First ESC Focused Update on dual antiplatelet therapy in CHD

The European Society of Cardiology (ESC) has published its first Focused Update on the use of dual antiplatelet therapy (DAPT) in coronary heart disease (CHD) (Valgimigli et al, 2017). Produced in collaboration with the European Society for Cardio-Thoracic Surgery (EACTS), the document addresses recommendations on a medical treatment that has seen conflicting advice over the years.

Conflicting evidence

According to Dr Marco Valgimigli, Chairperson of the ESC/EACTS Task Force, the conflicting evidence surrounding DAPT has resulted in many people calling it a controversial topic:

‘This has led to a great deal of uncertainty in the medical community, particularly regarding the optimal duration of DAPT after coronary stenting,’ he said.

A survey initiated by the European Association of Percutaneous Cardiovascular Interventions sought opinions from the medical community on the evidence relating to DAPT duration after coronary stenting (Valgimigli et al, 2015). It revealed considerable uncertainty over optimal duration of DAPT after stenting and therefore called for updated recommendations for practising physicians to guide treatment decisions.

Neglected populations

Alongside conflicting results in the published literature on DAPT, there is also limited evidence on various patient subsets—such as elderly patients—who may have a greater bleeding risk. Here, the benefits and risks of DAPT may be different to those seen in more selected patient cohorts included in randomised controlled trials. The aim of this Focused Update therefore is to address the current recommendations on DAPT in patients with CHD.

Dual antiplatelet therapy

Being one of the most intensively investigated treatments in cardiovascular medicine, there have been 35 randomised clinical trials of DAPT, including more than 225 000 patients. The first randomised clinical trial to establish the superiority of DAPT over anticoagulant therapy among patients undergoing percutaneous coronary intervention was published in 1996.

Platelets are small particles in the blood that can clump together to form clots; these can go on to cause myocardial infarction or the occlusion of a coronary stent. Antiplatelet agents are a class of drugs that are used to stop platelets from forming these clots. The use of two types of antiplatelet agents to prevent blood clotting is known as DAPT (American Heart Association, 2017).

The number of patients requiring dual antiplatelet therapy consisting of the combination of aspirin and an oral inhibitor of the platelet P2Y12 receptor for adenosine 5’-diphosphate has increased over time. In Europe, it is believed that around 1 400 000 patients per year may have an indication for DAPT after coronary intervention, and 2 200 000 after myocardial infarction.

P2Y12 inhibitors range from safer drugs, such as ticlopidine or clopidogrel, to the more potent and predictable, such as ticagrelor or prasugrel. The decision on when to initiate a P2Y12 inhibitor depends on both the specific drug and the disease.

DAPT reduces the risk of stent thrombosis from occurrences ranging from acute to late events. It also reduces the rate of spontaneous myocardial infarction after percutaneous coronary intervention and myocardial infarction.

For patients with stable CHD treated with percutaneous coronary intervention, the default P2Y12 inhibitor is considered to be clopidogrel. It is also commonly the default drug for patients with indication to concomitant oral anticoagulation, and in patients with acute coronary syndromes in whom ticagrelor or prasugrel are contraindicated. Ticagrelor or prasugrel is recommended in people with acute coronary syndromes unless drug-specific contraindications exist.

Recommendations for DAPT

A Task Force made up of selected medical experts carried out a comprehensive review of the published evidence for management of CHD according to ESC Committee for Practice Guidelines policy, and approved by the EACTS. A critical evaluation of diagnostic and therapeutic procedures took place, including assessment of the risk–benefit ratio. The level of evidence and the strength of the recommendation of particular management options were then weighed and graded according to predefined scales.

The Focused Update recommends a default DAPT duration of 12 months for patients with acute coronary syndrome. This is irrespective of revascularisation therapy, whether through medical therapy, percutaneous coronary intervention or coronary artery bypass surgery. In patients with high bleeding risk, 6 months of DAPT should be considered. Therapy over 12 months may be considered in patients with acute coronary syndrome who have tolerated DAPT without a bleeding complication.

The Task Force felt that the need for a short DAPT regimen should no longer justify the use of bare metal stents instead of newer generation drug-eluting stents. An assessment of the individual patient’s ischaemic risks versus bleeding risks should be used to establish duration of DAPT rather than the type of stent used.

For patients with CHD being treated with percutaneous coronary intervention who are believed to be stable, the duration of DAPT should be 1–6 months, depending on the bleeding risk. This is irrespective of the type of metallic stent implanted. For patients whose ischaemic risk is thought to be greater than the risk of bleeding, the Focused Update recommends a longer DAPT duration. The Task Force felt that there were insufficient data to recommend DAPT in patients with stable CHD treated with coronary artery bypass graft surgery.

The most controversial issue cited was the need for a prolonged DAPT regimen (anything over 12 months) in patients with acute coronary syndrome treated with percutaneous coronary intervention. This is owing to concern over ensuring benefits while diminishing risks.

‘This is a setting in which one needs to think twice about how to maximise the benefits over the risks,’ said Dr Valgimigli. ‘The most novel and important message here is that DAPT is a regimen to treat a patient, not the previously implanted stent. This is crucial and the community needs to adapt to this new treatment paradigm.’

Differing types and durations of DAPT therapy have not been seen as necessary for male and female patients, instead calling for a similar approach to care. Additionally, no difference in therapy is required for patients with diabetes.

Dr Valgimigli said:

‘The Task Force advocates a personalised medicine approach where each treatment and its duration is individualised as much as possible. The document highlights who should, and should not, receive long-term treatment, while at the same time outlining how to maximise the expected benefits over the risks.’

Conclusion

This year marks the 21st anniversary of the first randomised clinical trial that established the superiority of DAPT over anticoagulant therapy among patients undergoing percutaneous coronary intervention. However, differing advice on optimal duration of DAPT after coronary stenting makes this Focused Update long overdue—though it should go some way to guiding treatment decisions. BJCN

References

American Heart Association. 2017. What is Dual Antiplatelet Therapy (DAPT) [Internet]? Available from http://tinyurl.com/yajb9wmx

Valgimigli M, Costa F, Byrne R, Haude M, Baumbach A, Windecker S. Dual antiplatelet therapy duration after coronary stenting in clinical practice: results of an EAPCI survey. EuroIntervention. 2015;11(1):68-74. https://doi.org/10.4244/EIJV11I1A11

Valgimigli M, Bueno H, Byrne RA et al. 2017 ESC focused update on dual antiplatelet therapy in coronary artery disease developed in collaboration with EACTS: The Task Force for dual antiplatelet therapy in coronary artery disease of the European Society of Cardiology (ESC) and of the European Association for Cardio-Thoracic Surgery (EACTS). Eur Heart J; 2017. https://doi.org/10.1093/eurheartj/ehx419. [Epub ahead of print]

Taken from British Journal of Cardiac Nursing, published December 2017.