Background: Exercise stress test (EST) is the most practical method to diagnose coronary artery disease (CAD). Although it has a high negative predictive value (NPV), the positive predictive value (PPV) is low.

Objective: To increase the diagnostic accuracy of EST by combining the results with the delta change of high-sensitive cardiac troponin T (hscTnT) levels during stress exercise.

Materials and Methods: The authors conducted a diagnostic study in patients presenting with chest pain and having intermediate pretest probability of CAD who underwent EST at Queen Sirikit Heart Center of the Northeast in Khon Kaen, Thailand, between July 2018 and January 2019. Two blood samples were collected to measure hs-cTnT at 5-minute before and at 1-hour after exercise. The diagnosis of CAD was made from the coronary angiography (CAG) or coronary computed tomography angiography (CCTA) result. The authors created a ROC curve from the hs-cTnT delta change, selected a value that had high sensitivity, and combined it with EST results to enhance the PPV predicting CAD.

Results: Eighty-one patients were included in the present study. Thirty-one (38.3%) had positive EST, 47 (58.0%) had negative EST, and three (3.7%) had inconclusive results. To confirm the diagnosis of significant CAD, CAG was performed in 33 (40.7%) patients, and CCTA was performed in seven (8.6%) patients. Forty-two (51.8%) patients were determined not to have significant CAD based solely on negative EST results. Sixteen (19.8%) patients were in the CAD group and 65 (80.2%) in the non-CAD group. The average hs-cTnT at baseline, at 1-hour after EST, and delta change of patients in the CAD group were greater than those in the non-CAD group (7.81±3.62 ng/L and 4.83±2.97 ng/L, p<0.001, 9.21±4.41 ng/L and 4.94±2.92 ng/L, p<0.001, 17.99% and 9.18%, p=0.09, respectively). When the authors used a hs-cTnT delta-change of 3% as a cutoff point and combined this with the EST results, the PPV increased from 48% when using the EST alone to 63.2%.

Conclusion: Combining hs-cTnT delta change during an EST with EST results could raise the PPV of CAD diagnosis in patients with chest pain who had intermediate CAD pretest probability.

Keywords: Exercise stress test, Coronary artery disease, High-sensitive cardiac troponin T

DOI: doi.org/10.35755/jmedassocthai.2021.02.10416

Received 2 July 2019 | Revised 22 January 2020 | Accepted 25 September 2020