AUTHOR=Frey Simon M. , Huré Gabrielle , Leibfarth Jan-Philipp , Thommen Kathrin , Amrein Melissa , Rumora Klara , Schäfer Ibrahim , Caobelli Federico , Wild Damian , Haaf Philip , Mueller Christian E. , Zellweger Michael J. 

TITLE=Diagnostic utility of coronary artery calcium score percentiles and categories to exclude abnormal scans and relevant ischemia in rubidium positron emission tomography

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 11 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2024.1467916

DOI=10.3389/fcvm.2024.1467916

ISSN=2297-055X

ABSTRACT=Background
Despite clinical suspicion, most non-invasive ischemia tests for coronary artery disease reveal unremarkable results. Patients with coronary artery calcium score (CACS) of zero rarely have an abnormal PET and could be deferred from further testing. However, most patients have some extent of coronary calcification. 
Objectives
CACS percentiles could be useful to exclude abnormal perfusion in patients with CACS >0, but data from patients with 82Rb Positron Emission Tomography (PET) are lacking. Aim was to assess the diagnostic utility of CACS percentiles in comparison to zero calcium and absolute CACS classes. 
Methods
Consecutive patients with suspected CAD (n=1792) referred for 82Rb PET were included and analysed for abnormal PET (SSS ≥4) and relevant ischemia (>10% myocardium). Test characteristics were calculated.
Results
Mean age was 65±11 years, 43% were female and typical angina was reported in 21%. Abnormal PET/relevant ischemia (>10%) were observed in 19.8%/9.3%. Overall, sensitivity/negative predictive value (NPV) of CACS <25th percentile to rule out abnormal PET and relevant ischemia were 93.0%/95.7% and 98.2%/99.5%, respectively. Sensitivity/negative predictive value (NPV) of CACS 1-9 to rule out abnormal PET and relevant ischemia were 96.0%/91.8% and 97.6%/97.6%, respectively. Except for patients <50 years, sensitivity for abnormal PET was >90.9% in all age groups. 
Conclusion
In patients >50 years, the <25th percentile and CACS 1-9 had good test characteristics to rule out abnormal PET and relevant ischemia (>10%). They could be used to extend the scope of application of CACS 0 by 8-10% of deferred patients from further testing to overall 32-34%.