High numbers of false-positive stress tests are the result of inappropriate testing.

Patients who underwent coronary angiography preceded by stress testing during the period January 2009 through March 2012 were evaluated using the CathPCI database. The predictive accuracy of stress echocardiography (SE) and single-photon emission computed tomography (SPECT) were determined and used to back calculate the pretest probability of the population being tested. In total, 2662 catheterizations were performed, 866 (33%) of which were preceded by stress imaging. Overall, the positive predictive values of SE and SPECT did not differ significantly (61% and 66%, P = .15) and were much lower in certain subgroups. The overall pretest probabilities of patients without a documented history of coronary artery disease undergoing SE and SPECT in the study population were estimated to be 18% and 27%, respectively. This study shows that stress testing is performed too often in low-risk patients in whom it is unlikely to improve clinical decision making.