Dual antiplatelet therapy combines aspirin (typically 81 mg) with a P2Y12 receptor inhibitor (clopidogrel 75 mg, ticagrelor 90 mg BID, or prasugrel 10 mg daily). This combination prevents platelet activation through two distinct pathways, dramatically reducing stent thrombosis and recurrent coronary events after PCI.

Why not give DAPT indefinitely?

While DAPT reduces ischemic events, it increases bleeding risk — particularly gastrointestinal and intracranial hemorrhage. After 12 months, the incremental ischemic benefit decreases while bleeding risk accumulates linearly. The optimal strategy balances these competing risks based on individual patient factors.

What is triple therapy?

Triple therapy is the combination of oral anticoagulation (OAC) + aspirin + P2Y12 inhibitor, used when a patient with atrial fibrillation (or another OAC indication) undergoes PCI. It dramatically increases bleeding risk (2–3× vs. DAPT alone) and should be minimized to the shortest possible duration, typically 1–4 weeks.

Which P2Y12 inhibitor should I use?

For ACS: ticagrelor or prasugrel are preferred over clopidogrel. Ticagrelor (PLATO) reduced cardiovascular death by 21%. Prasugrel (TRITON-TIMI 38) reduced stent thrombosis but increased bleeding. For stable angina/elective PCI: clopidogrel is standard. For patients on OAC: clopidogrel is preferred (lower bleeding risk in triple/dual pathway therapy).

Can DAPT be stopped for surgery?

DAPT interruption for non-cardiac surgery should be avoided within 30 days of BMS or 3–6 months of DES. If surgery is urgent, continue aspirin and stop P2Y12 inhibitor 5–7 days before (clopidogrel, ticagrelor) or 7 days before (prasugrel). Always consult the patient's cardiologist.

What is the risk of stopping DAPT too early?

Premature DAPT discontinuation is the strongest predictor of stent thrombosis, which occurs acutely (clot formation within the stent) and is fatal in 20–40% of cases. The risk is highest in the first 30 days, but drug-eluting stents require longer DAPT because they delay endothelialization.

Dual Antiplatelet Therapy Duration Calculator

Review DAPT-duration context after coronary stenting using published bleeding and ischemic risk factors. DAPT score with stent type and OAC considerations.

⚠️ Medical Disclaimer: DAPT duration decisions require cardiology input. This calculator provides guidance based on published scoring systems but should not replace individualized clinical decision-making.

Age

years

Indication

Stent Type

On Oral Anticoagulant (OAC)?

Prior Major Bleeding?

Risk Criteria:

DAPT Score

0.0 points

Bleeding risk category: 3.6%

Recommended DAPT Duration

12–30 months

ACS patients benefit from extended DAPT unless bleeding risk is high.

Bleeding Risk

3.6%

Extended DAPT (>12 months) may be beneficial

Ischemic Risk

Standard — balance with bleeding risk

OAC Consideration

No OAC — standard DAPT guidance applies.

Relationship between two quantities

Prior Bleeding

No prior major bleeding.

Bleeding Risk by DAPT Score

Score	Bleeding Risk	Recommendation	Status
0	3.6%	Extended DAPT (>12 months) may be beneficial	◀ Your score
1	7.5%	Standard 12 months DAPT; consider extension
2	12.1%	Standard 6–12 months; bleeding risk rising
3	17.8%	Shorten to 6 months; high bleeding concern
4	26.0%	Consider 3–6 months DAPT only
5	35%+	Minimum duration; consult cardiology

DAPT Regimens

Regimen	Typical Duration	Common Use
Aspirin + Clopidogrel	6–12 months	Standard DAPT; lowest bleeding risk
Aspirin + Ticagrelor	12 months	ACS — superior to clopidogrel (PLATO)
Aspirin + Prasugrel	12 months	ACS with PCI — avoid in stroke/TIA/age ≥75
OAC + Clopidogrel	1–12 months	AF + PCI — dual pathway without aspirin

Planning notes, formulas, and examples

About the Dual Antiplatelet Therapy Duration Calculator

The Dual Antiplatelet Therapy (DAPT) Duration Calculator helps determine the optimal duration of dual antiplatelet therapy after coronary stenting or acute coronary syndrome by balancing bleeding risk against ischemic risk. DAPT — typically aspirin plus a P2Y12 inhibitor (clopidogrel, ticagrelor, or prasugrel) — is the cornerstone of post-PCI management, but the optimal duration remains one of the most debated topics in interventional cardiology.

Too short a course risks stent thrombosis and recurrent ischemic events, while excessively prolonged DAPT increases the risk of major bleeding. The DAPT Score, derived from the DAPT Study (12,866 patients), integrates multiple clinical factors to generate a composite risk score that predicts the net benefit of extended vs. shortened DAPT.

This calculator evaluates the entered factors as a worksheet for comparing DAPT-duration context, including age, indication, stent type, comorbidities, and concomitant anticoagulation. It also accounts for the increasingly common scenario of patients requiring oral anticoagulation (OAC) for atrial fibrillation, where triple therapy must be minimized to prevent life-threatening bleeding.

When This Page Helps

DAPT duration affects both stent thrombosis risk and bleeding risk, so the decision should reflect the individual patient scenario. A score-based approach can help frame the balance between extending therapy and stopping earlier.

How to Use the Inputs

Enter your age.
Select the indication (ACS or stable angina/elective PCI).
Select the stent type used.
Indicate if you're on oral anticoagulation (e.g., warfarin, DOAC).
Indicate any prior major bleeding history.
Select all applicable clinical risk factors.
Review the recommended DAPT duration and risk assessment.

Formula used

DAPT Score = Sum of weighted risk criteria:
• Age ≥ 75: +1 point
• Age 65–74: +0.5 points
• Diabetes: +1
• Renal dysfunction (CrCl <60): +1
• Current smoking: +1
• Prior MI/ACS: +1
• Prior PCI/CABG: +1
• Heart failure (EF <30%): +1
• Paclitaxel-eluting stent: +1
• Small vessel (<3mm): +1

Higher score = greater potential net benefit from prolonged DAPT; lower score = shorter DAPT is usually favored when bleeding risk dominates

Example Calculation

Result: DAPT Score: 2.5 — Recommended duration: 12 months

Age 68 (65–74 = 0.5 points), diabetes (1 point), prior MI (1 point) = 2.5 total points. This moderate bleeding risk balances against the ischemic benefit of extended DAPT in ACS. Standard 12-month DAPT is appropriate. No OAC simplifies management.

Tips & Best Practices

The DAPT Score was originally designed for decisions about extending DAPT beyond 12 months; scores ≥2 suggest more net benefit from extension in the right clinical context.
Ticagrelor is preferred over clopidogrel in ACS (PLATO trial: 16% relative reduction in cardiovascular death).
For patients on OAC + DAPT (triple therapy), drop aspirin early (1–4 weeks) and continue OAC + P2Y12 inhibitor.
P2Y12 inhibitor should not be stopped within 1 month of BMS or 3 months of DES without cardiology consultation.
Proton pump inhibitors (PPIs) should be co-prescribed with DAPT to reduce GI bleeding risk.
Genetic testing for CYP2C19 can identify poor metabolizers of clopidogrel who may benefit from ticagrelor or prasugrel.

The DAPT Study

The landmark DAPT Study randomized 9,961 patients who had received coronary stents to either continued DAPT (30 months total) or aspirin alone after 12 months. Extended DAPT reduced stent thrombosis (0.4% vs 1.4%) and MI (2.1% vs 4.1%) but increased GUSTO moderate/severe bleeding (2.5% vs 1.6%) and all-cause mortality (2.0% vs 1.5%). The DAPT Score was developed to identify patients who benefit from extension vs. those at higher net risk.

Modern Trends: Shorter DAPT

Recent trials (STOPDAPT-2, TWILIGHT, TICO) have demonstrated that shorter DAPT (1–3 months) followed by P2Y12 monotherapy (dropping aspirin) may be equally effective with less bleeding in selected patients. This "de-escalation" strategy is particularly appealing for older patients and those with high bleeding risk.

Managing DAPT with Anticoagulation

Approximately 5–8% of PCI patients require concurrent oral anticoagulation for atrial fibrillation. The WOEST, PIONEER AF-PCI, RE-DUAL PCI, and AUGUSTUS trials established that dual pathway therapy (OAC + single antiplatelet) is safer than triple therapy for most patients. Current guidelines recommend dropping aspirin after 1–4 weeks and continuing OAC + clopidogrel for 6–12 months.

Sources & Methodology

Last updated: March 28, 2026

Methodology

This worksheet summarizes the published DAPT score factors and related post-PCI context so users can compare bleeding and ischemic tradeoffs. It is a planning aid for discussion, not a prescription or a substitute for cardiology review.

Sources

DAPT Study (Mauri et al.) — Landmark randomized trial informing the DAPT score and extension context.
2016 ACC/AHA Focused Update on Duration of Dual Antiplatelet Therapy (ACC/AHA) — Guideline context for DAPT duration decisions after PCI or ACS.

Frequently Asked Questions

Dual antiplatelet therapy combines aspirin (typically 81 mg) with a P2Y12 receptor inhibitor (clopidogrel 75 mg, ticagrelor 90 mg BID, or prasugrel 10 mg daily). This combination prevents platelet activation through two distinct pathways, dramatically reducing stent thrombosis and recurrent coronary events after PCI.