p.26 抽出テキスト

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

Circulation. 2019;140:e596–e646. DOI: 10.1161/CIR.0000000000000678 September 10, 2019 e621 CLINICAL STATEMENTS AND GUIDELINES

6 Secondhand smoke exposure is known to cause

CVDS4.5-6 and strokeS4.5-16 in nonsmokers, and it can lead to immediate adverse events.S4.5-30 There is no safe lower limit of exposure to secondhand smoke.S4.5-31 Even brief exposure to secondhand smoke can trigger an MI.S4.5-30,S4.5-32 Even though exposure to secondhand smoke has steadily decreased over time, certain subgroups remain exposed to secondhand smoke in homes, vehicles, public places, and workplaces. It is estimated that 41 000 preventable deaths per year occur in adult nonsmokers as a result of exposure to secondhand smoke.S4.5-33 The US Department of Housing and Urban Development prohibited the use of combustible tobacco products in all public housing living units, indoor common areas, and public housing agency administrative office buildings, extending to all outdoor areas up to 25 feet from public housing buildings.S4.5-34 Therefore, the present writing committee recommends that clinicians advise patients to take precautions against exposure to secondhand smoke and aerosol from all tobacco products, such as by instituting smoking restrictions (including ENDS) inside all homes and vehicles and within 25 feet from all entryways, windows, and building vents.

4.6 Aspirin Use

Recommendations for Aspirin Use Referenced studies that support recommendations are summarized in Online Data Supplements 17 and 18.

COR LOE Recommendations

IIb A 1.  Low-dose aspirin (75-100 mg orally daily) might be considered for the primary prevention of ASCVD among select adults 40 to 70 years of age who are at higher ASCVD risk but not at increased bleeding risk.S4.6-1–S4.6-8

III: Harm B-R 2.  Low-dose aspirin (75-100 mg orally daily) should not be administered on a routine basis for the primary prevention of ASCVD among adults >70 years of age.S4.6-9

III: Harm C-LD 3.  Low-dose aspirin (75-100 mg orally daily) should not be administered for the primary prevention of ASCVD among adults of any age who are at increased risk of bleeding.S4.6-10

Synopsis

For decades, aspirin has been widely administered for ASCVD prevention. By irreversibly inhibiting platelet function, aspirin reduces risk of atherothrombosis but also increases risk of bleeding, particularly in the gastrointestinal tract.S4.6-11 Aspirin is well established for secondary prevention of ASCVDS4.6-12 and is widely recommended for this indication.S4.6-13 However, in primary prevention, aspirin use is more controversial. Because persons without prior ASCVD are inherently less likely to have future ASCVD events than are those with a prior history, it is more challenging for clinicians and patients to balance benefits and harms of prophylactic aspirin for primary prevention. This uncertainty is reflected in international guidelines, where, for example, aspirin is not recommended in European guidelines for primary ASCVD preventionS4.6-13 but is recommended in prior US guidelines for selected primary prevention for adults who have elevated risk of ASCVD based on traditional risk factors.S4.6-14,S4.6-15 Adding to this controversy are more recently conducted primary-prevention trials that, in contrast to older trials,S4.6-12 have shown less overall benefit of prophylactic aspirin alongside coadministration of contemporary ASCVD preventive treatments, such as evidence-based hypertension and cholesterol therapies.S4.6-5–S4.6-9,S4.6-16,S4.6-17

Recommendation-Specific Supportive Text

1 To balance the benefits and risks, prior US guide-

lines have recommended prophylactic aspirin only in the setting of elevated ASCVD risk (eg, as calculated by risk estimators like the PCE or based on the presence of specific ASCVD risk factors).S4.6-14,S4.6-18 Meta-regression analyses of historical trials show that observed ASCVD risk tracks reasonably well with baseline-estimated ASCVD risk.S4.6-19 In contrast, observed bleeding risk on aspirin is less well correlated with baseline-estimated ASCVD risk.S4.6-19 (A nonexhaustive list of scenarios associated with increased risk of bleeding includes: a history of previous gastrointestinal bleeding or peptic ulcer disease or bleeding from 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.) In this context, post hoc study of older trials suggests that the benefit–risk ratio for prophylactic aspirin generally becomes more favorable at >10% estimated 10-year ASCVD risk.S4.6-15,S4.6-19 However, the relative benefits of aspirin, specifically in preventing nonfatal MI and perhaps stroke (with a trend to lower mortality) have been less evident in more recent trials.S4.6-9,S4.6-16,S4.6-17,S4.6-20 Similarly, in these recent trials, the estimated ASCVD risk has generally exceeded the actual risk observed during follow-up.S4.6-17 These recent data are the rationale for the lower COR for prophylactic aspirin in the present guideline (Class IIb) and the removal of a specific PCE risk threshold as an inclusion criterion for aspirin consideration. These changes reflect the need to instead consider the totality of available

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