Perspective:

This analysis pooled data from two randomized studies with discordant findings. The SCOT-HEART trial randomized 4,146 stable chest pain patients to CCTA versus standard of care; 85% of all patients underwent stress electrocardiography testing prior to randomization, and stress imaging was rarely performed in the standard of care cohort (11%). There were no differences in mortality or myocardial infarction at 1.7 years, although the CCTA cohort had lower events at 5 years. The PROMISE trial randomized 10,003 stable chest pain patients to CCTA versus functional-testing, with patients in the functional-testing arm receiving stress imaging in 90% of cases; there were no differences in composite adverse events between the two groups at a median follow-up of 2 years.

The present study pools data from two trials comparing CCTA to usual care, with the usual care cohort having stress imaging in 11% of patients in one study and 90% in the other. This difference may in part explain the discordant findings between these studies and suggests that CCTA may improve outcomes compared to usual care with minimal stress imaging but may result in similar outcomes compared to usual care that usually includes stress imaging.

The key finding of this pooled analysis is that patients with low RF-CL risk randomized to CCTA had improved outcomes compared to usual care—but not very-low or moderate/high RF-CL risk. This highlights the importance of selecting patients for CCTA with an intermediate pretest probability of obstructive CAD. However, usual care is not defined consistently between these two pooled studies, which presents challenges interpreting these findings. Even in patients at low RF-CL risk, it is not clear whether CCTA would be associated with improved outcomes compared to usual care that frequently includes stress imaging.