Undetectable High-sensitivity Troponin T as a Gatekeeper for Coronary CT Angiography in Patients Suspected of Acute Coronary Syndrome.

OBJECTIVES The aim of this study was to characterize the safety and efficiency of a strategy employing the limit of detection (LoD) of high-sensitivity troponin T (hs-TnT) as a gatekeeper for coronary computed tomography angiography (CCTA) in suspected acute coronary syndrome (ACS) patients in the emergency department (ED). METHODS We included suspected ACS patients who underwent CCTA and were evaluated with hs-TnT. Patients were categorized as below the LoD and at or above the LoD. The primary outcome was 30-day major adverse cardiac events (MACEs), defined as all-cause mortality, ACS, or coronary revascularization. RESULTS The study population consisted of 177 patients (mean age 55 ± 10 years, 50.3% women), and 16 (9.0%) patients reached the primary outcome. None of the patients died, while 13 had an adjudicated diagnosis of ACS, and 3 underwent elective coronary revascularization. There were 77 patients (44%) with an hs-TnT value below the LoD (MACEs; n = 1 [1.3%]) and 100 (56%) with at or above the LoD levels (MACEs; n = 15 [15%]). None of 67 patients with an hs-TnT value below the LoD and <50% stenosis on CCTA experienced MACEs. Out of the 10 patients with an hs-TnT value below the LoD and ≥50% stenosis on CCTA, 1 patient underwent elective percutaneous coronary revascularization. In patients with an hs-TnT value at or above the LoD, 74 patients had <50% stenosis on CCTA, and 2 patients (3%) were diagnosed with myocardial infarction without obstructive coronary artery disease confirmed on invasive angiography. Thirteen (50%) patients with an hs-TnT value at or above the LoD and ≥50% stenosis on CCTA experienced MACEs (11 ACS and 2 elective percutaneous coronary revascularizations). CONCLUSION Our findings support that implementing the LoD of hs-TnT as a gatekeeper may reduce the need for CCTA in suspected ACS patients in the ED.