Optimizing Evaluation of Patients with Low-to-Intermediate-Risk Acute Chest Pain: A Randomized Study Comparing Stress Myocardial Perfusion Tomography Incorporating Stress-Only Imaging Versus Cardiac CT

The purpose of this study was to determine whether stress myocardial perfusion (SPECT) optimized with stress-only (SO) imaging is comparable to cardiac CT angiography (CTA) for evaluating patients with acute chest pain (ACP). Methods: This was a prospective randomized observational study in 598 ACP patients who underwent CTA versus SPECT. The primary endpoint was length of hospital stay, and secondary endpoints were test feasibility, time to diagnosis, diagnostic accuracy, radiation exposure, and overall cost. Median follow-up was 6.5 mo, with a 3.8% cardiac event rate defined as death or an acute coronary syndrome. Results: Of 2,994 patients screened, 1,703 (56.9%) were not candidates for CTA because of prior cardiac disease (41%) or imaging contraindications (16%). Time to diagnosis (8.1 +/- 8.5 vs. 9.4 +/- 7.4 h) and length of hospital stay (19.7 +/- 27.8 vs. 23.5 +/- 34.4 h) were significantly shorter with CTA than with SPECT (P = 0.002). However, time to diagnosis (7.0 +/- 6.2 vs. 6.8 +/- 5.9 h, P = 0.20), length of stay (15.5 +/- 17.2 vs. 16.7 +/- 15.3 h, P = 0.36), and hospital costs ($4,242 +/- $3,871 vs. $4,364 +/- 1781, P = 0.86) were comparable with CTA versus SO SPECT, respectively. SO was also superior to conventional SPECT regarding all of the above metrics and significantly reduced radiation exposure (5.5 +/- 4.4 vs. 12.5 +/- 2.7 mSv, P < 0.0001). Conclusion: Stress SPECT when optimized with SO imaging is similar to CTA in time to diagnosis, length of hospital stay, and cost, with improved prognostic accuracy and less radiation exposure. Our results emphasize the importance of SO imaging, particularly in low-intermediate-risk emergency room patients who are a population likely to have a normal test result.