Objective. In patients with chest pain, exercise stress test has a moderate accuracy for coronary artery disease (CAD). Adding a reliable cardiac biomarker to the exercise test could potentially improve the precision of the test. We investigated circulating NT-proBNP levels before and during exercise stress test in patients with and without angiographically verified CAD. We hypothesized that NT-proBNP would give an additive diagnostic value to the exercise stress test. Methods. In patients presenting with symptoms of stable CAD, venous blood samples were taken at rest and within 5 min of termination of a maximal stress test on a bicycle ergometer. All study participants underwent coronary angiography. Significant CAD was defined as ≥75% stenosis in one or more segments of the coronary arteries. Results. Of the 297 participants, significant CAD was found in 111 (37%) patients. Resting levels of NT-proBNP were significantly higher in patients with CAD compared with patients without CAD (74.18 vs. 56.03 ng/L), p = .005. During exercise, NT-proBNP levels increased in the total population (p < .001). The rise was, however, not significantly different between the two groups (8.24 vs. 8.51 ng/L), p = .700. Combining resting NT-proBNP with positive exercise stress test was superior to exercise test alone in predicting CAD, AUC = 0.68 vs. 0.64. Conclusion. Exercise-induced change in circulating NT-proBNP could not distinguish between patients with or without CAD. However, resting levels of NT-proBNP were significantly higher in patients with CAD than those without CAD.
Keywords: Coronary artery disease; NT-proBNP; coronary angiography; exercise stress test.