Cor Vasa 2006, 48(11):388-390 | DOI: 10.33678/cor.2006.125

NT-proBNP as a non-invasive marker of acute rejection in heart transplant recipients

Helena Bedáňová^1,*, Erik Petrikovits¹, Josef Nečas¹, Petr Pavlík¹, Pavel Studeník¹, Jiří Ondrášek¹, Jan Černý¹, Petr Breinek², Lenka Špinarová³

¹ Centrum kardiovaskulární a transplantační chirurgie

² Oddělení klinické biochemie

³ I. interní-kardioangiologická klinika, Fakultní nemocnice u sv. Anny, Brno, Česká republika

Aim:
The aim of our study was to determine whether NT-proBNP (N-terminal pro brain natriuretic peptide) could be used in clinical practice as a non-invasive marker of rejection after heart transplantation (HTx).

Method:
The study included 46 patients undergoing HTx, with the first four endomyocardial biopsy (EMB) samples of each assessed, giving a total of 184 samples and their respective NT-proBNP values. Excluded were patients with renal insufficiency, i.e., those with creatinine levels > 150 µmol/l on the day of biopsy. The remaining patients were divided into two groups. Group A comprised 116 biopsy samples (with results of grades 0 and 1A of the ISHLT [International Society for Heart and Lung Transplantation] classification) and Group B made up of 39 samples (grades 1B, 2, and 3A). NT-proBNP was determined using electroimmunoluminiscent analysis (ECLIA). Student s t-test was used to establish a correlation between NT-proBNP levels and acute rejection. The potential of NT-proBNP level determination in detecting acute rejection in clinical practice was established by assessing the sensitivity, specificity, and positive and negative predictive values of the method.

Results:
Overall, 89 biopsy samples were classified as (G) 0 (mean NT-proBNP, 583 ± 473 pmol/L), 27 as 1A (mean NT-proBNP, 665 ± 580 pmol/L); 28 as G 1B (mean NT-proBNP, 1,085 ± 1,194 pmol/L) whilst 10 samples were classified as G 2 (mean NT-proBNP, 955 ± 715 pmol/L), rejection classified as G 3A as seen in one case, with the NT-proBNP levels of 335 pmol/l. The difference between Group A (no rejection) and Group B (presence of rejection) was significant at a level of 2.5%. The test had a sensitivity of 86% and a specificity of 31%, with positive and negative predictive values of 42 and 78, respectively.

Conclusions:
NT-proBNP levels are elevated in HTx patients and increase with renal insufficiency. However, NT-proBNP does not seem to be an appropriate marker of acute rejection as its levels are dependent on a variety of factors; moreover, there seems to a fairly big inter-individual variability. While the difference between patients with and without rejection was significant in our group, and the specificity of the test was high, its sensitivity was very low. Endomyocardial biopsy thus continues to be the gold standard for detecting acute rejection in HTx recipients.

Keywords: NTpro-BNP; Heart transplantation; Rejection

Published: November 1, 2006  Show citation