and women, age 18-70, with a low to intermediate pretest probability of coronary artery disease who are referred for an exercise treadmill test for angina are eligible. Subjects are randomized either to an initial diagnostic strategy of exercise treadmill testing or exercise treadmill testing with coronary MSCT angiography. Subsequent diagnostic testing and treatment are the discretion of the referring physician. Subjects will be clinically followed for 24 months. The clinical impact on patient safety and downstream clinical resource utilization of this novel diagnostic strategy in which both coronary artery anatomy and function are initially evaluated will be determined. The primary outcome is a composite endpoint consisting of freedom from adverse cardiac events, further cardiac diagnostic testin