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.