Prognostic value of a coronary computed tomography angiography-derived ischemia algorithm: comparison against hybrid coronary computed tomography angiography/positron emission tomography imaging
Abstract
Background: Artificial intelligence-guided quantitative computed tomography ischemia (AI-QCT(ischemia)) is a novel machine-learning method for predicting myocardial ischemia from coronary computed tomography angiography (CCTA). This observational cohort study aimed to compare the long-term prognostic value of AI-QCT(ischemia) with hybrid CCTA/positron emission tomography (PET) myocardial perfusion imaging in suspected coronary artery disease (CAD). Methods: Symptomatic patients with suspected CAD underwent CCTA with selective downstream PET to detect ischemic CAD. Blinded reanalysis of CCTA images was done using the AI-QCT(ischemia) algorithm, providing a binary result (normal versus abnormal). Results: In the full analysis set (n=2271), hybrid CCTA/PET imaging was successful in 94% of the patients and AI-QCT(ischemia) evaluation was feasible in 83%, resulting in a per-protocol set of 1772 patients (19% with ischemic CAD on hybrid CCTA/PET and 25% with abnormal AI-QCT(ischemia)). There was moderate-to-substantial agreement between the methods (Cohen's kappa=0.61). During a median follow-up of 7.0 years, 177 (10%) patients experienced the composite end point of all-cause death, myocardial infarction, or unstable angina. Ischemic CAD on hybrid CCTA/PET was predictive of the composite end point (hazard ratio [HR], 2.35 [95% CI, 1.62-3.40]; P<0.001), after adjustment for clinical variables and early (6-month) myocardial revascularization. Similarly, an abnormal (ischemic) AI-QCT(ischemia) result was independently predictive of adverse outcomes (adjusted HR, 1.98 [95% CI, 1.39-2.80]; P<0.001). The adjusted models, including either hybrid CCTA/PET or AI-QCT(ischemia), demonstrated similar discriminative ability (C-index 0.734 versus 0.729; P=0.53). Conclusions: The AI-QCT(ischemia) algorithm demonstrated long-term prognostic value comparable to hybrid CCTA/PET perfusion imaging in suspected CAD.
