A 73-year-old female patient with a medical history of hypertension, type 2 diabetes, and stage 2 chronic kidney disease presented for follow-up in clinic. Nine months earlier, she was admitted for acute non-ST-segment elevation myocardial infarction (MI) and underwent coronary angiography, which showed 95% proximal circumflex artery stenosis and two 50% proximal stenoses in the dominant right coronary artery. The culprit lesion was treated with implantation of a second-generation drug-eluting stent (DES). Her baseline left ventricular ejection fraction was 50%, creatinine clearance was 65 ml/min, and hemoglobin was 12.5 g/dl.
Her medications include aspirin 100 mg daily, ticagrelor 90 mg twice daily, rosuvastatin 40 mg, bisoprolol fumarate 7.5 mg, and perindopril arginine 10 mg daily. The physical exam was unremarkable; her heart rate was 58 bpm, blood pressure was 115/67 mmHg, and saturation was 98% on room air. The patient stated that she had been feeling very well since the MI, without recurrence of chest pain or dyspnea. She also told you about concern that her primary care physician expressed about increased bleeding risk due to her current medication. The patient feels unsure whether to continue with both aspirin and ticagrelor and asked you to reconsider its necessity.
The correct answer is: D. Advise the patient to continue with both aspirin and ticagrelor for at least 12 months post-MI.
The 2016 ACC/AHA guideline focused update on duration of dual antiplatelet therapy in patients with coronary artery disease and 2017 ESC focused update on dual antiplatelet therapy in coronary artery disease developed in collaboration with EACTS recommend DAPT of P2Y12 inhibitor on top of aspirin for at least 12 months in patients with acute coronary syndrome (ACS) treated with coronary stent implantation unless the patient develops a high risk of bleeding (Class IA recommendation).1,2 Tailoring of DAPT duration depends on careful evaluation of both ischemic and bleeding risk based mostly on the patient's clinical and procedure characteristics. However, ischemic and bleeding risk factors frequently overlap, which may render the decision challenging. Risk scores specifically designed to guide DAPT duration (e.g., PRECISE-DAPT score3) might prove useful in clinical practice.
Given that there are no unfavorable factors in this patient's case that would argue against DAPT with potent P2Y12 inhibitor, such as excessive bleeding risk or bleeding while on medication, the most appropriate strategy would be to continue with current DAPT therapy. This should be explained carefully to the patient because her doubts could lead to premature cessation of the treatment.
The incorrect answers are explained below:
- Answer A. It may be reasonable to stop P2Y12 inhibitor therapy after 6 months following DES implantation in patients who are at high bleeding risk (e.g., prior bleeding on DAPT, oral anticoagulant therapy, coagulopathy, or major surgery) or develop significant overt bleeding (Class IIB recommendation). Regardless of the improved safety of second-generation DES, DAPT beyond 6 months may reduce the risk of non-target-vessel-related recurrent ischemic events in patients with ACS. In the SMART-DATE (Safety of 6-month Duration of Dual Antiplatelet Therapy After Acute Coronary Syndromes) study, both non-target-vessel MI and target-vessel MI occurred more frequently in the 6-month DAPT group than in the 12-month or longer DAPT group; the risk of stent thrombosis or major bleeding did not differ significantly between the 2 groups.4
- Answer B. DAPT with aspirin and a P2Y12 blocker for at least 12 months is currently standard of care in patients with ACS and after percutaneous coronary intervention. The efficacy and safety of P2Y12 inhibitor monotherapy compared with DAPT in patients with ACS after implantation of the current-generation DES has not been studied.
- Answer C. Ticagrelor and prasugrel have demonstrated superiority over clopidogrel in clinical outcomes and should be preferred in ACS patients with no contraindications (Class IIA recommendation). Nevertheless, switching to clopidogrel is not uncommon and can be pursued as an alternative approach when necessary for clinical (adverse bleeding or non-bleeding events) or economic reasons. Switching algorithms based on pharmacodynamic studies should be observed.5
- Answer E. The decision whether to prolong DAPT after a 12-month course with DAPT has previously been studied. The analysis of DAPT Study (The Dual Antiplatelet Therapy Study) data suggests that in patients who tolerated DAPT for 12 months without significant bleeding complications, the benefit/risk ratio with prolonged DAPT may be favorable for those with a high ischemic risk (DAPT score ≥2) because it reduced net (ischemic plus bleeding) events when compared with non-prolonged DAPT.6 These results are reflected in American College of Cardiology and American Heart Association and European Society of Cardiology guidelines on DAPT duration (Class IIB recommendation).
References
- Levine GN, Bates ER, Bittl JA, et al. 2016 ACC/AHA guideline focused update on duration of dual antiplatelet therapy in patients with coronary artery disease: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Thorac Cardiovasc Surg 2016;152:1243-75.
- 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. Eur J Cardiothorac Surg 2018;53:34-78.
- Costa F, van Klaveren D, James S, et al. Derivation and validation of the predicting bleeding complications in patients undergoing stent implantation and subsequent dual antiplatelet therapy (PRECISE-DAPT) score: a pooled analysis of individual-patient datasets from clinical trials. Lancet 2017;389:1025-34.
- Hahn JY, Song YB, Oh JH, et al. 6-month versus 12-month or longer dual antiplatelet therapy after percutaneous coronary intervention in patients with acute coronary syndrome (SMART-DATE): a randomised, open-label, non-inferiority trial. Lancet 2018;391:1274-84.
- Angiolillo DJ, Rollini F, Storey RF, et al. International Expert Consensus on Switching Platelet P2Y12 Receptor-Inhibiting Therapies. Circulation 2017;136:1955-75.
- Mauri L, Kereiakes DJ, Yeh RW, et al. Twelve or 30 months of dual antiplatelet therapy after drug-eluting stents. N Engl J Med 2014;371:2155-66.
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