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Arnett et al 2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease

September 10, 2019 Circulation. 2019;140:e596–e646. DOI: 10.1161/CIR.0000000000000678 e622

CLINICAL STATEMENTS AND GUIDELINES evidence for ASCVD risk [inclusive, where appropriate, of risk-enhancing factors, such as strong family history of premature MI, inability to achieve lipid or BP or glucose targets, or significant elevation in coronary artery calcium scoreS4.6-21] and to also tailor decisions about prophylactic aspirin to patient and clinician preferences. Depending on risk factors present, a given patient and his/her clinician may decide that lowering the risk of MI (which has potentially serious long-term consequences not captured by clinical trials of 5 to 10 years’ duration) is worth a slight excess risk of serious bleeding. Recent trials show that absolute risk for ASCVD events typically exceeds that of bleeding and, although the gap of relative benefit to relative harm for aspirin has narrowed, the number needed to treat to prevent an ASCVD event remains lower than the number needed to harm to cause bleeding. Others may feel that the benefit of prophylactic aspirin is comparable to the risk and may instead choose to focus on optimal control of other modifiable ASCVD risk factors. Therefore, a Class IIb recommendation remains more suitable than a Class III recommendation for adults 40 to 70 years of age. Given the narrow overall balance between benefits and harms of prophylactic aspirin, there is limited justification to use aspirin at doses >100 mg daily for primary prevention. Indeed, meta-analyses suggest that the ASCVD risk benefit for low-dose aspirin is equivalent to that for high-dose aspirin, but the bleeding risk is higher with high-dose aspirin. Recent observational studies motivate future research on the personalization of prophylactic aspirin dose according to patient-specific factors (eg, weight),S4.6-22 though we note that, regarding weight specifically, there was no evidence lowdose aspirin was any more effective in low-weight individuals than in high-weight individuals in the more recently published ASCEND (A Study of Cardiovascular Events iN Diabetes) trial,S4.6-16 trial. Most importantly, recent clinical trials also teach us that low-dose prophylactic aspirin may be best justified among persons at high ASCVD risk who cannot achieve optimal control of other ASCVD risk factors.S4.6-23

2 Prophylactic aspirin in primary-prevention adults

>70 years of age is potentially harmful and, given the higher risk of bleeding in this age group, difficult to justify for routine use.S4.6-9 In addition, for adults <40 years of age, there is insufficient evidence to judge the risk–benefit ratio of routine aspirin for the primary prevention of ASCVD. However, one caveat is that, although routine use is not recommended in these settings, there is also insufficient evidence to comment on whether there may be select circumstances in which physicians might discuss prophylactic aspirin with adults <40 years of age or >70 years of age in the context of other known ASCVD risk factors (eg, strong family history of premature MI, inability to achieve lipid or BP or glucose targets, or significant elevation in coronary artery calcium score). As inferred from the first recommendation, there is also no justification for the routine administration of lowdose aspirin for the primary prevention of ASCVD among adults at low estimated ASCVD risk. For example, in the recent ARRIVE (A Randomized Trial of Induction Versus Expectant Management) trial, observed average 10-year ASCVD risk was <10%, and the overall benefits of prophylactic aspirin by intention-to-treat were negligible.S4.6-17

3 The accumulated trial and observational data to

date support avoiding prophylactic aspirin in the setting of known risk factors for increased bleeding outcomes.S4.6-10 A nonexhaustive list of conditions associated with increased bleeding risk includes: a history of previous gastrointestinal bleeding or peptic ulcer disease or bleeding at other sites, age >70 years, thrombocytopenia, coagulopathy, CKD, and concurrent use of other medications that increase bleeding risk, such as nonsteroidal anti-inflammatory drugs, steroids, direct oral anticoagulants, and warfarin.S4.6-10

5 COST AND VALUE CONSIDERATIONS

The growing need to consider value stems directly from the goal of achieving the best possible health outcomes with finite healthcare resources in the primary prevention of CVD.S5-1 Value in health care can be defined as the incremental health benefits of a therapy or procedure relative to its incremental net long-term costs. The consideration of cost and value in the guideline development process supports key goals, including: 1) enhancing overall value in the delivery of cardiovascular care and 2) involving healthcare professionals in the challenging care decisions that must be made to increase value in the US healthcare system.S5-2 The integration of value assessments into our national guidelines involves inherent methodological challenges, including: 1) variability in costs across different healthcare settings; 2) variability in costs and benefits across different patient subgroups; 3) variability over time; 4) variability in who bears the burden of the health outcome (ie, typically the individual patient) versus who bears the burden of the healthcare cost (eg, often spread beyond the individual to third-party payers, taxpayers); and 5) an inadequate literature base on which to render a sound, evidence-based assessment of certain specific therapies.S5-1,S5-2

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