Cardiovascular Outcomes of Coronary Computed Tomography Angiography Versus Functional Testing in Suspected Coronary Syndromes: Real-World Evidence From the Nationwide Cohort

BACKGROUND: Real-world evidence for the selection of gatekeeping studies in patients with suspected coronary syndromes is limited. METHODS AND RESULTS: We identified 27 036 patients who underwent coronary computed tomography angiography (CCTA), single-photon emission computed tomography, and the treadmill test for suspected coronary syndromes from the Korean National Health Insurance Service–National Sample Cohort between 2006 and 2014. The primary end point was a composite of cardiac death and myocardial infarction, and the secondary end point was a composite of the primary end point and revascularization. During a median follow-up of 5.4 years, the risk of both primary and secondary end points was significantly higher in the single-photon emission computed tomography group (hazard ratio [HR], 1.81 [95% CI, 1.34–2.45]; and HR, 1.42 [95% CI, 1.22–1.66]), but significantly lower in the treadmill test group (HR, 0.53 [95% CI, 0.42–0.67]; and HR, 0.69 [95% CI, 0.62– 0.76]) compared with the CCTA group. After balancing baseline risk factors, there was no significant difference in the primary end point in those with single-photon emission computed tomography (HR, 1.11 [95% CI, 0.78–1.57]; P=0.58) or treadmill test (HR, 0.84 [95% CI, 0.65–1.08]; P=0.18) groups, compared with the CCTA group. The event rate of the secondary end point was significantly lower in the treadmill test group than in the CCTA group (HR, 0.87 [95% CI, 0.78–0.96]; P=0.008). CONCLUSIONS: Compared with functional testing, initial CCTA was not associated with a lower rate of cardiac death or myocardial infarction when used as an initial diagnostic test for patients with suspected coronary syndromes.