Use of Coronary Artery Calcium Scoring for Risk Reclassification

The following question refers to Section 3.3 of the 2021 ESC CV Prevention Guidelines. The question is asked by CardioNerds Academy Intern student Dr. Adriana Mares, answered first by Brigham & Women’s medicine intern & Director of CardioNerds Internship Dr. Gurleen Kaur, and then by expert faculty Dr. Allison Bailey.Dr. Bailey is an advanced heart failure and transplant cardiologist at Centennial Heart. She is the editor-in-chief of the American College of Cardiology's Extended Learning (ACCEL) editorial board and was a member of the writing group for the 2018 American Lipid Guidelines. The CardioNerds Decipher The Guidelines Series for the 2021 ESC CV Prevention Guidelines represents a collaboration with the ACC Prevention of CVD Section, the National Lipid Association, and Preventive Cardiovascular Nurses Association. Question #2 Mr. Early M. Eye is a 55-year-old man with a history of GERD who is seeing you in clinic as he is concerned about his family history of early myocardial infarction and would like to discuss if he should be taking a statin for cardiovascular prevention. He has never smoked tobacco. His 10-year CVD risk is estimated to be 8%. Which imaging modality is recommended by the ESC guidelines to reclassify his CVD risk?A. Coronary Artery Calcium (CAC) scoringB. Echocardiography C. Ankle brachial index D. Contrast enhanced computed tomography coronary angiography (CCTA)E. None of the above Answer #2 The correct answer is A.Coronary artery calcium (CAC) scoring can reclassify CVD risk upwards and downwards and should specifically be considered in patients with calculated risk scores that are around decision thresholds. CAC scores which are high-than-expected for age and sex increase estimated future CVD risk. Notably, CAC scoring may also be used to “de-risk” if CAC is absent or lower-than-expected. The 2021 ESC Prevention Guidelines give a Class IIb (LOE B) recommendation to consider CAC scoring to improve risk classification around treatment decision thresholds. However, one limitation of CAC is that it does not provide direct information on total plaque burden or stenosis severity. In addition, there is also a Class IIb (LOE B) recommendation to use plaque detection by carotid ultrasound as an alternative when CAC scoring is unavailable or not feasible. Plaque assessed through carotid ultrasound is defined as presence of wall thickening that is >50% greater than the surrounding vessel wall or a focal region with intima-media thickness measurement >1.5mm that protrudes into the lumen.Similar to the ESC Prevention Guidelines, the 2019 ACC/AHA guidelines on primary prevention of CVD also have a Class IIa recommendation for using CAC score, and explicitly mention its use for adults at intermediate risk (>7.5% to <20% 10-year ASCVD risk) with cut-offs including >100 Agatson units to reclassify risk upwards and CAC of 0 to reclassify risk downwards. However, the guidelines also mention that clinicians should not down-classify risk in patients who have CAC of 0 if they are current smokers, have diabetes, have a family history of ASCVD, or have chronic inflammatory conditions. Furthermore, the 2018 ACC/AHA Cholesterol guidelines have a Class IIa recommendation that if CAC is 0, it is reasonable to withhold statin therapy and reassess risk in 5 to 10 years, as long as higher risk conditions that we just discussed are absent. If CAC is 1-99, it is reasonable to initiate statin therapy for patients ≥ 55 years of age.Choice B is incorrect. Echocardiography is not recommended to improve CV risk prediction due to lack of convincing evidence that it improves CVD risk reclassification.Choice C is incorrect. While the 2013 ESC guidelines mentioned that ABI may be considered as a risk modifier in CVD risk estimation, the newer 2021 guidelines state that ankle brachial index has limited potential in terms of reclassification risk, though an individual patient data meta-analysis showed th...