New guideline recommends CAC scoring when there is uncertainty regarding benefit from statins
Friday, November 16, 2018
Posted by: Claire Johns
New guideline recommends coronary artery calcium scoring — a test that costs as little as $75 —
when there is uncertainty regarding benefit from statins
Vienna, VA (Nov. 14, 2018) — A key guideline released last week from the American Heart Association (AHA), the American College of Cardiology (ACC) and other groups recommends using a coronary artery calcium (CAC) score for certain at-risk patients to aid in the decision to use statin therapy.
A CAC score is a measurement of the amount of calcium, or hardening, in the walls of the arteries that supply the heart muscle, caused by atherosclerotic disease. It is measured by taking a noninvasive computed tomography (CT) scan of the heart. Numerous studies have indicated that this test, which costs between $75 and $200, is a reliable measure of risk for adverse heart events, such as heart attack and stroke.
The AHA/ACC guideline updates previous recommendations from 2013, and, taking into account this body of research, places increased emphasis on the value of CAC scores for certain groups of patients. These include intermediate-risk and some borderline-risk patients aged 45 to 70 years old with low-density lipoprotein, or LDL cholesterol levels of 70 to 189 mg/dL. A high proportion of LDL cholesterol is associated with a higher risk of heart disease.
A recent study published in the Journal of the American College of Cardiology shows that CAC scoring can identify, with a high degree of accuracy, patients who will or will not benefit from statin treatment. The study was based on over 13,500 patients followed for nearly 10 years.
“CAC testing’s true value is via the ‘power of zero,’ and lies in distinguishing who may or may not benefit from pharmacological preventive therapies,” explains Khurram Nasir, MD, FSCCT, of Yale University School of Medicine.
Dr. Nasir also notes “the guidelines also stipulate that apart from CAC testing, all other factors are ‘risk enhancers’ i.e., they upgrade risk but none of them have sufficient power to rule out disease, to meaningfully inform those who are at lower risk.”
The guideline aligns with a 2016 expert consensus statement from the Society of Cardiovascular Computed Tomography, “Clinical indications for coronary artery calcium scoring in asymptomatic patients.”
The new cholesterol guideline states: “If CAC is zero, treatment with statin therapy may be withheld or delayed, except in cigarette smokers, those with diabetes mellitus, and those with a strong family history of premature ASCVD. A CAC score of 1 to 99 favors statin therapy, especially in those ≥55 years of age. For any patient, if the CAC score is ≥100 Agatston units or ≥75th percentile, statin therapy is indicated unless otherwise deferred by the outcome of clinician-patient risk discussion.”
Valentin Fuster, MD, PHD, chief of cardiology of the Icahn School of Medicine at Mount Sinai in New York and editor of the Journal of the American College of Cardiology, interprets the new guideline for certain patient groups in this way: “The CAC score is important. If the calcium score is zero, forget about statins. If the score is more than 100, it’s better to take them. But the critical issue is the [doctor’s] discussion with the patient.”
Dr. Fuster’s full “7 Points to Remember” interpretation of the new guideline is available as a video that may be useful to both patients and physicians.
Providers should consider the new AHA/ACC cholesterol clinical practice guideline as well as the Society of Cardiovascular Computed Tomography expert consensus document, along with the overall patient risk proﬁle, in patient shared decision-making.