Coronary CT angiography in non-ST-segment elevation myocardial infarction

Introduction In patients with non-ST-elevation myocardial infarction (NSTEMI) invasive coronary angiography (ICA) is performed to identify those in need of coronary revascularization. However, a considerable proportion of these patients do not have obstructive coronary artery disease (CAD). With improved image quality, reduced radiation exposure and a high negative predictive value, coronary CT angiography (CCTA) has become the diagnostic method of choice for stable patients with low to intermediate risk for CAD. The use of CCTA in acute coronary syndromes is less explored and current guidelines do not recommend CCTA in the diagnostic work-up of patients with NSTEMI. This population accounts for a large proportion of referrals to cath labs. If CCTA can safely identify patients with NSTEMI who do not need revascularization, unnecessary ICAs may be avoided. This will reduce procedural risk, limit interhospital transfers, shorten hospital stays and lower healthcare costs. Aim The aim of this study was to evaluate whether CCTA can safely identify patients with NSTEMI who do not need invasive evaluation. Methods We conducted a prospective, blinded, multicenter observational study including one university hospital and seven local hospitals. Patients with NSTEMI and a clinical indication for ICA were eligible for inclusion. The main exclusion criteria were indications for immediate ICA, GRACE score > 140, age > 75 years, previous coronary revascularization and more than two hypokinetic segments on echocardiography. CCTA was performed prior to ICA, analyzed at an independent core lab and evaluated regarding the need for ICA. The core lab was blinded to clinical data and ICA results. Revascularization, either performed or not performed, was defined as the gold standard. Results A total of 274 patients (mean age 62, 32% women) were included. Mean GRACE score was 92 and median troponin-T was 146 (IQR 366). Following ICA, 37% did not undergo revascularization. With revascularization as the gold standard, CCTA demonstrated a sensitivity of 89%, specificity of 90%, positive predictive value of 84% and negative predictive value of 83 %. Conclusions A substantial proportion of patients with NSTEMI do not need revascularization. Our findings suggest that CCTA may have a role in the evaluation of patients with low risk NSTEMI. Further studies are warranted to explore the potential of CCTA in this large patient group.