A randomized trial of exercise treadmill ECG versus stress SPECT myocardial perfusion imaging as an initial diagnostic strategy in stable patients with chest pain and suspected CAD: cost analysis.

BACKGROUND: Exercise electrocardiography (ETT) is frequently used in patients with suspected coronary artery disease (CAD). Single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) improves diagnostic stratification. There are no randomized trials comparing ETT and MPI. We hypothesized that first-line MPI would be effective and cost-saving versus ETT. METHODS AND RESULTS: We randomized 457 outpatients with stable chest pain and suspected CAD to either treadmill electrocardiography or MPI. The post-test likelihood incorporated the pretest likelihood and the test result, with clinically driven testing. The primary endpoint was cost to diagnosis based on institutional and National Institute for Clinical Excellence costs. MPI significantly reduced the intermediate post-test likelihood of CAD (30% for ETT vs 3% for MPI, P < .0001) and further investigations (71% for ETT vs 16% for MPI, P < .0001). Despite the reduction in downstream resource utilization after MPI, mean costs were not different between the 2 initial strategies: 490.44 pounds sterling (95% confidence interval, 453.80-527.08) for ETT versus 512.41 pounds sterling (95% confidence interval, 481.41-543.41) for MPI. MPI cost was no different from ETT cost in patients with an intermediate or high pretest likelihood (P = not significant). ETT was less expensive in low-risk patients. CONCLUSIONS: In this study there was no difference in cost to diagnosis between initial ETT and MPI. In low-likelihood patients ETT was less costly, whereas there was no cost difference in intermediate- or high-likelihood patients.