How this instrument works
The DAPT score comes from a 2016 JAMA paper by Yeh, Secemsky, Kereiakes, and colleagues, derived from the DAPT Study — a randomized trial of close to 10,000 patients who had already completed 12 months of dual antiplatelet therapy after coronary stenting without a major bleeding or ischemic event — and validated separately in the PROTECT trial. The question it answers is narrow and specific: among patients who tolerated a year of treatment, who benefits enough from continuing another 18 months to justify the added bleeding exposure?
Eight of the nine factors add points for ischemic risk: current smoking, diabetes, a heart attack at presentation, a prior PCI or heart attack, a stent under 3mm, a paclitaxel-eluting stent, congestive heart failure or a low ejection fraction, and stenting of a saphenous vein graft each contribute 1 or 2 points. The ninth factor, age, is the only one that subtracts — 0 points under 65, −1 for 65 to 74, −2 at 75 or older — and it comes first in the sum rather than as an afterthought.
That subtraction is not an oversight. Older patients are simultaneously more likely to bleed on extended antiplatelet therapy and less likely to gain the ischemic benefit that would justify the extra bleeding exposure, so age pulls the total toward stopping sooner even as other risk factors pull it toward continuing. A total of 2 or higher identifies patients in whom the derivation data showed extended therapy reduced heart attack and stent thrombosis without a matching rise in major bleeding; below 2, the trade-off tips the other way.
The score only applies to the population it was built from: patients who already completed a full year of dual antiplatelet therapy uneventfully. It says nothing about patients who cannot tolerate that first year, and it is not a bleeding-risk score in the way PRECISE-DAPT is — it weighs ischemic benefit and bleeding harm together into one number, calculated at the 12-month mark rather than at the time of stenting.
- Set Age — under 65 scores 0, 65 to 74 scores −1, 75 or older scores −2.
- Set Smoker, Diabetes, MI at presentation, Prior PCI or MI, Stent under 3mm, and Paclitaxel-eluting stent, each Yes or No.
- Set CHF or LVEF under 30% and Saphenous vein graft PCI, each worth 2 points if present.
- Read the DAPT score; 2 or higher favors extended therapy, below 2 favors the standard duration.
Worked example — 65–74, smoker, diabetic, paclitaxel stent
A 65-to-74-year-old, a current smoker with diabetes, who had a heart attack at presentation and received a paclitaxel-eluting stent, with no prior PCI or MI, no small stent, no heart failure, and no vein-graft PCI. Age term: −1. Smoker: +1. Diabetes: +1. MI at presentation: +1. Paclitaxel stent: +1. The other four factors: 0 each. Total: −1 + 1 + 1 + 1 + 0 + 0 + 1 + 0 + 0 = 3 — at or above the 2-point threshold, favoring extended dual antiplatelet therapy.
Age alone can swing the total a long way. A patient 75 or older with none of the eight ischemic risk factors present scores −2, favoring the standard 12-month duration outright. At the opposite extreme, a patient under 65 with every risk factor present — smoker, diabetic, MI at presentation, prior PCI or MI, a small stent, a paclitaxel stent, heart failure, and vein-graft PCI — sums to 0+1+1+1+1+1+1+2+2 = 10, the maximum possible score, strongly favoring the extended 30-month course.
Questions
Why does age subtract from the DAPT score instead of adding?
Because age works against extended therapy from two directions at once. Older patients bleed more easily on prolonged dual antiplatelet therapy, and the derivation data showed they also gain less ischemic protection from continuing past 12 months than younger patients do. Rather than treat age as neutral, the score subtracts points for it before any ischemic risk factors are added, so an older patient needs more countervailing ischemic risk to still land in favor of extension.
What does a DAPT score of 2 or higher actually mean?
In the derivation and validation cohorts, patients scoring 2 or higher who continued dual antiplatelet therapy to 30 months had fewer heart attacks and less stent thrombosis than those who stopped at 12 months, without a corresponding rise in major bleeding. Patients scoring below 2 showed the opposite pattern — continuing added bleeding risk without a matching ischemic benefit. The threshold marks where that trade-off flips, not a guarantee of outcome for any individual patient.
Who does the DAPT score actually apply to?
Only patients who have already completed 12 months of dual antiplatelet therapy after coronary stenting without a major bleeding event or a major ischemic event in that first year. It is a tool for the 'continue or stop' decision at that 12-month mark, not a tool for deciding how to start antiplatelet therapy or for patients who couldn't tolerate the first year at all.
Is the DAPT score the same thing as PRECISE-DAPT?
No — they answer different questions at different times. PRECISE-DAPT is calculated around the time of stenting and focuses specifically on predicting bleeding risk to help set an initial treatment duration. The DAPT score is calculated at the 12-month mark, only in patients who tolerated that first year, and weighs both ischemic benefit and bleeding harm together to guide whether to extend.
Why is a paclitaxel-eluting stent scored as a risk factor?
In the DAPT Study cohort, paclitaxel-eluting stents were associated with a higher rate of late stent thrombosis than some other drug-eluting stent types, so the derivation analysis carried that forward as a 1-point risk factor. It reflects the stent technology used in that trial population rather than a universal property of every paclitaxel-coated device on the market today.
Does a score below 2 mean extended therapy is unsafe?
Not automatically — the score reflects average outcomes across the derivation population, not a hard rule for any one patient. A low score means the population-level trade-off leans toward stopping at 12 months, but individual factors like a strong personal reason to fear stent thrombosis, or conversely a personal bleeding history the score doesn't capture, should still shape the final decision alongside the number.
References
- Yeh et al. 2016, JAMA — DAPT score derivation and validation (PubMed)
- Mauri et al. 2014, N Engl J Med — the DAPT Study trial (PubMed)
Read this first: This instrument computes a screening figure from population formulas — it is not a diagnosis, and it cannot see the whole picture a clinician can. Use it to inform a conversation, not to replace one.