Coronary Computed Tomographic Angiography (CCTA) in non-ST elevation acute coronary syndromes
Authors: Chapman I , Furmento J F , Viruel M V , Kuschnir P , Ricapito M P , Sciancalepore A , Capobianco M , Giacomozzi F , Lambardi M F , Conde D , Costabel J P 
Published: October 2024

Abstract

Background
In patients presenting with an acute coronary syndrome (ACS), a diverse range of coronary artery disease is observed from structurally normal vessels to non-obstructive atherosclerosis and severe/obstructive coronary artery disease (CAD). In current clinical practice guidelines, the main diagnostic route for optimal management of patients with non-ST segment elevation acute coronary syndrome is invasive coronary angiography. However, in 30-40% of cases, no significant coronary lesions are evident. The purpose of this study is to describe the role of coronary computed tomographic angiography (CCTA) in non-ST elevation acute coronary syndromes in low and intermediate risk patients.

Methods
We describe the results of 504 patients evaluated with a protocol that includes the use of CCTA in patients with ACS. Patients over 18 years of age with a diagnosis of ACS without ST elevation who did not meet high-risk criteria (hemodynamic instability, dynamic changes in the ST segment or T wave, ventricular arrhythmia, GRACE score &gt;140, refractory angina, heart failure or cardiorespiratory arrest) were included. They underwent CCTA as the initial coronary evaluation. Data collection was carried out between May 11, 2022 and February 20, 2024.

Results
504 patients were included, with a mean age of 58 years, of which 44% were women and 56% men. Among the admission diagnoses, 26% were NSTEMI and 74% were unstable angina according to the 4th universal definition of acute myocardial infarction (AMI). The median high-sensitivity cardiac troponin T value was 7 nanograms per liter (interquartile range, 7 to 15) for the first troponin measurement.
CCTA was performed in 93% of the patients. It was observed that 28% did not have any coronary lesions or plaques. 36% had non-obstructive coronary artery disease (plaques &lt;50%). The rest had significant lesions in at least one vessel (27%), predominantly in the left anterior descending artery, or were nondiagnostic (9%). 31% had myocardial bridges, while in 13% of the patients a high-risk plaque was found. 38% of the patients included underwent invasive coronary angiography and 23% required revascularisation.

Conclusion
This study shows that the prevalence of ACS with coronary arteries without significant lesions by CCTA was 28%, which suggests CCTA could have a predominant role in the diagnostic algorithm of acute coronary syndromes without high-risk criteria, implying a decrease in the need of invasive studies in these patients. Only 38% required invasive coronary angiography, while revascularisation was performed in 23% of the patients. Furthermore, CCTA allowed a better detection of non-obstructive coronary artery disease (NOCAD) in 36% of the patients, and a more complete characterization of the atherosclerotic plaque, which could prompt to an initiation of preventive therapies or the optimization of medical treatment in these patients.Table 1CCTA findings