JAMA JUNE 11, 2019

Effect of 1-month dual antiplatelet therapy followed by clopidogrel vs 12-month dual antiplatelet therapy on cardiovascular and bleeding events in patients receiving PCI: The STOPDAPT-2 Randomized Clinical Trial

Hirotoshi Watanabe, Takeshi Domei, Takeshi Morimoto, et al.

Bottom Line

In patients undergoing percutaneous coronary intervention (PCI), one month of dual antiplatelet therapy (DAPT) followed by clopidogrel monotherapy was both non-inferior and superior to 12-month DAPT at reducing a composite of cardiovascular and bleeding events at one year.

Key Findings

1. The primary composite endpoint (cardiovascular death, myocardial infarction, stroke, definite stent thrombosis, or TIMI major/minor bleeding) occurred in 2.36% of patients in the 1-month DAPT group compared to 3.70% in the 12-month DAPT group (HR 0.64; 95% CI 0.42-0.98; P < 0.001 for non-inferiority; P = 0.04 for superiority).
2. The reduction in the primary endpoint was driven primarily by a significant reduction in bleeding events, while ischemic events remained similar between groups.
3. Specifically, TIMI major or minor bleeding occurred in 0.4% of the 1-month DAPT group compared to 1.5% of the 12-month DAPT group (P = 0.004).
4. Definite or probable stent thrombosis was not significantly increased in the shorter DAPT arm (0.3% vs 0.07%, P = 0.21).

Study Design

Design
RCT
Open-Label
Sample
3,045
Patients
Duration
1 yr
Median
Setting
Multicenter, Japan
Population Patients undergoing percutaneous coronary intervention (PCI) with cobalt-chromium everolimus-eluting stents.
Intervention One month of dual antiplatelet therapy (aspirin and clopidogrel) followed by clopidogrel monotherapy for 12 months.
Comparator Standard 12-month dual antiplatelet therapy (aspirin and clopidogrel).
Outcome A composite of cardiovascular death, myocardial infarction, ischemic or hemorrhagic stroke, definite stent thrombosis, or Thrombolysis in Myocardial Infarction (TIMI) major or minor bleeding at 12 months.

Study Limitations

The study was open-label, which may introduce observer bias regarding the reporting of bleeding and clinical outcomes.
The study was conducted exclusively in Japan using cobalt-chromium everolimus-eluting stents, which may limit the generalizability of findings to other populations or stent platforms.
The trial was originally powered for non-inferiority, and the observed event rates were lower than anticipated, potentially impacting the power to detect superiority for specific secondary endpoints.

Clinical Significance

The STOPDAPT-2 trial supports the feasibility of shortening DAPT duration to one month followed by clopidogrel monotherapy in selected patients undergoing PCI, offering a potential strategy to reduce bleeding risk without compromising ischemic safety, particularly in populations with stable coronary artery disease.

Historical Context

Traditional management of patients post-PCI involved at least 6 to 12 months of DAPT to prevent stent thrombosis and recurrent ischemic events, despite an inherent increase in bleeding risk. STOPDAPT-2 challenged this paradigm by exploring whether newer-generation drug-eluting stents, which have lower inherent thrombogenicity, allowed for a safe reduction in the duration of DAPT, shifting the focus toward minimizing bleeding complications.

Guided Discussion

High-yield insights from every perspective

Med Student
Medical Student

What is the physiological rationale for using Dual Antiplatelet Therapy (DAPT) rather than single agent therapy immediately following percutaneous coronary intervention (PCI), and how does the mechanism of clopidogrel facilitate this goal?

Key Response

Following stent placement, the metallic struts cause endothelial denudation and local inflammation, creating a highly thrombogenic surface. DAPT addresses this via two pathways: aspirin inhibits thromboxane A2 via COX-1, while clopidogrel blocks the P2Y12 adenosine diphosphate (ADP) receptor. This synergistic inhibition is critical during the early 'neointimalization' phase to prevent acute stent thrombosis.

Resident
Resident

The STOPDAPT-2 trial suggests a benefit for 1-month DAPT. How should this study influence your decision-making for a patient with stable coronary artery disease who is scheduled for an elective hip replacement shortly after receiving a drug-eluting stent (DES)?

Key Response

STOPDAPT-2 demonstrates that with modern second-generation DES (like the cobalt-chromium everolimus-eluting stent used in the study), shortening DAPT to 1 month significantly reduces bleeding risk without a significant increase in ischemic events. This provides clinical confidence for early discontinuation of aspirin in patients who need semi-urgent surgery or those at high risk for surgical bleeding, transitioning them to P2Y12 monotherapy sooner than the traditional 6-12 month window.

Fellow
Fellow

Unlike the TWILIGHT trial which utilized ticagrelor monotherapy, STOPDAPT-2 used clopidogrel. Given the East Asian Paradox regarding clopidogrel metabolism, how do these results reconcile with the high prevalence of CYP2C19 loss-of-function alleles in the study population?

Key Response

The 'East Asian Paradox' refers to the observation that East Asian patients have a lower 'ischemic window' and higher bleeding sensitivity despite a higher prevalence of CYP2C19 loss-of-function alleles (which leads to higher on-treatment platelet reactivity with clopidogrel). STOPDAPT-2 suggests that in this specific population, the reduction in bleeding achieved by early aspirin cessation outweighs the theoretical risk of reduced clopidogrel efficacy, a finding that might not be directly applicable to Caucasian populations where ischemic risk profiles differ.

Attending
Attending

STOPDAPT-2 achieved superiority for the primary endpoint of Net Adverse Clinical Events (NACE). How does the 'bleeding-ischemia tradeoff' observed here challenge the historical prioritization of preventing stent thrombosis over preventing major bleeding in the first year post-PCI?

Key Response

The study highlights a paradigm shift: as stent technology has improved (thinner struts, more biocompatible polymers), the absolute risk of stent thrombosis has plummeted. Consequently, the 'cost' of intensive DAPT (major bleeding, which has a mortality risk similar to MI) now often exceeds its ischemic benefit. STOPDAPT-2 provides level 1 evidence that 'less is more' in the modern era, suggesting that bleeding prevention is now a primary target for improving long-term post-PCI outcomes.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD
PhD

STOPDAPT-2 used a non-inferiority design with a composite primary endpoint of NACE. Critically evaluate the risk of 'pseudo-superiority' when combining endpoints with widely disparate event rates, such as major bleeding versus definite stent thrombosis.

Key Response

In NACE composites, if a study is powered for a common event (bleeding) and a rare event (stent thrombosis), a large reduction in the common event can mask a relative increase in the rare event, leading to a statistically 'superior' NACE result. Methodologically, this requires careful inspection of the individual components' point estimates and confidence intervals to ensure that the safety of the ischemic component is truly preserved, rather than just statistically drowned out by the bleeding benefit.

Journal Editor
Journal Editor

If you were the lead reviewer for this manuscript, what concerns would you raise regarding the 'open-label' design and the potential for 'ascertainment bias' in the reporting of bleeding events?

Key Response

In an open-label trial, both patients and investigators know the treatment assignment. This can lead to biased reporting or more aggressive searching for bleeding symptoms in the 12-month DAPT group (who expect more bleeding) or under-reporting in the experimental group. A tough reviewer would demand a strictly blinded, independent clinical events committee (CEC) to adjudicate all suspected events to mitigate this threat to internal validity.

Guideline Committee
Guideline Committee

Current ACC/AHA and ESC guidelines recommend a standard 6-12 month DAPT duration for most patients post-DES. Does STOPDAPT-2 provide sufficient evidence to change the Class of Recommendation for 1-month DAPT in non-high-bleeding-risk (HBR) patients, or is its impact limited by its geographic homogeneity?

Key Response

While STOPDAPT-2 provides strong evidence for 1-month DAPT (Class I or IIa in specific HBR scenarios), its implementation into general guidelines for non-HBR patients is tempered by its Japanese-only cohort. Current guidelines (e.g., 2023 ESC Guidelines on ACS) are moving toward shorter DAPT (3-6 months as standard), but 1-month durations are typically reserved for those at high bleeding risk (HBR) until more multi-ethnic, large-scale RCT evidence confirms the ischemic safety of such an ultra-short protocol globally.

Clinical Landscape

Noteworthy Related Trials

2018

GLOBAL LEADERS Trial

n = 15,968 · Lancet

Tested

1-month DAPT followed by 23-month ticagrelor monotherapy

Population

Patients undergoing PCI with biolimus-eluting stents

Comparator

12-month DAPT followed by 12-month aspirin monotherapy

Endpoint

All-cause mortality or new Q-wave MI at 2 years

Key result: The experimental strategy of ticagrelor monotherapy did not significantly reduce the primary endpoint compared to standard DAPT.
2019

SMART-CHOICE Trial

n = 2,993 · JAMA

Tested

3-month DAPT followed by P2Y12 inhibitor monotherapy

Population

Patients undergoing PCI with drug-eluting stents

Comparator

12-month DAPT

Endpoint

Major Adverse Cardiac and Cerebrovascular Events (MACCE) at 12 months

Key result: P2Y12 inhibitor monotherapy was noninferior to prolonged DAPT regarding the risk of MACCE.
2019

TWILIGHT Trial

n = 7,119 · NEJM

Tested

Ticagrelor monotherapy after 3-month DAPT

Population

High-risk patients undergoing PCI

Comparator

Ticagrelor plus aspirin for 12 months

Endpoint

Bleeding Academic Research Consortium (BARC) type 2, 3, or 5 bleeding

Key result: Ticagrelor monotherapy resulted in a significantly lower incidence of clinically relevant bleeding without increasing the risk of ischemic events.

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