Age and the power of zero CAC in cardiac risk assessment: overview of the literature and a cautionary case

John P Sheppard; Suvasini Lakshmanan; Seth J Lichtenstein; Matthew J Budoff; Sion K Roy

doi:10.5837/bjc.2022.023

Age and the power of zero CAC in cardiac risk assessment: overview of the literature and a cautionary case

Br J Cardiol. 2022 Jul 19;29(3):23. doi: 10.5837/bjc.2022.023. eCollection 2022.

Authors

John P Sheppard¹, Suvasini Lakshmanan², Seth J Lichtenstein³, Matthew J Budoff⁴, Sion K Roy⁵

Affiliations

¹ Resident Physician Department of Internal Medicine, Yale New Haven Hospital, 20 York Street, New Haven, Connecticut, 06510, USA.
² Physician Fellow Division of Cardiovascular Medicine, University of Iowa Hospitals & Clinics, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA.
³ Physician Fellow Harbor-UCLA Medical Center, 1000 West Carson Street, Torrance, California, 90502, USA.
⁴ Professor of Medicine, David Geffen School of Medicine at UCLA, Investigator, Lundquist Institute, and Program Director and Director of Cardiac CT Harbor-UCLA Medical Center, 1000 West Carson Street, Torrance, California, 90502, USA.
⁵ Associate Program Director and Director of Inpatient Cardiac CT Harbor-UCLA Medical Center, 1000 West Carson Street, Torrance, California, 90502, USA.

Abstract

The coronary artery calcium (CAC) score is a marker of advanced coronary atherosclerosis. Numerous prospective cohorts have validated CAC as an independent marker that improves prognostication in atherosclerotic cardiovascular disease (ASCVD) beyond traditional risk factors. Accordingly, CAC is now incorporated into international cardiovascular guidelines as a tool to inform medical decision-making. Particular interest concerns the significance of zero CAC score (CAC=0). While many studies report CAC=0 to virtually exclude obstructive coronary artery disease (CAD), non-negligible rates of obstructive CAD despite CAC=0 are reported in certain populations. Overall, the current literature supports the power of zero CAC as a strong downward risk classifier in older patients, whose CAD burden predominantly involves calcified plaque. However, with their higher burden of non-calcified plaque, CAC=0 does not reliably exclude obstructive CAD in patients under 40 years. Illustrating this point, we present a cautionary case of a 31-year-old patient found to have severe two-vessel CAD despite CAC=0. We highlight the value of coronary computed tomography angiography (CCTA) as the gold-standard non-invasive imaging modality when the diagnosis of obstructive CAD is in question.

Keywords: calcium score; coronary artery calcium; coronary computed tomography angiography (CCTA); heart disease risk factors.

Publication types

Review

Grants and funding

This work was supported by funding from the National Heart, Lung, and Blood Institute (NHLBI) of the United States National Institutes of Health (NIH) under award number NIHR01HL146666.