You Got a Ticket to Ride

If You Have a Zero CAC Score

Arteries try to “heal” atherosclerotic plaques by calcifying them. Consequently, the presence of coronary artery calcium (CAC) indicates that there is at least some coronary atherosclerotic plaque. The amount of coronary calcium is quantified using the “Agatston” CAC score, named after Arthur Agatston, the Florida cardiologist who also developed the South Beach Diet. Different studies have examined the frequency of atherosclerotic disease outcomes in individuals with various CAC values, usually 100, 300 or 400 Agatston units. The key point is that the higher the score, the higher the probability that there is important coronary atherosclerosis and the higher the probability that there is an increased risk of atherosclerotic events.

Coronary calcium tells you there is some atherosclerosis but not how tight the lesions are. The score is most useful when it’s zero because an individual with a zero score has an incidence of an atherosclerotic event of only 0.3% a year over the next 5 years. (1)

I tell patients that they, like the Beatles 1965 hit, “have a ticket to ride” if they have a zero CAC score. There are exceptions. We reported two women with markedly elevated lipoprotein (a) levels Lp (a) who had tight coronary lesions but little (a CAC score of 1) or no coronary calcification (2). We would also treat someone who is young with terrible lipid levels and a CAC score of zero because they may be developing atherosclerosis, but have not calcified it yet.

So, don’t make decisions that a patient has very low risk on the CAC score alone; make sure his/her Lp (a)  is not elevated. But CAC scoring is in general a great way to further risk-stratify patients as to how aggressively their cardiac risk factors need to be treated. The CAC is performed by chest CT without contrast, but is often not covered by insurance.

I used to sing “you’ve got a ticket to ride” to patients with zero scores, but I was concerned that my singing might prove fatal, so I quit that. (Spoiler alert - that was an attempt at humor .)

1.   Sheppard JP, Lakshmanan S, Lichtenstein SJ, Budoff MJ, Roy SK. Ageand the power of zero CAC in cardiac risk assessment: overview of theliterature and a cautionary case. Br J Cardiol. 2022 Jul 19;29(3):23. PMID: 36873724

2.   Haxhi J, Pershwitz G, Thompson PD. Coronary artery disease withnormal lipids and low coronary artery calcium in two women withhigh lipoprotein(a). J Clin Lipidol. 2020 Mar-Apr;14(2):186-188.PMID: 31983675