p.24 抽出テキスト

Circulation. 2019;139:e1082–e1143. DOI: 10.1161/CIR.0000000000000625 June 18/25, 2019 e1105 CLINICAL STATEMENTS AND GUIDELINES

individuals whose ASCVD risk may indicate risk of genetic hypercholesterolemia and hence who may benefit from a moderate- to high-intensity statinS4.4.2-21 (Table 6). 5.	 In those with intermediate ASCVD risk, defined as an ASCVD risk of 7.5% to ≤20%, knowledge of risk-enhancing factors is useful in understanding patient characteristics that increase ASCVD risk both short and long-term (Table 6). As in the 2013 ACC/AHA guideline, an ASCVD score does not assign a statin; it begins the decision process, which includes consideration of risk-enhancing factors. For example, in an RCT,S4.4.2-9 a family history of premature ASCVD identified women ≥60 years of age with elevated high-sensitivity C-reactive protein but without ASCVD who benefitted from high-intensity statin therapy. Those with primary elevations of LDL-C ≥160 mg/dL (4.1 mmol/L) have elevated lifetime ASCVD risk and benefit from statin therapy.S4.4.2-21,S4.4.2-22,S4.4.2-25,

S4.4.2-29,S4.4.2-30 Increased ASCVD riskS4.4.2-2 is seen with metabolic syndrome;S4.4.2-20 inflammatory diseases, including psoriasisS4.4.2-31 and RA; and HIV when treated with protease inhibitors.S4.4.2-32 In women, a history of pregnancy complicated by preeclampsia or premature menopause (age <40 years) also enhances ASCVD risk (see Section 4.4.5.3.). If measured, ABI <0.9 has been shown to reclassify risk by the 2013 Risk Assessment Guidelines.S4.4.2-33 The presence of risk-enhancing factors may affect the threshold for statin initiation or intensification (see Sections 4.4.2, 4.4.4, and 4.5). Finally, in selected individuals, biomarkers, if measured, may identify individuals with increased risk of ASCVD events. Lp(a) levels, especially in those with a family history of premature ASCVD, can increase risk.S4.4.2-16 However, no available RCT evidence supports Lp(a) levels as a target of therapy. Moderate primary elevations of triglycerides, non–HDL-C (TC minus HDL-C), and, if measured, apolipoprotein B (apoB) can improve selection of those at increased ASCVD risk.S4.4.2-22 6.	 Evidence shows that a CAC score of zero can “down-risk” individuals who otherwise would qualify for a statin on the basis of their ASCVD 10-year risk. The ability to select those who would benefit greatly from statin therapy, as shown by RCTs in primary-prevention populationsS4.4.2-6,S4.4.2-8 and yet to withhold statin therapy in those least likely to benefit would improve specificity.S4.4.2-34 For example, a CAC score of zero in an analysis of pooled US population-based studies accurately discriminated between lower and higher CHD risk in older adults.S4.4.2-19,S4.4.2-27 The BioImage Study in older adultsS4.4.2-15 and MESAS4.4.2-17 showed improved detection of individuals not likely to benefit from statins when the CAC score was zero. Selected examples of candidates for CAC scoring who might benefit from knowing their CAC score is zero are listed in Table 8. Clinicians should not down-risk patients who are persistent cigarette smokers, have diabetes mellitus, or have a strong family history of ASCVD, as well as possibly those with chronic inflammatory conditions whose CAC of zero does not rule out risk from noncalcified plaque.S4.4.2-35

7.	 In adults at intermediate-risk (predicted 10-year risk of 7.5% to <20%), substantial data indicate how CAC measurement can be effective in meaningfully reclassifying risk in a large proportion of individuals.S4.4.2-15,S4.4.2-17,S4.4.2-36–S4.4.2-49 In such intermediate-risk adults, those with a CAC score ≥100 Agatston units or CAC ≥75th percentile appear to have ASCVD event rates suggesting that statin therapy would be beneficial.S4.4.2-17,S4.4.2-23 Those with a CAC of zero appear to have 10-year event rates in a lower range that suggests statin therapy may be of limited value for these patients, with few exceptions including patients with diabetes mellitus, persistent smoking, and family history or premature ASCVD. Cigarette smoking remains a strong risk factor even in the presence of CAC score of zero.S4.4.2-50,S4.4.2-51 In asymptomatic diabetes mellitus, a CAC score of zero is associated with a favorable 5-year prognosis; but after 5 years, the risk of mortality increases significantly for diabetic individuals even in the presence of a baseline CAC score of zero.S4.4.2-52 In patients with a family history of ASCVD, CAC score of zero may impart less short-term benefit from statin therapy, but considering a high lifetime risk, long-term

Table 8.  Selected Examples of Candidates for CAC Measurement Who Might Benefit From Knowing Their CAC Score Is Zero

CAC Measurement Candidates Who Might Benefit From Knowing Their CAC Score Is Zero Patients reluctant to initiate statin therapy who wish to understand their

risk and potential for benefit more precisely Patients concerned about need to reinstitute statin therapy after

discontinuation for statin-associated symptoms Older patients (men, 55-80 y of age; women, 60-80 y of age) with low

burden of risk factorsS4.4.2-25 who question whether they would benefit from statin therapy Middle-aged adults (40-55 y of age) with PCE-calculated 10-year risk

of ASCVD 5% to <7.5% with factors that increase their ASCVD risk, although they are in a borderline risk group Caveats: If patient is intermediate risk and if a risk decision is uncertain and a CAC score is performed, it is reasonable to withhold statin therapy unless higher risk conditions such as cigarette smoking, family history of premature ASCVD, or diabetes mellitus are present, and to reassess CAC score in 5-10 years. Moreover, if CAC is recommended, it should be performed in facilities that have current technology that delivers the lowest radiation possible. ASCVD indicates atherosclerotic cardiovascular disease; CAC, coronary artery calcium; LDL-C, low-density lipoprotein cholesterol; and PCE, pooled cohort equations.

Downloaded from http://ahajournals.org by on October 7, 2026