Racek Jaroslav, Králová Hana, Trefil Ladislav, Rajdl Daniel, Eiselt Jaromír
Institute of Clinical Biochemistry and Haematology, Department of Clinical Biochemistry and Haematology, Charles University Hospital, Pilsen, Czech Republic.
Nephron Clin Pract. 2006;103(4):c162-72. doi: 10.1159/000092914. Epub 2006 Apr 25.
Brain natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) are released into circulation as a result of congestive heart failure (HF). As HF and water overload are frequent complications in haemodialysis (HD) patients, we decided to study the levels of BNP and NT-proBNP and their changes during HD.
BNP and NT-proBNP levels were determined in 94 HD patients before and after a regular 4-h HD. We followed changes in these peptides during HD depending on age, sex, HF (NYHA classification and left ventricular ejection fraction [LVEF]), duration on HD, presence of hypertension, coronary artery disease, type of membrane used for HD [low-flux (LFx) or high-flux (HFx)] and body mass change during HD. Furthermore, patients basic medication and creatinine levels and presence of diabetes mellitus were monitored.
Respectively,94% and 100% of the patients had pre-dialysis concentrations of BNP and NT-proBNP above the cut-off values for HF. The marker levels correlated significantly both before and after HD (r = 0.903 and 0.888, respectively, p < 0.001). BNP levels significantly decreased (p < 0.0001), whereas NT-proBNP significantly increased (p < 0.0001) during HD on LFx membranes. HD on HFx membranes caused greater decrease of BNP (compared to LFx membranes, p < 0.001), but also a decrease of NT-proBNP (p < 0.001).We did not find any significant differences in marker levels for HF and non-HF patients (NYHA classification). However, both peptides reached higher levels in the group with LVEF < or = 50% (p < 0.001 for both peptides). Body mass change during HD negatively correlated only with the change of NT-proBNP (r = -0.27, p < 0.05). In the multiple regression model, the change of both peptides during HD was significantly influenced by membrane type (p = 0.003 for BNP and p = 0.001 for NT-proBNP). NT-proBNP change during HD was further significantly influenced by LVEF (p = 0.012), sex (p = 0.002) and duration on HD (p = 0.006).
Both BNP and NT-proBNP levels were significantly increased in HD patients prior to dialysis. The change in concentrations of both peptides during HD is influenced by membrane type. HD probably triggers increased production of both peptides and this increase is emphasized by impaired LVEF. This fact can be clinically observed only on NT-proBNP levels, because BNP levels are biased by significant removal of this protein during HD.
由于充血性心力衰竭（HF），脑钠肽（BNP）和N末端前脑钠肽（NT-proBNP）释放入血循环。由于HF和水负荷过重是血液透析（HD）患者常见的并发症，我们决定研究HD患者的BNP和NT-proBNP水平及其在HD过程中的变化。
测定94例HD患者在常规4小时HD前后的BNP和NT-proBNP水平。我们根据年龄、性别、HF（纽约心脏协会分级和左心室射血分数[LVEF]）、HD时长、高血压、冠状动脉疾病的存在、HD所用膜的类型[低通量（LFx）或高通量（HFx）]以及HD过程中的体重变化，追踪HD过程中这些肽的变化。此外，监测患者的基础用药、肌酐水平以及糖尿病的存在情况。
分别有94%和100%的患者透析前BNP和NT-proBNP浓度高于HF的临界值。HD前后标志物水平均显著相关（r分别为0.903和0.888，p<0.001）。在LFx膜上进行HD时，BNP水平显著降低（p<0.0001），而NT-proBNP显著升高（p<0.0001）。与LFx膜相比，HFx膜上的HD导致BNP下降幅度更大（p<0.001），但NT-proBNP也下降（p<0.001）。我们未发现HF患者和非HF患者（纽约心脏协会分级）的标志物水平有任何显著差异。然而，在LVEF≤5%的组中，两种肽均达到更高水平（两种肽p均<0.001）。HD过程中的体重变化仅与NT-proBNP的变化呈负相关（r=-0.27，p<0.05）。在多元回归模型中，HD过程中两种肽的变化均受膜类型的显著影响（BNP的p=0.003，NT-proBNP的p=0.001）。HD过程中NT-proBNP的变化还进一步受到LVEF（p=0.012）、性别（p=0.002）和HD时长（p=0.006）的显著影响。
HD患者透析前BNP和NT-proBNP水平均显著升高。HD过程中两种肽浓度的变化受膜类型影响。HD可能触发两种肽的产生增加，而LVEF受损会加重这种增加。这一事实仅在NT-proBNP水平上可临床观察到，因为HD过程中BNP水平因该蛋白的大量清除而有偏差。
