Servicio de Nefrología, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
Nephrol Dial Transplant. 2012 Dec;27 Suppl 4:iv31-5. doi: 10.1093/ndt/gfs420.
Expansion of extracellular volume (ECV) is a frequent cause of resistant hypertension (RHT) in patients with chronic kidney disease (CKD). The aim of this exploratory study was that of applying bioimpedance spectroscopy (BIS) for the identification of CKD patients with RHT and expansion of ECV, while trying to control blood pressure (BP) using an intensification of diuretic treatment.
We included 50 patients with RHT and CKD who underwent BIS. In order to control BP, diuretic treatment was intensified in those patients with expansion of the ECV. In all other cases, another antihypertensive drug was added.
The mean age was 68.2 ± 10.4 years, 68% were male and 58% were diabetic. The mean estimated glomerular filtration rate (eGFR) was 50.7 ± 22.4 mL/min/1.72 m(2). Baseline systolic BP was 167.2 ± 8.6 mmHg and diastolic BP was 84.8 ± 9.5 mmHg. The mean number of antihypertensive drugs received was 3.8 ± 0.9. Expansion of ECV was recorded in 30 (60%) patients and was more frequent in diabetics and in patients with more albuminuria. At 6 months of follow-up, a decline of 21.4 ± 7.1 mmHg was observed in systolic BP in the patients with expansion of ECV, compared with a decrease of 9.4 ± 3.4 mmHg in the normal ECV group (P < 0.01). We did not find differences in the decrease in diastolic BP between the groups. Nine patients (30%) with ECV expansion who increased diuretic therapy reached the target blood pressure (BP) of <140/90 mmHg, when compared with only two patients (10%) who had normal ECV and in whom other antihypertensive drug was added. A total decrease in body water of 1.9 ± 1.1 L was observed in patients with ECV expansion who intensified diuretic treatment at the expense of a decline in ECV of 1.1 ± 1 L. eGFR remained stable in both groups (47.1 ± 21.1 versus 54.1 ± 25.2 mL/min/1.73 m(2); P = 0.37).
An increase in ECV as measured by BIS frequently occurs in RHT in patients with CKD. Diabetic and severe proteinuric patients are more exposed to expansion of ECV. BIS is a potentially useful method for identifying and treating patients with RHT and expansion of ECV. The hypothesis generated by this exploratory study needs to be tested in a randomized clinical trial.
细胞外液容量扩张（ECV）是慢性肾脏病（CKD）患者发生难治性高血压（RHT）的常见原因。本探索性研究的目的是应用生物电阻抗谱（BIS）识别 RHT 合并 ECV 扩张的 CKD 患者，并尝试通过强化利尿剂治疗来控制血压（BP）。
我们纳入了 50 名 RHT 合并 CKD 患者，进行 BIS 检查。为了控制血压，对 ECV 扩张的患者强化利尿剂治疗。在其他所有情况下，均加用另一种降压药物。
患者平均年龄为 68.2 ± 10.4 岁，68%为男性，58%为糖尿病患者。平均估算肾小球滤过率（eGFR）为 50.7 ± 22.4 mL/min/1.72 m2。基线收缩压为 167.2 ± 8.6 mmHg，舒张压为 84.8 ± 9.5 mmHg。患者平均接受 3.8 ± 0.9 种降压药物治疗。30 名（60%）患者出现 ECV 扩张，糖尿病患者和蛋白尿较多的患者更易发生 ECV 扩张。随访 6 个月时，与正常 ECV 组收缩压下降 9.4 ± 3.4 mmHg 相比，ECV 扩张患者收缩压下降 21.4 ± 7.1 mmHg（P < 0.01）。两组间舒张压下降无差异。与仅加用另一种降压药物的正常 ECV 组的 2 名患者（10%）相比，增加利尿剂治疗的 9 名（30%）ECV 扩张患者达到了<140/90 mmHg 的目标血压。ECV 扩张患者强化利尿剂治疗后，总去水量为 1.9 ± 1.1 L，同时 ECV 下降 1.1 ± 1 L。两组 eGFR 均保持稳定（47.1 ± 21.1 与 54.1 ± 25.2 mL/min/1.73 m2；P = 0.37）。
BIS 测量的 ECV 增加在 CKD 合并 RHT 患者中较为常见。糖尿病和严重蛋白尿患者更易发生 ECV 扩张。BIS 可能是识别和治疗 RHT 合并 ECV 扩张患者的有用方法。本探索性研究提出的假设需要在随机临床试验中进行检验。
