💊 DAPT Score Calculator
Determine optimal duration of dual antiplatelet therapy after percutaneous coronary intervention (PCI) with drug-eluting stent.
What is DAPT?
Dual Antiplatelet Therapy (DAPT) refers to the combination of two antiplatelet medications — typically aspirin and a P2Y12 inhibitor (such as clopidogrel, prasugrel, or ticagrelor). This combination is the standard treatment after percutaneous coronary intervention (PCI) with drug-eluting stent placement.
The purpose of DAPT is to prevent stent thrombosis — a dangerous condition where blood clots form inside the stent, potentially leading to heart attack or death. However, prolonged DAPT also increases the risk of bleeding complications.
What Are Platelets?
Platelets (thrombocytes) are small, colorless cell fragments in the blood that play a critical role in hemostasis — the process of stopping bleeding. When a blood vessel is injured, platelets aggregate at the site to form a "platelet plug" that stops blood loss.
While this clotting function is essential for wound healing, it can become problematic when it occurs inside an artery, particularly around a stent. Antiplatelet medications work by preventing platelets from clumping together inappropriately.
The DAPT Score
The DAPT score was developed from data collected in the DAPT trial (Dual Antiplatelet Therapy Study), which enrolled 11,648 patients who had PCI with drug-eluting stents. The score helps clinicians decide whether to extend DAPT beyond the standard 12 months.
Score ≥ 2: Favors prolonged DAPT (continued thienopyridine + aspirin)
Score ≤ 1: Favors discontinuing thienopyridine (aspirin alone)
DAPT Score Components
| Criterion | Points |
|---|---|
| Age ≥ 75 | −2 |
| Age 65–74 | −1 |
| Age < 65 | 0 |
| Current/recent cigarette smoking | +1 |
| Diabetes mellitus | +1 |
| MI at presentation | +1 |
| Prior PCI or prior MI | +1 |
| Stent diameter < 3 mm | +1 |
| Paclitaxel-eluting stent | +1 |
| CHF or LVEF < 30% | +2 |
| Saphenous vein graft stent | +2 |
The total score ranges from −2 to +10.
Understanding the Score
The DAPT score balances two competing risks:
- Ischemic risk (stent thrombosis, MI): Higher scores indicate greater benefit from prolonged DAPT in preventing these events
- Bleeding risk: All patients on DAPT face increased bleeding risk; age is a major factor (hence the negative points for older patients)
Patients with a score ≥ 2 had a significantly reduced rate of stent thrombosis and MI with continued DAPT compared to aspirin alone, and the bleeding risk was acceptable. Patients with a score ≤ 1 did not benefit significantly from prolonged DAPT, and the bleeding risk outweighed the ischemic benefit.
How to Use This Calculator
- Select the patient's age category
- Indicate whether each of the 8 clinical criteria is present
- Click "Calculate DAPT Score"
- Review the total score and treatment recommendation
This calculator is designed for patients who have already completed 12 months of DAPT without major bleeding or ischemic events, to help decide whether to continue or discontinue the thienopyridine component.
Clinical Limitations
- The DAPT score was derived from patients with drug-eluting stents; applicability to bare-metal stents is limited
- Individual patient factors (e.g., history of GI bleeding, concurrent anticoagulation) should be considered
- Newer generation stents may have different thrombosis risk profiles
- The score does not account for all bleeding risk factors
⚠️ Disclaimer: This calculator is for educational purposes. Treatment decisions should be made in consultation with a cardiologist who can consider the full clinical picture.