#400 Antiplatelets, Anticoagulation for Coronary Artery Disease and Afib

June 19, 2023 | By Matthew Watto, MD

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Master the prescription of antiplatelets and anticoagulation for coronary artery disease and afib (atrial fibrillation). We discuss why, when, and how long to prescribe aspirin, clopidogrel, ticagrelor, prasugrel, and/or anticoagulation for primary, secondary, and “primary and a half” prevention including the definition and discussion of mono, dual, and triple therapy for patients with coronary disease who need anticoagulation for atrial fibrillation. We’re joined by preventive cardiologist, Dr. Donald Lloyd-Jones MD, ScM (@dmljmd from NMCardioVasc)! This episode was recorded in person at ACP’s (@ACPIMPhysicians) Internal Medicine Meeting 2023 #im2023 in San Diego.

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Show Segments

• Intro
• Getting to know our guest
• Definition mono, dual, triple therapy, DAPT
• Post-PCI for NSTEMI with existing afib
• Stable CAD with new Afib
• CABG with New Afib
• Prior stent with New Afib
• Antiplatelet therapy after Acute Coronary Syndrome
• Primary Prevention
• Primary “and a half” Prevention
• Life’s Essential 8
• Outro

Antiplatelet, Anticoagulation Pearls

1. Monotherapy with a P2Y12 inhibitor (e.g. clopidogrel) might eventually replace aspirin for secondary prevention, especially for patients with high ischemic risk (expert opinion).
2. Individualize the duration of dual and triple therapy for patients with coronary disease, and atrial fibrillation based on ischemic, and bleeding risk.
3. Monotherapy with an oral anticoagulant can be used for patients with stable ischemic heart disease who develop atrial fibrillation (afib) —Knuuti, 2019.
4. Short-duration (1 to 3 months) dual antiplatelet therapy can be considered in select patients undergoing percutaneous intervention (PCI) followed by monotherapy with a P2Y12 inhibitor (Lawton, 2022).
5. Aspirin 100-325 mg is recommended after coronary artery bypass to reduce saphenous vein graft closure (Hillis, 2011, Lawton, 2022).
6. Know your P2Y12 inhibitors. Ticagrelor can cause dyspnea and/or bradyarrhythmia. Prasugrel should be avoided in patients with active bleeding, prior stroke, or age ≥75.
7. “Primary and a half” prevention with low-dose aspirin should be considered for patients with coronary artery calcium (CAC) score ≥100 (expert opinion).

Antiplatelet, Anticoagulation Show Notes

Definitions

• P2Y12 inhibitors (P2Y12i) include clopidogrel, prasugrel, and ticagrelor. P2Y12 is a receptor on platelets that binds adenosine 5’diphosphate (ADP) and plays a role in platelet function, hemostasis, and thrombosis (Cattaneo, 2015). 
• Stable ischemic heart disease (AHA term) and chronic coronary syndrome (ESC term) refer to patients with known coronary disease and are at least 6-12 months from revascularization or an acute cardiac event
• Dual antiplatelet therapy (DAPT) = aspirin, plus a P2Y12i
• Anticoagulation = in this episode refers to oral anticoagulants with a preference for direct oral anticoagulants over vitamin K antagonists (Abadie, 2020)
• Monotherapy = use of a single agent (e.g. aspirin, a P2Y12i, or anticoagulation alone)
• Dual therapy = use of an antiplatelet (aspirin or a P2Y12i), plus anticoagulation
• Triple therapy = use of aspirin, plus a P2Y12i, plus anticoagulation

Know your P2Y12 inhibitors

• Ticagrelor can cause dyspnea and/or bradyarrhythmia (Krakowiak, 2020). 
• Prasugrel has a black box warning for bleeding risk and should not be used in patients with active bleeding, prior stroke, or age ≥75 (Lexicomp; Sampat, 2022).
• Dr. Lloyd-Jones points out that switching the P2Y12 from ticagrelor (or prasugrel) to clopidogrel can be done after three months, but he recommends a 300 mg clopidogrel loading dose to ensure adequate coverage (expert opinion). We recommend a discussion with the person who performed the revascularization before making changes!
• Routine genetic testing for clopidogrel is NOT part of Dr. Lloyd-Jones’ practice. P2Y12 activity level testing is available, but not yet recommended for routine practice (Senzel, 2019).

Kashlak Pearl: Dr. Lloyd-Jones has a low threshold to temporarily start a proton pump inhibitor for gastrointestinal prophylaxis, especially if the person has a history of gastrointestinal bleeding (ESC guidelines section 3.3.2.4 Proton pump inhibitors, Knuuti, 2019). 

Patient with existing afib who undergoes PCI

What is recommended for the patient with underlying atrial fibrillation (afib) already on oral anticoagulation who undergoes percutaneous intervention (PCI) for an acute coronary syndrome?

Dr. Lloyd-Jones mentions the following strategy as a standard pathway (see Figure 2, Abadie, 2020) that can be modified based on an individual’s risk of ischemia, and bleeding.

• First, start triple therapy in the hospital and continue for *one week to one month from PCI (Lawton, 2022). *Consider triple therapy for up to three months if high ischemic risk and lower bleeding risk. Conversely, consider triple therapy for only one week if high bleeding risk –expert opinion)
• Next, scale back to dual therapy with a P2Y12i, plus anticoagulation for 6-12 months from PCI. 
• Finally, after 6-12 months from PCI many patients can be scaled back to oral anticoagulation as monotherapy. 
• HAS-BLED is a 9-point score for bleeding risk in patients with afib. Dr. Lloyd-Jones reminds us that a score of three or more is NOT a contraindication to anticoagulation. Try your best to mitigate falls and the risk of bleeding (expert opinion).

Kashlak Pearl: Talk to the person who performed the revascularization about the patient’s ischemia risk to help individualize the duration of antiplatelet therapy (expert opinion). An interventionalist will consider factors such as successful stent deployment, stent location, anatomy, and other patient factors to make a recommendation.

Stable Ischemic Heart Disease with new Afib

In a patient with stable ischemic heart disease (aka chronic coronary syndrome) should we continue aspirin for secondary prevention when a patient develops new afib? 

These patients are by definition at least 6-12 months from revascularization or an acute cardiac event and can be on oral anticoagulation monotherapy (see section 3.3.2.3 Anticoagulant drugs in atrial fibrillation Knuuti, 2019). In his practice, Dr. Lloyd-Jones might continue aspirin for one month in case there is an issue with bleeding or the cost of oral anticoagulation (expert opinion). 

History of CABG with Afib and need for Anticoagulation

Aspirin 100-325 mg is recommended after coronary artery bypass graft (CABG) to reduce saphenous vein graft closure (Hillis, 2011, Lawton, 2022). In his expert opinion, Dr. Lloyd-Jones prefers 325 mg long-term (Kulik, 2016).

Oral anticoagulant monotherapy may be used in patients with prior CABG and afib, but dual therapy with an antiplatelet and an oral anticoagulant is reasonable in those with high ischemic risk and low bleeding risk (see Figure 12, Kirchof, 2016; Yasuda, 2019; see UpToDate, Sarafoff, 2023). 

Antiplatelet therapy after PCI

• Discuss a patient’s ischemic risk (e.g. coronary anatomy and stent characteristics) with the physician who performed revascularization. 
• Prasugrel and ticagrelor have a quicker onset of action and more potency compared to clopidogrel among the P2Y12 inhibitors (Lawton, 2022).
• Short-duration (1 to 3 months) dual antiplatelet therapy can be considered in select patients undergoing percutaneous intervention (PCI) followed by monotherapy with a P2Y12 inhibitor (Lawton, 2022). Dr. Lloyd-Jones often prefers six months or more of DAPT (expert opinion).
• After 12 months either aspirin or clopidogrel can be continued as monotherapy, but dual antiplatelet therapy is reasonable in patients at high ischemic and without high bleeding risk (Knuuti, 2019, Lawton, 2022). 
• Dr. Lloyd-Jones speculates that P2Y12 inhibitors might eventually replace aspirin as the standard for secondary prevention, especially in patients with higher ischemic risk (Zhu, 2023). 

Primary “and a half” Prevention

Three trials in 2018 (​​ASCEND, ARRIVE, ASPREE) made us rethink aspirin for primary prevention in patients with diabetes, patients middle-aged or older with at least moderate cardiac risk, and patients over 70 years old. Dr. Lloyd-Jones speculates that better control of blood pressure and the use of statins blunted the effect of aspirin for primary prevention. He rates control of blood pressure and smoking cessation as key to risk reduction. 

Dr. Lloyd Jones encourages clinicians to consider “primary and a half” prevention, which refers to the use of aspirin for primary prevention in a patient with a coronary calcium (CAC) score ≥100. In an observational study using data from MESA, patients with CAC  ≥100 had a number needed to treat below the number needed to harm over five years (Cainzos-Achirica, 2020).

Links

1. Yosemite National Park ‘firefall’ (Glacier Point)
2. Life’s Essential Eight (AHA)

Goal

Listeners will develop an approach to prescribing antiplatelets and anticoagulants for primary and secondary prevention of cardiovascular disease 

Learning objectives

After listening to this episode listeners will…

1. Choose the appropriate antiplatelet agent(s) and duration of therapy for primary and secondary prevention of cardiovascular disease
2. Determine the appropriate antiplatelet strategy in patients with atrial fibrillation or another indication for anticoagulation after PCI

Disclosures

Dr. Lloyd-Jones has no relevant financial disclosures. The Curbsiders report no relevant financial disclosures. 

Citation

Watto MF, Lloyd-Jones D, Williams PN. “#400 Antiplatelets, Anticoagulation for Coronary Artery Disease and Afib”. The Curbsiders Internal Medicine Podcast. thecurbsiders.com/category/curbsiders-podcast Final publishing date June 19, 2023.