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CLINICAL STATEMENTS AND GUIDELINES

August 29, 2023 Circulation. 2023;148:e9–e119. DOI: 10.1161/CIR.0000000000001168

Virani et al 2023 AHA/ACC/ACCP/ASPC/NLA/PCNA Chronic Coronary Disease Guideline

showed that shorter DAPT was associated with lower all-cause mortality.4 Patients treated with DAPT for ≤6 months had similar mortality rates, MI, and stent thrombosis, but lower rates of major bleeding than patients treated with 1-year DAPT.4 Data supporting the use of DAPT for 6 months with continued use of aspirin after 6 months come from several trials. The largest trial was ISAR-SAFE (Randomized, Double Blind Trial of 6 Versus 12 Months of DAPT After DES- Implantation; N=4005 patients, of which 60% had stable CAD).7 In these trials, aspirin use continued for the duration of the 12-month trial design.5,12 Data are limited on which antiplatelet agent—aspirin or clopidogrel—is best for indefinite therapy after a 12-month period after PCI. The HOST-Exam (Harmonizing Optimal Strategy for Treatment of coronary artery diseases-Extended Antiplatelet Monotherapy) trial enrolled 5530 East Asian participants if they tolerated DAPT for 6 to 18 months without any ischemic or major bleeding complication and randomized them to receive clopidogrel 75 mg daily or aspirin 100 mg daily for 24 months.46 The benefit of clopidogrel over aspirin was observed in both thrombotic and bleeding complications. This study used an openlabel design in a homogenous East Asian population known to have lower rates of thrombotic complications, and the observed event rate was lower than expected. Therefore, further clinical trials would be useful to guide recommendations regarding the long-term use of clopidogrel versus aspirin as SAPT in CCD.46,48,49 3.	 Multiple clinical trials (SMART CHOICE [Comparison Between P2Y12 Antagonist Monotherapy and Dual Antiplatelet Therapy after DES], STOP-DAPT2 [Short and Optimal Duration of Dual Antiplatelet Therapy after Everolimus- Eluting Cobalt-Chromium Stent-2 Acute Coronary Syndrome], TWILIGHT [Ticagrelor With Aspirin or Alone in High-Risk Patients After Coronary Intervention], and GLOBAL LEADERS [A Clinical Study Comparing Two Forms of Antiplatelet Therapy After Stent Implantation]) found reduced bleeding complications without increased ischemic complications when DAPT was used for 1 to 3 months followed by P2Y12 monotherapy.8,9,47,50–52 These trial populations comprised 35% to 62% in stable patients with stable CAD. In a network meta-analysis that included 29 089 patients randomized to short-term DAPT followed by P2Y12 inhibitor monotherapy versus standard duration DAPT, a net clinical benefit was seen that favored short-term DAPT followed by P2Y12 inhibitor monotherapy with less MI and bleeding.8 A metaanalysis showed discontinuation of aspirin after 1 to 3 months with continuation of a P2Y12 agent (mostly prasugrel or ticagrelor) reduced the risk of major bleeding by 40% without an increased risk of MACE.10 These trials were not powered to assess ischemic events, particularly stent thrombosis. Therefore, longer duration DAPT may be needed for patients with higher thrombotic risk (eg, several lesions, long stent length, bifurcation location, atherectomy use, lesion location [left main], bypass graft, or chronic occlusion). 4.	 A systematic review and meta-analysis of pro-

spective RCTs of secondary prevention examined data from 33 435 participants. Of these, 20 203 were treated with DAPT and 13 232 were given only aspirin. Patients were considered high risk and almost half had previous MI. Comorbidities also included diabetes, previous PCI, and CKD. Extended DAPT for >1 year reduced MACE (relative risk, 0.78 [95% CI, 0.67-0.90]; P=0.001) and absolute risk difference of 1.09%, or a number needed to treat for benefit of 91 to prevent 1 MACE over 31-month follow up. This came with an increased absolute 0.8% risk of major bleeding without significant intracranial or fatal bleeding.13 Similarly, a systematic review conducted for the 2016 ACC/AHA guidelines on DAPT34 examined the incidence of death, major hemorrhage, MI, stent thrombosis, and major adverse cardiac events in 33 051 patients in 11 RCTs of prolonged versus short-course DAPT after stenting with DES and in secondary prevention after MI. Among those treated with DES, prolonged DAPT reduced stent thrombosis and MI but increased major hemorrhage. Patients with previous MI had evidence of reduced cardiovascular events at the expense of increased bleeding.53–55 The PEGASUS-TIMI 54 (Prevention of Cardiovascular Events in Patients with Prior Heart Attack Using Ticagrelor Compared to Placebo on a Background of Aspirin-Thrombolysis in Myocardial Infarction 54) trial enrolled 21162 patients who had MI 1 to 3 years before being given ticagrelor 90 mg or 60 mg twice daily compared with placebo on a background of low-dose aspirin.56 Treatment with ticagrelor 60 mg reduced the risk of cardiovascular death, MI, or stroke by 16% and increased the risk of major bleeding at 33-month follow up.14 5.	 Given multiple pathways of platelet activation,

options for additional suppression of platelet activity have been studied. PAR-1 is a key receptor for thrombin activation. Vorapaxar selectively inhibits PAR-1 on platelets, thereby potently inhibiting thrombin-induced platelet aggregation. The TRAP 2P TIMI 50 (Trial to Assess the Effects of SCH 530348 in Preventing Heart Attack and Stroke in Patients with Atherosclerosis) trial

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