This Duke treadmill score calculator predicts mortality and coronary artery disease morbidity based on treadmill stress ECG testing. Below the form, there are in depth instructions for the score and on how to extract the risk category.
How does the Duke treadmill score calculator work?
This health tool predicts the 5-year mortality based on treadmill ECG stress testing and the likelihood of coronary artery disease. It is based on the weighted index developed in 1987 as the result of a 2842 chest pain patient study. All subjects have undergone treadmill testing cardiac catheterization.
The variables included in the Duke treadmill score calculator are:
■ Treadmill exercise time – measured in minutes and using the standard Bruce protocol.
■ Maximum net ST segment deviation – whether it is depression or elevation in any lead except lead aVR. Abnormal exercise ST responses were defined as ≥1 mm of horizontal or down sloping ST depression (J point+80 ms) or ≥1 mm of ST-segment elevation in leads without pathological Q waves.
■ Angina – the presence or absence of exercise induced angina. Each situation is assigned a numerical value to use in the formula (where 0 = no angina, 1 = non-limiting angina, 2 = exercise limiting angina).
This treadmill score is used for diagnostic and prognostic purposes for patients with suspected CHD. It is praised for accurate results in both inpatient and outpatient ischemic heart disease populations.
The score is calculated as below:
Duke treadmill score = Exercise time (minutes) - (5 x ST deviation in mm) - (4 x angina index)
The results of the original study were the following:
■ 13% of patients at high risk;
■ 53% of patients at moderate risk;
■ 34% of patients at low risk.
The score results can help clinicians decide whether they need to refer outpatients with suspected coronary disease for cardiac catheterization.
It has been incorporated in the American College of Cardiology-American Heart Association's guidelines for exercise testing.
Duke treadmill score interpretation
The typical possible range of Duke treadmill scores is from -25 (highest risk) to +15 (lowest risk). There is also an intermediary risk category.
■ Scores of -11 and below are considered high risk and indicate a 5-year survival of 65%.
■ Scores higher than -11 and lower or equal to 4 are considered intermediate risk and carry a 5-year survival of 90%.
■ Scores of 5 and higher are considered low risk and carry a 5-year survival of 97%.
Patients with intermediate and high risk scores should be referred for additional risk stratification with cardiac imagining components (myocardial perfusion scanning or coronary angiography, or both). The lower the score, the higher the risk of severe angiographic coronary disease.
One of the comments is that low scores in female patients are better at excluding ischemic heart disease than in male patients.
74% of high risk patients in one of the studies had 3-vessel or left main occlusive coronary disease on angiography.
References
1) Mark DB, Hlatky MA, Harrell FE Jr, Lee KL, Califf RM, Pryor DB. (1987) Exercise treadmill score for predicting prognosis in coronary artery disease. Ann Intern Med; 106(6):793-800.
2) Mark DB, Shaw L, Harrell FE Jr, Hlatky MA, Lee KL, Bengtson JR, McCants CB, Califf RM, Pryor DB. (1991) Prognostic value of a treadmill exercise score in outpatients with suspected coronary artery disease. N Engl J Med; 325(12):849-53.
3) Shaw LJ et al. (1998) Use of a prognostic treadmill score in identifying diagnostic coronary disease subgroups. Circulation; 98; 1622-30.
4) Alexander KP, Shaw LJ, Shaw LK, Delong ER, Mark DB, Peterson ED. (1998) Value of exercise treadmill testing in women. J Am Coll Cardiol; 32(6):1657-64.
16 Nov, 2016