Analysis of influence factors in treadmill exercise test for the diagnostic accuracy of coronary heart disease

Objective To probe the diagnostic and prognostic value and the related influence factors of treadmill exercise test for coronary heart disease.Methods One hundred and eighty-two patients with suspected coronary heart disease underwent treadmill exercise test exam and coronary artery angiography,some of these patients underwent intravascular unltrasound exam,and their clinical characteristic and main risk factors were also analyzed.Results If the diameter stenotic rate of a diseased coronary artery ≥50% is regarded as the diagnostic standard of coronary heart disease,treadmill exercise test resulted in 76.0% sensitivity,30.0% of specificity,56.4% of accuracy rate,43.6% of false-positive predictive value,and 22.7% of false-negative predictive value.The results of treadmill exercise test were influenced by many factors,such as sex,resting electrocardiogram before exercise and amount of exercise.The age,percentage of male,and the number of typical angina and 2 or greater risk factors in patients with ≥50% stenotic coronary artery were significantly higher than those in patients with normal coronary artery.Among patients with ≥50% stenotic coronary artery,the METs value,the episode time or duration of abnormal ST segment and maximum ST segment depression value of treadmill exercise test in patients with single-vessel disease had significant difference from those in patients with two or three vessel-disease(P0.05).The majority(70.2%) of patients with angiographically mildly-moderately diseased coronary arteries had also two or more than two risk factors,nearly half of theses patents(44.7%) had typical angina.Thirty-nine coronary artery segments with mildly-moderately stenosis found by coronary angiography in 26 patients were measured by intravascular ultrasound,33 eccentric and soft plaques were demonstrated in intravascular ultrasound,the area stenosis rate of seven injured vessel segments were also found to be more than 50% in intravascular ultrasound.If a angiographically mildly-moderately diseased coronary artery with the positive result of treadmill exercise test or typical angina or ≥ two main risk factors is regarded as the diagnostic standard of coronary heart disease,treadmill exercise test resulted in an increase of accuracy rate(about 70%),though had an unchanged sensitivity and specificity.Conclusion Treadmill exercise test combined with clinical characteristic,typical angina or ≥ 2 risk factors can result in the an increased accuracy for diagnosis of coronary heart disease,its multi-parameters may be helpful for the prognosis of coronary artery disease,study the reason of false-positive and false-negative in the treadmill exercise test to improve the accuracy of diagnosis.