Prevalence of hypertension in patients on peritoneal dialysis: results of an Italian multicentre study.

BACKGROUND: The tenet that peritoneal dialysis is capable of either normalizing or improving blood pressure control in uraemic patients is based on outdated or monocentric experiences. Therefore, we assessed the prevalence of hypertension and the efficacy of antihypertensive therapy in a large, multicentric cohort of patients on peritoneal dialysis. METHODS: Twenty seven out of the 50 centres belonging to the Italian Co-operative Peritoneal Dialysis Study Group took part in the study. The main patient selection criteria were: peritoneal dialysis therapy for at least 3 months and no peritonitis or changes in dialysis technique for at least 1 month. Clinical blood pressure was measured according to WHO/ISH guidelines. Ambulatory blood pressure monitoring was carried out using a SpaceLabs 90207 recorder. Hypertension was defined according to WHO/ISH criteria and staged according to the criteria of the Joint National Committee on Detection, Evaluation and Treatment of High Blood Pressure (JNC), 5th Report. Ambulatory blood pressure monitoring recordings were used to evaluate white-coat hypertension, blood pressure load and the dipping phenomenon. RESULTS: Five hundred and four subjects were evaluated. Hypertension was prevalent in 88.1% of the population, and 362 out of 444 hypertensive patients were on antihypertensive therapy. JNC staging revealed that 188 patients had moderate to severe hypertension. Blood pressure load was pathological in 77.3% of the patients receiving antihypertensive treatment. White-coat hypertension was identified in 9.1% of the hypertensive patients not on antihypertensive therapy, and 53.1% of the patients were non-dippers. CONCLUSIONS: The study demonstrates that hypertension is a dramatic, unsolved problem in uraemic patients treated with peritoneal dialysis, and casts doubts on the effectiveness of our current peritoneal dialysis strategies and pharmacological management of hypertension.

Myths and reality concerning hypertension in peritoneal dialysis patients: results of a multicenter study.

OBJECTIVES: To evaluate the prevalence of hypertension, the average blood pressure level, the 24 h blood pressure profile, and the efficacy of antihypertensive therapy for a large population of peritoneal dialysis patients.DESIGN: A cross-sectional, observational multicenter study. METHODS: From 504 peritoneal dialysis patients (18% of the Italian peritoneal dialysis population) involved in a multicenter observational study, we selected 414 who had undergone successful ambulatory blood pressure monitoring (i.e. no hours with data absent, >/= 75% successful readings and monitoring duration >/= 24 h). Office blood pressure measurements and ambulatory blood pressure monitoring were performed for each patient on the same day with a standard mercury sphygmomanometer and a SpaceLabs 90207 device, respectively.RESULTS: According to World Health Organization/International Society of Hypertension criteria, 44 peritoneal dialysis patients (10.6%) were normotensive and 370 patients (89.4%) were hypertensive, 304 (82.1%) of whom were being administered antihypertensive therapy. Daytime systolic and diastolic blood pressures were both significantly lower than office systolic and diastolic blood pressures (140.7 +/- 19.7/72.1 +/-11.1 versus 148.3 +/- 23.6/85.6 +/- 12 mmHg; P < 0.001). The difference between office blood pressure and daytime blood pressure was significantly correlated to office blood pressure (P < 0.001 for systolic and P < 0.001 for diastolic). The diurnal blood pressure rhythm evaluated by visual inspection of hourly mean plots was not influenced by sex, age, antihypertensive treatment, and peritoneal dialysis modality. Systolic and diastolic blood pressures exhibited a day-night mean decreases of 8.6 +/- 11.7 and 7.7 +/- 6.9 mmHg, respectively, and daytime blood pressure values were significantly higher than night-time ones (P < 0.001). Two hundred and twenty patients (53.1%) were nondippers according to O'Brien's criteria, 247 patients (59.7%) were nondippers according to Verdecchia's criteria, and 269 patients (65.0%) were nondippers according to Staessen's criteria. Only 39 patients (9.4%) had a reversed circadian rhythm. The day-night differences of systolic and diastolic blood pressures were in a unimodal distribution. Among hypertensive patients not being administered antihypertensive therapy, only six patients ( five women and one man) had white-coat hypertension. Among hypertensive patients being administered antihypertensive therapy, 235 patients (77.3%) had 24 h blood pressure loads > 30%.CONCLUSION: There is a high prevalence of hypertension among peritoneal dialysis patients. White-coat hypertension is very rare in this population. Despite the extensive use of antihypertensive therapy, control of blood pressure is maintained in a large number of our peritoneal dialysis patients. Any classification of patients into dipers and nondippers must be interpreted cautiously.

Dialysis-related amyloidosis in a large CAPD population.

We studied 212 patients from 13 Italian dialysis centers to evaluate the clinical aspects of dialysis-related amyloidosis in continuous ambulatory peritoneal dialysis (CAPD). The mean age was 64.2 +/- 12.3 years and mean time on dialysis was 36.9 +/- 25.1 months. Residual diuresis was 615.7 +/- 554.0 mL/day and plasma beta 2-microglobulin (beta 2M) level was 27.0 +/- 12.8 mg/L. Radiological skeletal examination, neurological problems related to beta 2M, and urinary and dialytic balance of beta 2M were evaluated. Correlations between age, time on dialysis, residual diuresis, beta 2M plasma levels, beta 2M peritoneal and renal removal, carpal tunnel syndrome, and bone disease were studied. Only the number of bone lesions had a significant positive correlation with patient age and negative correlation with residual diuresis. The latter had an inverse relation with beta 2M plasma levels. Dialytic age did not correlate with any of the parameters. No other correlation was observed. Hand lesions were found in 85% of patients with bone dialysis-related amyloidosis. In conclusion, residual diuresis in our patients played a positive role in the number of bone localizations. Only age, but not time on dialysis, had a positive impact on the bone lesions. The high percentage of hand lesions suggests that the observation of this skeletal segment is a simple, safe, and effective modality of bone follow-up for dialysis-related amyloidosis.

Forecasting correct sodium balance in hemodiafiltration procedures involving infusions.

Four patients, stable on acetate hemodialysis (AHD), were switched to acetate-free biofiltration (AFB) which differs from AHD and bicarbonate hemodialysis (BHD) in that the dialysate contains no buffer, which is given intravenously as a hypertonic (1/6 M) Na bicarbonate solution. Within the 1st month the patients developed thirst and hypertension attributed to a positive Na balance. The aim of this investigation was to check this (1) by a study based on the predictable changes induced in the body compartments of 13 patients by the infusion and ultrafiltration (UF) of a hypertonic solution and (2) by direct determination and calculation of 28 Na mass balances in BHD and AFB. The theoretical model indicated that infusion of 4.87 liters of a 166.7 mEq/l Na bicarbonate solution and UF of the same amount caused a positive balance of 233 mosm of Na. The Na mass balances showed a relationship between Na transmembrane gradient and loss or gain of Na in both methods (p less than 0.0001). The slopes of the regression lines were not significantly different but there was a highly significant difference between the y axis intercepts (p less than 0.0001), which indicates that the same Na transmembrane gradient that gives no net change of Na in BHD, induces a net gain of 240 mosm (120 mEq of Na) in AFB and that to obtain the same Na balance dialysate Na should be reduced by about 8 mEq/l in AFB. These data are the same as the theoretical forecast which could be extended to all hemodiafiltration methods in which solutions of any tonicity have to be infused, in order to correctly predict the Na balance.

[Flow cytometry in micturitional urine: its clinical application in cases of bladder cancer]. / La citometria di flusso sulle urine minzionali: sua applicazione clinica in casi di neoplasia vescicale.

The paper discusses a particular use of flow cytometric analysis, namely the quantitative study of DNA in the cellular sediment obtained from micturitional urine in patients with vesical tumours. Forty cases of carcinoma of varying degrees and stages were studied and, despite the small number of cases, interesting results have emerged regarding the close correlation between the test and the different clinical, cytological and histopathological aspects of the disease, and relating to the relative simplicity of the method used.

Transport of water and solutes in uremic patients with chronic hepatic disease in CAPD.

Ten patients with chronic hepatic disease (CHD) were compared with 34 non-CHD (N) pts. All patients underwent a peritoneal equilibration test; the asymptotic curves for small solutes transport were transformed into straight lines; protein transport was also expressed as a straight line; the slopes of these linear functions were used as index of solute transfer. CHD patients showed increased UF and transport of all solutes. The well-known relationships between UF and glucose absorption and between UF and dialysate sodium concentration were observed in N, but not in CHD patients. In patients without hepatic disease there was also a relationship between UF and the glucose transport slope, which was not observed in CHD pts. These results are probably due to the influence of hepatic lymph production plus increased lymphatic removal, observed in non uremic patients affected by cirrhosis, on the mechanisms of water and solute transport in CAPD. CHD patients can be managed either with CAPD or with short frequent exchanges. Ascites production can be evaluated by the difference between the observed UF in a patient with CHD and the expected UF in N patients.

[Potassium removal: a factor limiting the correction of acidosis during dialysis]. / La soustraction potassique: facteur limitant la correction de l'acidose pendant la dialyse.

The diffusional fluxes of urea, potassium and bicarbonate across the dialytic membrane (external balance), and across the cellular membrane (internal balance), were determined in 7 patients in haemodialysis using potassium free dialysate and dialysate containing 2.0 mEq/1 of potassium. The results obtained show an inverse correlation between extraction of potassium and intake of bicarbonate in both external and internal balance. This is probably due to the increase in membrane electrical potential resulting from a fall in blood potassium and emphasizes the importance of electrical driving forces in diffusional fluxes across cellular membranes.

Potassium removal as a factor limiting the correction of acidosis during dialysis.

The diffusional fluxes of urea, potassium and bicarbonate across the dialysis membrane (external balance) were determined in seven patients during haemodialysis using potassium free dialysate and dialysate containing 2.0mEq/L of potassium. The results show an inverse correlation between extraction of potassium and intake of bicarbonate in both external and internal balances. This is probably due to the increase in cell membrane electrical potential resulting from a fall in blood potassium and emphasises the importance of electrical driving forces in diffusional fluxes across cellular membranes.

Hemodialysis with "adequate" sodium concentration in dialysate.

This investigation was undertaken to define the "adequate" sodium concentration in the dialytic fluid allowing to maintain a stable plasma effective osmolality during dialysis. Isonatric dialysate is shown to miss this aim by inducing a predictable postdialytic hypernatremia. To avoid this effect a new approach was made. 17 clinically stabilized patients, previously dialyzed over a period of at least 2 years with a dialysate sodium concentration of 133 mEq/l, underwent dialysis with the "adequate" sodium concentration in the dialysate for over 3 years. During dialysis cramps, headache, hypotension, hypertensive crises and postdialytic weakness were reduced in frequency and nearly disappeared. No deterioration in blood pressure control occurred and improvement in some general parameters (hematocrit, glucose and insulin metabolism, well-being) was reported after prolonged treatment.