When can I stop dual antiplatelet therapy in patients with drug-eluting stents?

TOOLS TO HELP DECISION-MAKING

The decision to stop DAPT in a patient at high risk of bleeding requires a careful assessment of the risks and benefits. Risk factors for bleeding include advanced age, history of major bleeding, anticoagulation, chronic kidney disease (serum creatinine level ≥ 2 mg/dL), platelet count 100 × 10⁹/L or lower, and history of stroke.¹¹

• Age 75 or older: −2 points
• Ages 65 to 74: −1
• Age under 65: 0
• Diabetes mellitus: 1
• Myocardial infarction at presentation: 1
• History of percutaneous coronary intervention or myocardial infarction: 1
• Stent diameter less than 3 mm: 1
• Paclitaxel drug-eluting stent: 1
• Current smoker: 2
• Percutaneous coronary intervention with saphenous vein graft: 2
• Congestive heart failure or left ventricular ejection fraction less than 30%: 2.

A score of 2 or greater favors continuing DAPT, as it indicates higher ischemic risk. A score less than 2 favors discontinuing DAPT, as it indicates higher bleeding risk.^1,2

IF BLEEDING RISK IS HIGH

Preventing and controlling bleeding associated with DAPT is important. The gastrointestinal tract is the most common site of bleeding.

Aspirin inhibits prostaglandin synthesis, leading to disruption of the protective mucous membrane. Therefore, a proton pump inhibitor should be started along with DAPT in patients at high risk of gastrointestinal bleeding.

If a patient’s bleeding risk significantly outweighs the risk of stent thrombosis, or if active hemorrhage makes a patient hemodynamically unstable, antiplatelet therapy must be stopped.¹

FACING SURGERY

For patients with a drug-eluting stent who are on DAPT and are to undergo elective noncardiac surgery, 3 considerations must be kept in mind:

• The risk of stent thrombosis if DAPT needs to be interrupted
• The consequences of delaying the surgical procedure
• The risk and consequences of periprocedural and intraprocedural bleeding if DAPT is continued.

Because clinical evidence for bridging therapy with intravenous antiplatelet or anticoagulant agents is limited, it is difficult to make recommendations about stopping DAPT. However, once bleeding risk is stabilized, DAPT should be restarted as soon as possible.¹

CURRENT RESEARCH

Several trials are under way to further evaluate ways to minimize bleeding risk and shorten the duration of DAPT.

A prospective multicenter trial is evaluating 3-month DAPT in patients at high bleeding risk who undergo placement of an everolimus-eluting stent.¹¹ This study is expected to be completed in August 2019.

Another strategy for patients at high bleeding risk is use of a polymer-free drug-coated coronary stent. In a 2015 trial comparing a biolimus A9-coated stent vs a bare-metal stent, patients received DAPT for 1 month after stent placement. The drug-coated stent was found to be superior in terms of the primary safety end point (cardiac death, myocardial infarction, or stent thrombosis).¹² This stent is not yet approved by the US Food and Drug Administration at the time of this writing.

Further study is needed to evaluate DAPT durations of less than 3 months and to establish the proper timing for safely discontinuing DAPT in difficult clinical scenarios.

WHEN STOPPING MAY BE REASONABLE

According to current guidelines, in patients at high bleeding risk with a second-generation or newer drug-eluting stent for stable ischemic heart disease, discontinuing DAPT 3 months after stent placement may be reasonable.¹ The decision to stop DAPT in these patients requires a careful assessment of the risks and benefits and may be aided by a tool such as the DAPT risk score. However, these recommendations cannot be extrapolated to patients with an acute coronary syndrome within the past year, as they are at higher risk.

TAKE-HOME MESSAGES

• A cardiologist should be consulted before discontinuing DAPT in patients with a drug-eluting stent, especially if the stent was recently placed.
• The duration of therapy depends on the indication for stent placement (stable ischemic heart disease vs acute coronary syndrome) and on stent location.
• Based on the 2016 American College of Cardiology/American Heart Association guidelines,¹ in patients at high bleeding risk with a second-generation drug-eluting stent, discontinuing DAPT is safe after 3 months in patients with stable ischemic heart disease, and after 6 months in patients with an acute coronary syndrome.
• When prescribing DAPT, available evidence favors clopidogrel in patients with stable ischemic heart disease who have a second-generation drug-eluting stent and are at high bleeding risk.
• In these patients, the risk-benefit ratio based on the DAPT score may be useful when considering stopping clopidogrel.