CT Coronary Angiography is a Useful Diagnostic Test Following Equivocal Exercise Stress ECG in Troponin-negative Chest Pain

Abstract

Background: Exercise stress ECG (ETT) is commonly the first-line investigation in troponin-negative chest pain patients. Inconclusive results are common and often lead to repeated functional testings. CT coronary angiography (CTCA) has excellent negative predictive value for coronary artery disease detection and may play an important role in their diagnostic workup. Methods: We retrospectively identified consecutive troponin-negative chest pain patients undergoing CTCA (320-slice Aquillon ONE, Toshiba Medical Systems), referred following “equivocal” stress ECG (ETT), from August 2011 to February 2013. Stress ECGs were reviewed blinded to the CTCA results. The prevalence of obstructive coronary disease, as well as their clinical and ETT predictors, are identified. Results: 346 patients (age 57 ± 11, female 54%, BMI 28 ± 5) underwent CTCA after equivocal (49%), positive (30%), non-diagnostic (10%) or negative (11%) ETTs. Average exercise duration was 8.7 ± 2.9 min. CTCA identified obstructive coronary artery disease in 20%, non-obstructive atherosclerosis in 35%, and normal coronary arteries in 41%. Significant predictors for obstructive coronary artery disease included advanced age, male gender (29% vs. 13%, p = 0.0001), abnormal ETT findings (positive vs. equivocal vs. negative); but not exercise duration. In women, ETT findings (equivocal vs. positive vs. non-diagnostic) did not predict obstructive disease. Conclusion: In the patient cohort referred for CTCA following “equivocal” ETT, obstructive coronary disease prevalence is 20%. In this diagnostic pathway, CTCA appears useful in establishing definitive diagnosis in many while avoiding further functional testings. In women, ETT findings did not predict the presence or absence of obstructive disease.