New Guidelines on Blood-Thinning Therapy

Recommendations stress individualized treatment

Many of the approximately 15.5 million Americans with coronary heart disease will receive new advice regarding whether and how long to take aspirin combined with another blood-thinning antiplatelet to prevent clotting under updated guidelines released by the American College of Cardiology (ACC) and the American Heart Association (AHA).

For some patients, this will mean a shorter time on so-called dual antiplatelet therapy (DAPT)––for example, six months instead of the 12 months commonly recommended under previous guidelines. But others could see their time on the therapy lengthened, such as those with a greater risk of clotting or a low risk of the bleeding problems sometimes seen with aspirin and antiplatelet drugs, such as clopidogrel, prasugrel, and ticagrelor.

Among the major changes:

  • Patients with stable ischemic heart disease who have received a drug-eluting stent to open a blocked artery need DAPT for only six months instead of 12 months. Even then, it might be reasonable to reduce the duration to three months in the presence of a high bleeding risk, or to increase the time past six months if the risk of bleeding is not high.
  • DAPT may be resumed in patients with acute coronary syndrome after a coronary artery bypass graft, as well as in patients who receive a heart stent and subsequent bypass––an area where the previous guidelines were essentially silent. Other bypass surgery patients may also be considered for one year of DAPT.
  • Patients treated with a drug-eluting stent should wait six months rather than one year to receive other types of elective surgery not related to the heart.
  • In patients who have had a heart attack, 12 months of DAPT is generally recommended, but it might be reasonable for physicians to discontinue treatment after six months if the bleeding risk is high or to continue DAPT past 12 months if there is no such risk.
  • Because of the increased bleeding risk with little additional protection against clotting, the recommendation to use low-dose aspirin––81 mg/day––has been strengthened. The aspirin component of DAPT is usually continued indefinitely.

The big take-away from the updates, published online in Circulation, may be a greater emphasis on tailoring treatment to the individual patient, the AHA says.

“Doctors and patients should weigh the benefit–risk ratio of either shorter-duration DAPT or longer-duration DAPT,” said Glenn N. Levine, MD, chair of the group that composed the updated guidelines.

Bates likened the new approach to a teeter-totter, with a high risk of clotting adding weight to the argument to extend DAPT, and a patient’s high risk for bleeding pushing down the other side.

The new guidelines provide a list of factors that increase clotting and heart attack risk, as well as a list of factors that suggest an increased risk of bleeding.

In updating the guidelines, the ACC/AHA Task Force on Clinical Practice Guidelines considered new research into the risks and benefits of longer- and shorter-duration DAPT, as well as the benefits from newer-generation drug-eluting stents that might justify shorter treatment. In addition, Bates said, there was a need to bring the sometimes-conflicting DAPT guidelines contained in six different heart disease treatment guidelines––for bypass graft surgery, catheter-placed stents, and patients who have had a heart attack, among others––into harmony.

Source: AHA News; March 29, 2016.