Coronary artery disease
Relation of Plaque Characteristics Defined by Coronary Computed Tomographic Angiography to ST-Segment Depression and Impaired Functional Capacity During Exercise Treadmill Testing in Patients Suspected of Having Coronary Heart Disease

https://doi.org/10.1016/j.amjcard.2008.08.029Get rights and content

Sixty-four-detector-row coronary computed tomographic angiography (CCTA) has been proposed for the evaluation of low- to intermediate-risk patients with suspected coronary artery disease (CAD). Historically, exercise treadmill testing (ETT) measures of ST-segment depression (STD) and the Duke treadmill score (DTS) have been used to evaluate myocardial ischemia and functional capacity. The relation of plaque characteristics on CCTA to STD and DTS is unknown. In this study, 156 low- to intermediate-risk patients without known CAD who underwent ETT and CCTA were evaluated. By ETT, 22% (n = 35) had STD and 27% (n = 42) had abnormal DTS. On CCTA, 21% (n = 33) had obstructive CAD (≥70% stenosis) and 49% (n = 77) had nonobstructive CAD (<70% stenosis). Forty-six percent of patients (n = 16) with and 15% (n = 15) without STD had obstructive CAD. After multivariate adjustment, only age and obstructive CAD on CCTA predicted STD (odds ratio [OR] 1.59, 95% confidence interval [CI] 1.08 to 2.34 per decade, and OR 3.38, 95% CI 1.32 to 8.64, respectively) and abnormal DTS (OR 1.61, 95% CI 1.14 to 2.28, and OR 4.67, 95% CI 1.97 to 11.03, respectively). After adjustment for age, more coronary segments with mixed plaque, in contrast to calcified or noncalcified plaque, predicted STD (OR 1.48, 95% CI 1.18 to 1.85) and abnormal DTS (OR 1.30, 95% CI 1.05 to 1.61). In conclusion, measures of plaque on CCTA identify patients more likely to have STD and higher risk DTS, while providing incremental diagnostic yield for the detection of obstructive CAD beyond ETT.

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Methods

Consecutive patients who underwent clinically indicated CCTA and ETT from July 2005 to May 2007 were identified retrospectively. Patients with previous known CAD, unstable angina pectoris, cardiomyopathy, or congenital heart disease were excluded from analysis. Demographic and clinical data were prospectively obtained at the time of ETT by a nurse using a standardized questionnaire. This study was conducted with the approval of the institutional review board at Weill Medical College of Cornell

Results

One hundred fifty-nine patients without preexisting cardiac disease and with interpretable baseline electrocardiograms underwent ETT and CCTA. One patient was excluded for nondiagnostic results on CCTA, and 2 were excluded for life-threatening noncardiac findings on CCTA. The remaining 156 patients were middle aged, with an intermediate prevalence of traditional cardiac risk factors (mean age 56.7 ± 12.2 years, 44% women; Table 1) and a low to intermediate prevalence of abnormalities on ETT or

Discussion

To our knowledge, these data represent the first to relate plaque characteristics on CCTA to functional myocardial ischemia, exercise capacity, and the DTS on ETT in a low- to intermediate-risk population. In our cohort, plaque severity, location, and composition on CCTA were significant predictors of exercise-induced STD. The association of STD with CCTA-identified obstructive CAD in the present study is consistent with past evidence relating STD to the anatomic and functional extent of

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