Identical decline of residual renal function in high-flux biocompatible hemodialysis and CAPD.

BACKGROUND: Patients on conventional hemodialysis lose residual renal function more rapidly than patients on continuous ambulatory peritoneal dialysis (CAPD). The effect of dialysis using synthetic membranes and ultrapure water is less clear. METHODS: The decline of urea clearance was compared in a cohort of 475 incident end-stage renal failure patients who received treatment with CAPD (N=175) or hemodialysis (HD) utilizing high-flux polysulphone membranes, ultrapure water, and bicarbonate as the buffer (N=300). RESULTS: CAPD patients were significantly younger, fitter (lower comorbidity severity score), less dependent (higher Karnofsky performance score) and less likely to have presented late than HD patients. There was no difference in the mean urea clearance in each group at dialysis initiation, or at any 6-month time point during the ensuing 48 months. This was true even after exclusion of patients who had died in the first year after initiation, those transferred to another dialysis modality, or those who had been transplanted. Only age and chronic interstitial disease predicted retention of urea clearance at one year. The rate of decline of urea clearance was similar in pre- and post-dialysis initiation phases, though there may have been a step-decline of about 2 mL/min at initiation, which requires further investigation. CONCLUSIONS: In hemodialysis using high-flux biocompatible membranes and ultrapure water, residual renal function declines at a rate indistinguishable from that in CAPD. This may have important implications, since preservation of residual renal function has major benefits and is a valid therapeutic goal.     

肾衰合剂对维持性腹膜透析患者残余肾功能的影响

目的：观察肾衰舍剂对连续不卧床腹膜透析（CAPD）患者残余肾功能的影响，探讨中药治疗对CAPD患者残余肾功能的保护作用及其机制。方法：将56例脾肾气（阳）虚型的CAPD患者随机分为常规腹膜透析对照组，及加服中药肾衰合剂治疗组。治疗6个月，比较残余肾KT／V、残余肾CCr的变化及下降速率。结果：在维持总体透析效能的前提下，治疗组残余肾KT／V、残余肾CCr下降速度较对照组明显缓慢。结论：肾衰合荆能有效延缓PD患者的RRF的下降。     

Peritoneal sodium mass removal in continuous ambulatory peritoneal dialysis and automated peritoneal dialysis: influence on blood pressure control.

BACKGROUND/AIM: Sodium and water retention is common in peritoneal dialysis patients and contributes to cardiovascular disease. As peritoneal sodium removal depends partly on dwell time, and automated peritoneal dialysis (APD) often uses short dwell time exchanges, the aim of this study was to compare the 24-hour peritoneal sodium removal in APD and standard continuous ambulatory peritoneal dialysis (CAPD) patients and to analyze its possible influence on blood pressure control. METHODS: A total of 53 sodium balance studies (30 in APD and 23 in CAPD) were performed in 36 stable peritoneal dialysis patients. The 24-hour net removal of sodium was calculated as follows: M = ViCi - VdCd, where Vd is the 24-hour drained volume, Cd is the solute sodium concentration in Vd, Vi is the amount of solution used during a 24-hour period, and Ci is the sodium concentration in Vi. Peritoneal sodium removal was compared between APD and CAPD patients. Residual renal function, serum sodium concentration, daily urinary sodium losses, weekly peritoneal Kt/V and creatinine clearance, 4-hour dialysate/plasma creatinine ratio, proportion of hypertonic solutions, net ultrafiltration, systolic and diastolic blood pressures, and need for antihypertensive therapy were also compared between the groups. RESULTS: Peritoneal sodium removal was higher (p < 0.001) in CAPD than in APD patients. There were no significant differences in residual renal function, serum sodium concentration, urinary sodium losses, peritoneal urea or creatinine clearances, 4-hour dialysate/plasma creatinine ratio, or proportion of hypertonic solutions between groups. The net ultrafiltration was higher in CAPD patients and correlated strongly (r = 0.82; p < 0.001) with peritoneal sodium removal. In APD patients, peritoneal sodium removal increased significantly only in those patients with a second daytime exchange. The systolic blood pressure was higher (p < 0.05) in APD patients, and the proportion of patients with antihypertensive therapy was also higher in APD patients, although no significant relationship between blood pressure values and amount of peritoneal sodium removal was found. CONCLUSIONS: The 24-hour sodium removal is higher in CAPD than in APD patients, and there is a trend towards better hypertension control in CAPD patients. As hypertension control and volume status are important indices of peritoneal dialysis adequacy, our results have to be considered in the choice of the peritoneal dialysis modality.     

依贝沙坦对维持性腹膜透析患者残存肾功能的保护作用

目的 探讨血管紧张素Ⅱ受体拮抗剂（ARB）依贝沙坦能否延缓腹膜透析患者残存肾功能（RRF）的丢失。 方法 将入选的48例病情稳定的维持性腹膜透析患者随机分为依贝沙坦组和对照组。依贝沙坦组予安博维300 mg/d。所有患者每3个月行残存肾功能测定（eGFR），研究前后检测Kt/V、肌酐清除率（CCL）、血钾、血红蛋白，并记录血压和24 h尿量。 结果 研究结束时，依贝沙坦组和对照组的收缩压和舒张压、血红蛋白、血钾水平差异均无统计学意义；依贝沙坦组CCL[单位：L&#8226;周-1&#8226;(1.73 m2)-1] 高于对照组 （63.0±16.9 比 59.0±14.8，P < 0.05）；两组24 h尿量均减少，但对照组较依贝沙坦组减少明显 [(663±312) 比(885±276) ml/d，P < 0.05]。前6个月两组eGFR都明显下降，而依贝沙坦组更明显，6个月后依贝沙坦组下降变缓，研究结束时依贝沙坦组eGFR较对照组高[（1.68±1.01）比（1.04±0.76）ml/min，P < 0.05]。 结论 长期使用依贝沙坦可以延缓腹透患者的残存肾功能的丢失     

Factors influencing residual renal function of CAPD patients

It is generally accepted that residual renal function has significant meaning in dialysis adequacy of CAPD patients. However, the factors influencing the residual renal function have not been investigated yet. We evaluated the consequences of following factors on residual urine volume in 50 CAPD patients: deterioration rate of renal function (slope of I/serum creatinine) before dialysis, renal creatinine clearance at the initial point of dialysis and the episodes of rapid reduction of residual urine volume. There was no correlation between the deterioration rate of renal function before dialysis and the residual urine volume. On the contrary, there was significant correlation between renal creatinine clearance at the initial point of dialysis and the residual urine volume in the first 4 years on CAPD. We recognized 67 episodes of rapid reduction of residual urine volume after initiation of CAPD. Inappropriate management or complications attributed to the rapid urine volume reduction in 50 episodes. The residual urine volume did not recover to the previous level in 40 episodes. We concluded that early initiation of CAPD and evasion of decreasing residual urine volume caused by inappropriate management or complications have important meaning and will preserve residual renal function of CAPD patients.     

Preservation of residual renal function and factors affecting its decline in patients on peritoneal dialysis

SUMMARY:     The decline of residual renal function (RRF) in peritoneal dialysis (PD) patients was analysed and assessed, and risk factors affecting its decline were identified. Residual glomerular filtration rate (GFR) was calculated from averaging the urea and creatinine clearance by 24-h urine collection, and peritoneal solute removal was evaluated by creatinine clearance calculated from 24-h effluent collection. Both GFR and peritoneal solute removal were chronologically examined in 34 PD patients from the time of initiation, and risk factors associated with rapid GFR decline were investigated. The RRF contributed to 43.1 ± 17.6% of total (peritoneal and renal) weekly creatinine clearance at 1 month after initiation of PD. Residual GFR, however, declined continuously with time (−0.19 ± 0.14 mL/min per month), and the reduction rate was high with a higher GFR, higher normalized dietary protein intake, higher urine volume and higher urine protein excretion at the initiation of PD. Other factors related to the rapid decline of GFR were: being older than 60 years of age, automated peritoneal dialysis (APD) rather than continuous ambulatory peritoneal dialysis, mean blood pressure higher than 110 mmHg, and serum human atrial natriuretic peptide level higher being than 60 pg/dL. These data suggest that while RRF plays an important role in the removal of uraemic solute in PD patients, they show a significant decrease over 2 years. The factors related to the rapid decline of GFR corresponded to older age, modality of PD (APD), higher GFR and higher amount of urine protein at initiation, higher dietary protein intake, and inadequate control of hypertension and body fluid volume.     

The relationship among asymmetric dimethylarginine (ADMA) levels, residual renal function, and left ventricular hypertrophy in continuous ambulatory peritoneal dialysis patients

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of endothelial-based nitric oxide synthase. Its level is increased by end stage renal disease. However, most studies showing an increase in ADMA in dialysis patients have focused on hemodialysis. Results with peritoneal dialysis patients have been more inconclusive. Recent studies suggest that ADMA may be a new cardiovascular risk factor. The aim of the present study was to evaluate the relationship between ADMA levels, residual renal function, and left ventricular hypertrophy in peritoneal dialysis patients. Serum ADMA measurements and echocardiographic evaluations were performed in 54 peritoneal dialysis patients and 26 healthy volunteers. Residual renal function was measured in peritoneal dialysis patients by urea clearance from a urine collection. Thirty-two of the 54 peritoneal dialysis patients had residual renal function. ADMA levels of the peritoneal dialysis group were found to be significantly higher than those of healthy individuals (p = 0.03). Within the peritoneal dialysis group, ADMA levels of patients with residual renal function were significantly lower than those without residual renal function (p = 0.01), though they were still higher than the ADMA levels of the control group (p = 0.04). Serum levels of ADMA were positively correlated with left ventricular mass index (r = 0.29, p = 0.01) and negatively correlated with early mitral inflow velocity (Em) (r = -0.28, p = 0.01), Em/Late mitral inflow velocity (Am) (r = -0,32, p = 0.00), and isovolumetric relaxation time (r = -0.30, p = 0.01). In conclusion, increased ADMA levels seem to be associated with left ventricular hypertrophy in peritoneal dialysis patients, and residual renal function may lead to a reduction of serum ADMA levels.     

高血脂对腹膜透析患者的残余肾功能影响

目的：观察高血脂对连续性不卧床腹膜透析（CAPD）患者的残余肾功能（RRF）的作用。方法：定期监测共72例CAPD患者血脂成分及残余肾功能,根据血脂的变化将患者分为胆固醇（TC）增高组、三酰甘油（TG）增高组及二者均增高组与TC、TG正常组,比较各组残余肾功能变化。结果：CAPD治疗初期残余肾功能无明显变化（P〉0.05）。第12月时,TC增高组RRF较同组透析初月时下降（P〈0.05）。TG增高组及TC、TG均增高组的RRF分别与透析初月时同组RRF比较显著下降（P〈0.001）。第18月时3个血脂增高组RRF与TC、TG组比较均有下降（P〈0.05）。RRF下降数值与TC（r=0.234,P〈0.05）、TG（r=0.528,P〈0.05）均呈正相关。结论：CAPD患者的RRF随着透析时间的延长而降低。高血脂与RRF改变值有正相关性。     

The importance of residual renal function in dialysis patients

Preserving residual renal function has always been the primary clinical goal for every nephrologist managing patients with chronic kidney disease. There is no reason why this important goal should not extend to patients with stage 5 chronic kidney disease receiving dialysis. Indeed, there is now clear evidence that preserving residual renal function remains important after the commencement of dialysis. Residual renal function contributes significantly to the overall health and well-being of dialysis patients. It not only provides small solute clearance but also plays an important role in maintaining fluid balance, phosphorus control, and removal of middle molecular uremic toxins, and shows strong inverse relationships with valvular calcification and cardiac hypertrophy in dialysis patients. Decline of residual renal function also contributes significantly to anemia, inflammation, and malnutrition in patients on dialysis. More importantly, the loss of residual renal function, especially in patients on peritoneal dialysis, is a powerful predictor of mortality. In addition, there is increasing evidence that residual renal and peritoneal dialysis clearance cannot be assumed to be equivalent qualitatively, thus indicating the need to preserve residual renal function in patients on dialysis. In this article, we will review evidence that residual renal function is important in dialysis patients (especially peritoneal dialysis) and outline potential strategies that may better preserve residual renal function in dialysis patients.     

The Relationship among Asymmetric Dimethylarginine (ADMA) Levels,Residual Renal Function,and Left Ventricular Hypertrophy in Continuous Ambulatory Peritoneal Dialysis Patients

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of endothelial-based nitric oxide synthase. Its level is increased by end stage renal disease. However, most studies showing an increase in ADMA in dialysis patients have focused on hemodialysis. Results with peritoneal dialysis patients have been more inconclusive. Recent studies suggest that ADMA may be a new cardiovascular risk factor. The aim of the present study was to evaluate the relationship between ADMA levels, residual renal function, and left ventricular hypertrophy in peritoneal dialysis patients. Serum ADMA measurements and echocardiographic evaluations were performed in 54 peritoneal dialysis patients and 26 healthy volunteers. Residual renal function was measured in peritoneal dialysis patients by urea clearance from a urine collection. Thirty-two of the 54 peritoneal dialysis patients had residual renal function. ADMA levels of the peritoneal dialysis group were found to be significantly higher than those of healthy individuals (p = 0.03). Within the peritoneal dialysis group, ADMA levels of patients with residual renal function were significantly lower than those without residual renal function (p = 0.01), though they were still higher than the ADMA levels of the control group (p = 0.04). Serum levels of ADMA were positively correlated with left ventricular mass index (r = 0.29, p = 0.01) and negatively correlated with early mitral inflow velocity (Em) (r = ?0.28, p = 0.01), Em/Late mitral inflow velocity (Am) (r = ?0,32, p = 0.00), and isovolumetric relaxation time (r = ?0.30, p = 0.01). In conclusion, increased ADMA levels seem to be associated with left ventricular hypertrophy in peritoneal dialysis patients, and residual renal function may lead to a reduction of serum ADMA levels.     

Tailoring the Peritoneal Dialysis Prescription

M. D., a 62-year-old female with renal disease secondary to bilateral polycystic kidneys and hypertension, opted for continuous ambulatory peritoneal diaiysis (CAPD) when her renal function deteriorated (24-hr urinary creatinine clearance of 6.8 ml/ min in a total urinary volume of 1200 ml) and uremic symptoms developed. The patient lived about a 3-hr drive from the nearest dialysis center. This factor weighed heavily in the patient's decision to choose home dialysis .
A Swan Neck Missouri peritoneal dialysis catheter was inserted by a surgeon under local anesthesia with no complications. Since the patient was symptomatic from the uremia, peritoneal dialysis using a cycler in the supine position was initiated about 18 hr after the catheter insertion. To avoid dialysis solution leak from the incision site, 1 1 volumes per exchange and a 0.5-hr cycle time were chosen. The cycler dialysis continued for 36 hr. The amount of ultrafiltration achieved was 2200 ml. The patient received two additional treatments using cycler dialysis during the next seven days before CAPD training was begun. CAPD training was accomplished in five working days. A baseline peritoneal equilibration test (PET) was carried out and thr residual renal function was determined. Based on the D/P creatinine ratio and the glucose results of the PET, the patient was classified as having a high peritoneal membrane transport rate. The renal creatinine and urea clearances were 5.7 and 4.2 ml/min, respectively (24-hr urine volume was 926 ml ).     

Role of diuretics in the preservation of residual renal function in patients on continuous ambulatory peritoneal dialysis

BACKGROUND: Patients on continuous ambulatory peritoneal dialysis (CAPD) are dependent on residual renal function for solute and water clearances, and this declines with time on dialysis. Loop diuretics have been postulated to slow this decline. METHODS: Sixty-one patients new to dialysis were randomly assigned to either furosemide 250 mg every day or no furosemide at the time of CAPD training and were followed prospectively. Urine volume (UV), urea clearance (C(Urea)), and creatinine clearance on cimetidine (C(Cr)) were measured at randomization at six months and at one year. Patients underwent a standard four-hour peritoneum equilibrium test, and total body water was measured by bioelectrical impedance. Results were expressed on an intention-to-treat basis. RESULTS: UV, C(Cr), and C(Urea) were similar at randomization (1020 +/- 104 vs. 1040 +/- 130 mL/24 hours, 4.95 +/- 0.51 vs. 4.07 +/- 0.40 mL/min/1.73 m2, 0.91 +/- 0.09 vs. 0.84 +/- 0.08, diuretic vs. control). UV in the diuretic-treated group increased, whereas in the control group, it declined (+176 vs. -200 mL/24 hours at 6 months and +48.8 vs. -305 mL/24 hours at 1 year, P < 0.05). C(Cr) and C(Urea) declined at a constant rate and were unaffected by diuretic administration (0.12 +/- 0.05 vs. 0.071 +/- 0.04 mL/min/1.73 m2/month, 0.020 +/- 0.01 vs. 0.019 +/- 0.01 per month). Urinary sodium excretion increased in the diuretic group and declined in the control group (+0.72 +/- 0.85 vs. -2.56 +/- 1.31 mmol/24 hours/month, P = 0.04). Body weight rose in both groups (4.3 vs. 3.0 kg), but the percentage of total body weight rose in the control group and remained constant in the diuretic group (52 +/- 2.4 vs. 64 +/- 6.6%, P = 0.10). CONCLUSIONS: Long-term furosemide produces a significant increase in UV over 12 months when on CAPD and may result in clinically significant improvement in fluid balance. However, furosemide has no effect on preserving residual renal function.     

持续性非卧床腹膜透析患者119例死亡原因分析

目的 分析持续性非卧床腹膜透析（CAPD）患者的死亡原因,为延长患者生存时间提供依据.方法 回顾性分析119例CAPD患者的死亡原因,并与同期126例CAPD存活患者相比较,以寻找其死亡的高危因素.结果 心血管并发症、脑血管意外和营养不良是最主要的死亡原因,分别占30.3%、24.4%和16.8%.与存活组相比,死亡组的年龄、动脉血压（收缩压和舒张压）、胆固醇和C反应蛋白升高（P〈0.05或P〈0.01）,死亡组左心室肥大的比例升高（P〈0.01）,而心脏射血分数、血红蛋白、血浆白蛋白、主观综合性营养评估、尿素氮清除率、透析前残余肾功能和透析前尿量降低（P〈0.01）.结论 心脑血管并发症和营养不良是CAPD患者最主要的死亡原因,与残余肾功能减退、左心室肥大、高血压、蛋白质丢失和微炎症等因素有关.保护残余肾功能、积极有效地控制高血压、纠正营养不良和减少腹膜炎的发生率将有助于延长患者生存时间,降低死亡率.     

Dissociation between the Correlation of Peritoneal and Urine Kt/V with Sodium and Fluid Removal: A Possible Explanation of their Difference on Patient Survival

Background: It has been shown that residual renal function but not peritoneal clearance predicted patients’ survival in peritoneal dialysis therapy. In the present study, we tried to explore the potential causes resulting in the difference between residual renal function and peritoneal dialysis in continuous ambulatory peritoneal dialysis (CAPD) patients. Methods: A cross sectional study was performed during July and August 2003 to evaluate the dialysis adequacy in CAPD patients who were clinically stable and had daily urinary volume more than 100 ml. Results: A total of 45 patients (male 27 and female 18) with an average ( ± SD) age of 61.76 ± 13.27 years were included in this study. The daily urinary volume and dialysate ultrafiltration volume were 570.33 ± 395.47 ml and 726.09 ± 454.01 ml, respectively. Peritoneal urea clearance (Kt/V) correlated significantly with the drained daily dialysate volume (r = 0.362, P < 0.01), but not with peritoneal net fluid removal (ultrafiltration) (r = 0.232, P > 0.05) and sodium removal (r = 0.139, P > 0.05). On the other hand, there were strong positive correlations between residual renal Kt/V and daily urine volume (r = 0.802, P < 0.001), as well as between residual renal Kt/V and urinary sodium removal (r = 0.670, P < 0.001). Conclusions: High residual renal Kt/Vurea represents both higher solute clearance and higher sodium and fluid removal, but higher peritoneal Kt/Vurea is not necessarily associated with better sodium and fluid removal. This dissociation might explain the differences on the survival of patients and peritoneal clearances.     

Impact of dialysis adequacy on the mortality and morbidity of anuric Chinese patients receiving continuous ambulatory peritoneal dialysis

Dialysis adequacy has a major impact on the outcome of continuous ambulatory peritoneal dialysis (CAPD) patients. However, most studies on peritoneal dialysis adequacy have focused on patients with significant residual renal function. The present study examined the effect of dialysis adequacy on anuric CAPD patients. A single-center prospective observational study on 140 anuric CAPD patients was performed. These patients were followed for 22.0 +/- 11.9 mo. Dialysis adequacy and nutritional indices, including Kt/V, creatinine clearance (CCr), protein equivalent nitrogen appearance, percentage of lean body mass, and serum albumin level were monitored. Clinical outcomes included actuarial patient survival, technique survival, and duration of hospitalization. In the study population, 64 were male, 36 (25.7%) were diabetic, and 59 (42.1%) were treated with 6 L exchanges per day. The body weight was 59.2 +/- 10.2 kg. Average Kt/V was 1.72 +/- 0.31, and CCr was 43.7 +/- 11.5 L/wk per 1.73m(2). Two-yr patient survival was 68.8%, and technique survival was 61.4%. Multivariate analysis showed that DM, duration of dialysis before enrollment, serum albumin, and index of dialysis adequacy (Kt/V or CCr) were independent factors of both patient survival and technique survival. It was estimated that for two patients who differed only in weekly Kt/V, a 0.1 higher value was associated with a 6% decrease in the RR of death (P: < 0.05; 95% confidence interval, 0.92 to 0.99). Serum albumin and CCr were the only independent factors that predicted hospitalization. It was found that even when there is no residual renal function, higher dialysis dosage is associated with better actuarial patient survival, better technique survival, and shorter hospitalization. Dialysis adequacy has a significant impact on the clinical outcome of CAPD patients, and the beneficial effect is preserved in anuric patients as well as in an ethnic group that has a low overall mortality.     

A novel association between residual renal function and left ventricular hypertrophy in peritoneal dialysis patients

BACKGROUND: Left ventricular hypertrophy (LVH) and dialysis adequacy are both important predictors for mortality in dialysis patients. This study evaluated the association between residual renal function (RRF) and the severity of LVH in endstage renal failure (ESRF) patients undergoing long-term continuous ambulatory peritoneal dialysis (CAPD). METHODS: A cross-section study was performed with left ventricular mass index (LVMi), determined in 158 non-diabetic CAPD patients using echocardiography and its relationship with residual glomerular filtration rate (GFR), peritoneal dialysis (PD) and total weekly urea clearance (Kt/V) and other known risk factors for LVH was evaluated. RESULTS: Twelve patients had no LVH (group I). The remaining 146 patients were stratified [group II (lowest), III and IV (highest)] according to the LVMi (median 207 g/m2; range 103 to 512 g/m2). Across the four groups of patients with increasing LVMi, there was significant decline in GFR (2.27 +/- 1.98 vs. 1.49 +/- 1.58 vs. 1.61 +/- 1.91 vs. 0.80 +/- 1.42 mL/min/1.73 m2; P = 0.011) and total weekly Kt/V (1.98 +/- 0.44 vs. 1.96 +/- 0.38 vs. 1.92 +/- 0.42 vs. 1.71 +/- 0.42; P = 0.037); however, PD Kt/V was similar for all four groups. Patients with better-preserved residual GFR not only had significantly higher total Kt/V, but were less anemic and hypoalbuminemic and had a trend toward lower systolic blood pressure and arterial pulse pressure. Multiple regression analysis showed that other than age, gender, body weight, arterial pulse pressure, hemoglobin and serum albumin, known factors for LVH, residual GFR (estimated mean -7.94; 95% confidence interval -15.13 to -0.74; P = 0.031) was also independently associated with LVMi. CONCLUSIONS: Other than anemia, hypoalbuminemia and arterial pulse pressure, this study demonstrates an important, novel association between the degree of RRF and severity of LVH in ESRF patients undergoing long-term CAPD. Prospective studies are needed to define if indeed there is a cause-effect relationship between this association, to evaluate if a decline in residual GFR is independently associated with an increase in LVMi, and to determine whether treatment directed at preserving RRF will reduce the severity of LVH, improve cardiac performance and hence survival of these patients.