Timeline for Dual Antiplatelet Therapy (DAPT) Post-Revascularization
1. Post-Bare Metal Stent Placement:
- Initial DAPT Duration: 1 Month
- Rationale: To reduce the risk of stent thrombosis and remote ischemic events.
2. Post-Drug-Eluting Stent Placement:
- Initial DAPT Duration: 6 Months
- Rationale: To minimize the risk of stent thrombosis and adverse ischemic events.
- Extended Therapy Considerations:
- High Risk for Thrombosis: Consider continuing DAPT beyond 6 months in patients with depressed left ventricular (LV) function, saphenous vein graft stenting, diabetes, and a favorable bleeding profile.
3. De-Escalation of Therapy (Select Patients):
- After 1-3 Months:
- Possible Change: Discontinue aspirin and continue only the P2Y12 inhibitor in patients at high risk for bleeding.
- After 3 Months:
- Possible Change: Discontinue the P2Y12 inhibitor and continue lifelong aspirin in patients with high bleeding risk or overt bleeding.
4. Patients Requiring Oral Anticoagulation for Atrial Fibrillation:
- Initial Therapy: Triple therapy (ASA + P2Y12 inhibitor + anticoagulant) for 1 to 4 Weeks.
- Subsequent Therapy:
- Preferred: Transition to oral anticoagulant (DOAC) + clopidogrel without aspirin.
5. Patients with Mechanical Valve Prosthesis:
- Recommended Therapy: Warfarin plus clopidogrel (DOACs are contraindicated).
6. Post-Coronary Artery Bypass Grafting (CABG) for Stable CAD:
- Recommended DAPT Duration: 12 Months
- Rationale: To improve the patency of vein grafts.
Key Points
- Stable Ischemic Syndromes: Goals of revascularization include reducing angina and improving quality of life.
- Percutaneous Coronary Intervention (PCI): Does not decrease mortality or risk of myocardial infarction in stable angina patients.
- CABG vs. PCI: CABG is generally preferred for severe left main or multi-vessel coronary artery disease, particularly with diabetes, and improves long-term survival in certain patients.
This timeline provides a structured approach to managing DAPT based on the type of revascularization, patient-specific risk factors, and clinical scenarios.
https://www.coreimpodcast.com/2021/04/07/5-pearls-on-dual-antiplatelet-therapy/#show-notes
Pearl 1: Indications
Q: What is the primary use of antiplatelet therapy in high-velocity flow states like myocardial infarction and cerebrovascular accident?
A: Antiplatelet therapy, such as COX-1 inhibitors and P2Y12 inhibitors, is used to manage high-velocity flow states, including myocardial infarction (MI), cerebrovascular accident (CVA), and peripheral arterial disease (PAD). These therapies help to prevent clot formation in high-flow conditions.
Q: When should anticoagulants be used?
A: Anticoagulants are indicated for low-velocity flow states such as deep vein thrombosis (DVT), pulmonary embolism (PE), and stroke prophylaxis in atrial fibrillation (AF). They are also used in patients with mechanical heart valves, where Warfarin (a Vitamin K antagonist) is commonly prescribed.
Q: What are the indications for dual antiplatelet therapy (DAPT) post-acute coronary syndrome (ACS)?
A: Post-ACS, DAPT is typically recommended for 12 months regardless of stent placement due to the thrombotic nature of these patients. The CURE trial demonstrated that DAPT reduced cardiovascular events compared to aspirin alone, although it did increase the risk of major bleeding.
Q: How does the use of DAPT differ in stable ischemic heart disease (SIHD) compared to ACS?
A: In SIHD, DAPT may be considered if a stent is placed to reduce the risk of stent thrombosis and de novo ischemic events. The primary short-term goal is to prevent stent thrombosis during endothelialization, while the long-term goal is to prevent new ischemic events.
Q: Should DAPT be used in patients with severe diffuse atherosclerosis or peripheral artery disease (PAD)?
A: Yes, DAPT may be used in patients with severe diffuse atherosclerosis, PAD, and cerebrovascular disease, especially if they have comorbid coronary artery disease (CAD). This approach can be beneficial in high-risk phenotypes.
Pearl 2: Medications
Q: What are the key considerations when choosing antiplatelet agents?
A: When choosing antiplatelet agents, consider:
- Potency: Prasugrel is the most potent, followed by ticagrelor, then clopidogrel.
- Bleeding risk: Higher potency increases bleeding risk. Prasugrel is avoided in patients over 75 or with a history of TIA/stroke, and ticagrelor is avoided in those with a history of intracranial hemorrhage (ICH).
- Feasibility: Side effects, dosing frequency, and cost should be evaluated. Ticagrelor, for example, is twice daily and can cause bradycardia and dyspnea, whereas clopidogrel and prasugrel are once daily.
Q: What does the TRITON-TIMI 38 trial reveal about prasugrel?
A: The TRITON-TIMI 38 trial showed that prasugrel reduced the rate of stent thrombosis compared to clopidogrel but was associated with a higher risk of major bleeding.
Q: What did the PLATO trial find regarding ticagrelor?
A: The PLATO trial found that ticagrelor was superior to clopidogrel in reducing composite death from MI, stroke, and vascular causes, and it also had lower rates of stent thrombosis. However, it was associated with an increased risk of non-procedure-related bleeding.
Q: How do prasugrel and ticagrelor compare in the ISAR-REACT 5 trial?
A: The ISAR-REACT 5 trial showed that prasugrel reduced rates of death, MI, and stroke compared to ticagrelor but also had a trend towards higher major bleeding rates.
Q: What should be done when transitioning between P2Y12 inhibitors?
A: When transitioning between P2Y12 inhibitors, it is important to RELOAD patients with the new agent to maintain effective antiplatelet therapy.
Pearl 3: Duration
Q: What is the current recommendation for DAPT duration following an ACS event?
A: The current recommendation is to continue DAPT for 12 months following an ACS event, whether or not a stent was placed.
Q: How does DAPT duration differ for patients with stents placed in non-ACS settings?
A: For patients with stents placed in non-ACS settings, the recommended duration of DAPT is typically 6 months. This is based on improvements in stent design and lower thrombogenic risk.
Q: What does the STOPDAPT2 study suggest about shorter DAPT durations?
A: The STOPDAPT2 study suggested that 1-month DAPT followed by clopidogrel monotherapy might be superior to 12-month DAPT in preventing major adverse ischemic events, with fewer bleeding complications.
Q: When might longer DAPT duration be considered?
A: Longer DAPT duration may be considered for patients with complex coronary artery disease, multiple stents, or high burden of atherosclerotic disease, as well as those with recurrent MIs, peripheral vascular disease, or cerebrovascular disease.
Q: How can risk calculators assist in determining DAPT duration?
A: Risk calculators such as DAPT, PRECISE-DAPT, and PARIS can help evaluate whether prolonged DAPT is beneficial by assessing bleeding and thrombotic risks, though they may not account for patient frailty.
Pearl 4: De-escalation
Q: What does de-escalation of antiplatelet therapy involve?
A: De-escalation involves discontinuing one of a patient’s two antiplatelet agents. This is typically considered for patients with a very stable ischemic profile or very high-risk bleeding profile.
Q: What does recent data suggest about de-escalation strategies?
A: Recent data, such as the TWILIGHT study, suggest that de-escalating to ticagrelor monotherapy after 3 months of ASA + ticagrelor may result in less bleeding compared to prolonged DAPT. There is no strong recommendation for discontinuing aspirin versus the P2Y12 inhibitor; both approaches may be beneficial.
Pearl 5: Anticoagulation
Q: What is the difference between triple therapy and dual therapy?
A: Triple therapy includes ASA, a P2Y12 inhibitor, and an oral anticoagulant (OAC), while dual therapy consists of ASA or a P2Y12 inhibitor combined with an OAC. Triple therapy is rarely indicated beyond 1 month, with guidelines suggesting transitioning to dual therapy at hospital discharge.
Q: What are the recommendations for choosing anticoagulants in patients undergoing PCI?
A: Generally, DOACs are preferred over warfarin, and a P2Y12 inhibitor is preferred over ASA in dual therapy. Transitioning to dual therapy and dropping aspirin when appropriate can reduce bleeding risks while maintaining efficacy.
Q: What did the WOEST trial find about dual versus triple therapy?
A: The WOEST trial found that dual therapy (P2Y12 + clopidogrel) significantly reduced bleeding complications compared to triple therapy (P2Y12 + clopidogrel + ASA).
Q: What did the REDUAL trial reveal about dual therapy with dabigatran?
A: The REDUAL trial showed that dual therapy with a thienopyridine antiplatelet and dabigatran was associated with a significant reduction in major and clinically relevant non-major bleeding compared to triple therapy.
Q: How does low-dose rivaroxaban compare to warfarin in the PIONEER trial?
A: The PIONEER trial found that low-dose rivaroxaban plus either single or dual antiplatelet therapy reduced bleeding risks compared to warfarin plus DAPT.
Q: What were the findings of the AUGUSTUS trial regarding apixaban and aspirin?
A: The AUGUSTUS trial found that apixaban was superior to warfarin in reducing major or clinically relevant non-major bleeding. Aspirin use in addition to apixaban increased bleeding risk, so a general approach is to continue triple therapy for up to 1 month and then switch to dual therapy with a DOAC if appropriate.
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