A year after a coronary stent is placed, medicine has long struggled to answer a deceptively simple question: how much protection is enough, and at what cost? A large Korean trial presented this summer at the European Society of Cardiology Congress offers not a universal answer, but something more honest — evidence that the right choice depends on who the patient is, how many risks they carry, and how those risks compound one another. In high-risk patients, continuing aspirin alongside clopidogrel beyond the first year reduced heart attacks and deaths, even as it raised the likelihood of bleed
Korean trial shows extended aspirin use cuts heart attack risk after stenting
The more the risks overlapped, the worse the outcomes were.
Mark
So the trial shows that continuing aspirin doesn't help overall—the combined event rate is basically the same. Why does Kim argue for extended dual therapy?
Mimi
Because the combined endpoint masks what actually happened. Ischemic events—heart attacks, strokes, deaths—were cut in half with dual therapy. Bleeding went up, yes, but Kim's point is that you can't treat a fatal heart attack and a bleeding complication as equivalent harms. The mortality difference alone, 1.3 percent versus 0.4 percent, suggests the protection matters.
Luke
But that's a single-trial finding in a specific population. The trial was open-label, meaning both doctors and patients knew which treatment they were getting, which can bias how events are reported. And it enrolled fewer events than the researchers anticipated. How confident should we be in those mortality numbers?
Mimi
Fair questions. The open-label design is a real limitation. But the mortality difference was substantial enough that it showed up despite those constraints. And the trial did follow patients for three years total, so there was time for events to accumulate.
Mark
What about the patients themselves—who actually benefits from this? Is it everyone with a stent?
Mimi
No, that's the key insight. The trial enrolled only high-risk patients—people with acute coronary syndrome, diabetes, complex coronary anatomy, multivessel disease. And Kim found that the more risk factors a patient had, the worse their outcomes were. So it's not a one-size-fits-all answer.
Luke
But the trial doesn't tell you which specific combination of factors should trigger dual therapy versus monotherapy. Kim says further analyses are underway to clarify that. So clinicians don't actually have a decision tool yet—they have evidence that high-risk patients do better on dual therapy, but no precise way to identify who is high-risk enough.
Mimi
True. The trial included both clinical factors and anatomical features—things like left main disease or chronic total occlusion—and Kim argues that's important because a patient's treatment needs reflect both their underlying disease and the complexity of what was treated. But you're right that the next step is translating that into a practical scoring system.
Mark
What about the bleeding risk? Four percent is not trivial.
Mimi
It's not. But in this population—younger than 80, no need for anticoagulation—the bleeding was serious but manageable. And the trial showed that adding aspirin didn't tank adherence. Patients tolerated it.
Luke
One more thing: this is all Korean patients. Kim himself notes that we shouldn't assume the results apply equally to other populations. The trial excluded older patients and those on anticoagulation, so we don't know how the findings hold in those groups. And women were only 18 percent of the trial population.
Mimi
All true. The findings are strongest for the population studied. Whether they generalize requires more research. But within that population, the evidence is clear: extended dual therapy reduces ischemic events in high-risk patients, even if it increases bleeding.
The Pulse
- For patients with stents and overlapping risk factors — diabetes, complex coronary anatomy, prior acute coronary syndrome — the threat of a future heart attack or stroke does not simply fade after the first year of recovery.
- The A-CLOSE trial's headline numbers created immediate tension: dual therapy cut ischemic events nearly in half (1.6% vs 3.7%) but more than doubled serious bleeding (4.1% vs 1.8%), leaving no clean winner in the combined endpoint.
- All-cause mortality told a starker story — 0.4% versus 1.3% — signaling that the ischemic side of the ledger carries a weight that raw percentages can obscure.
- The trial's 3,203 Korean patients revealed a compounding effect: the more risk factors a patient accumulated, the worse their outcomes, shifting the clinical question from 'which factor matters most' to 'how do they interact in this person.'
- Researchers and clinicians are now navigating toward individualized reassessment at the one-year mark, using a patient's specific burden of ischemic and bleeding risk to guide whether aspirin should be continued or withdrawn.
- The field remains open — questions about therapy duration beyond two years and the role of more potent agents like ticagrelor or prasugrel are unresolved, but the one-year decision now rests on considerably firmer evidence.
A year after a coronary stent is placed, medicine has long struggled to answer a deceptively simple question: how much protection is enough, and at what cost? A large Korean trial presented this summer at the European Society of Cardiology Congress offers not a universal answer, but something more honest — evidence that the right choice depends on who the patient is, how many risks they carry, and how those risks compound one another. In high-risk patients, continuing aspirin alongside clopidogrel beyond the first year reduced heart attacks and deaths, even as it raised the likelihood of bleeding, reminding clinicians that individualized judgment, not protocol alone, is the instrument of care.
A year after a coronary stent procedure, patients and their doctors face a question with no perfect answer: stay on two blood thinners, or step back to one? The A-CLOSE trial, conducted across 19 Korean hospitals and presented at the European Society of Cardiology Congress in Munich in late August, was designed to bring clarity to exactly that moment. Its 3,203 participants had all received drug-eluting stents and carried meaningful risk of future cardiac events. At the one-year mark, they were randomly assigned either to continue clopidogrel alone or to add aspirin back for two more years.
The combined primary endpoint — death, heart attack, stent clotting, stroke, and serious bleeding — showed no overall difference between groups, at roughly 5% each. But the components diverged sharply. Patients on clopidogrel alone experienced ischemic events at a rate of 3.7%, compared to 1.6% in those continuing both drugs. Bleeding ran in the opposite direction: 1.8% with monotherapy versus 4.1% with dual therapy. All-cause mortality was notably higher in the single-drug group — 1.3% versus 0.4% — a gap that Professor Kim Byeong-keuk of Severance Hospital, who led the trial, described as clinically significant in a way that aggregate percentages alone fail to capture.
The trial's deeper contribution was in mapping which patients benefit most from continued dual therapy. Participants carried overlapping risk factors — acute coronary syndrome, diabetes, chronic kidney disease, and complex coronary anatomy — and Kim's analysis showed that as these risks accumulated in a single patient, outcomes worsened in compounding ways. The question shifted from whether clinical or anatomical factors mattered more to recognizing that their combination determined individual need.
Kim also noted that the differences in both bleeding and ischemic events widened gradually across the two-year follow-up, not just in the early weeks — suggesting the treatment decision remained consequential well beyond the initial recovery period. He cautioned against allowing generalized concerns about bleeding susceptibility in Asian populations to override assessment of an individual patient's ischemic burden.
A-CLOSE does not resolve how long dual therapy should extend beyond two years, nor does it address more potent antiplatelet agents. What it provides is a clearer foundation for the one-year reassessment: in patients with substantial overlapping ischemic risks, continuing aspirin offers measurable protection against heart attack and death, even at the cost of increased bleeding. The task now is matching that evidence to each patient's particular constellation of risks — a judgment that, for the first time, has concrete data behind it.
A year after a stent is placed in a blocked coronary artery, a patient faces a choice that has no perfect answer. Should they continue taking two blood thinners—aspirin and clopidogrel—to prevent the artery from closing again? Or should they step back to one drug, accepting a higher risk of clotting in exchange for a lower risk of dangerous bleeding? A Korean trial presented this summer offers the clearest evidence yet that the answer depends entirely on who the patient is.
The A-CLOSE trial, conducted across 19 Korean hospitals and presented at the European Society of Cardiology Congress in Munich on August 29, enrolled 3,203 patients who had received drug-eluting stents and carried substantial risk of future heart attacks. At the one-year mark after their procedure, researchers randomly assigned them either to continue clopidogrel alone or to add aspirin back for another two years of dual therapy. The results, published simultaneously in the New England Journal of Medicine, showed no difference in the combined rate of death, heart attack, stent clotting, stroke, and serious bleeding—5.0 percent in the single-drug group versus 5.1 percent in the dual-therapy group. But the components told opposite stories.
Patients taking only clopidogrel suffered more ischemic events—heart attacks, strokes, deaths—at a rate of 3.7 percent compared to 1.6 percent in those continuing both drugs. Bleeding complications, by contrast, occurred in 1.8 percent of the monotherapy group and 4.1 percent of the dual-therapy group. All-cause mortality was notably higher with clopidogrel alone: 1.3 percent versus 0.4 percent. Professor Kim Byeong-keuk of Severance Hospital, who led the trial, emphasized that these numbers cannot simply be weighed against each other as if one life saved from bleeding equals one life saved from a heart attack. The ischemic endpoint included death itself, making the mortality difference clinically significant in a way that raw percentages alone do not convey.
The trial's real contribution lies not in declaring a universal winner but in identifying which patients benefit from which approach. The 3,203 participants carried overlapping risk factors—acute coronary syndrome, diabetes, chronic kidney disease, complex coronary anatomy including left main disease, bifurcation lesions, chronic total occlusion, and multivessel disease. Kim's analysis revealed that the more these risks accumulated in a single patient, the worse the outcomes became. A patient with diabetes and a complex lesion faced different stakes than one with either risk alone. This observation shifted the question from whether clinical or anatomical factors mattered more to recognizing that their combination determined individual need.
Kim noted that the trial examined a treatment decision later than most prior studies—not whether to shorten dual therapy immediately after stenting, but whether to continue it beyond the first year in patients already identified as high-risk. The differences in both bleeding and ischemic events widened gradually throughout the two-year follow-up, suggesting the choice remained relevant well beyond the initial recovery period. Events continued occurring throughout those 24 months, not just in the early weeks.
The findings carry particular weight for how clinicians approach East Asian patients. Kim cautioned against allowing concerns about bleeding susceptibility in Asian populations to overshadow individual ischemic burden. The trial population was entirely Korean, with women comprising 18.4 percent of participants, and it excluded patients over 80 or those requiring long-term anticoagulation for other conditions. Treatment adherence did not differ meaningfully between groups, and adding aspirin did not substantially reduce how well patients stuck with their medications.
Kim emphasized that A-CLOSE does not settle the question of how long dual therapy should continue beyond two years, nor does it address whether more potent blood thinners like prasugrel or ticagrelor might change the calculus. What it does provide is concrete evidence for the one-year reassessment conversation: in patients with substantial overlapping ischemic risk factors, continuing aspirin alongside clopidogrel offers measurable protection against heart attack and death, even as it increases bleeding risk. The practical task ahead is matching that evidence to each patient's particular constellation of risks—a decision that now rests on firmer ground.
Notable Quotes
We cannot simply say that one outcome went up and the other went down, so they cancel each other out. The ischemic endpoint included death, and mortality differed between the groups.— Professor Kim Byeong-keuk, Severance Hospital
We should not become so focused on the idea that we are different that we overlook ischemic risk or emphasize bleeding factors too much.— Professor Kim Byeong-keuk, on assessing East Asian patients
Want the full story?
Read the original at Korea Biomedical Review ↗
Health & Medicine