What Is the Optimal Dual Antiplatelet Therapy Strategy After Percutaneous Coronary Intervention in the Era of New-Generation Drug-Eluting Stent?
論文ID: CJ-20-0658
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論文ID: CJ-20-0658
The appropriate duration of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) has been evaluated and debated in many clinical trials worldwide. The development of new-generation drug-eluting stent (DES) enabled to safely shorten the duration of DAPT after PCI.1 However, the optimal duration of DAPT after PCI is not fully understood. The current guidelines of European Society of Cardiology (ESC) recommend 6-month DAPT after PCI in patients with stable angina.2 On the other hand, 3-month DAPT is recommended in patients with high bleeding risk. Recently, it becomes mainstream to shorten the duration of DAPT after PCI to prevent bleeding events while controlling ischemic events.
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STOPDAPT-1 was a prospective trial evaluating the efficacy of 3-month DAPT followed by aspirin monotherapy after successful PCI with cobalt-chromium everolimus-eluting stent (CoCr-EES).3 The result showed that 3-month DAPT after CoCr-EES implantation was at least as safe as the prolonged DAPT in both aspects of bleeding and ischemic events. STOPDAPT-2 was a prospective and randomized trial comparing the efficacy of 1-month DAPT followed by clopidogrel monotherapy with 12-month DAPT after CoCr-EES implantation.4 The results showed that 1-month DAPT followed by clopidogrel monotherapy compared with 12-month DAPT resulted in a significantly lower rate of a composite of cardiovascular and bleeding events.
In this issue of the Journal, Natsuaki et al compare the clinical outcomes of patients who were treated with 3-month DAPT followed by aspirin monotherapy in the STOPDAPT-1 trial and those with 1-month DAPT followed by clopidogrel monotherapy in the STOPDAPT-2 trial (Figure).5 Ischemic events defined as a composite of cardiovascular death, myocardial infarction (MI), stroke and stent thrombosis (ST) were similar between the 2 trials at 1 year (1.8% vs 1.9%). Bleeding events defined as Thrombolysis in Myocardial Infarction (TIMI) major/minor bleeding were also similar between the 2 trials at 1 year (0.5% vs 0.4%). Importantly, when analyzed during the first 3 months after PCI, the ischemic events and the bleeding events did not differ between the 2 trials (0.6% vs. 0.5% for ischemic events and 0.1% vs. 0.1% for bleeding events, respectively). All these findings may support the shorter duration of DAPT (1 month) after PCI.
Ischemic and bleeding events in patients with 3-month dual antiplatelet therapy (DAPT) followed by aspirin monotherapy and in those with 1-month DAPT followed by clopidogrel monotherapy. Cumulative incidences of ischemic and bleeding events at 0–3 months, 3–12 months, and 1 year in the patients in the STOPDAPT-1 and STOPDAPT-2 trials are shown. There were no significant differences in ischemic and bleeding events at any time point between the 2 trials. Ischemic events were defined as a composite of cardiovascular death, myocardial infarction; stroke and definite ST. Bleeding events were defined as TIMI major/minor bleeding. Cumulative incidences of ischemic and bleeding events at 0–3 months were calculated using the data shown in the Tables in Natsuaki et al.5 PCI, percutaneous coronary intervention; ST, stent thrombosis; TIMI, Thrombolysis In Myocardial Infarction.
It should be noted that only 60% of the patients in the STOPDAPT-2 trial were treated with aspirin plus clopidogrel at the DAPT phase and the rest were given aspirin plus prasugrel, whereas all patients in STOPDAPT-1 trial had aspirin plus clopidogrel. Prasugrel is a thienopyridine antiplatelet agent that provides more prompt, potent and consistent platelet inhibition than clopidogrel.6 Previous study demonstrated that DAPT with prasugrel resulted in significantly fewer ischemic events but had higher bleeding events compared with DAPT with clopidogrel in patients with acute coronary syndrome who underwent PCI.7 Further detailed analysis regarding antiplatelet drugs at DAPT phase is of interest.
The authors further evaluated the difference in the event rates at 3–12 months after PCI between the 2 trials by the landmark analysis. All patients had a single antiplatelet therapy at 3–12 months after PCI, aspirin monotherapy in STOPDAPT-1 trial and clopidogrel monotherapy in STOPDAPT-2 trial. They found that the ischemic events and the bleeding events did not differ between the 2 trials (1.2% vs. 1.4% for ischemic events and 0.5% vs. 0.3% for bleeding events, respectively). These findings indicate that it is important to continue the antiplatelet monotherapy, either aspirin or clopidogrel, for 3–12 months after PCI.
Attention should be paid to the inclusion bias of that study, as the authors described in the limitations section. Patients who underwent complex PCI were considered to be at high risk of ischemic events if DAPT was discontinued in the early phase after PCI. Therefore, many of these patients were not enrolled into the STOPDAPT-1 and STOPDAPT-2 trials by local physicians’ judgement, and consequently there was a lower frequency of patients treated with complex PCI such as left main or multivessel treatment compared with previous studies.8,9 Further larger-scale and consecutive all-comer trials might be necessary to evaluate the effect of shorter DAPT after complex PCI.
There were 231 (17%) patients in the STOPDAPT-1 and 369 (25%) in the STOPDAPT-2 trials who were diagnosed with acute MI (AMI) and underwent PCI with CoCr-EES; the incidence of the primary endpoint was not significantly different between the 2 trials in patients with AMI. Although the number of patients in both trials was small, the result is very important in regard to the efficacy of short DAPT (1-month DAPT followed by clopidogrel monotherapy) for AMI patients. Ischemic events such as MI or ST occur more frequently in the acute phase of AMI compared with the chronic phase, and therefore intensive medical treatment such as DAPT is considered necessary to prevent ischemic events. Further large-scale studies in patients with AMI or acute coronary syndromes are clearly warranted.
In conclusion, it is of considerable importance to assess the risks of both ischemic and bleeding events and to strike a balance between both risks in individual cases in order to safely shorten the duration of DAPT after PCI. Although further studies are clearly needed, the present study provides important clinical evidence regarding shortening the duration of DAPT after PCI.
