Six Years’ Experience of CAPD at One Centre: A Survey of Major Findings

This study summarizes the overall experience of the first six years of CAPD treatment at one centre, during which time all patients (n = 124) were selected, trained, and treated in a uniform way. Patient selection was largely influenced by a high transplantation activity. The patients had a high mean age, 54 years at start of CAPD, and there was a high proportion of diabetics, 26%.

Patient survival was 81% after two years and 60% after four years for all patients, and 100% after four years for non-diabetic patients < 50 years of age. Patient and technique survival was significantly superior in younger non-diabetics than in diabetics and in non-diabetics ≥ 60 years. Thirty-nine percent of transfers to other forms of dialysis were due to peritonitis. The main reason for a high early discontinuation rate was transplantation.

The mean treatment time in hospital was 27.7 d per patient year, one-third of which was attributable to peritonitis. The risk of developing peritonitis within the first year on CAPD was 55%.

During CAPD, serum urea remained unchanged, serum potassium, creatinine, and uric acid levels increased, and serum albumin levels decreased. These findings suggest that patients being treated with four 2 L exchanges Id, may not be sufficiently dialyzed as the residual renal function deteriorates, thereby increasing the risk of anorexia and subsequent malnutrition.

Potential Hazards of Glycerol Dialysate in Diabetic CAPD Patients

The use of glycerol-containing CAPD solutions caused some specific problems, related to the potential accumulation of the glycerol in the blood. The mean peak free glycerol levels during the exchanges with the 1.4% glycerol solution were 0.628 ± 0.079 mmol/l. With the use of the 2.5% glycerol solution, the mean peak levels increased up to 11.650 ± 2.380 mmol/1 with peak values up to 49.670 mmol/l. Sometimes, these high glycerol levels may induce a hyperosmolar syndrome, as in one of our patients. Also they cause an elevation of the blood triglyceride levels, which must be corrected for the free glycerol levels. Before we can recommend the general use of glycerol-containing CAPD solutions in diabetic patients further studies are necessary to better understand the metabolism of glycerol in uremic and diabetic patients.

Risk Factors of Ischemic Cardiac Disease in Patients on Continuous Ambulatory Peritoneal Dialysis

Elevated plasma levels of fibrinogen, factor VII coagulant activity (F VIIc), and plasminogen activator inhibitor (PAI-1) have been reported to be strictly associated with thrombotic events and are considered to be important risk markers of atherothrombotic caridovascular disease. Therefore, we evaluated in 15 patients on continuous ambulatory peritoneal dialysis (CAPD) the plasma levels of these coagulation factors, basal insulin values, and the lipid pattern in comparison with 33 hemodialysis (HD) patients and 59 healthy subjects.

In CAPD the total cholesterol and triglyceride results were significantly increased, but no difference was found in HDL cholesterol.

Fibrinogen and F VIIc results were significantly higher In CAPD and HD than In the control group, probably due to an increased hepatic synthesis as a nonspecific response to the peritoneal protein loss.

Elevated F VIIc activity may be caused by the presence of large negatively charged lipoproteins, in viva thrombin formation, or reduced hepatic clearance.

Both PAl 1 and t-PA results were higher in CAPD, probably due to an increased synthesis by endothelial cells activated by glucose peritoneal absorption and hypertonic dialysis solutions.

The contemporary elevation of fibrinogen, F VIIc, PAI-1, and t-PA suggests that CAPD patients present a hypercoagulability and hypofibrinolysis condition, which may promote the development of atherothrombotic events.

Effect of Dietary Fish Oil on Lipid Abnormalities in Patients on Continuous Ambulatory Peritoneal Dialysis

Fifteen patients receiving continuous ambulatory peritoneal dialysis (CAPD) were given 10 mL of a dietary fish oil rich in omega-3 fatty acids (MaxEPA) b.i.d. for eight weeks without other dietary manipulation. Fasting lipids, vitamins A and E, and glucose were measured at 0, 4, and 8 weeks, and again at 4 and 8 weeks after the cessation of treatment.

Basal serum triglyceride concentrations were raised, and fell by 29% (p < 0.005) with treatment, returning to baseline values over the washout period. The fall in triglyceride during treatment correlated with the initial value (As = 0.57; p < 0.05). Total, HDL and LDL cholesterol, apolipoprotein A, vitamin A, glucose, lean body mass, and dietary fat/CHO intake were unchanged throughout. Apolipoprotein B concentrations tended to rise during the first half of treatment but fell thereafter. Vitamin E concentrations rose significantly during supplementation and fell after withdrawal (p < 0.001 for both).

Supplementation with dietary fish oil significantly reduced hypertriglyceridemia. Its long-term use might be accompanied by beneficial effects on the excess cardiovascular morbidity seen in patients on CAPD.

Risk Factors of Ischemic Cardiac Disease in Patients on Continuous Ambulatory Peritoneal Dialysis

Elevated plasma levels of fibrinogen, factor VII coagulant activity (F VIIc), and plasminogen activator inhibitor (PAI-1) have been reported to be strictly associated with thrombotic events and are considered to be important risk markers of atherothrombotic caridovascular disease. Therefore, we evaluated in 15 patients on continuous ambulatory peritoneal dialysis (CAPD) the plasma levels of these coagulation factors, basal insulin values, and the lipid pattern in comparison with 33 hemodialysis (HD) patients and 59 healthy subjects.

In CAPD the total cholesterol and triglyceride results were significantly increased, but no difference was found in HDL cholesterol.

Fibrinogen and F VIIc results were significantly higher In CAPD and HD than In the control group, probably due to an increased hepatic synthesis as a nonspecific response to the peritoneal protein loss.

Elevated F VIIc activity may be caused by the presence of large negatively charged lipoproteins, in viva thrombin formation, or reduced hepatic clearance.

Both PAl 1 and t-PA results were higher in CAPD, probably due to an increased synthesis by endothelial cells activated by glucose peritoneal absorption and hypertonic dialysis solutions.

The contemporary elevation of fibrinogen, F VIIc, PAI-1, and t-PA suggests that CAPD patients present a hypercoagulability and hypofibrinolysis condition, which may promote the development of atherothrombotic events.

Evaluation of Short-Chain Polypeptides as An Osmotic Agent in Continuous Ambulatory Peritoneal Dialysis Patients

Objectives

To assess whether dialysate containing short-chain polypeptides is well tolerated in continuous ambulatory peritoneal dialysis (CAPD) patients and to determine its effect on fluid and solute transport, plasma amino acid levels, and biochemical parameters.

Design

Two -treatment, two-period cross -over design.

Setting

Renal Unit, Academic Medical Center, Amsterdam and Renal Unit, University Hospital, Gent.

Patients

Two groups of 10 stable CAPD patients.

Intervention

All patients received a trial solution (1.36% glucose and 1% peptides, 381 mOsm/kg) and a control solution (2.27% glucose, 404 mOsm/kg) in randomized order. The patients were examined on four consecutive days in which two dwell periods on days 1 and 3 of either 4 (Group I) or 8 hours (Group II) were performed.

Results

The peptide solution was well tolerated in all patients. In addition, no differences were found in the parameters for the effective peritoneal surface area and the intrinsic permeability, implying that no irritating effect of the peptide solution was present. Net ultrafiltration was not different in Group I: -43±125 versus 86±125 mL (mean±SEM) and marginally lower in Group II: -94±64 versus 51±64 mL, despite the lower osmolality of the trial solution compared to the control solution. Glucose absorption was higher than the peptide absorption in all patients: Group I: 66±10% versus 57±13% (p = 0.0003); Group II: 80±5% versus 72±11% (p = 0.006). No differences in plasma amino acid profiles could be detected.

Conclusion

Short-chain polypeptides are absorbed less than glucose and can be used as an osmotic agent in CAPD patients. However, longer-term studies are needed to evaluate possible additional effects of peptides on the nutritional status of CAPD patients.

Amino-Acid-Based Continuous Ambulatory Peritoneal Dialysis (CAPD) Fluid over Twelve Weeks: Effects on Carbohydrate and Lipid Metabolism

Aspects of lipid and carbohydrate metabolism were studied in 8 patients established on continuous ambulatory peritoneal dialysis (CAPD) with plasma albumin < 35 g/L, before, during, and after substitution of 1 of the daily glucose exchanges by a commercial 1 % amino acid dialysis fluid for 12 weeks. The amount of glucose absorbed from the dialysis fluid was consequently reduced by about 25%, hence total energy intake decreased by about 100 Kcallday, but peritoneal glucose transfer kinetics were unaffected. Glucose was lost into amino acid dialysate as expected (2 g/day).

Excluding 1 patient with a large rise in calorie intake, total and LDL cholesterol fell at 8 and 12 weeks (LDL cholesterol week 0, 5.26 ± 1.13; week 8, 4.32 ± 0.74; week 12,4.30 ± 1.22; mean ± SD, p < 0.01 for both), but returned to baseline 2 weeks after the restoration of glucose fluid (LDL 4.91 ± 1.22, p < 0.05 vs. week 12). Apolipoprotein B concentration also fell at 12 weeks (p < 0.01). No changes were seen in body weight, body fat, arm muscle circumference, fasting plasma glucose, insulin, growth hormone, triglyceride, non esterified fatty acids, or HDL cholesterol. The response of these biochemical indices to single 8-h glucose and amino acid morning exchanges at 0 and 12 weeks were studied. After 12 week's use of amino acid dialysis fluid, plasma cholesterol and apolipoprotein B were significantly lower throughout the exchange.

The decrease in cholesterol and apolipoprotein B during the substitution of 1% amino acid dialysis fluid may be associated not only with the reduction in glucose intake, but also with a gradual change in lipid metabolism. The routine use of such solutions may lower cardiovascular morbidity and mortality in CAPD but further evaluation is indicated.

Serum lipids and lipoproteins during continuous ambulatory peritoneal dialysis

The effects of continuous ambulatory peritoneal dialysis (CAPD) on serum lipids and lipoproteins over the initial year of therapy were studied in 23 uremic patients. Lipoprotein abnormalities typical for the uremic dyslipoproteinemia were present at the start of CAPD. During the first months of CAPD these abnormalities were accentuated. The concentrations of very low density lipoprotein (VLDL)-cholesterol (CHOL), low density lipoprotein (LDL)-CHOL, serum CHOL and serum triglycerides (TG) increased significantly. However, after one year of CAPD only the VLDL-CHOL and serum CHOL levels remained significantly higher than the baseline values. VLDL-TG, VLDL-CHOL and serum TG, and the changes of these variables over the study period, correlated with the amount of glucose in the dialysates. We conclude that the continuous peritoneal absorption of glucose (100-200 g/24 h) during CAPD contributes to potentially atherogenic changes in serum lipids and lipoproteins. However, some of the changes are transitory, indicating an adaptation to the peritoneal glucose load.

Glucose degradation products (GDP's) and peritoneal changes in patients on chronic peritoneal dialysis: will new dialysis solutions prevent these changes?

As peritonitis rates are declining, the rate of technique failure due to ultrafiltration failure and inadequate solute removal is becoming more important. The failure of the peritoneal membrane to provide adequate dialysis increases with longer duration on PD and correlates with the structural changes in the peritoneal membrane. The exact mechanism responsible for these structural changes is unclear. Conventional PD fluids with glucose as the osmotic agent and more importantly the glucose degradation products (GDP) generated during the heat sterilization of these solutions seems to be responsible for inducing many of these changes in the peritoneum. GDP's in addition to causing structural and functional alterations of the peritoneal cells is also a leading cause of advanced glycation end-products (AGE) production. There is evidence to suggest that the GDP's and AGE's are not limited to the peritoneal cavity and the membrane. They have been shown to get deposited in the vascular walls. In addition they also interact with receptors on endothelial cells and smooth muscle. Thus they could contribute to the vascular dysfunction similar to that seen in diabetes. Formation of GDP's can be reduced and even be avoided with the use of newer "biocompatible" solutions by sterilizing the glucose and the buffer in separate chambers. These newer solutions have been shown to have several local and systemic advantages over the conventional PD solutions. It remains to be seen whether their chronic use from the start of peritoneal dialysis will prevent the development of peritoneal damage thus allowing these patients to remain on this modality for longer periods.

Lipid Metabolism and Cardiovascular Morbidity and Mortality in Hemodialysis Patients: Role of Factors Modulating Cytosolic Calcium

Animal studies indicate that insulin resistance and glucose intolerance leading to dyslipidemia in uremic rats are associated with increased cytosolic calcium ([Ca⁺⁺ i]). The resistance and intolerance are reversed with verapamil, but recur after its discontinuation. This finding suggests that hyperparathyroid-induced [Ca ⁺⁺ i] increase is responsible for the metabolic derangement. We retrospectively examined, over a 12-year period, the effects of factors that lower [Ca ⁺⁺ i] on total serum cholesterol and triglycerides in 332 hemodialysis (HD) patients. Because the study was retrospective, detailed lipid profiles were not available. We therefore relied on morbidity and mortality outcomes related to atherosclerotic vascular disease. Patients with diabetes mellitus were excluded, because their dyslipidemia and vascular disease are mediated via a different mechanism. Four groups emerged: group I [high parathormone (PTH) in the absence of calcium channel blockers (CCBs), n = 107], representing the highest [Ca⁺⁺ i]; group II (high PTH in the presence of CCBs, n = 76) and group III (lower PTH in the absence of CCBs, n = 66), representing intermediate [Ca ⁺⁺ i]; and group IV (lower PTH in the presence of CCBs, n = 83) representing the lowest [Ca ⁺⁺ i]. The theoretically lower [Ca ⁺⁺ i] was achieved via CCB therapy or lower PTH, or both. The mean serum cholesterol in group I was 322 ± 24 mg/dL and the level of triglycerides was 398 ± 34 mg/dL. Group II had mean serum cholesterol of 196 ± 16 mg/dL and triglycerides of 157 ± 17 mg/dL. Group III had a mean serum cholesterol of 202 ± 19 mg/dL and triglycerides of 160 ± 15 mg/dL. Group IV had a mean serum cholesterol of 183 ± 9 mg/dL and triglycerides of 94 ± 6 mg/dL. The differences in cholesterol and triglyceride levels among four groups were significant (p < 0.001) by one-way analysis of variance (ANOVA). The incidence of cardiovascular morbidity and mortality events was 61% in group I, 24% in group II, 28% in group III, and 18% in group IV (χ ² = 47.7, p < 0.001). We conclude that, in non diabetic HD patients, hyperparathyroidism, especially in the absence of CCBs, is associated with severe dyslipidemia and increased risk of cardiovascular morbidity and mortality. Dyslipidemia may be related to a hyperparathyroid-induced increase in cytosolic calcium [Ca⁺⁺ i]. Lowering [Ca⁺⁺ i] by decreasing PTH or by blocking calcium entry into cells (via CCBs), or both, is associated with less dyslipidemia and improved long-term cardiovascular morbidity and mortality. Prospective randomized studies, with actual measurement of [Ca ⁺⁺ i], are needed to verify the results of this study.

Renal replacement therapies in the elderly: Part 1. Hemodialysis and chronic peritoneal dialysis

Recent demographic data from the United States and Europe demonstrate that the dialysis population is growing progressively older. In the United States the median age at onset of end-stage renal disease (ESRD) had reached 61 years in 1990, and the fraction of ESRD patients older than 65 years will approach 60% by the year 2000. The primary treatment of geriatric ESRD is center hemodialysis (82% of elderly patients). Chronic peritoneal dialysis in this age group is limited in the United States to less than 10%. Only 2.7% of elderly patients have a functioning transplant. Despite their complex medical and psychosocial conditions, survival and rehabilitation are acceptable in the elderly dialysis patient and these patients tend to be more complaint. Five-year dialysis patient survival rates in the United States are 19% and 10%, respectively, for the 65 to 74 and 75 to 84 age groups compared with 32% and 19%, respectively, for the same age groups in Europe. Five-year survival, particularly in the elderly, is even higher in Japan. Several factors favor the delivery of low doses of hemodialysis in the elderly and discontinuing dialysis is more common in the elderly. Continuous ambulatory peritoneal dialysis is a satisfactory alternative treatment modality for geriatric ESRD. Most studies confirm that survival of elderly patients on continuous ambulatory peritoneal dialysis and hemodialysis is similar. The 1991 United States Renal Data System report showing higher mortality among diabetic continuous ambulatory peritoneal dialysis patients than among hemodialysis patients may reflect selection of such patients, who may have more co-morbid conditions. In special cases, continuous cyclic peritoneal dialysis can be an alternative treatment for elderly ESRD patients.

The relationship between plasma and dialysate lipoproteins and apoproteins in patients treated by continuous ambulatory peritoneal dialysis

End-stage renal disease is frequently associated with lipoprotein abnormalities, manifested primarily by elevated very low-density lipoprotein levels combined with a decrease in high-density lipoprotein levels. These lipoprotein disturbances are further exacerbated in continuous ambulatory peritoneal dialysis. We examined the lipoprotein and apolipoprotein profiles in the blood and dialysate effluents of eight normolipidemic and five hypertriglyceridemic patients with end-stage renal failure treated with continuous ambulatory peritoneal dialysis. The normolipidemic patients were found to have significantly greater losses, as expressed by the fractional catabolic rates through the dialysate, for protein, total cholesterol, and very low-density lipoprotein cholesterol. These results suggest that the hypertriglyceridemia associated with continuous ambulatory peritoneal dialysis may be mitigated in some patients by the excessive loss of very low-density lipoprotein, or some other plasma constituent, into the dialysate effluent.

CAPD versus haemodialysis: a comparison in the same patients

Most studies comparing CAPD and haemodialysis (HD) were done in different populations, matched for sex and age. The present report compared 13 non-diabetic end-stage renal failure patients who were treated for at least six months with each type of therapy. Analysis of the data revealed a higher haemoglobin during CAPD but no differences in the blood transfusion requirements. Serum creatinine, BUN and potassium were lower during CAPD and serum calcium was higher during HD. Serum cholesterol levels were higher during CAPD and returned to pre-CAPD levels during the fourth month after being transferred to HD. Hospitalization rates were similar with the two treatments. Our study confirmed previous sex- and age-matched studies comparing CAPD and HD therapy.

Kinetics of peritoneal protein loss during CAPD: II. Lipoprotein leakage and its impact on plasma lipid levels

We quantified the plasma levels and peritoneal loss of lipids and lipoproteins, and studied the composition of plasma and effluent lipoproteins in 16 patients on CAPD (5 females and 11 males, 18 to 76 years old). Five patients were studied prospectively (at 0, 1, 3 and 6 months) and 11 patients at 6 to 58 months on CAPD (N = 30). Elevated levels of plasma VLDL and reduced levels of plasma HDL were maintained in these patients throughout 58 months of CAPD, whereas the initially increased LDL levels showed a tendency towards normalization. All plasma lipoproteins (VLDL, IDL, LDL and HDL) were present in the peritoneal effluent. The lipoproteins isolated from plasma and peritoneal fluid shared a similar lipid and apolipoprotein composition. The peritoneal transport characteristics of plasma lipoproteins were similar to other plasma macromolecules. Their clearance correlated with their molecular mass, plasma concentration and dwell time, but was not affected by duration of CAPD treatment. The plasma lipid and lipoprotein levels were unaffected by the rate of glucose absorption. The peritoneal protein clearance correlated positively with plasma levels of triglyceride and LDL, and negatively with plasma HDL. An inverse correlation was observed also between plasma levels of HDL and its peritoneal clearance (r = -0.393, P less than 0.025, N = 30). The continuous peritoneal loss of HDL and the hypertriglyceridemia were found to contribute most to the persistent low plasma levels of HDL in CAPD patients, and thus may lead to the accelerated atherosclerosis observed in these patients.

Effects of dietary fish oil on serum lipids and blood coagulation in peritoneal dialysis patients

The effects of a daily fish oil supplement rich in eicosapentaenoic acid were studied in 11 stable continuous ambulatory peritoneal dialysis (CAPD) patients. Serum lipids, platelet aggregation studies, and template bleeding times were determined before and after 4 weeks of fish oil treatment. The lipid studies were repeated approximately 20 weeks after stopping fish oil supplement. At the end of the treatment period, serum triglycerides (mean +/- SEM) decreased from 297 +/- 42 to 211 +/- 29 mg/dL (P less than .01), high density lipoprotein (HDL) cholesterol fell from 45 +/- 3 to 41 +/- 3 mg/dL (P less than .05), and low density lipoprotein (LDL) cholesterol increased from 172 +/- 16 to 208 +/- 19 mg/dL (P less than .05). After discontinuing the fish oil supplement, the triglycerides increased to 278 +/- 39 mg/dL, which was no different than the value before fish oil treatment. No significant changes occurred in template bleeding time (TBT), platelet count, hematocrit, or platelet aggregation response. Clinically important uremic bleeding was not apparent. We conclude that in CAPD patients a fish oil supplement favorably effects hypertriglyceridemia and can be ingested without promoting uremic bleeding. The likely beneficial impact on atherogenesis resulting from the lowering of the triglycerides may, however, be counteracted by concomitant changes in HDL- and LDL-cholesterol.

A 2 year evaluation of diabetic patients on continuous ambulatory peritoneal dialysis

Nineteen diabetic patients with end-stage renal disease on CAPD were evaluated over a 2 year period. All but one patient was insulin-dependent, with a mean age of 47.7 years. Average time on CAPD was 16.1 months (range, 2-28 months). Thirteen patients were followed for more than 12 months, and nine for more than 18 months. The mean training period was 22.9 days. Good blood glucose control was obtained with intraperitoneal (IP) insulin in all of the patients. Mean blood glucose levels of 125 +/- 23.08 mg/dl were achieved with 103 +/- 38.5 U/day of regular IP insulin. Glycosalated hemoglobin decreased from a mean of 12.7 +/- 2.35% before CAPD to 10.08 +/- 0.97% during CAPD. Peritoneal creatinine clearance remained stable during the study period, with a concommitant decrease (P less than 0.001) in the mean residual renal creatinine clearance. The incidence of peritonitis was one episode per 7.8 patient-months. Average length of hospitalization was 33.24 days/year. Visual acuity remained stable after 1 year in 73% of the 26 eyes evaluated. No amputations were required in more than 2 years of follow-up. Actuarial survival was 100% at 1 year and 86% at 2 years, and the technique survival of CAPD was 91 and 79%, respectively. These results demonstrate that CAPD is a good dialysis procedure for treating diabetic patients with chronic renal failure, and it offers the advantage of controlling glycemia better than other dialysis methods.

Acute renal failure in a burn patient: the advantages of continuous peritoneal dialysis

An 8-year-old girl sustained 65-70 per cent body surface area burns when her clothes caught fire. Two weeks later, she developed acute renal failure (ARF) and needed dialysis therapy. The extensive, infected burn area prevented the establishment of a safe vascular access for haemodialysis. Continuous peritoneal dialysis proved to be a valid alternative form of treatment and even had advantages over haemodialysis. Large amounts of fluids, calories and electrolytes could be administered via the peritoneal route. This facilitated the treatment of the catabolic state of the uraemic burn patient and served to correct the electrolyte losses via the skin. Peritoneal dialysis is a valuable adjunct to the treatment of acute renal failure in burn patients who need renal replacement therapy.

Problems of CAPD: Progress of the 4 years’ experience

Results of four years’ experience of CAPD in our Centre are reported. The incidence of peritonitis in 13 patients dropped with the use of Y-set from 1/4 patient-months to 1/26 p-m).

As experience was gained we reduced the use of hypertonic bags and improved diet suggestions. By these interventions during the past year, we obtained a good control of triglycerides and cholesterol concentration and a reduction in weight gain.

Update on continuous ambulatory peritoneal dialysis

By now many patients have been successfully maintained on CAPD for five years or more, thus demonstrating that CAPD is a viable long-term treatment for end-stage renal disease. Peritonitis--the main concern of the earlier years--is now a less frightening complication. We know better how to treat peritonitis and its incidence has decreased from one episode every 8 months initially to one episode every 18 months now. In addition, several innovations, which have been or soon will be introduced, promise to decrease the frequency of peritonitis to an even lower rate. The problem of peritonitis is now being replaced by the chronic complications of CAPD, predominantly malnutrition and decrease in peritoneal ultrafiltration. CAPD has become an important adjunct in the treatment of children with ESRD, especially the very young. Even though not normal, their growth on CAPD is better than that of children on hemodialysis and as good as that after a successful transplant. CAPD has become a promising treatment for the diabetic with ESRD. This experience has stimulated interest and research in the role of intraperitoneal administration of insulin for blood glucose control. With the present worldwide experience of CAPD, this treatment has ceased to be experimental. A percentage of patients requiring dialysis will be better off on CAPD than on hemodialysis. Even though this percentage will vary among various countries, the nephrologist who wants to provide the best treatment for each patient must be well experienced in and have all treatments at his disposal including CAPD.