Coronary Artery Calcium Scoring and Primary Care

My use of CT-coronary artery calcium (CAC) scoring had become a bit muddled. If patients asked if they should have the test, I was not sure how to answer. An short article hot of the press brought that blurry image into sharp focus.

The article from the Cleveland Clinic Journal of Medicine, goes back in time to the earliest iterations of coronary calcium scoring (1996-2002). The sensitivity of the test was a whopping 95%, but specificity was merely 44%. Since a score of 0 was consistent with the absence of coronary disease, the test was helpful in that era excluding coronary disease and making it less likely in individuals who were at intermediate risk.

Fast forwarding to 2013, the value of the traditional 10-year risk prediction calculation was found wanting. Poor CV outcomes, including sudden death, occurred in people who were estimated to be at low or only intermediate risk by 10-year risk calculations. The numbers were even worse for younger individuals (women age ≤55 years; men age ≤65 years). In light of the downsides of risk calculation by the numbers, the American College of Cardiology/American Heart Association Guidelines (ACC/AHA 2016) brought about change. CT coronary calcium scores were suggested in those who had a 10-year calculated risk of 5% to 20% and in selected patients with a family history of premature coronary disease and a 10-year risk of an event <5%.

The paper then offers a specific prescription about utilizing the CT for coronary calcium scoring. People who are at intermediate risk based on the ACC/AHA risk calculation and who are either reluctant to start statin therapy or want a more visible or personally tangible representation of coronary disease get the test.

The authors then present 3 patients and implement their decision making process regarding CT calcium scoring.

The first individual is an asymptomatic 55-year-old man with a 10-year risk of atherosclerotic disease of 7% (intermediate risk). The patient does not want to initiate lifestyle modification or statin therapy. Yes, the test is indicated. It can change the approach completely.

The second patient is also 55-years-of-age, but has diabetes and smokes cigarettes. He has experienced 3 months of exertional chest pain. This patient should already be on statin therapy and needs a stress test, not coronary calcium scoring!

The last patient is 30-years-of-age with atypical chest pain. EKG and enzymes are normal. Since the history is atypical for coronary disease, and since at her younger age, calcification is unusual (median age is 5th decade), the test is not indicated.

The original reference is well worth the read. It will change my approach to coronary calcium scoring with solid evidence.

Source: Parikh P, Shah N, Haitham A, et al. Coronary artery calcium scoring: Its practicality and clinical utility in primary care. Clev Cl J Med. 2018; 85:707-716.