DAPT Calculator
Estimate your daptcalculator with our free cardiovascular system calculator. See reference ranges, risk factors, and next-step guidance.
Reviewed by Rahul Singh, Health & Wellness Specialist
Formula
DAPT Score = Age points + Smoking + Diabetes + MI + Prior PCI + Stent size + Stent type + CHF + Vein graft
Age provides -2 (75+), -1 (65-74), or 0 (<65) points. Other factors add +1 or +2 points each. Total ranges from -2 to 10. Score of 2 or higher favors extended 30-month DAPT; below 2 favors standard 12-month duration.
Worked Examples
Example 1: Score Favoring Prolonged DAPT
Problem:A 58-year-old male smoker with diabetes who presented with MI, received a 2.5mm DES. No prior PCI, no CHF, no vein graft. Calculate DAPT score at 12 months.
Solution:Age <65: 0 points\nCigarette smoking: +1\nDiabetes: +1\nMI at presentation: +1\nPrior PCI/MI: 0\nStent diameter <3mm: +1\nPaclitaxel stent: 0\nCHF/LVEF <30%: 0\nVein graft: 0\nTotal DAPT Score = 4
Result:DAPT Score: 4 (>=2, prolonged DAPT for 30 months is favored)
Example 2: Score Favoring Standard Duration
Problem:A 76-year-old non-smoking, non-diabetic patient who had elective PCI with a 3.5mm DES for stable angina. No prior PCI, no CHF, no vein graft.
Solution:Age >=75: -2 points\nCigarette smoking: 0\nDiabetes: 0\nMI at presentation: 0 (stable angina)\nPrior PCI/MI: 0\nStent diameter <3mm: 0 (3.5mm stent)\nPaclitaxel stent: 0\nCHF/LVEF <30%: 0\nVein graft: 0\nTotal DAPT Score = -2
Result:DAPT Score: -2 (<2, standard 12-month DAPT duration is favored)
Frequently Asked Questions
What is the DAPT score and what does it determine?
The DAPT (Dual Antiplatelet Therapy) score is a clinical decision-support tool developed to help determine the optimal duration of dual antiplatelet therapy after coronary stent implantation. The score was derived from the landmark DAPT Study, which randomized over 11,000 patients who had tolerated 12 months of DAPT without events to either continued thienopyridine therapy or placebo for an additional 18 months. The score integrates nine clinical and procedural variables to produce a value ranging from -2 to 10. A score of 2 or higher identifies patients who derive greater ischemic benefit from prolonged DAPT (30 months) relative to the increased bleeding risk, while a score below 2 suggests the bleeding risk of extended therapy outweighs the ischemic benefit. The tool helps personalize treatment duration rather than applying a one-size-fits-all approach.
How is the DAPT score calculated and what are its components?
The DAPT score assigns points based on nine clinical and procedural factors assessed at the time of the decision about extending DAPT beyond 12 months. Age provides negative points: age 75 or older gets -2, age 65-74 gets -1, and age under 65 gets 0 points. Positive points are assigned for current cigarette smoking (+1), diabetes mellitus (+1), MI at presentation (+1), prior PCI or prior MI (+1), stent diameter less than 3 mm (+1), paclitaxel-eluting stent (+1), CHF or LVEF less than 30 percent (+2), and saphenous vein graft PCI (+2). The total score ranges from -2 to 10. The scoring reflects the balance between ischemic risk factors (which favor prolonged therapy) and bleeding risk factors (primarily age, which favors shorter therapy).
When should the DAPT score be applied in clinical practice?
The DAPT score should be applied at or around the 12-month mark after coronary stent implantation to guide the decision about whether to continue or discontinue the P2Y12 inhibitor component of dual antiplatelet therapy. Critically, the score is only valid for patients who have completed 12 months of DAPT without experiencing a major bleeding event, myocardial infarction, or stroke during that period. Patients who have complications during the initial 12 months require individualized assessment rather than score-based guidance. The score is most applicable to patients who received drug-eluting stents, as bare-metal stents typically require only 1 month of DAPT. Additionally, the score was developed primarily for patients on clopidogrel and may not directly apply to those on prasugrel or ticagrelor, though the risk factor principles remain relevant.
What are the risks of stent thrombosis if DAPT is stopped too early?
Stent thrombosis is among the most feared complications after coronary intervention, occurring when a blood clot forms within the stent and abruptly occludes the coronary artery. It presents as acute myocardial infarction with mortality rates of 20 to 45 percent per event. Stent thrombosis is classified by timing: acute (within 24 hours), subacute (1-30 days), late (30 days to 1 year), and very late (beyond 1 year). Premature discontinuation of DAPT is the strongest predictor of stent thrombosis, with risk increasing 90-fold in the first 30 days and remaining elevated for months. First-generation drug-eluting stents had higher rates of very late stent thrombosis (0.4-0.6 percent per year) compared to newer-generation stents (0.1-0.2 percent per year), which have thinner struts and more biocompatible polymers. The improved safety profile of contemporary stents has enabled consideration of shorter DAPT durations in selected low-risk patients.
References
- Yeh RW, et al. Development and Validation of a Prediction Rule for Benefit and Harm of Dual Antiplatelet Therapy. JAMA. 2016;315(16):1735-1749.
- Mauri L, et al. Twelve or 30 Months of Dual Antiplatelet Therapy after Drug-Eluting Stents (DAPT Study). N Engl J Med. 2014;371(23):2155-2166.
- Levine GN, et al. 2016 ACC/AHA Focused Update on Duration of DAPT. Circulation. 2016;134(10):e123-e155.
Reviewed by Rahul Singh, Health & Wellness Specialist · Editorial policy