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

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

doi:10.3389/fcvm.2024.1467916

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

Front Cardiovasc Med. 2024 Sep 23:11:1467916. doi: 10.3389/fcvm.2024.1467916. eCollection 2024.

Authors

Simon M Frey^{1

2}, Gabrielle Huré², Jan-Philipp Leibfarth², Kathrin Thommen¹, Melissa Amrein², Klara Rumora², Ibrahim Schäfer², Federico Caobelli^{1

3}, Damian Wild⁴, Philip Haaf^{1

2}, Christian E Mueller^{1

2}, Michael J Zellweger^{1

2}

Affiliations

¹ Department of Cardiology, University Hospital Basel, University of Basel, Basel, Switzerland.
² Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, University of Basel, Basel, Switzerland.
³ Department of Nuclear Medicine, University Hospital Bern, University of Bern, Bern, Switzerland.
⁴ Division of Nuclear Medicine, University Hospital Basel, University of Basel, Basel, Switzerland.

Abstract

Background: Despite clinical suspicion, most non-invasive ischemia tests for coronary artery disease (CAD) reveal unremarkable results. Patients with a coronary artery calcium score (CACS) of zero rarely have an abnormal positron emission tomography (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 PET are lacking. The aim of this study 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 = 1,792) referred for ⁸²Rb PET were included and analyzed for abnormal PET (SSS ≥4) and relevant ischemia (>10% myocardium). Test characteristics were calculated.

Results: The 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, the sensitivity/negative predictive value (NPV) of a <25th percentile CACS to rule out abnormal PET and relevant ischemia were 93.0%/95.7% and 98.2%/99.5%, respectively. The sensitivity/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 old, 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% to 32%-34% overall of patients who could be deferred from further testing.

Keywords: coronary artery calcium score (CACS); coronary artery disease (CAD); gatekeeper; ischemia; patient stratification; percentile; positron emission tomography (PET).

Grants and funding

The authors declare financial support was received for the research, authorship, and/or publication of this article. SF received funding from the University Basel Research Fund (3MS1089). Laboratory tests were funded by a grant of the Basel Cardiology Foundation, Switzerland. Both foundations were not involved in study design, data interpretation or drafting of the manuscript and had no access to the data.