Low Risk Non St Elevation Acute Coronary Syndrome with a Normal High Sensitivity Troponin Level – Do We Need Further Evaluation?

Introduction: With recent introduction to high-sensitivity troponin (hsTn), the incremental benefit of stress Myocardial Perfusion Imaging (MPI) in the evaluation of patients who present to the emergency department (ED) with Acute Coronary Syndrome (ACS) is not clear.

Objective: To assess the added value of MPI in low risk ACS patients with normal range HsTn.

Methods: Retrospective analysis of all patients hospitalized at our center from the introduction of HsTn I on february 2016 till november 2017, with low risk ACS who underwent MPI stress testing and in whom hsTnI was in normal range.

Results: During the study period, 161 patients were admitted with a diagnosis of unstable angina (i.e. ACS with normal range HsTn I) and underwent stress MPI during index admission. The study population included 52/161 patients (31.7%) with low risk ACS, who had no indication for initial invasive strategy. No patients had positive MPI. One patient underwent coronary angiography due to suggestive history, however he did not have a significant coronary artery disease and had no indication for PCI.

Conclusions: In patients with low risk ACS unstable angina normal range HsTnI without additional high risk features, stress MPI adds little additional value to the correct diagnosis and management. Prospective studies are warranted to confirm whether resting hsTnI could serve as a powerful triage tool in chest pain patients in the ED before diagnostic testing, and improve the effectiveness of patient management.