SUMMARY:

The ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease (2019) provides guidance regarding low-dose aspirin use. Low-dose aspirin (70 to 100 mg orally daily) still plays a role in prevention of ASCVD. However, the new recommendations advise against routine administration of aspirin to those >70 years of age. 

40 to 70 years of age

• Low-dose aspirin “might be considered” for primary ASCVD if individual is
  • At higher ASCVD risk and
  • Not at increased bleeding risk
• Class (strength) of recommendation
  • IIb: Weak (Benefit ≥ Risk)
• Level (Quality) of Evidence
  • A: High (High quality RCT based)
• Historically, studies demonstrated benefit at >10% estimated 10-year ASCVD risk but more recent studies are less conclusive and therefore
  • Specific risk cut-off not included in current guideline
  • Consider overall risk, including risk-enhancing factors
  • Base management on patient and clinician preferences
  • Some may opt to focus on modifiable risk factors
  • The guideline states

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.

>70 years of age

• Low-dose aspirin “should not be administered on a routine basis” for primary ASCVD prevention
  • Risk of bleeding with potential harm greater than benefit
• Class (strength) of recommendation
  • III: Harm (Risk > Benefit)
• Level (Quality) of Evidence
  • B-R: (Randomized, Moderate quality)
• There may be clinical scenarios where low-dose aspirin ‘might’ be discussed, such as
  • Strong family history of premature MI
  • Inability to achieve lipid, BP or glucose targets
  • High coronary artery calcium score

<40 years of age

• Insufficient evidence to judge the risk–benefit ratio of routine aspirin for the primary prevention of ASCVD
  • As above for those >70, there may be clinical high ASCVD scenarios where clinicians ‘might’ discuss with their patients the use of low-dose aspirin

Note: Low-dose aspirin should not be used for primary ASCVD prevention when there is increased risk of bleeding, regardless of age

KEY POINTS:

Increased Bleeding Risk Factors

• Increased bleeding risk includes, but is not limited, to the following
  • History of previous GI bleeding or peptic ulcer disease or bleeding at other sites
  • Age >70 years
  • Thrombocytopenia
  • Coagulopathy
  • Chronic kidney disease
  • Concurrent use of other medications that increase bleeding risk e.g.,
    • NSAID | Steroids | Direct oral anticoagulants | Warfarin

Risk Enhancers

• Family history of premature ASCVD
  • Males <55 years | Females <65 years
• Primary hypercholesterolemia
  • LDL-C 160 to 189 mg/dL (4.1 to 4.8 mmol/L)
  • Non-HDL-C 190 to 219 mg/dL (4.9 to 5.6 mmol/L)
• Chronic kidney disease
  • eGFR 15 to 59 ml/min per 1.73m2 with or without albuminuria
  • Not treated with dialysis or kidney transplantation
• Metabolic syndrome
• Conditions specific to women
  • Preeclampsia
  • Premature menopause (<40 years)
• Inflammatory disease, especially
  • Psoriasis
  • RA
  • HIV
• Ethnicity
  • Asian American | Hispanic/ Latino Americans / Blacks
  • There is heterogeneity in risk between and within racial and ethnic groups
  • Native American/ Alaskan populations have higher ASCVD rates compared to non-Hispanic whites
• Lipid/biomarkers
  • Persistently elevated triglycerides (≥175 mg/dL)
• Additional markers if measured
  • High sensitivity (hs)-CRP: ≥2.0 mg/L
  • Lp(a) levels: ≥50 mg/dL or ≥125 nmol/l
  • apoB: ≥130 mg/dL especially at higher levels of Lp(a)
  • Elevated apo B ≥130 mg/dL corresponds to an LDL-C >160 mg/dL and constitutes a risk enhancing factor
  • ABI (ankle-brachial index) <0.9

ACC/AHA Guidelines Differ from the USPSTF Recommendations

• The ACC/AHA guidelines differ from the USPSTF recommendations (see ‘Learn More – Primary Sources’ below)
• Key differences include

Ages 40 to 59 years and ≥10-year CVD Risk

• Decision to initiate low-dose aspirin use for the primary prevention of CVD should be an individual one
  • Evidence indicates that the net benefit of aspirin use in this group is small
  • Persons who are not at increased risk for bleeding and are willing to take low-dose aspirin daily are more likely to benefit
• C recommendation
  • The USPSTF recommends selectively offering or providing this service to individual patients based on professional judgment and patient preferences
  • There is at least moderate certainty that the net benefit is small
  • Offer or provide this service for selected patients depending on individual circumstances

≥60 years

• D recommendation
  • The USPSTF recommends against initiating low-dose aspirin use for the primary prevention of CVD

Learn More – Primary Sources:

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

JAMA Viewpoint: A Practical Approach to Low-Dose Aspirin for Primary Prevention

Hypertension: New heart-disease prevention guideline: What physicians must know (AMA)

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