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June 18/25, 2019 Circulation. 2019;139:e1082–e1143. DOI: 10.1161/CIR.0000000000000625 e1106

CLINICAL STATEMENTS AND GUIDELINES benefit cannot be discounted.S4.4.2-53 The same holds for CAC score of zero and a high 10 year risk (eg, ≥20%).S4.4.2-34 For those with CAC scores of 1 to 99 Agatston units, 10-year ASCVD event rates are 3.8%, 6.5%, and 8.3% for age groups 45 to 54, 55 to 64, and 65 to 74 years,S4.4.2-23 suggesting that CAC scores in this range favor statin initiation only in adults >55 years of age and indicating that risk reclassification is modest for individuals with CAC scores of 1 to 99. Therefore, for patients with CAC scores of 1 to 99, it is reasonable to repeat the risk discussion. If these patients remain untreated, repeat CAC measurement in 5 to 10 years may have some value in reassessing for CAC progression, but data are limited.S4.4.2-12,S4.4.2-13 A systematic review and meta-analysis suggests that knowledge that a patient’s CAC score is greater than zero is beneficial.S4.4.2-38 Selected examples of candidates for CAC scoring who might benefit from knowing that their CAC score is zero are listed in Table 8. There is an increased likelihood that lifestyle therapies and drug therapy will be started or continued with significant, albeit modest, changes in risk factor levels and predicted risk levels. 8.	 Clinicians may need to address reducing ASCVD risk in higher-risk primary-prevention patients who either do not wish to take a statin or cannot tolerate the recommended intensity of statin therapy. In such patients, it may be reasonable to use LDL-C–lowering drugs that have been proven safe and effective in RCTs, either as monotherapy or combined with a statin.S4.4.2-9 One alternative is a cholesterol absorption inhibitor. An RCT in adults ≥40 years of age with advanced CKD and without known CHD at baseline found that the addition of ezetimibe to a moderate-intensity statin lowered LDL-C 43 mg/dL (1.1 mmol/L) at 1 year.S4.4.2-54 After a median 4.9 years, ezetimibe and simvastatin 40 mg per day resulted in a 17% proportional reduction in major atherosclerotic events compared with placebo.S4.4.2-2 Another alternative is a nonsystemic bile acid sequestrant. Bile acid sequestrants used as monotherapy reduced CHD endpoints in a large primary-prevention trial.S4.4.2-55 Bile acid sequestrants can bind other drugs, so other medications must be avoided for 1 hour before and at least 3 to 4 hours after administration. Adding psyllium can minimize constipation and can reduce the bile acid sequestrant dose.S4.4.2-56 These therapies should be considered in the context of a risk discussion that reviews potential for benefit along with tolerability and safety issues. 9.	 Benefit from statin therapy is seen in lower-risk individuals.S4.4.2-24 Consideration of enhancing factors in selected younger individuals in this lower risk range, will improve the ability to detect younger patients who develop MI before age 50 years.S4.4.2-58,S4.4.2-59 Nonetheless, the challenge among those in a lower ASCVD risk category is to include those who would benefit yet avoid casting too wide a net, to minimize treating those who would derive little benefit from statin assignment. This risk group benefits greatly from a clinician–patient risk discussion. To arrive at a shared risk decision, clinicians should assess the patient’s priorities for health care, perceived ASCVD risk, and prior risk-reduction experiences and should use best practices to communicate numerical risk.S4.4.2-27 The presence of risk-enhancing factors provides useful information about short term ASCVD risk favoring initiation of statin therapy (Table 6).S4.4.2-58 Although a CAC score can be useful in selected individuals, it will be positive less often in this lower-risk group than in those with higher levels of ASCVD risk and is not recommended routinely.S4.4.2-17

4.4.3 Monitoring in Response to LDL-C–Lowering Therapy

Recommendation for Monitoring Referenced studies that support the recommendation are summarized in Online Data Supplement 17.

COR LOE Recommendation

I A 1.  Adherence to changes in lifestyle and effects of LDL-C–lowering medication should be assessed by measurement of fasting lipids and appropriate safety indicators 4 to 12 weeks after statin initiation or dose adjustment and every 3 to 12 months thereafter based on need to assess adherence or safety.S4.4.3-1–S4.4.3-3

Recommendation-Specific Supportive Text

1.	Goals for LDL-C lowering in response to lifestyle therapies or a prescribed intensity of statin therapy are defined by percentage responses. Clinical efficacy is monitored by measurement of percentage reductions in LDL-C relative to baseline levels. Baseline LDL-C can be estimated by pretreatment measurements, chart reviews, or measurement after a short interruption of drug therapy. Some clinicians are reluctant to interrupt therapy, although risk is low. Unless a baseline level is established, it will be difficult to evaluate response to therapy. Good adherence to various LDL-lowering diets will reduce LDL-C levels by 10% to >15%.S4.4.3-3 Moderate-intensity statins can be expected to reduce LDL-C levels by another 30% to 49%, and high-intensity statins by ≥50%

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