Comparison of Predicted Significant Coronary Lesion by Duke Treadmill Score among Coronary Heart Disease Risk Factors in Patients with Positive Ischemic Response Treadmill Test

Background: According to Framingham Study, independent risk factors for coronary heart disease (CHD) are diabetes, hypertension, smoking, dyslipidemia, family history of CHD and obesity. Previous study reported cut-off value of Duke Treadmill Score (DTS) < -0.5 represents a significant coronary lesion with positive predictive value 88.4%. Objective: To compare the incidence of predicted significant coronary lesions by DTS among various risk factors for coronary heart disease. Methods: A cross sectional study was done on 292 patients age 18 to 74 years old who had positive exercise testing for CAD screening during period of June 1st 2016 until May 30th 2017. DTS was calculated from treadmill test as: exercise time (5 x ST deviation in mm) (4 x exercise angina). A coronary lesion was predicted significant with DTS cut-off value < -0.5. Results: Subjects mean age was 57 years old, male were 60.4%. The risk factors for CHD were found sequentially from the most frequent were hypertension 51.9%, smoking 35.3%, diabetes mellitus 23.1%, dyslipidemia 11.9%, obesity 4.2% and family history of CHD 6.3%. It was found that diabetes was significantly different from its effect on DTS value with p value = 0.021, while hypertension, obesity, dyslipidemia and family history CHD had no significant effect. Logistic regression found consistently that diabetes was significant (p=0.019). Conclusion: Predicted significant coronary lesions by DTS developed more frequent in diabetes compared to, hypertension, smoking, dyslipidemia, obesity and family history of coronary heart disease.


INTRODUCTION
Coronary artery disease is the leading cause of morbidity and mortality worldwide, and the incidence of coronary heart disease (CHD) has increased gradually. 1The cost of diagnostic and therapeutic interventions performed after clinical manifestations of CHD is substantially high.In the era of advanced cardiac imaging nowadays, East Java still does not have many facilities of MSCT, MRI or nuclear imaging.
Therefore, it is important to combat risk factors prior to disease progression and to identify the presence of CHD by a simple and valid method before clinical signs of CHD appear.
Stratified risk during diagnostic and therapeutic CHD processes forms the basis of current guidelines. 2 Risk assessment systems, such as the Framingham risk model, created using a variety of risk factors, are currently used to predict the risk of developing cardiovascular disease (CVD) or to determine treatment goals for prevention of disease progression. 3However, it is not used to predict the severity of CHD and plan for invasive and noninvasive diagnostic processes.
Duke treadmill score (DTS) has been shown to demonstrate the stratification of prognosis and has a good diagnostic value in predicting the number of coronary arteries involved in a patient population with ischemic heart disease.In addition, DTS has also been shown to have a strong correlation with the severity of coronary lesions assessed on the basis of the value of Syntax. 4DTS can estimate the presence and severity of CHD before coronary angiography and may be able to determine the method of revascularization required after the procedure. 4DTS has a sensitivity of 83.3 % and a specificity of 71.5% in assessing future 30-day cardiovascular events, with a negative predictive value of 99.2% for the following 30 day free cardiovascular events. 5baldo et al reported that all patients with high-risk DTS scores had significant coronary lesions or weight.Patients with moderate and mild-risk DTS scores obtained no significant coronary lesions in 50-90% of cases.High risk DTS scores indicate high potential for immediate coronary angiography. 6 aim to determine the differences of predicted significant coronary lesionby DTS among CHD risk factors in patients with positive ischemic response treadmill test.Coronary angiographies were performed in our hospital using the standard Judkins method with contrast agent manually delivered.

This
C o r o n a r y a n g i o g r a m s w e r e a s s e s s e d independently by invasive cardiologists who were blinded to the clinical findings.Significant coronary lesion is an angiographic finding that is one or more coronary lesion met the criteria stenosis ≥ 50% at left main (LM), LAD stenosis in ostial / proximal > 50%, LAD, mid-distal stenosis > 70%, LCx stenosis > 70%, and RCA stenosis > 70%. 8In this study predicted significant coronary lesion was DTS value < -0.5 which were in accordance with in previous study. 9r statistics analysis, data was coded and analyzed using significant cut off value of p ≤ 0.05.The category variable is expressed as number and percentage.Hypertension, diabetes, smoking, dyslipidemia and obesity were nominal variable.The DTS values associated with significant coronary lesion was nominal variables which were divided into less than < -0.5 (significant lesion) and > -0.5 (non significant lesion).The values of association between each CHD risk factors were analysed using chi square and logistic regression test on SPSS 24 software for windows.Among patients proven to be ischemic positive response and coronary angiography results with significant lesions it was found that the youngest age was 43 years.The patient had a smoking risk factor and was able to achieve 10 METs.There most frequent performed treadmill with the Naughton treadmill protocol.

During
Fewer patients performed Naughton protocol due to osteoarthritis and another elderly patient who is unable to walk on a treadmill machine with inclination.Nine patients were then excluded because they are more than 75 years old.
The DTS data was obtained as numerical variables, then a cut-off point determined from previous study in our data was -0.5.We divided DTS group into < -0.5 as predicted significant lesion and ≥ -0.5 as predicted nonsignificant lesion ( The limitations of the study of our study should be declared.Our study design was cross-sectional.We realize that this study was still not perfect where the weakness was study was designed as a crosssectional observational study.The sample was derived from treadmill registry of Dr. Saiful Anwar Hospital Malang, Indonesia of 905 consecutive patients underwent CAD screening.The study protocol was approved by the Local Ethics Committee (ethical clearance: no.400/184/K.3/302.2017).The inclusion criteria were no history of prior CAD, admitted to the outpatient clinic with chest pain (typical angina, atypical angina, non-anginal chest pain) had a positive stress test and underwent coronary angiography (CAG) between June 2016 and May 2017.Patients with inadequate and negative ischemic response and age >75 years were excluded from the study.Patients with left bundle branch block, left ventricu lar hypertrophy, and Wolff-Parkinson-White syndrome were not included in the study. 7Coronary risk factors were included such as hypertension, diabetes, smoker, dyslipidemia, obesity, and family history CAD which are modified risk factors that had been identified by referral cardiologist and or cardiologist in charge in treadmill test.For exercise treadmill testing, symptom-limited Bruce, modified Bruce and/or Naughton protocols were applied to all pa tients.Resting heart rate, blood pressure, and 12-lead ECG were recorded in the supine and upright positions before exercise.An ECG was repeated every 3 minute.Exercise testing was discontinued if exertional hypotension, malignant ventricular arrhythmias, marked ST depression (3 mm), or limiting chest pain were observed.An abnormal exercise ST response was defined as 1 mm or more horizontal or downsloping ST depression (J point ± 60 ms) or 1 mm or more ST-segment elevation in all leads excluding aVR without pathological Q waves. 7The equation for calculating the Duke Treadmill Score (DTS) was as follows: DTS = exercise time -(5 × ST deviation) -(4 × exercise angina).Exercise angina was assessed as one of three levels: 0, none; 1, non-limiting; and 2, exercise-limiting.The DTS typically ranges from -25 to +15. 7 still a retrospective study with medical record data which of course we could not control the confounding factor and its bias.The identification of CHD risk factors was generally from referral cardiologist and partly from cardiologist in charge.In the measurement of the DTS value component the researcher could not ascertain uniformity in the assessment of angina because the operator accompanying the examiner was differrent over that period.The study sample was not taken randomly because of the limitations of patients who had fulfilled the inclusion requirements, especially those patients who had undergone coronary angiography.Further studies with larger patient populations and cohort are suggested.

Table 1 .
the study period, 905 patients were Demographic and Clinical Characteristics of Research Subjects

Table 2
11ars.Meanwhile, data from the United States for a population of 60-79 years, estimated the prevalence rate of 23% of men and 15% of women are increasing at age > 80 years, i.e. 33% in men and 22% in women.11Thisstudyprovesthat patients with CHD are majority males.It is as previously reported that women are less populated than men and the age of CHD patients in women is 10-15 years older than men.11

Table 2 .
The DTS value of predicted significant coronary lesions

Table 3 .
Logistic regression analysis of influence of CHD risk factors to DTS