Wizemann V, Lotz C, Techert F, Uthoff S
Georg-Haas-Dialysezentrum, Giessen, Germany.
Nephrol Dial Transplant. 2000;15 Suppl 1:43-8. doi: 10.1093/oxfordjournals.ndt.a027963.
Current methods of renal replacement therapy lead only to an insignificant removal of larger, potentially toxic, substances, which are excreted by healthy kidneys. On-line preparation of substituate from dialysate and the use of high-flux membranes allow substantial convective removal of such substances. A modified on-line haemodiafiltration method with the use of a large membrane surface and a high convective part was chosen to test whether the elimination of larger substances, such as low-molecular-mass proteins, has a clinical impact.
In a prospective, controlled study over 24 months, 44 unselected chronic dialysis patients were randomized to undergo either low-flux haemodialysis (HD; n = 21) or haemodiafiltration (HDF; n = 23). To eliminate confounding factors, low-molecular efficacy was matched (Kt/V 1.8), and the same membrane material (polysulfone), ultrapure dialysate and the same treatment duration (4.5 h) were applied to each group.
Morbidity, mortality, blood pressure, dialysis-associated hypotensive episodes, haematocrit and erythropoietin dose did not differ between the groups. The same was true for body weight and, accordingly, bioimpedance values, clinical hydration score, skinfold thickness, plasma albumin, prealbumin and transferrin. beta2-Microglobulin in the plasma did not change in the HD group and varied between 32 and 43 mg/l throughout the 2 years. In HDF, beta2 microglobulin decreased from similar values to 18 mg/l predialysis (P<0.01) in the first 6 months of HDF treatment and then remained constant during the remaining 18 months.
In the absence of any clinical marker of uraemic toxicity the removal of larger molecules over the time-span of 2 years during HDF had no clinical implication compared with extremely (and for routine practice unrealistically) well-dialysed patients with low-flux HD. In the absence of any side-effects of on-line HDF and supposing that plasma beta2-microglobulin is a marker of morbidity, on-line HDF ensures an excellent dialysis quality which apparently takes time to translate into measurable clinical sequelae.
目前的肾脏替代治疗方法仅能少量清除较大的、可能具有毒性的物质，而这些物质可由健康肾脏排出。利用透析液在线制备置换液以及使用高通量膜可大量对流清除此类物质。我们选择了一种改良的在线血液透析滤过方法，该方法使用大的膜面积和高对流部分，以测试清除较大物质（如低分子量蛋白质）是否具有临床影响。
在一项为期24个月的前瞻性对照研究中，44例未经挑选的慢性透析患者被随机分为接受低通量血液透析（HD；n = 21）或血液透析滤过（HDF；n = 23）。为消除混杂因素，两组的低分子清除效能相匹配（Kt/V 1.8），且每组均使用相同的膜材料（聚砜）、超纯透析液以及相同的治疗时长（4.5小时）。
两组在发病率、死亡率、血压、透析相关低血压发作、血细胞比容和促红细胞生成素剂量方面无差异。体重以及相应的生物电阻抗值、临床水合评分、皮褶厚度、血浆白蛋白、前白蛋白和转铁蛋白情况也是如此。HD组血浆β2微球蛋白无变化，在整个2年期间维持在32至43 mg/l之间。在HDF组，β2微球蛋白在HDF治疗的前6个月从相似值降至透析前的18 mg/l（P<0.01），然后在剩余的18个月保持稳定。
在没有任何尿毒症毒性临床指标的情况下，与采用低通量HD且透析效果极佳（在常规实践中不切实际）的患者相比，HDF在2年时间内清除较大分子对临床并无影响。在没有在线HDF任何副作用的情况下，假设血浆β2微球蛋白是发病的一个指标，在线HDF可确保极佳的透析质量，而这种质量转化为可测量的临床后果显然需要时间。
