Reviews/P2Y12 Antiplatelets/Short DAPT is noninferior to 12-month DAPT for ischemic events post-PCI
Duration · P2Y12-DUR-01 · v1
Several head-to-head trials gave some heart-stented patients a brief course of two blood thinners and then a single potent platelet drug, and compared them with patients kept on both drugs for a full year. For the clot-related outcomes these shorter-course patients did about as well as the year-long group [1],[15],[17],[18]. The picture is not uniform: one trial in patients with a recent heart attack, which simply dropped a drug at six months rather than switching to a potent single agent, saw heart attacks occur more than twice as often [2]. Other studies found that patients with more complex or extensive blockages still gained protection from clotting events by staying on both drugs longer [3],[6],[10]. The panel therefore treats the shorter strategy as a reasonable equal in many patients but not a universal rule, which is why it sits below the top tier.
Four direct noninferiority randomized trials comparing a short course of dual therapy followed by P2Y12 monotherapy against 12 months of dual therapy met their noninferiority thresholds for ischemic or combined cardiac-cerebrovascular endpoints, together enrolling over 14,000 patients [1],[15],[17],[18]. In SMART-CHOICE the composite of death, myocardial infarction, or stroke was 2.9% versus 2.5% [17], and in SHARE major cardiac and cerebrovascular events were 1.5% versus 2.0% [1]. The one direct trial that dropped a drug to leave aspirin-based six-month therapy in acute coronary syndrome met its composite margin yet showed myocardial infarction occurring more frequently in the short arm [2]. Pooled and observational data point the other way in higher-risk anatomy: long-term therapy reduced ischemic events in complex, non-high-bleeding-risk PCI [3] and in multivessel disease [6], and a left-main cohort showed a lower composite event rate with therapy beyond 12 months (2.6% versus 4.6%) [10]. The contested point: The evidence divides on whether noninferiority holds across all populations and strategies. Direct trials of short therapy plus potent monotherapy support it [1],[15],[17],[18], while the acute-coronary-syndrome trial [2] and the complex, multivessel, and left-main data [3],[6],[10] show short duration ceding ischemic protection in sicker or higher-risk anatomy.
All 18 papers behind this claim with their DOIs and what each does to it, the panel’s arbitration, the evidence gap map and the open research questions. Free, and sent to your inbox.
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The supporting RCTs ([1],[15],[17],[18]) test short DAPT followed by potent P2Y12 inhibitor MONOTHERAPY, not true antiplatelet discontinuation; the bare claim 'short DAPT' overreaches past the monotherapy-continuation strategy actually tested.
SMART-DATE [2], the one direct trial of aspirin-based 6-month DAPT in ACS, showed myocardial infarction more than doubled (HR 2.41, p=0.02); its authors explicitly decline to conclude short-term DAPT is safe in ACS-PCI.
Where it remains uncertain. A six-month aspirin-based trial in acute coronary syndrome showed myocardial infarction occur more than twice as often [2], and longer therapy still reduced ischemic events in multivessel and left-main disease [6],[10].
Aleatory
SHARE reports lower-than-expected event rates and states further research is required, so apparent equivalence partly reflects sparse events rather than demonstrated equality [1].
The load-bearing papers from a corpus of 18, each classified by what it does to the claim. Every DOI is taken from the corpus the claim was graded on.
Direct: no significant ischemic difference for 3-month short DAPT vs 12-month.
“major adverse cardiac and cerebrovascular events occurred in 8 patients (1.5%) in the P2Y12 inhibitor monotherapy group and in 12 patients (2.0%) in the DAPT group (absolute difference, -0.49 [95% CI, -2.07 to 1.09] percentage points; P = .54).”
Panel auditInternal validity: medium · scope of inference: Patients with coronary artery disease undergoing PCI with bioabsorbable-polymer everolimus-eluting stents in South Korea.Key limitations: open-label · low event rate / underpowered · ischemic result is secondary not primary endpoint
Counter-evidence: extending DAPT beyond 12 months further reduced ischemic events in multivessel disease.
“A primary efficacy end-point event occurred in 222 patients in the DAPT group and in 266 patients in the aspirin-monotherapy group (36-month Kaplan-Meier cumulative incidence, 5.8% vs. 6.8%; hazard ratio, 0.82; 95% confidence interval [CI], 0.69 to 0.98; P = 0.03).”
Panel auditInternal validity: medium · scope of inference: Event-free stable patients with multivessel coronary disease 12 months after DES implantation in China.Key limitations: no short-DAPT arm · extended-vs-standard contrast · open-label
Direct NI of ischemic endpoint for 1-month short DAPT vs 12-month.
“The major secondary cardiovascular end point occurred in 1.96% with 1-month DAPT and 2.51% with 12-month DAPT (absolute difference, -0.55% [95% CI, -1.62% to 0.52%]; HR, 0.79 [95% CI, 0.49-1.29]), meeting criteria for noninferiority (P = .005) but not for superiority (P = .34).”
Panel auditInternal validity: medium · scope of inference: Patients undergoing PCI with drug-eluting stents at 90 hospitals in Japan.Key limitations: open-label · wide relative noninferiority margin · ischemic endpoint secondary
Discordant direct evidence: 6-month aspirin-based short DAPT increased MI in ACS.
“myocardial infarction occurred more frequently in the 6-month DAPT group than in the 12-month or longer DAPT group (24 [1·8%] patients vs ten [0·8%]; 2·41 [1·15-5·05]; p=0·02).”
Panel auditInternal validity: medium · scope of inference: Patients with acute coronary syndrome (unstable angina, NSTEMI, STEMI) undergoing PCI with current-generation DES in South Korea.Key limitations: open-label · wide noninferiority margin · MI signal against short DAPT
4 of 18 papers shown. The full review lists all of them, with the panel’s arbitration →
Claims are graded at each quarterly release, and re-graded between releases only when a pivotal trial lands. Every change is a new version of the claim.
Consistent direct RCT support warrants a high tier, but the SMART-DATE MI signal, generous margins, East Asian predominance, and longer-DAPT ischemic benefit in complex disease hold confidence below Established.
Release 2026-q4 re-graded every claim from its corpus under protocol v0.19. An earlier release's grade is shown for the record; it came from an earlier protocol and is not a movement.
Assumptions that carry weight but are not themselves established.
The panel records the gap that would most move the claim, and the study that would close it.
Short duration in acute coronary syndrome. The only direct ACS trial dropped to aspirin-based six-month therapy and saw myocardial infarction occur more frequently, so short-duration safety in ACS is unresolved [2]. The panel rates this the highest-importance open gap for the claim, and names the study design that would close it: A direct noninferiority RCT of short DAPT followed by potent P2Y12 monotherapy versus 12-month DAPT, restricted to ACS-PCI, powered on ischemic endpoints.
Open question: Is short DAPT followed by potent P2Y12 monotherapy ischemically noninferior to 12-month DAPT specifically in acute coronary syndrome? Why it is still open: The only direct ACS trial used aspirin-based six-month therapy and showed myocardial infarction occur more frequently, and its authors declined to conclude short-term therapy is safe in ACS [2].
Priors is a sceptical first reader, not peer review, and not medical advice.
Release 2026-q4 · graded 21 Oct 2026 · protocol v0.19