The impact of cardiac CT on the appropriate utilization of catheter coronary angiography

The purpose of this study was to evaluate the impact of computed tomography coronary angiography (CTCA) on the appropriate utilization of catheter angiography (CA). This observational trial analyzed all patients undergoing CA in 2006 and 2007 in one hospital. In 2007, patients having a low to intermediate cardiovascular risk and suspicion of coronary artery disease (CAD) and those with suspicion of progression of known organic heart disease (OHD) underwent CTCA either prior to CA or as the sole imaging modality. Appropriate utilization of CA was defined as: (1) percentage of patients showing normal or non-significant findings at CA, (2) percentage of self-referred patients to CA, and (3) percentage of patients with known OHD undergoing CA without immediate operative or interventional consequences. Use of CTCA resulted in a significant drop in the percentage of CA examinations in patients with suspected CAD showing normal or non-significant findings (19% in 2006, 10% in 2007, P