Peritoneal Dialysis and Hemodialysis in Pregnancy

Management of women who require dialysis during pregnancy is an unusual and challenging clinical problem for both the nephrologist and the obstetrician. More than 200 pregnancies have been reported in women requiring hemodialysis, and more than 50 pregnancies in women on peritoneal dialysis. Surveys from several countries of pregnancy in dialysis patients provide data regarding management and outcomes. Conception rates are significantly lower in women on dialysis, and when these women do become pregnant, the spontaneous abortion rate usually exceeds 40%. However, in the pregnancies that continue, as many as 71% result in surviving infants. Pregnant women require longer, more intense hemodialysis, and enough experience has been reported to support the use of peritoneal dialysis as well as hemodialysis during pregnancy. The patients typically experience anemia, hypertension, and premature delivery. Most infants are small for gestational age, and the stillbirth rate is as high as 12%. While the potential problems are many, sufficient data has been accumulated to provide clinicians with guidelines to help them manage pregnant women on dialysis and to achieve successful outcomes.     

A Comparative Study of C‐Reactive Protein Plasma Levels in Patients on Hemodialysis and Peritoneal Dialysis

In dialysis patients, C‐reactive protein (CRP), a well‐recognized marker of inflammation, predicts mortality. Higher levels have been described in hemodialysis (HD) patients as compared with peritoneal dialysis (PD) patients. Our aim was to determine, based on CRP plasma levels, the degree of inflammation in HD patients using low‐permeability polysulfone membranes and relatively pure dialysate, and that in PD patients. A secondary objective was to study factors associated with hypoalbuminemia and inflammation in both populations. We studied 69 stable patients on dialysis (32 on HD and 37 on PD). The mean age was 69.9 ± 8.2 years, and the mean time on dialysis was 27 months. The two populations were comparable for overall and cardiovascular comorbidities. Nephelometry was used to measure CRP plasma levels (normal levels < 0.6 mg/dL). The Kt/V_urea, corrected for residual renal clearance, and the equivalent of protein nitrogen appearance (PNA) were also calculated. Of the patients studied, 53% showed CRP plasma levels higher than 0.6 mg/dL; in 36%, the levels were higher than 1 mg/dL. No significant differences in these percentages were noted between the two dialysis groups. Patients with CRP levels higher than 1 mg/dL showed lower serum albumin, iron, hemoglobin, and transferrin levels, and higher ferritin values and leukocyte counts. Under logistic regression analysis, CRP levels higher and lower than 1 mg/dL were significantly associated with serum albumin [p = 0.01; odds ratio (OR): 0.15], iron (p = 0.006; OR: 0.96), transferrin (p = 0.004; OR: 0.97), and hemoglobin (p = 0.02; OR: 0.67). Serum albumin levels were significantly lower in PD patients. Under regression analysis, serum albumin levels correlated with cholesterol (r: 0.25; p = 0.04), serum iron (r: 0.5; p = 0.0001), transferrin (r: 0.3; p = 0.015), ultrafiltration capacity (r: 0.42; p = 0.008), and CRP values above 0.6 mg/dL (r: –0.65; p = 0.001). In conclusion, the frequent elevation of CRP plasma levels observed in both HD and PD patients suggests the presence of a silent inflammatory state. Hemodialysis performed with biocompatible, low‐permeability membranes is not associated with higher CRP plasma levels than those seen in PD. In both groups, hypoalbuminemia is related to CRP level. Levels of serum albumin, slightly lower in PD patients, are also related to peritoneal ultrafiltration capacity.     

腹膜透析及包装用高分子材料的应用现状

为了概括腹膜透析及包装用高分子材料的发展与应用,就作为CAPD重要组成部分的透析液包装和透析导管的发展状况,以及材料、加工和应用中的相关问题进行综述。     

Knowledge of Home Dialysis Among Inner‐City Satellite Hemodialysis Patients

There is limited use of home renal replacement therapies in the U.S.A. One percent of dialysis patients are on home hemodialysis (HHD) and only 9% undergo peritoneal dialysis (PD). In an effort to better understand this, 161 satellite hemodialysis patients in 6 units in Brooklyn were surveyed. Forty‐eight percent of patients were women, 86% were black, 5% white, 8% Hispanic, and 1% other. Mean age was 49.4 years (range 22 – 69 years). Etiology of renal disease was hypertension (41%), diabetes mellitus (31%), polycystic kidney disease (3%), systemic lupus erythematosus (4%), and other or unknown (21%). Patients were queried about knowledge of and attitudes toward home therapies. Seventy‐nine percent of patients knew of home dialysis. The source of this information was the nephrologist (59%), the social worker (14%), a nurse (8%), other patients (4%), and other sources (15%). Only 10% of patients had ever considered HHD. Fifty‐four percent were afraid to do self‐care at home and 35% were not interested. Surprisingly, only 3% felt they had no reliable helper and 8% felt that their housing was not suitable. Similarly, 78% of patients had been spoken to about PD, but only 11% had considered it. Forty‐one percent were afraid of doing self‐care on PD, and 45% were not interested. We conclude that, although the majority of patients in six inner‐city dialysis units had heard of home dialysis, only a small number ever considered it. As many patients were afraid of doing home therapy, better education about the risks and benefits needs to be disseminated.     

Length of Dialysis Session Is More Important Than Large Kt/V in Hemodialysis

Long, slow hemodialysis (3 × 8 hours/week) has been used without significant modification in Tassin, France, for 30 years with excellent morbidity and mortality rates. A long dialysis session easily provides high Kt/V_urea and allows for good control of nutrition and correction of anemia with a limited need for erythropoietin (EPO). Control of serum phosphate and potassium is usually achieved with low-dose medication. The good survival achieved by long hemodialysis sessions is essentially due to lower cardiovascular morbidity and mortality than in short dialysis sessions. This, in turn, is mainly explained by good blood pressure (BP) control without the need for antihypertensive medication. Normotension in this setting is due to the gentle but powerful ultrafiltration provided by the long sessions, associated with a low salt diet and moderate interdialytic weight gains. These allow for adequate control of extracellular volume (dry weight) in most patients without important intradialytic morbidity. Therefore, increasing the length of the dialysis session seems to be the best way of achieving satisfactory long-term clinical results.     

International Comparisons of Survival on Dialysis: Are They Reliable?

Sharp discrepancies between reported survivals on maintenance hemodialysis in the United States compared with Europe and Japan have provoked broad criticism of the American system of treating irreversible uremia. Although this negative view of renal therapy in the United States is supported by the National Kidney Foundation (NKF), consensus conferences of the National Institutes of Health (NIH), and numerous social critics of the American health care system, the contention has not been sustained by appropriate statistical analysis. The United States has the world's highest treatment rate for incident kidney failure — double that in Europe. This is mainly due to universal acceptance for uremia therapy. In comparisons with Japan, studies have not taken into account unique aspects of Japanese health care and genetic differences between sampled cohorts of studied kidney patients. In fact, no properly conducted analysis has found that the quality of uremia therapy in the U.S. has been inferior to that of anywhere else. While the allegation may yet be proven true, thus far there is no scientific basis for indicting dialysis in the United States as lacking in quality or quantity when ranked with other industrialized nations.     

The Practice of Dialysis in the Developing Countries

There are few organized data on the practice of dialysis in developing countries, mostly because of a lack of renal registries. The economic, human, and technical resources required for long-term dialysis make it a major economical and political challenge. Most countries do not have not well-formed policies for treatment of end-stage renal disease. The dialysis facilities are grossly inadequate, and there are no reimbursement schemes to fund long-term dialysis. Hemodialysis units are mostly in the private sector and consist of small numbers of refurbished machines. Water treatment is frequently suboptimal, and this problem has led to a number of complications. Hepatitis B and C infections are widespread in dialysis units. Continuous ambulatory peritoneal dialysis (CAPD) seems to be the ideal dialysis option for patients living in remote areas, but high costs preclude its widespread usage. The Mexican experience suggests that even after it becomes affordable, CAPD needs to be used judiciously. Inadequate dialysis, infections, and malnutrition account for the high mortality among the dialysis population in developing countries. Acute peritoneal dialysis using rigid stylet-based catheters is the main form of dialysis in remote areas. Pediatric dialysis units are almost nonexistent. A significant lack of resources exists in developing countries, making the provision of highly technical and expensive care like dialysis a challenge.     

Results of Daily Hemodialysis in Catanzaro: 12-Year Experience With 22 Patients Treated For More Than One Year

Since 1985, we have been treating patients with daily hemodialysis (D-HD). We report our results with 22 patients treated on D-HD and daily home hemodialysis (DHHD) for a long-term period. Patients had very good survival of native forearm arteriovenous fistula access, and upper arm access with superficialized basilic vein. One access survived 18 years: 8 years on standard hemodialysis (STND-HD) and 10 years on D-HD. Only two fistulas failed. Blood pressure control in 12 hypertensive patients was obtained without antihypertensive drugs in 8 and with fewer medications in 4. Hematocrit and hemoglobin improved in all patients. Cardiothoratic index decreased in all patients, and we noticed a reduction in the most important echocardiographic indices in 12 patients with cardiac hypertrophy: intraventricular septum thickness, left ventricle posterior wall thickness, left ventricle internal diastolic diameter, and left atrium diameter. Data also showed improvement in nutritional status. For the most part, the levels of hormones normalized, with regular menstrual cycles in women and good sexual function in men. In our experience both elderly and young patients with severe cardiovascular diseases, severe hypertension or hypotension, anemia, and nutritional problems can, with D-HD, achieve good quality of life and start work again. D-HD, in our opinion, is the treatment of choice for patients without comorbid conditions, because good metabolic control, good nutrition, and a more normal hormonal status allow them to feel well and to have an almost normal lifestyle.     

Inherent Errors in the Quantitation of Dialysis Delivery: Implications For CAPD and Daily Hemodialysis

When compared to intermittent dialysis, the theoretical advantages of continuous dialysis may be less important than its practical disadvantage: the inability to accurately quantify dialysis. With intermittent dialysis the change in blood urea nitrogen over the course of the treatment allows the ratio of K (urea clearance) to V (volume of distribution of urea or total body water) to be determined, hence an accurate Kt/V. In continuous dialysis this approach cannot be used due to the steady-state nature of blood urea levels. Instead, V is estimated, generally from the Watson equations. This estimate has sufficient inaccuracy to result in substantial unrecognized underdialysis in many patients.     

Physiologic Inhibitors of Coagulation in Patients on Chronic Hemodialysis

Patients on hemodialysis are at increased risk for bleeding and thromboses. The intriguing balance between these risks is more complex than once thought, as endogenous clotting factors and their regulators come into contact with bioincompatible dialyzer membranes, in the setting of an extracorporeal circuit of blood flow, in the face of the uremic state. In this review, we summarize the current data on the interaction between the physiologic inhibitors of coagulation and hemodialysis. Data sources and study selection were obtained from research and review articles related to the endogenous anticoagulation pathway published in English on MEDLINE from 1972 to 2002. While protein C activity and protein S antigen concentrations are increased, there is no change in antithrombin III levels during hemodialysis in relation to predialysis levels. Plasma protein Z, which has only recently been studied in uremic subjects, is increased as well. In addition, hemodialysis leads to elevated tissue factor plasminogen inhibitor, thrombomodulin, tissue plasminogen activator, and plasminogen activator inhibitor-1 activities. The potential functional significance of these observations is discussed. Finally, as erythropoietin is commonly prescribed to uremic patients and is recognized to be prothrombotic, an appraisal of its interaction with the naturally occurring anticoagulants is presented. It is apparent that we are only beginning to realize the complexity of the interplay between this myriad of serum factors and hemodialysis. Further research is needed to shed light on this underexplored area of hemodialysis.     

Relation between Access-Related Infection and Preinfection Serum Albumin Concentration in Patients on Chronic Hemodialysis

Background: Hemodialysis (HD) access‐related infection is a major cause of morbidity and mortality in HD patients. We tested whether hypoalbuminemia is a risk factor for HD access infection and whether mortality of HD catheter infection is affected by removal of the infected catheter. Methods: We analyzed the records of 87 patients on chronic HD who were hospitalized for HD access‐related infection. We obtained data on age, sex, preinfection serum albumin level, comorbidities, complications, infecting organism, type of infection, mode of management, and mortality. We compared preinfection serum albumin levels in 79 patients with HD access infection with the serum albumin levels of 198 control patients on chronic HD without HD access infection admitted to the hospital during the same time for other reasons. In the HD catheter infection subgroup, we compared mortalities between patients treated with catheter removal plus antibiotics as the primary mode of management and those treated initially with antibiotics alone. Results: Preadmission serum albumin level was lower in the HD access infection group (2.4 ± 0.6 g/dL) than in the control group (3.2 ± 0.6 g/dL, P < 0.0001). Logistic regression identified preadmission serum albumin level as a strong independent predictor of HD access infection. In a logistic regression model, with age, sex, HIV status, diabetes, and type of HD vascular access (excluding arterovenous fistula) as the covariates, the odds ratio of HD access infection was 9.8 (95% confidence interval [CI] 4.9–19.7) for a serum albumin level ≤ 3.0 g/dL (P < 0.0001), 10.4 (95% CI 4.97–21.6) for a serum albumin level ≤ 2.5 g/dL (P < 0.0001), and 28.0 (95% CI 5.8–135.9) for a serum albumin level ≤ 2.0 g/dL (P < 0.0001). Case mortality was 25.0% (4/16) in patients with tunneled HD catheter infection initially treated with antibiotics alone and 2.8% (2/71) in those treated with catheter removal plus antibiotics at the time of presentation (P = 0.0096). Conclusion: Hypoalbuminemia is associated with increased risk of HD access infection. Treatment of HD access infection with antibiotics alone is associated with increased risk of death.     

Comparison of Preventive Care Provided to Dialysis Patients by Nephrologists and to Patients Followed in General Medical Clinics: Compliance with American College of Physicians Guidelines

Most end‐stage renal disease (ESRD) patients do not have primary‐care providers, and preventive medicine often is provided by their nephrologists. Little has been written about their success in providing this care. We studied all patients on dialysis at our hospital and compared their preventive care to a control group followed in the general medical clinic. The general medical group showed higher compliance with Pap smears (89% vs 48%), mammography (87% vs 62%), fecal occult blood testing (75% vs 50%), and pneumococcal vaccination (55% vs 28%). The ESRD group had better compliance with influenza vaccination (70% vs 55%) and lipid profile (100% vs 75%). When the subgroup of patients on hemodialysis (HD) was compared with patients on peritoneal dialysis (PD), it was shown that HD patients were more likely than PD patients to receive preventive care. We also compared diabetes‐specific care. The ESRD group had a higher rate of HbA _1C (100% vs 78%) and lipid monitoring (100% vs 76%), diabetes education (100% vs 84%), and podiatry visits (70% vs 38%). There was no difference in ophthalmologic examination or influenza vaccination. We found that nephrologists provide preventive care to ESRD patients with success approximately equal to primary‐care physicians in our institution, although in different parameters. Ready access to dialysis patients and their blood and unit‐specific policies contribute to compliance that is above national averages. Further improvements can be made by additional preventative measures policies, by physician and patient education, and by monitoring primary‐care compliance in the chart.     

Resource settings have a major influence on the outcome of maintenance hemodialysis patients in South India

Chronic kidney disease is reaching epidemic proportions and the number of patients on renal replacement therapy (RRT) is increasing worldwide and also in developing countries. To meet the challenge of providing RRT, a few charity organizations provide hemodialysis units for underprivileged patients, as the private hospitals are unaffordable for the majority. There is a paucity of information on the outcome of dialysis in these patients. Here, we describe the outcome of hemodialysis patients comparing the middle‐ and upper‐class income group with the lower class income group. A retrospective analysis was carried out in 558 CKD patients initiated on maintenance hemodialysis in two different dialysis facilities. Group A (n=247) included those who belonged to the lowermost socioeconomic status and were undergoing dialysis in two nonprofit, charity (TANKER)‐run dialysis units, and Group B (n=311) was undergoing dialysis in a nonprofit hospital setting where no subsidy was given. Those patients of a low socioeconomic status, especially those who are diabetics, have a higher death rate (Group A‐38.1%, Group B‐4.2%) and loss to follow‐up (Group A‐25.9%, Group B‐0.3%) compared with those who are in the middle‐ and high‐income group. Higher EPO use and hence higher hemoglobin levels (Group A‐6.4±1.2, Group B‐8.9±1.5 P<0.001) were observed in those who were in the middle and the higher income group. Lower serum phosphorus level was observed in the low‐socioeconomic group (Group A‐4.7±1.5, Group B‐5.5±1.9, P<0.001). Patients belonging to the middle and higher socioeconomic group undergo more transplantations compared with the lower socioeconomic group (Group A‐2.4%, Group B‐65.6%).     

Mini mental status examination (MMSE) in stable chronic renal failure patients on hemodialysis: The effects of hemodialysis on the MMSE score. A prospective study

Cognitive impairment is common in hemodialysis (HD) patients. The mini mental status examination is a simple screening test for dementia. The objectives of this study were to (1) study and compare the predialysis and postdialysis mini mental status examination score and 2 subscores and compare them with those of a control group and (2) determine the factors affecting these scores. This was a prospective study of 54 HD patients, which involved calculation of their predialysis (PrHDSc) and (2–4 weeks later) postdialysis (PoHDSc) scores and comparison of these with the control scores (CoSc). The mean scores for PreHDSc and PoHDSc were 26.5±2.7 and 26.4±3.3, respectively. Both were significantly lower than CoSc, 28.4±1.6 (95% CI for score difference 0.99–2.97, P<0.001). The subscores for orientation, registration, and recall (ORR) and attention (ATT) before and after HD were 14.2±1.3, 14.3±1.8, and 3.5±1.7, 3.2±1.8, respectively. Both were significantly lower than the CoSc, 15.2±1.2 and 4.2±1.1 (P=0.001 and 0.004, respectively). There were no significant differences between the PrHDSc and PoHDSc (P values of 0.87, 0.63, and 0.45, respectively). Patients' PrHDSc correlated positively with PoHDSc and dialysis efficiency measured by the urea reduction ratio and Kt/V (r=0.58, 0.4, and 0.34, respectively). Education level correlated positively with PrHDSc r=0.41 but not PoHDSc. Hemodialysis duration correlated negatively with PrHDSc r=−0.3. There was no correlation among age, chronic renal failure duration, HD frequency, weight loss, systolic or diastolic blood pressure drop, and PrHDSc or PoHDSc. Hemodialysis patients scored significantly less than the control patients. Their score was not affected by HD. This may reflect the stable cognitive function/dysfunction or the mild sensitivity of the test.     

Effect of Valsalva Maneuver on QT Dispersion in Hemodialysis Patients

Increased QT dispersion seems to be related to an increased risk of arrhythmia and sudden death, a common cause of mortality in hemodialysis (HD) patients. Increase in sympathetic tone has been documented in HD patients. In this study, we aimed to investigate the effect of changes in the autonomic tone on QT dispersion (QTd) in HD patients. Twenty HD patients (M/F 13/7; age, mean ±SD, 28 ± 10 years) and 22 age‐ and sex‐matched healthy controls (M/F 12/10; age, 30 ± 10 years) were included. The patients were dialyzed three‐times weekly; time on dialysis was 17 ± 8 months. The QT durations were measured from 12 lead surface EKGs and were corrected for RR intervals. Corrected maximum (QT_c max) and minimum (QT_cmin) QT intervals and their difference (QT _c d) were recorded. The effect of the Valsalva maneuver in the release phase on QT _c intervals and dispersion was assessed. The HD patients had prolonged values compared to controls: QT _c d, 59 ± 17 ms versus 35 ± 7 ms, p < 0.001; QT _c max, 458 ± 41 ms versus 397 ± 21 ms, p < 0.001; and QT _c min, 398 ± 36 ms versus 362 ± 25 ms, p < 0.001. After the Valsalva maneuver no changes were observed in controls: QT _c max, 397 ± 21 ms versus 396 ± 22 ms, p = 0.9; QT _c min, 362 ± 24 ms versus 358 ± 19 ms, p = 0.5; and QT _c d, 35 ± 7 ms versus 38 ± 10 ms, p = 0.15. Whereas, in HD patients all values were significantly shortened: QT_cmax, 458 ± 41 ms versus 427 ± 35 ms, p = 0.003; QT_c min, 398 ± 36 ms versus 379 ± 34 ms, p = 0.04; and QT_c d, 59 ± 17 ms versus 48 ± 15 ms, p = 0.01. The decrease in QTmax was more prominent than the decrease in QTmin, hence QT dispersion was significantly decreased after the Valsalva maneuver, but differences from controls were still significant. In conclusion, increased sympathetic activity may have a role in the prolonged QT duration and increased QT dispersion in HD patients.     

Cardiovasoactive Peptides in Hemodialysis Patients: Diagnostic Tools and Predictors of Outcome: A Review of Present Knowledge and Future Directions

The main cardiovasoactive peptides involved in cardiovascular adaptation to renal failure and dialysis are reviewed with a special focus on their possible role in pathophysiology, diagnosis of cardiovascular and fluid volume abnormalities, and prognostic information.
The role of vasoactive peptides in cardiovascular stability during hemodialysis (HD) are best seen in sequential HD, where the release of vasoconstrictors is stimulated by volume reduction during ultrafiltration, but is blunted during isovolemic HD, whereas plasma vasodilators increase.
Plasma levels of the natriuretic peptides atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are elevated in fluid volume overload and heart failure and decrease during dialysis. Neuropeptide Y (NPY) is elevated in severe volume overload and hypertension and calcitonin gene-related peptide in large-volume overload. Plasma BNP increases with left ventricular failure and improves during dialysis.
Activation of the sympathetic nervous system as reflected by increased plasma levels of NPY is associated with poor prognosis. High levels of the natriuretic peptides ANP and BNP are likewise predictors of poor prognosis.
Determinations of plasma levels of cardiovasoactive peptides may be helpful in clinical practice to diagnose volume overload and heart failure and to assess the severity of heart failure and of hypertension, as a guide to the choice of dialysis treatment and pharmacotherapy and to monitor treatment. Clinical studies will be needed in HD patients to establish the value of measurement of plasma cardiovasoactive peptides in clinical practice.
The research in this field is still in its infancy and promises to be exciting in the future. There appears to be a balance of vasomotor tone and cardiac response to meet any emergency and stress such as intermittent dialysis. Further knowledge will increase our chances for major therapeutic interventions.