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 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, dif- ficult 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 rou- tine 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 physi- cians might discuss prophylactic aspirin with adults <40 years of age or >70 years of age in the con- text of other known ASCVD risk factors (eg, strong family history of premature MI, inability to achieve lipid or BP or glucose targets, or significant eleva- tion in coronary artery calcium score). As inferred from the first recommendation, there is also no justification for the routine administration of low- dose 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. 