活动平板运动试验对冠心病诊断准确性影响因素的探讨

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

目的评价心电图活动平板运动试验诊断冠心病、判断预后的价值及其影响因素。方法对182例可疑冠心病患者,同期内行活动平板运动试验和冠状动脉造影以及部分患者行血管内超声检查,并分析这些患者的临床特征及其主要危险因子。结果若以冠脉造影冠脉狭窄≥50%为冠心病诊断标准,心电图活动平板运动试验诊断冠心病的敏感性76.0%、特异性30.0%、准确性56.4%、假阳性率43.6%和假阴性率22.7%;活动平板运动试验假阳性和假阴性产生原因是多方面的,如性别、运动前的静息心电图、运动量等;冠脉狭窄≥50%患者的年龄、男性所占比例、存在典型胸痛以及≥2个主要的冠心病危险因子所占的比例显著高于正常冠脉者;在冠脉狭窄≥50%的患者中,1支、2支和3支冠脉病变者平板运动试验所达METs值、异常ST段出现时间或持续时间、ST下移最大值存在显著差异(P<0.05);大多数(70.2%)冠脉造影为轻中度冠脉病变者也存在≥2个主要危险因子,近半数(44.7%)存在典型胸痛;血管内超声显示26例冠脉造影为轻中度冠脉病变者有39处病变,33处病变属于偏心性斑块和软斑块,7处病变面积狭窄率超过50%;若轻中度冠脉病变结合阳性运动试验结果或典型胸痛症状或≥2个主要冠心病危险因子为标准来诊断冠心病,则运动试验诊断冠心病的敏感性和特异性基本同前,但准确性增加到70%左右。结论活动平板运动试验结果结合临床特征、典型胸痛或主要危险因子分析能提高冠心病的诊断价值,活动平板运动试验的多项指标能判断冠心病的病变程度和估计预后,了解活动平板运动试验假阳性和假阴性产生原因可提高诊断准确性。

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（P〈0.05）. 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 invessel 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.