Duke Treadmill Score Calculator
A validated risk assessment tool for coronary artery disease
Calculate Duke Treadmill Score
Duke Treadmill Score
About the Duke Treadmill Score
The Duke Treadmill Score (DTS) is a validated risk assessment tool that helps predict the prognosis of patients with known or suspected coronary artery disease who undergo a standard exercise stress test.
Risk Categories
- Low Risk (Score ≥ +5): Excellent prognosis with ~99% 4-year survival. Typically managed with medication and lifestyle changes.
- Intermediate Risk (Score -10 to +4): Uncertain prognosis with ~95% 4-year survival. Requires careful clinical judgment.
- High Risk (Score ≤ -11): Poor prognosis with ~79% 4-year survival. Often needs coronary angiography and possible intervention.
Limitations
The DTS should not be used for patients with certain ECG abnormalities (e.g., left bundle branch block, paced rhythm) and was developed using the Bruce protocol.
Disclaimer: This calculator is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with a qualified healthcare provider for medical concerns.
The Duke Treadmill Score (DTS) is a widely used, validated risk assessment tool that helps doctors predict the prognosis of a patient with known or suspected coronary artery disease (CAD) who undergoes a standard exercise stress test (treadmill test).
In simple terms, it takes data from the stress test and converts it into a single number. This number helps classify patients into low, intermediate, or high-risk categories for future cardiac events, such as a heart attack or cardiac death.
The Components of the Duke Treadmill Score
The score is calculated using three key pieces of information gathered during the exercise test:
- Exercise Time (in minutes): This is a proxy for functional capacity (how well the heart and lungs work under stress). It uses the standard Bruce Protocol, which increases in speed and incline every 3 minutes. Longer exercise time is better.
- ST-Segment Deviation (in millimeters): This is measured on the ECG. It indicates how much myocardial ischemia (lack of blood flow to the heart muscle) is induced by exercise. More deviation is worse.
- Exercise Angina (Chest Pain): This notes whether the patient experienced their typical angina during the test.
0= No angina1= Non-limiting angina (chest pain occurred but the test could continue)2= Exercise-limiting angina (chest pain was so severe the test had to be stopped)
The Formula
The Duke Treadmill Score is calculated as follows:
DTS = Exercise Time (in minutes) – (5 × ST-segment deviation in mm) – (4 × Exercise Angina Index)
Interpretation: What the Score Means
Once calculated, the score places the patient into one of three risk categories:
| Risk Category | Duke Treadmill Score | 4-Year Survival Rate | Implication |
|---|---|---|---|
| Low Risk | ≥ +5 | ~99% | Excellent prognosis. Typically managed with medication and lifestyle changes alone. Further invasive testing (like angiogram) is usually not needed. |
| Moderate/Intermediate Risk | -10 to +4 | ~95% | Uncertain prognosis. These patients require careful clinical judgment. The doctor will consider other factors (age, other health problems) to decide if more testing is warranted. |
| High Risk | ≤ -11 | ~79% | Poor prognosis. High likelihood of severe coronary artery disease. These patients often need a referral for coronary angiography to directly visualize the blockages and consider procedures like stenting or bypass surgery. |
A Practical Example
A 60-year-old man completes 9 minutes on the Bruce protocol. During the test, he has 2 mm of ST-segment depression on his ECG and reports exercise-limiting angina (index of 2).
His Duke Treadmill Score would be:
- Exercise Time: 9
- ST Deviation: 5 × 2 mm = 10
- Angina Index: 4 × 2 = 8
- DTS = 9 – 10 – 8 = -9
A score of -9 places him in the Intermediate Risk category. His doctor would likely discuss this result in detail, optimize his medications, and may consider further testing based on his overall clinical picture.
Clinical Significance and Limitations
Why is it important?
- Prognostic Power: It’s one of the best-established tools for predicting long-term outcomes from a simple, non-invasive test.
- Guides Management: It provides an objective, evidence-based framework to help physicians decide “what to do next” with a patient.
- Cost-Effective: It helps avoid unnecessary and expensive invasive procedures in low-risk patients.
What are its limitations?
- Not for Everyone: It should not be used for patients with certain baseline ECG abnormalities (e.g., left bundle branch block, paced rhythm, significant ST depression at rest), as these make the ST-segment analysis unreliable.
- Depends on Protocol: It was developed using the Bruce protocol. While it can be adapted, its accuracy is highest with this specific protocol.
- Doesn’t Include All Factors: It doesn’t incorporate other important data like heart rate recovery, blood pressure response, or non-ECG imaging findings (which is why stress echocardiograms or nuclear stress tests are often used for a more comprehensive assessment).
In summary, the Duke Treadmill Score is a crucial, simple, and powerful clinical tool that translates exercise stress test results into a clear risk stratification, directly guiding patient management decisions in coronary artery disease.
