Changes in NT-proBNP Level after the Exercise Test in Patients with Suspected Coronary Artery Disease
Background:To assess changes in N-terminal pro-brain natriuretic peptide (NT-proBNP) following exercise training, we evaluated the changes in the circulating NT-proBNP level after diagnostic exercise testing in patients with suspected coronary artery disease (CAD).
Methods:Twenty patients with chest pain and clinical suspicion of CAD were recruited as the case group, and from among those scheduled for the exercise test without any clinical evidence of cardiovascular disease, 20 were randomly selected as the control group. In both groups, an exercise test was conducted according to the Bruce Protocol. The NT-proBNP level was measured with the Roche Diagnostics kits and electrochemiluminescence immunoassay immediately before and also 2 to 5 minutes after exercise testing. The severity of coronary artery stenosis was presented by the number of significant stenotic vessels according to coronary angiography.
Results:The mean levels of the pre- and post-exercise test NT-proBNP levels were significantly higher in the case group. Also, in both groups, the plasma BNP was significantly increased after the exercise test; however, the change in the NT-proBNP level was significantly higher in the former group (ΔBNP, 103.08 ± 57.54 pg/mL vs 4.24 ± 5.46 pg/mL; P < 0.001). There was a positive relation between the number of the involved coronaries and changes in the NT-proBNP concentration (ΔBNP, 34.37 ± 23.59 pg/mL for the normal coronary group, 102.87 ± 32.06 pg/mL for the single-vessel disease group, 113.50 ± 17.25 pg/mL for the 2-vessel disease group, and 146.64 ± 39.00 pg/mL for the 3-vessel disease group; P < 0.001). Multivariable linear regression analysis showed that among the different study indicators, only CAD severity was strongly associated with the changes in the plasma NT-proBNP level after the exercise test (β, 31.10; SE, 5.16; P < 0.001).
Conclusions:The NT-proBNP level was increased after the exercise test both in the patients with suspected CAD and in the healthy controls. However, the elevation in the NT-proBNP level was notably higher in the former group. The change in the NT-proBNP following the exercise test was strongly able to predict the severity of the involvement of the coronary arteries.