Comparison of the Diagnostic Power of Computed Tomography Coronary Angiography and Exercise Electrocardiography as a First Screening Test in Real-World Practice: Is It Ready for Clinical Use? / 대한내과학회지

Exercise electrocardiography (XECG) is a widely used noninvasive test for screening coronary artery disease that is endorsed by current clinical guidelines. However, its clinical use is limited by its modest diagnostic accuracy. Coronary computed tomographic angiography (CCTA) has emerged as a new tool for screening coronary artery disease. In this issue, CCTA performed better diagnostically than XECG when invasive coronary angiography was used as the diagnostic standard. In addition, invasive coronary angiography was chosen based on CCTA, rather than XECG. Although this study suffers from the lack of an appropriate diagnostic standard, the clinical course identified implies that clinical practice might be influenced by sophisticated anatomical imaging to a considerably greater extent than by a simple physiological assessment.

Comparison of Computed Tomography Coronary Angiography and Exercise ECG Test for Diagnostic Accuracy in Real-World Practice / 대한내과학회지

BACKGROUND/AIMS: The exercise ECG test (XECG) and computed tomography coronary angiography (CTCA) have been used widely in initial evaluations of coronary artery disease (CAD) in real-world practice. In this study, we compared the diagnostic power of CTCA and XECG, based on conventional coronary angiography (CCA). METHODS: We enrolled 589 consecutive patients retrospectively who had been examined with both XECG and CTCA for the evaluation of CAD in outpatient clinics. Significant stenosis was defined as more than 50% diameter stenosis. Triage to CCA and/or revascularization treatment (RT) by the results of XECG and CTCA and the diagnostic accuracy of both exams, based on CCA, were investigated. RESULTS: In the 589 patients, 107 (19%) were triaged to CCA for further evaluation; in 77 (12.8%) significant stenosis was detected on CCA. Also, 65 (11%) patients underwent RT. In the CTCA results, 120 patients had significant stenosis. Of them, 58 (48%) and 75 (62%) patients were triaged to RT and CCA, respectively. Based on the XECG, 115 positive patients were triaged to RT and CCA (23 [20%]/41 [35%]). Among 107 patients with CCA, the sensitivity, specificity, positive predictive value, and negative predictive value for significant stenosis on CCA of CTCA were 89.9%, 74.0%, 90.6%, and 71.4%, respectively, and those of XECG were 50.0, 67.9, 78.0, and 37.3, respectively. The kappa value of CCA and CTCA was 0.62 (p < 0.001) and that of CCA and XECG was 0.145 (p = 0.113). CONCLUSIONS: In real-world practice, CCA was decided on more frequently, based on CTCA. CTCA showed better diagnostic accuracy than XECG.

Ischemia-modified albumin (IMA) is not useful for detecting myocardial ischemia during symptom-limited exercise stress tests

BACKGROUND/AIMS: We examined the ischemia-modified albumin (IMA) level during exercise in patients with coronary artery disease (CAD). METHODS: Forty patients with a history of chest pain underwent both symptom-limited treadmill exercise stress testing and coronary angiography within one week. During the treadmill tests, blood samples were obtained at baseline and 5 min after exercise to measure the serum IMA level. RESULTS: Of the 40 patients, fourteen (35%, CAD group) had significant coronary artery stenosis, while the other 26 (65%, non-CAD group) did not. The baseline and post-exercise IMA levels in the two groups did not differ significantly (105.2+/-7.2 vs. 107.7+/-6.7 U/mL at baseline and 93.1+/-10.1 vs. 94.8+/-5.7 U/mL at post-exercise in the CAD and non-CAD groups, p=0.29 and 0.57, respectively). The changes in IMA after exercise did not differ either (-10.4+/-7.5 vs. -14.0+/-7.6 U/mL in the CAD and non-CAD groups, respectively, p=0.10). Similarly, the change in IMA between the exercise ECG test positive (TMT positive, n=9) and negative (TMT negative, n=20) groups did not differ (-14.63+/-5.19, vs -8.50+/-9.01 U/mL, p=0.15, in the TMT positive and negative groups, respectively). CONCLUSIONS: Our results suggest that IMA has limitation in detecting myocardial ischemia during symptom-limited exercise stress tests.

Characteristic Findings of Exercise ECG Test, Perfusion SPECT and Coronary Angiography in Patients with Exercise Induced Myocardial Stunning / 대한핵의학회잡지

PURPOSE: Transient wall motion abnormality and contractile dysfunction of the left ventricle (LV) can be observed in patients with coronary artery disease due to post-stress myocardial stunning. To understand clinical characteristics of stress induced LV dysfunction, we have compared the findings of exercise stress test, myocardial perfusion SPECT and coronary angiography between subjects with and without post-stress LV dysfunction. MATERIALS AND METHODS: Among subjects who underwent exercise stress test, myocardial perfusion SPECT and coronary angiography within a month of interval, we enrolled 36 patients with post-stress LV ejection fraction (LVEF) was > or=5% lower than rest (stunning group) and 16 patients with difference of post-stress and rest LVEF was lesser than 1% (non-stunning group) for this study. Treadmill exercise stress gated myocardial perfusion SPECT was performed with dual head SPECT camera using 740 MBq Tc-99m MIBI and coronary angiography was also performed by conventional Judkins method. RESULTS: Stunning group had a significantly higher incidence of hypercholesterolemia than non-stunning group (45.5 vs. 7.1%, p=0.01). Stunning group also had higher incidence of diabetes mellitus and lower incidence of hypertension, but these were not statistically significant. Stunning group had larger and more severe perfusion defect in stress perfusion myocardial SPECT than non-stunning group (extent 18.2 vs. 9.2%, p=0.029; severity 13.5 vs. 6.9, p=0.040). Stunning group also had higher degree of reversibility of perfusion defect, higher incidence of positive exercise stress test and higher incidence of having severe stenosis (80~99%) in coronary angiography than non-stunning group, but these were not statistically significant. In stunning group, all of 4 patients without perfusion defect had significant coronary artery stenosis and had received revascularization treatment. CONCLUSION: Patients with post-stress LV dysfunction had larger and more severe perfusion defect and severe coronary artery stenosis than patients without post-stress LV dysfunction. All of the patients without perfusion defect in stunning group had significant coronary artery stenosis and needed revascularization. Therefore, we suggest that invasive diagnostic procedures and therapeutic interventions might be needed in patients with post-stress LV dysfunction.

Evaluation of Severity of Coronary Artery Disease by Exercise Electrocardiographic Test

Exercise-induced ischemic ST responses were analyzed in 36 patients who presented with chest pain and had exercise test and the results were compared with their coronary angiographic findings. Among 36 exercise test positives, the incidences of one-, two- and three vessel disease, and left main disease were 25%(9 cases), 30%(11 cases), 25%(9 cases) and 9%(3 cases), respectively. The incidence of multivessel disease(i.e., two-to three vessel disease or left main disease) in patients with ST depression > or =2.0mm was 72% and that in those with ST depression of 1.0-1.9mm was 45%. In patients with downsloping ST depression, the incidence of multivessel disease was significantly higher than that of one vessel disease(86% vs 14%, p<0.001). But both incidences of one vessel disease and multivessel disease were similar in patients with flat and slowly upsloping ST depression. More than two thirds of patients with ischemic ST depression appearing in the first 6 minutes of exercise or those lasting past 7 minutes in recovery were associated with multivessel disease. It is concluded that attention to depth, type, appearance time and duration of ST depression during exercise test is particularly helpful in detecting patients with advanced coronary disease.