prevention

Coronary Calcium Scan: The Role of Calcium Scoring in Preventing a First Myocardial Infarction

Author:
Rolando L. deGoma, MD
Capital Cardiology Associates

Citation:
deGoma RL. Coronary calcium scan: the role of calcium scoring in preventing a first myocardial infarction [published online September 25, 2019]. Cardiology Consultant.

 

About 720,000 new coronary events and 335,000 recurrent coronary events occur each year, according to data from the American Heart Association.1 How many of the 720,000 first coronary events can be prevented? Most of them. First, we need to identify high-risk patients, and then quickly treat the patients to prevent plaque rupture, stop plaque progression, and induce plaque regression.

IDENTIFYING HIGH-RISK PATIENTS

The Framingham Risk Score2 is the most common method for calculating patients’ 10-year risk for coronary heart disease (CHD). It is very inaccurate, though, resulting in undertreatment, overtreatment, and even nontreatment if the patient or care provider is nonadherent. Patients with a Framingham Risk Score of more than 20% are at high risk for cardiovascular disease (CVD) events, but the approach does not answer two fundamental questions: (1) does the patient have or not have plaque, and (2) how much plaque is present?

This approach is like reading the patient’s palm to determine the likelihood of having a myocardial infarction, stroke, or sudden vascular death based on one’s age, sex, blood pressure, high-density lipoprotein cholesterol (HDL-C), smoking status, and other risk factors. In the last 10 years, coronary calcium scoring has become more accessible and affordable, at $39 to $400 for the test, and most patients are willing to pay out-of-pocket if they understand what the test is for.

Calcium scoring is like mammography for the heart but only needs to be performed once for most patients. It is not an annual test and requires no special preparation, no fasting, no intravenous line, no injection, no exercise, and very low radiation exposure. Moreover, the test is usually completed in less than 30 seconds. The results show the presence or absence of calcified plaques—an accurate reflection of total plaque burden. The score can range from 0 to more than 4000. Someone with a score between 100 and 300 has moderate plaque deposits and a high risk for myocardial infarction in the next 3 to 5 years.3 The need for and the intensity of medical therapy are determined accordingly.

Some patients may ask about undergoing a nuclear stress test instead. Hospital charges for a nuclear stress test are around $30,000! About 68% of plaques that rupture only obstruct the artery by 50% or less and therefore do not cause an abnormal stress test. Stress testing plays no role in the risk assessment of asymptomatic patients. Normal results from a nuclear stress test do not mean that the patient is not at high risk or that the patient is at low risk. A patient can have a calcium score of more than 2000 and still have normal stress test results.

PREVENTING CVD EVENTS

My journey to myocardial infarction (and stroke) prevention started in 2001 when I realized that the future of CVD management will not require implanting more stents and performing more heart bypass procedures. A nationwide physician survey4 had revealed that only 18% of patients with CHD were successful in achieving a low-density lipoprotein cholesterol (LDL-C) level of less than 100 mg/dL; 82% were either not being treated with a statin or were not treated adequately.4

I decided to find a way to incorporate aggressive prevention as part of every patient visit. This led to my creation and development of a numerically goal-oriented clinical management system that includes CVD risk assessment for every patient and setting treatment goals based on the magnitude of risk. The higher the risk, the lower the LDL-C treatment goal. I called this approach the PaKS-ACCEPT system.5

We published our first analysis of LDL-C treatment performance data6 in 2006 and the second analysis5 in 2017. In 2006, 85% of high-risk patients (CHD and CHD risk-equivalent patients) were successfully treated to an LDL-C level of less than 100 mg/dL using our PaKS-ACCEPT system, and 32% had an LDL-C level below 70 mg/dL.6

In 2017, 89% of patients had reached LDL-C levels of less than 100 mg/dL, and 52% were below 70 mg/dL.5 CVD events declined progressively every year to the point that they had become uncommon. The duration of treatment is directly proportional to the magnitude of event reduction. Therefore, if we are able to identify the patients who may experience a first myocardial infarction before it happens, we can accurately prevent these debilitating events.

PRACTICAL IMPLICATIONS

There are many practical implications of knowing the coronary calcium score for the primary prevention of CHD and CVD events. For one, patients are more likely to accept and take appropriate medical therapy. For example, a 50-year-old man and a 60-year-old woman had calcium scores of 850 and 450, respectively. They were both started on statin therapy, and their on-treatment LDL-C levels were both less than 70 mg/dL. They would not have been prescribed a statin if they did not have their calcium score.

Another of my patients needed to be on statin therapy but had refused for years. Once he found out that his calcium score was 500, he started taking a statin.

Conversely, another of my patients had been on several different statins but continued to experience intermittent muscle aches. We conducted a calcium score scan and found that her calcium score was 0. The statins were discontinued, and her myalgia resolved after several weeks.

Another of my patients was taking low-dose statin but was not achieving her LDL-C goal. She refused to take a higher-dose statin in combination with ezetimibe. However, after finding her calcium score was 1200, the patient agreed to take statin-ezetimibe combination therapy. Her on-treatment LDL-C level dropped to 45 mg/dL.

ENDING THE WAR ON HEART DISEASE

For decades, the American Heart Association and the American College of Cardiology have been actively waging a war to end heart disease. In 2016, the American College of Cardiology’s president, Kim Allan Williams, MD, said, “We must turn off the faucet instead of just mopping the floor.”7 He meant that we, as cardiologists, need to prevent cardiac events before they start, effectively ending the war on heart disease. Coronary calcium scoring provides the new tool that we need to continue our fight and stop myocardial infarctions before they happen.

Rolando L. deGoma, MD, FACC, FNLA, is a cardiologist at Capital Cardiology Associates in Trenton, New Jersey.

References:

  1. Benjamin EJ, Muntner P, Alonso A, et al; American Heart Association Council on Epidemiology and Prevention Statistics Committee and Stroke Statistics Committee. Heart disease and stroke statistics—2019 update: a report from the American Heart Association. Circulation. 2019;139(10):e56-e528. https://doi.org/10.1161/CIR.0000000000000659.
  2. Coronary heart disease (10-year risk). Framingham Heart Study. https://www.framinghamheartstudy.org/fhs-risk-functions/coronary-heart-disease-10-year-risk. Published 1998. Updated 2008. Accessed September 16, 2019.
  3. Heart scan (coronary calcium scan). Mayo Clinic. Accessed September 17, 2019. https://www.mayoclinic.org/tests-procedures/heart-scan/about/pac-20384686.
  4. Pearson TA, Laurora I, Chu H, Kafonek S. The Lipid Treatment Assessment Project (L-TAP): a multicenter survey to evaluate the percentages of dyslipidemic patients receiving lipid-lowering therapy and achieving low-density lipoprotein cholesterol goals. Arch Intern Med. 2000;160(4):459-467. https://doi.org/10.1001/archinte.160.4.459.
  5. deGoma RL, deGoma EM. A practical office-based cholesterol management system. J Clin Lipidol. 2017;11(3):806-807. https://doi.org/10.1016/j.jacl.2017.04.058.
  6. deGoma RL, deGoma EM. A practical office-based cholesterol management system. CholesterolClinic.com. http://degomamd.com/more-about-rolando-l-degoma/request-for-consultation/file-drawer/smallversionsgimposter.pdf. 2006. Accessed September 16, 2019.
  7. ACC.16 kicks off with focus on population health, prevention [published online April 4, 2016]. ACC Scientific Session Newspaper. https://www.acc.org/latest-in-cardiology/articles/2016/04/03/12/09/acc16-kicks-off-with-focus-on-population-health-prevention.