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For decades, aspirin has been promoted to reduce the risk of a heart attack or stroke in patients who have not had these events. In 2018, three trials turned this thinking on its head leaving patients and clinicians with uncertainty regarding the need for aspirin for primary prevention. This module updates providers on the most recent aspirin literature, providing tools to incorporate the changes into their practice, discusses dual antiplatelet therapy, focusing on the duration of use and reviews the role of antiplatelet agents for stroke and peripheral arterial disease.

A summary of the 2018 aspirin for primary prevention trials1-3

ASPREE and ARRIVE found no reduction in CV events compared to placebo in patients taking 100 mg of aspirin over the course of the study while observing an increased risk of bleeding. Based on this new information, older patients, such as those in ASPREE and moderate risk patients in ARRIVE, do not benefit from a daily low-dose aspirin. Patients with diabetes in the ASCEND trial saw benefit from aspirin but at the cost of an increase in bleeding events.

Recommendations for when aspirin can help based on level of risk4-6

Aspirin for secondary prevention

Aspirin continues to be recommended in patients who have already had an event. In these patients the question may be whether they need dual antiplatelet therapy (DAPT) with aspirin plus either clopidogrel (Plavix), prasugrel (Effient), or ticagrelor (Brillinta). Patients who present with acute coronary syndromes (ACS), such as a myocardial infarction or unstable angina, or who undergo percutaneous coronary intervention (PCI) in stable coronary artery disease may require a course of DAPT. The duration of treatment depends on the patient’s bleeding risk and what kind of stent was placed, if any.

Recommended duration of DAPT by indication

For details regarding antiplatelet agents for stroke and peripheral arterial disease, see the Evidence Document above.

Information current at time of publication, July 2019.

The content of this website is educational in nature and includes general recommendations only; specific clinical decisions should only be made by a treating physician based on the individual patient’s clinical condition.

Additional Resources

ASCVD Risk Estimator +

  1. McNeil JJ, Wolfe R, Woods RL, et al. Effect of Aspirin on Cardiovascular Events and Bleeding in the Healthy Elderly. N Engl J Med. 2018;379(16):1509-1518.
  2. Bowman L, Mafham M, Wallendszus K, et al. Effects of Aspirin for Primary Prevention in Persons with Diabetes Mellitus. N Engl J Med. 2018;379(16):1529-1539.
  3. Gaziano JM, Brotons C, Coppolecchia R, et al. Use of aspirin to reduce risk of initial vascular events in patients at moderate risk of cardiovascular disease (ARRIVE): a randomised, double-blind, placebo-controlled trial. Lancet. 2018;392(10152):1036-1046.
  4. Capodanno D, Alfonso F, Levine GN, Valgimigli M, Angiolillo DJ. ACC/AHA Versus ESC Guidelines on Dual Antiplatelet Therapy: JACC Guideline Comparison. J Am Coll Cardiol. 2018;72(23 Pt A):2915-2931.
  5. Mauri L, Kereiakes DJ, Yeh RW, et al. Twelve or 30 Months of Dual Antiplatelet Therapy after Drug-Eluting Stents. N Engl J Med. 2014;371(23):2155-2166.
  6. Bonaca MP, Bhatt DL, Cohen M, et al. Long-Term Use of Ticagrelor in Patients with Prior Myocardial Infarction. N Engl J Med. 2015;372(19):1791-1800.