[Association between serum NT-proBNP/hs-CRP and acute rejection after heart transplantation]

Abstract

Objective: The aim of the present work was to investigate the potential relationship between acute rejection and serum concentrations of N-terminal pro-brain natriuretic peptide (NT-proBNP)/high sensitivity C reactive protein (hs-CRP) in post-transplant patients.

Methods: Sixty-one consecutive orthotopic heart transplantation recipients were prospectively recruited from the cardiac transplantation programme at Fuwai Hospital. Endomyocardial biopsies (EMB) were performed routinely at 3 weeks, 3, 6 and 12 months after transplantation. EMB were also performed when patients had new symptoms of heart failure or at 2 weeks after steroid pulse therapy. Serum NT-proBNP and hs-CRP were simultaneously measured before EMB procedure.

Results: A total of 126 biopsy samples were obtained from the 61 patients. Serum NT-proBNP concentrations progressively decreased after transplantation (spearman correlation coefficient -0.520, P = 0.000). NT-proBNP levels within 6 months after transplantation were significantly higher than those beyond 6 months post transplantation [(11.86 +/- 11.16) x 10(-16) mol/L vs.(5.83 +/- 6.58) x 10(-16) mol/L, P = 0.002]. NT-proBNP concentrations in patients with rejection tended to be higher than patients without rejection (13.68 x 10(-16) mol/L vs. 9.26 x 10(-16) mol/L, P = 0.073). After time adjustment, the difference of NT-proBNP concentrations between patients with or without rejection becomes statistically significant (14.45 x 10(-16) mol/L vs. 9.1 x 10(-16) mol/L, P = 0.025). Receiver operating characteristics analysis for NT-proBNP versus rejection grade revealed an area under the curve of 0.566, indicating a low predictive value for NT-proBNP. A cutoff of 6.00 x 10(-16) mol/L yielded poor specificity (44.8%) and sensitivity (57.1%), the sensitivity and specificity were 38.1% and 61.0%, respectively with a cutoff of 8.00 x 10(-16) mol/L. hs-CRP levels within 6 months after transplantation tended to be higher than those beyond 6 months [(2.39 +/- 3.90) mg/L vs. (1.34 +/- 2.73) mg/L, P = 0.069]. hs-CRP concentrations in patients with rejection were similar as patients without rejection (2.995 mg/L vs. 1.833 mg/L, P = 0.138). The incidence of rejection was similar in patients with two higher biomarkers (5/20, 25%) compared to patients with two low biomarkers (3/26, 11.5%, P = 0.232).

Conclusions: NT-proBNP level decreased after transplantation. Although increased NT-proBNP concentrations were related to rejection, the diagnostic capacity was low. Elevated hs-CRP concentrations were not related to rejection after heart transplantation.