Vnitr Lek 2006, 52(6):563-570

Comparison of plasmatic levels of B-natriuretic peptide with echocardiographic indicators of left ventricle function after doxorubicin therapy

L. Elbl^1,*, I. Vášová², M. Navrátil², J. Vorlíček², L. Malášková³, J. Špinar¹

¹ Interní kardiologická klinika Lékařské fakulty MU a FN Brno, pracoviště Bohunice, přednosta prof. MUDr. Jindřich Špinar, CSc., FESC

² Interní hematoonkologická klinika Lékařské fakulty MU a FN Brno, pracoviště Bohunice, přednosta prof. MUDr. Jiří Vorlíček, CSc.

³ Oddělení klinické biochemie a hematologie FN Brno, pracoviště Bohunice, přednosta doc. MUDr. Milan Dastych, CSc.

The study objective:
The aim of the study was to find out the relationship between plasmatic levels of brain natriuretic peptide (BNP) and echocardiographic indicators of left ventricle (LV) function in patients who were in a long-term remission after the therapy of hematological malignity and examined in order to diagnose the late cardiotoxicity of doxorubicin.


Methods and patient sample:
We enrolled 55 patients (31 men/24 women) aged 43 ± 16 (median 41; 21-79) who were treated for historically diagnosed malignant lymphoma. At the time of examination, all patients were in a long-term remission and, at the same time, they completed their initial therapy 6.2 ± 1.5 (median 5; 5-10) years ago. Patients were examined via resting echocardiography before and after the therapy and during the follow-up examination. We determined the left ventricle ejection fraction (LV EF), parameters of diastolic function and the Doppler parameters of systolic and diastolic function (MPI-Tei index). During the follow-up examination, we measured plasmatic levels of BNP (standard levels were between 0 and 29 pmol/l).

Results:
Follow-up examination showed that EF of five patients (9 %) decreased below 50% and three patients had symptoms of heart failure. Although EF of another eleven patients (20%) was in the physiological range, it decreased by more than 10 % as compared with their pre-treatment EF values. Seventeen patients (30 %) showed higher MPI > 0.55 and twenty patients (36 %) demonstrated diastolic dysfunction (impaired relaxation). BNP > 29 pmol/l was observed only in patients with EF < 50 % and heart failure symptoms. BNP values significantly correlated only with endsystolic (r = 0.82; p < 0.0001) and enddiastolic (r = 0.72; p < 0.0001) volume of LV. On the other hand, BNP of 11.4 pmol/l showed negative predictive value for the following parameters: 80% for decrease of EF by more than 10%; 72% for detection of MPI > 0.55; and 70% for detection of relaxation disorder, i.e. the diagnostics of subclinical cardiotoxicity.

Conclusions:
The present study highlights the practical importance of measuring BNP levels when diagnosing the late changes of LV functions after doxorubicin chemotherapy. Standard cut-off BNP (29 pmol/l) used in diagnostics of heart failures identifies patients with pathological EF and heart failure symptoms. Cut-off BNP of 11.4 pmol/l has sufficient negative predictive value to exclude subclinical damage to the myocardium.

Keywords: B-natriuretic peptide; late cardiotoxicity; doxorubicin

Received: January 5, 2006; Accepted: January 18, 2006; Published: June 1, 2006  Show citation