Is it possible to increase the diagnostic value of exercise electrocardiography by post-exercise B-type natriuretic peptide levels?

Abstract

Objective — Exercise electrocardiography is commonly available and a cost-effective test and therefore is widely used for the diagnosis of coronary artery disease. However, false positivity remains an important problem resulting in many unnecessary coronary angiographic examinations. In this study, we aimed to test the hypothesis that post-exercise B-type natriuretic peptides secreted in response to transient myocardial ischaemia induced by exercise, add any further information on positive test results.

Methods — Patients who underwent exercise electrocardiography with the suspicion of coronary artery disease were screened and those with positive test results based on standard electrocardiography criteria were selected. Blood samples for B-type natriuretic peptides were obtained within 5minutes after exercise test. Patients included in the study had preserved left ventricular function on echocardiography. At least 70% stenosis of one epicardial coronary artery on coronary angiography was diagnosed as significant coronary artery disease.

Results — Of the 55patients (age 59.8 ± 7.6 y; 48men) included in the study 29 had (52.7%) coronary artery disease requiring revascularization (CAD+) and 26 (47.3%) did not have significant coronary artery disease (CAD-).The cardiovascular risk factor profile of CAD+ and CAD-patients were similar (all p>0.05).The median post-exercise B-type natriuretic peptide level was significantly higher in CAD+ (47.20 pg/ml) than CAD- patients (18.90 pg/ml) (P=0.001).The sensitivity and specificity of a post-exercise B-type natriuretic peptide level>30 pg/ml for the diagnosis of coronary artery disease in exercise test positive patients were calculated as 72% and 69%, respectively.

Conclusion — The measurement of post-exercise B-type natriuretic peptide levels may increase the diagnostic value of positive exercise electrocardiography.

Key Words:

• B-type natriuretic peptide
• exercise electrocardiogram
• specificity