血液透析患者脑钠肽与细胞外液的关系

Association between brain natriuretic peptide and extracellular water in hemodialysis patients.

作者信息

Fagugli Riccardo Maria, Palumbo Barbara, Ricciardi Daniela, Pasini Paolo, Santirosi Paola, Vecchi Luigi, Pasticci Franca, Palumbo Renato

机构信息

Nephrology-Dialysis Department, Ospedale Silvestrini, Azienda Ospedaliera di Perugia, Perugia, Italy.

出版信息

Nephron Clin Pract. 2003;95(2):c60-6. doi: 10.1159/000073669.

DOI:10.1159/000073669

PMID:14610331

Abstract

BACKGROUND

Brain natriuretic peptide (BNP) is a hormone released by the left ventricle (LV) as a consequence of pressure or volume load. BNP increases in left ventricle hypertrophy (LVH), LV dysfunction, and it can also predict cardiovascular mortality in the general population as well as those undergoing hemodialysis (HD). We investigated the association between BNP and volume load in HD patients.

METHODS

We studied 32 HD patients (60 +/- 17.1 years) treated thrice-weekly for at least 6 months. Exclusion criteria were: LV dysfunction, atrial fibrillation, malnutrition. Blood chemistries and BNP were determined on mid-week HD day. Blood pressure (BP) and cardiac diameters were determined on mid-week inter-HD day by using 24-hour ambulatory blood pressure monitoring and echocardiography. Bioimpedance was performed after HD and extracellular water (ECW%), calculated as a percentage of total body water, was considered as the index of volume load.

RESULTS

Patients were divided into quartiles of 8 patients depending on the BNP value: 1st qtl BNP < or =45.5 pg/ml (28.4 +/- 10.9 pg/ml), 2nd qtl BNP > 45.5 pg/ml and < or =99.1 pg/ml (60.9 +/- 15.8 pg/ml), 3rd qtl BNP > 99.1 pg/ml and < or =231.8 pg/ml (160.5 +/- 51.8 pg/ml), 4th qtl BNP > 231.8 pg/ml (664.8 +/- 576.6 pg/ml). No inter-quartile differences were reported in age, HD age, body mass index spKt/V, or blood chemistries. As expected patients in the 4th BNP quartile showed the highest values of 24-hour pulse pressure (PP) and LV mass index (LVMi). The study of body composition revealed significant differences in ECW%, which was higher in the 4th quartile when compared to the others (4th q: 50 +/- 9.6%, vs 1st q. 40.1 +/- 2.4%, 2nd q. 41.9 +/- 5%, 3rd q. 42.8 +/- 6.9%). Using multiple stepwise linear regression where BNP was the dependent variable, and PP and ECW% the independent variables, only ECW% maintained statistical significance as a predictor of BNP levels (PP: Beta = 0.86, p = 0.58; ECW%: Beta = 0.64, p < 0.001 p < 0.001).

CONCLUSIONS

Few studies have investigated the relationship between plasma BNP and volume load, and direct evidence is lacking. We used bioimpedance and the determination of ECW% to assess volume state in HD patients finding an association between BNP and ECW. The increased synthesis and release of BNP from the LV in HD patients appear to be mainly related to volume stress rather than to pressure load.

摘要

背景

脑钠肽（BNP）是左心室（LV）因压力或容量负荷而释放的一种激素。在左心室肥厚（LVH）、左心室功能障碍时BNP水平升高，并且它还可以预测普通人群以及接受血液透析（HD）患者的心血管死亡率。我们研究了HD患者中BNP与容量负荷之间的关联。

方法

我们研究了32例HD患者（年龄60±17.1岁），每周进行3次HD治疗，至少持续6个月。排除标准为：左心室功能障碍、心房颤动、营养不良。在HD治疗周中的某天测定血液化学指标和BNP。在HD治疗周中的非HD日，通过24小时动态血压监测和超声心动图测定血压（BP）和心脏直径。HD治疗后进行生物电阻抗分析，细胞外液（ECW%）以占总体水的百分比计算，被视为容量负荷指标。

结果

根据BNP值将患者分为4个四分位数组，每组8例：第1四分位数组BNP≤45.5 pg/ml（28.4±10.9 pg/ml），第2四分位数组BNP＞45.5 pg/ml且≤99.1 pg/ml（60.9±15.8 pg/ml），第3四分位数组BNP＞99.1 pg/ml且≤231.8 pg/ml（160.5±51.8 pg/ml），第4四分位数组BNP＞231.8 pg/ml（664.8±576.6 pg/ml）。在年龄、HD治疗时长、体重指数、标准Kt/V或血液化学指标方面，各四分位数组之间未报告有差异。正如预期的那样，第4 BNP四分位数组的患者24小时脉压（PP）和左心室质量指数（LVMi）最高。身体成分研究显示ECW%存在显著差异，第4四分位数组的ECW%高于其他组（第4四分位数组：50±9.6%，第1四分位数组：40.1±2.4%，第2四分位数组：41.9±5%，第3四分位数组：42.8±6.9%）。使用以BNP为因变量，PP和ECW%为自变量的多元逐步线性回归分析，只有ECW%作为BNP水平的预测指标保持统计学意义（PP：β = 0.86，p = 0.58；ECW%：β = 0.64，p＜0.001）。