Cor Vasa 2003, 44(1):22-26

NT-proBNP determination in the diagnosis of exercise-induced ischemia or latent heart failure

David Stejskal^1,*, Bořek Lačňák², Dalimil Horalík², Renata Juráková¹, Jitka Prošková¹, Sylva Adamovská¹, Ivana Hrabovská¹, Ivo Oral³, Josef Bartek⁴

¹ Oddělení laboratorní medicíny

² Interní oddělení, Nemocnice Šternberk

³ Interní klinika, Institut postgraduálního vzdělávání ve zdravotnictví, Zlín

⁴ Ústav lékařské chemie a biochemie, Lékařská fakulta Univerzity Palackého, Olomouc, Česká republika

Introduction:
Natriuretic peptides (NT-proBNP) can be used as surrogate markers in assessing heart failure, its severity, and in the differential diagnosis of dyspnoe. There are also guidelines referring to use of monitoring the dynamics of natriuretic peptides in standardized physical exercise in estimating latent heart failure.


Aim of study:
Can NT-proBNP be used to diagnose exercise-induced ischemia or latent heart failure?




Methods:
A group of 18 probands (10 men, 8 women). They were at-risk individuals with a non-specific EKG picture, and no signs of overt heart failure. All probands had exercise testing (bicycle ergometry) to subjective peak effort, myocardial SPECT with left ventricular ejection fraction estimate at peak exercise. The following laboratory investigations were performed in all probands:


a) before ergometry:
NT-proBNP, CRP, TNF-", Hb, Htc, lactate,


b) on reaching subjective peak:
NT-proBNP, Hb, Htc, lactate,


c) 30 minutes after the end of exercise:
NT-proBNP,


d) 60 minutes after the end of exercise:
NT-proBNP.
All probands' data were adjusted to blood volume changes (estimate based on Htc dynamics, Hb involving calculation of metabolic changes in NT-proBNP). To evaluate NT-proBNP dynamics, the whole group was divided into subgroups according to exercise testing results.

Results:
94% of probands had baseline NT-proBNP levels within normal (< 59 pmol/L, 500 ng/L). 94% of probands reached submaximal heart rate during exercise testing; 59% developed ischemic changes on EKG during exercise; 35% of probands showed typical clinical signs of heart ischemia during exercise. 47% of the group showed signs of cardiac dysfunction, as assessed by SPECT, while 43% showed signs of ischemia. On average, the probands on peak exercise showed a decrease in plasma volume by 24%, and all probands were found to have significantly increased plasma lactate levels. Conversion of NT-proBNP levels to blood volume changes revealed an increase in NT-proBNP was present in only 22% of probands; the changes were not significant. The difference in NT-proBNP before exercise and at peak exercise prior to, and after adjustment to volume changes, was not significant. Thirty and 60 minutes after the end of exercise, no significant differences were seen in NT-proBNP levels. No significant differences in NT-proBNP levels were likewise observed after dividing the group into subgroups.

Conclusion:
Evaluation of the dynamics of changes in NT-proBNP during exercise testing and immediately after it cannot be used in the diagnosis of exercise-induced heart failure. Our findings are consistent with the information suggesting high stability of NT-proBNP depending on physical activity.

Keywords: NT-proBNP; Latent heart failure; Ergometry

Published: January 1, 2003  Show citation