What Is the Duke Treadmill Score?
The Duke Treadmill Score (DTS) is a widely validated prognostic tool used to stratify risk in patients with suspected or known coronary artery disease (CAD). Developed by researchers at Duke University Medical Center, this simple yet powerful scoring system integrates three key exercise stress test parameters: exercise duration, ST-segment deviation, and angina severity. The DTS provides a quantitative estimate of 5-year survival, helping clinicians identify patients at low, moderate, or high risk for cardiovascular events.
This calculator is designed for healthcare professionals, cardiology trainees, and patients who have undergone exercise stress testing using the Bruce protocol. By entering the three test parameters, you’ll receive a DTS score ranging from highly positive (low risk) to highly negative (high risk). The tool includes quick examples for common clinical scenarios and displays the corresponding risk category and 5-year survival estimate.
How to Use the Duke Treadmill Score Calculator
Enter the Exercise Duration from the Bruce protocol treadmill test in minutes.
Enter the ST-Segment Deviation in millimeters (mm), the maximal horizontal or downsloping ST depression.
Select the Angina Index: No angina, Non-limiting angina, or Exercise-limiting angina.
Use the quick example buttons to test common clinical scenarios.
Click Calculate to view your Duke Treadmill Score.
Check your Risk Category (Low, Moderate, or High) with a color-coded badge.
View the 5-Year Survival estimate corresponding to your score.
Review the Recommendation for clinical guidance.
Read the Clinical Interpretation for context.
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How the Duke Treadmill Score Formula Works
The Duke Treadmill Score is calculated using a straightforward formula that integrates the three stress test parameters:
Formula: DTS = Exercise Duration (minutes) − (5 × ST-segment deviation in mm) − (4 × Angina Index)
Angina Index Values:
0 = No angina during exercise
1 = Non-limiting angina (chest pain that does not stop the test)
2 = Exercise-limiting angina (chest pain that stops the test)
Score Interpretation:
≥ +5: Low risk (5-year survival ~97%)
−10 to +4: Moderate risk (5-year survival ~90%)
≤ −11: High risk (5-year survival ~65%)
The formula is based on the Bruce protocol, the standard exercise testing protocol used in the original Duke studies. The ST-segment deviation component uses the maximum horizontal or downsloping ST depression during exercise or recovery.
Worked Example
A 58-year-old patient undergoes a Bruce protocol exercise stress test with the following results:
Exercise Duration: 6.5 minutes
ST-Segment Deviation: 2.0 mm
Angina: Exercise-limiting (angina that stopped the test)
Step 1 — Apply the formula:
DTS = 6.5 − (5 × 2.0) − (4 × 2)
DTS = 6.5 − 10.0 − 8.0
DTS = −11.5
Step 2 — Determine risk category:
Step 3 — Recommendation:
“Your Duke Treadmill Score indicates high risk. The 5-year survival is reduced (~65%). Strongly consider coronary angiography and aggressive medical therapy. Close follow-up with a cardiologist is essential.”
This patient requires urgent cardiology evaluation and likely coronary angiography to assess the need for revascularization.
Frequently Asked Questions
What is the Duke Treadmill Score Calculator and how does it work?
The Duke Treadmill Score Calculator estimates risk in patients with suspected or known coronary artery disease using three exercise stress test parameters. It applies the formula DTS = Duration − (5 × ST Deviation) − (4 × Angina Index) to classify patients into Low, Moderate, or High risk categories with corresponding 5-year survival estimates.
What is the Bruce protocol?
The Bruce protocol is a standard treadmill exercise test protocol with progressively increasing speed and incline every 3 minutes. The Duke Treadmill Score was developed using this protocol and is validated for Bruce protocol stress tests. Other protocols may produce different results.
What is a normal Duke Treadmill Score?
A normal Duke Treadmill Score is ≥ +5, indicating low risk with ~97% 5-year survival. Scores between −10 and +4 indicate moderate risk (~90% survival), and scores ≤ −11 indicate high risk (~65% survival).
What does the Duke Treadmill Score measure?
The DTS measures the risk of cardiovascular events (death, myocardial infarction) in patients with suspected or known CAD. It provides a quantitative estimate of 5-year survival based on exercise stress test results.
What is the angina index in the Duke Treadmill Score?
The angina index quantifies the severity of angina during exercise: 0 (no angina), 1 (non-limiting angina – chest pain that does not stop the test), or 2 (exercise-limiting angina – chest pain that stops the test). Higher values indicate more severe symptoms.
What is the 5-year survival for each Duke Treadmill Score category?
Low risk (≥ +5): ~97% survival. Moderate risk (−10 to +4): ~90% survival. High risk (≤ −11): ~65% survival. These estimates are derived from the original Duke population studies.
Can the Duke Treadmill Score be used in women?
Yes, the DTS has been validated in both men and women. However, women may have lower exercise capacity and different symptom presentations, which should be considered in the clinical interpretation.
Does medication affect the Duke Treadmill Score?
Beta-blockers can limit heart rate response and exercise duration, potentially affecting the score. Calcium channel blockers may also affect ST-segment changes. The DTS should be interpreted considering the patient’s medication status.
What is the role of the Duke Treadmill Score in clinical guidelines?
The DTS is recommended by the ACC/AHA guidelines for interpreting exercise stress test results and guiding further evaluation. It helps clinicians decide which patients need coronary angiography.
What should I do if my Duke Treadmill Score indicates high risk?
A high-risk DTS (≤ −11) suggests significant ischemia and poor prognosis. You should discuss the results with a cardiologist and consider further evaluation (coronary angiography) and aggressive medical therapy.
