Home haemodialysis in the Netherlands: State of the art.

Home haemodialysis (HHD) has gained popularity in recent years, due to improved clinical outcomes associated with frequent or prolonged haemodialysis sessions, best achievable at home. However, several barriers to HHD are perceived by the physician and patient, among which lack of experience and education, logistic difficulties and reimbursement issues seem to be the most important ones. HHD, in particular when performed with intensified frequency or duration, is associated with improved quality of life, blood pressure control and survival. Serious adverse events are rare; however, more vascular access complications arise due to frequent needling. This emphasises the importance of comprehensive education and training. This review aims to provide the physician with a detailed state of the art overview on HHD in the Netherlands, discussing potential barriers and benefits, and offering practical advice.

[Relationship between pre-dialysis period and mortality and morbidity; the importance of timely pre-dialysis care]. / Relatie predialyseduur met mortaliteit en morbiditeit; het belang van een tijdige voorbereiding op dialyse.

OBJECTIVE: To investigate if the duration of pre-dialysis nephrology care is a predictive factor for mortality and morbidity in the first year of renal replacement therapy (RRT). DESIGN: Cohort study. METHOD: We included all patients with chronic or acute-on-chronic renal failure whose estimated glomerular filtration time (eGFR) was < 30 ml/min/1.73 m2 6 months before starting RRT and in whom RRT was initiated in 2005-2006 or 2009-2010. Depending on the duration of the pre-dialysis period we allocated patients to the short (< 6 months) or the long (≥ 6 months) pre-dialysis group. Data regarding mortality and morbidity were registered at the initiation of RRT (T0), after 3 (T3), 6 (T6) and 12 (T12) months. RESULTS: Thirty-nine patients with a short pre-dialysis period and 49 patients with a long pre-dialysis period were included. Patients with a short pre-dialysis period had higher mortality (T6: 23.1% vs. 8.2%; p = 0.05), more hospital stays (2 vs. 1 stay; p = 0.02), and longer hospital stays (16 vs. 3 days; p < 0.01). Additionally, in this group RRT more often had to be started through an acute route of administration for dialysis, which was associated with a higher mortality at T6 (23.8% vs. 6.5%; p = 0.02). CONCLUSION: A too short pre-dialysis period is predictive for higher mortality and morbidity in the first year after initiation of RRT. The necessity for an acute route of administration for dialysis seems to be the most important predictor.

Patients' representations of their end-stage renal disease: relation with mortality.

BACKGROUND: Self-regulation theory explains how patients' illness perceptions influence self-management behaviour (e.g. via adherence to treatment). Following these assumptions, we explored whether illness perceptions of ESRD-patients are related to mortality rates. METHODS: Illness perceptions of 182 patients participating in the NECOSAD-2 study in the period between December 2004 and June 2005 were assessed. Cox proportional hazard models were used to estimate whether subsequent all-cause mortality could be attributed to illness perception dimensions. RESULTS: One-third of the participants had died at the end of the follow-up. Mortality rates were higher among patients who believed that their treatment was less effective in controlling their disease (perceived treatment control; RR = 0.71, P = 0.028). This effect remained stable after adjusting for sociodemographic and clinical variables (RR = 0.65, P = 0.015). CONCLUSIONS: If we consider risk factors for mortality, we tend to rely on clinical parameters rather than on patients' representations of their illness. Nevertheless, results from the current exploration may suggest that addressing patients' personal beliefs regarding the effectiveness of treatment can provide a powerful tool for predicting and perhaps even enhancing survival.

The influence of increasing dialysis treatment time and reducing dry weight on blood pressure control in hemodialysis patients: a prospective study.

A good blood pressure control can be achieved with long hemodialysis sessions (dialysis center of Tassin, France). However, it is not well known whether a higher dialysis dose or a lower dry weight is responsible for this phenomenon. In a preliminary study, 21 hypertensive dialysis patients, dialyzed three times a week for 3-5 h, were randomized into three groups during a 3-month study period. In 6 patients, the dialysis treatment time was increased by 2 h, and the dry weight was gradually decreased (group 1). In 7 patients the dialysis treatment time was increased by 2 h without a change in dry weight (group 2). In 8 patients the dry weight was gradually lowered without changing the dialysis treatment time (group 3). Before and after the study, cardiac index and left ventricular mass index (echocardiography) and forearm vascular resistance (strain gauge plethysmography) were determined on a middialytic day. The blood pressure was assessed by 48-hour ambulatory monitoring. The antihypertensive medication was reduced when the postdialytic blood pressure became <130/80 mm Hg. The dry weight was reduced by 2.6 +/- 1.4 kg in group 1 and by 2.3 +/- 0.8 kg in group 3 (p < 0.05). The number of classes of antihypertensive medication was reduced from 3.3 to 1.8 in group 1 (NS), from 2.4 to 1.7 in group 2 (NS), and from 3.1 to 1.3 in group 3 (p < 0.05). The dose of the remaining antihypertensive drugs was reduced by 50% in group 1 (p < 0.05), by 32% in group 2 (NS), and by 72.2% in group 3 (p < 0.05). The interdialytic systolic blood pressure decreased significantly after increasing the dialysis time without changing the dry weight (group 2: 7 +/- 5 mm Hg; p < 0.05). The systolic blood pressure was also lower in the other patients groups: group 1: 13 +/- 26 mm Hg, group 3 : 7 +/- 16 mm Hg (NS). The pulse pressure decreased significantly in group 2 (7 +/- 5 mm Hg; p < 0.05) and in group 3 (6 +/- 7 mm Hg; p < 0.05) and tended to decrease in group 1 (11 +/- 12 mm Hg; p = 0.08). The diastolic blood pressure and the day-night blood pressure difference did not change significantly, nor did cardiac index and left ventricular mass index. The forearm vascular resistance tended to decrease in the patients on long dialysis sessions. This preliminary study suggests that the dialysis treatment time might have an independent beneficial effect on blood pressure control.

Fluid state and blood pressure control in patients treated with long and short haemodialysis.

BACKGROUND: Patients treated at the haemodialysis (HD) centre in Tassin, France have been reported to have superior survival and blood pressure (BP) control. This control has been ascribed to maintenance of an adequate fluid state, antihypertensive drugs being required in < 5% of the patients, although it could not be excluded that a high dose of HD regarding removal of uraemic toxins might also have been of value. METHODS: The aim of the study was to assess the fluid state and BP in normotensive patients on long HD (8 h) in Tassin (group TN) using bioimpedance to measure extracellular volume (ECV), ultrasound for determining the inferior vena cava diameter (IVCD), and 'on-line' monitoring of the change in blood volume (BV), and to compare them with normotensive (group SN) and hypertensive (group SH) patients on short HD (3-5 h) at centres in Sweden. ECV was normalized (ECVn) by arbitrarily setting the median ECV (in % of body weight) in SN patients at 100% for each gender, recalculating the individual values and combining the results for male and female patients in each group. RESULTS: The dose of HD (Kt/V urea) was higher for TN patients than for Swedish patients who had a similar Kt/V, whether hypertensive or not. SH patients had significantly higher ECVn and IVCD than TN and SN patients. TN and SN patients did not differ significantly regarding ECVn and IVCD before and after HD. However, in a subgroup of eight TN patients, ECVn was below the range of that in SH and SN patients, due to obesity with a high body mass index. Another subgroup of 14 TN patients had a higher ECVn than most of the SN patients and also higher than the median ECVn in the SH group, without any difference in body mass index, but they were nevertheless normotensive. The fall in BV was greater in SN than in TN patients, presumably due to a higher ultrafiltration rate in SN patients. However, SH patients had a smaller change in BV than SN patients, presumably because their state of overhydration facilitated refilling of BV from the interstitial fluid. CONCLUSIONS: Normotension can be achieved independently of the duration and dose (Kt/V urea) of HD, if the control of post-dialysis ECV is adequate. However, this is more difficult to achieve with short than with more prolonged HD during which the ultrafiltration rate is lower, BV changes are smaller and intradialysis symptoms less frequent. The results in the subgroup of patients with high ECVn at Tassin suggest that normotension may also be achieved in patients with fluid overload provided that the dialysis time is long enough to ensure more efficient removal of one or more vasoactive factors that cause or contribute to hypertension.

Blood pressure control and hemodynamic changes in patients on long time dialysis treatment.

In dialysis patients blood pressure can be well controlled with long dialysis (3 times a week for 8 h) in contrast to a more common short dialysis regime (3 times a week for 4 h). We studied whether the good blood pressure control in patients on long dialysis as compared to patients on short dialysis was associated with a decrease in extracellular fluid volume. Two-day interdialytic ambulatory blood pressure monitoring was performed in 26 non-diabetic patients on long dialysis, in 22 patients on short dialysis, matched for the years they were on dialysis treatment, and during 24 h in 19 healthy volunteers. After full equilibration, 24 h after dialysis, echography of the inferior caval vein was performed to determine fluid state. Cardiac dimensions and stroke index were measured by echocardiography. A blood sample was drawn for the determination of electrolytes and vasoactive hormones. 73% of the patients on short dialysis were using antihypertensive medication in contrast to none of the patients on long dialysis. However, blood pressure was significantly lower in patients on long dialysis (115 +/- 21/67 +/- 11 mm Hg) when compared to patients on short dialysis (143 +/- 26/81 +/- 16 mm Hg). Indexed caval vein diameter, left ventricular diameter index, and atrial natriuretic peptide were not significantly different in patients on long dialysis compared to patients on short dialysis. Also the cardiac index was comparable in patients on long and short dialysis. However, the total peripheral resistance index was significantly lower in patients on long dialysis compared to the patients on short dialysis and normal controls. The left ventricular mass index was increased in both patients on long and short dialysis compared to controls. We conclude that patients on long dialysis have adequate blood pressure control that seems mainly to be caused by a low total peripheral resistance. These data also suggest that factors other than a lower fluid state contribute to the good blood pressure control in patients on long dialysis.

Salt and hypertension in end-stage renal disease.

Salt and fluid overload play an important role in the pathogenesis of hypertension in patients with end-stage renal disease. However, in the individual patient, the relation between salt loading and blood pressure response is variable and appears to be influenced by various neurohumoral regulatory mechanisms. This may also have implications for the pathogenesis of structural cardiovascular abnormalities in patients with end-stage renal disease.

Effects of hypervolemia on interdialytic hemodynamics and blood pressure control in hemodialysis patients.

The influence of hypervolemia on hemodynamics and interdialytic blood pressure, as well as in relation to vascular compliance, was investigated in 10 hemodialysis patients who were not receiving vasoactive medication. All subjects were studied during a relative normovolemic interdialytic period (from 1 kg below dry weight postdialytic until dry weight predialytic) and a hypervolemic interdialytic period (from 1 kg above dry weight postdialytic until 3 kg above dry weight predialytic). Interdialytic blood pressure was measured with an ambulatory blood pressure monitor. Cardiac output was echographically measured and total peripheral resistance calculated postdialytic, mid-interdialytic, and predialytic. At the same time, a blood sample was drawn for analyzing vasoactive hormones, sodium, and hematocrit. In all patients, ideal dry weight was estimated by echography of the caval vein. Arterial and venous compliance were measured with an ultrasound vessel wall movement detector system and a strain-gauge plethysmograph. After fluid load, an increase in intravascular volume, an increase in caval vein diameter and cardiac output, and a decrease in peripheral resistance was observed. No significant influence of a 3-L fluid load was found on interdialytic blood pressure course (153+/-24 mm Hg/90+/-19 mm Hg in the hypervolemic period and 146+/-27 mm Hg/89+/-22 mm Hg in the normovolemic period). Sodium and osmolality were similar in the hypervolemic and normovolemic interdialytic periods. After fluid load, a decrease in arginine vasopressin and angiotensin II was observed, which probably contributed to the decreased systemic vascular resistance. Catecholamines were not influenced by fluid load, but increased during the interdialytic period, suggesting accumulation after dialysis. Three of the 10 patients had higher systolic but not diastolic blood pressures after fluid load (159+/-13 mm Hg/81+/-22 mm Hg in the hypervolemic period and 135+/-16 mm Hg/81+/-22 mm Hg in the normovolemic period). No correlation could be found between arterial or venous compliance and blood pressure changes. We concluded that a 3-L interdialytic fluid load does not result in higher blood pressure in most hemodialysis patients.

Arterial compliance in patients on long-treatment-time dialysis.

Arterial compliance is found to be reduced in haemodialysis patients. It is not clear whether decreased arterial compliance in uraemic patients is a consequence of long-standing increased mean arterial blood pressure or a consequence of the uraemic state. An adequate blood pressure can be achieved by long-treatment-time dialysis of 8 h three times a week. We studied femoral and carotid artery wall properties in 24 normotensive patients on long-treatment-time dialysis and 24 normal controls matched for mean arterial pressure, age, sex, and body mass index. Arterial distensibility coefficient and compliance coefficient were determined with a vessel wall movement detector system, 24 h after dialysis in the supine position. The patients were 5.9 +/- 6.6 years on long-treatment-time dialysis at a Kt/V of 1.8 +/- 0.4. We found no significant differences in mean arterial pressure or pulse pressure between patients (85 +/- 13, 55 +/- 17 mmHg) and controls (84 +/- 6, 50 +/- 13 mmHg). Femoral distensibility coefficient and compliance coefficient were lower in patients (6.0 +/- 2.4 10(-3)/kPa; P < 0.05, 0.52 +/- 0.28 mm2/kPa; n.s.) compared to the controls (8.8 +/- 4.0 10(-3)/kPa, 0.67 +/- 0.38 mm2/kPa). No differences in carotid distensibility coefficient and compliance coefficient were found between patients (12.8 +/- 4.6 10(-3)/kPa, 0.72 +/- 0.30 mm2/kPa) and controls (14.1 +/- 4.4 10(-3)/kPa, 0.70 +/- 0.23 mm2/kPa). We conclude that patients on long-treatment-time-dialysis have an increased stiffening of the muscular femoral artery but not of the more elastic carotid artery. Results suggest that the uraemic state itself has a deleterious effect on the elastic properties of the muscular femoral artery.

Preventing haemodynamic instability in patients at risk for intra-dialytic hypotension.

Although as yet no major breakthroughs have occurred to improve long-term survival of haemodialysis patients with impaired cardiovascular function, it is possible to reduce morbidity by intra-dialytic hypotension in these patients by the use of relatively simple manoeuvres. In our experience, this can be achieved using the following approach (Table 1). First, the decline in plasma volume can be reduced by adequate estimation of the optimal dry weight by objective methods, such as echography of the inferior caval vein or bioimpedance measurements. Furthermore, the ultrafiltration rate during haemodialysis should be moderate and should be limited to a maximum value, which has to be defined empirically for each individual patient. Especially in patients with excess inter-dialytic weight gain, isolated ultrafiltration should be used when the required amount of fluid cannot be removed during haemodialysis. The use of low-sodium dialysate should be avoided. Probably it is best to use a physiological sodium concentration of the dialysate because a greater sodium concentration may result in increased thirst and intra-dialytic weight gain. Sodium profiling should be based on further studies concerning plasma volume changes during haemodialysis in different patient groups. Because of the deleterious impact of acetate on vascular reactivity, it should never be used in patients prone to hypotensive periods. Vascular reactivity can also be impaired by the use of vasoactive medication prior to haemodialysis treatment. Therefore, in patients prone to hypotensive periods, vasoactive medication should be withheld the morning before haemodialysis, if possible. Also, one should be very cautious with the use of low-calcium dialysate in patients with frequent hypotensive periods, and ideally it should be avoided. If the use of these manoeuvres fails to control intra-dialytic hypotension, one should consider the use of cold dialysate. Switching to haemofiltration or to continuous treatment modes such as CAPD are other options. Future studies should address haemodynamics during other treatment modes, such as haemodiafiltration or acetate-free biofiltration.

Vascular reactivity during haemodialysis and isolated ultrafiltration: thermal influences.

BACKGROUND: The present study was performed to assess the role of the extracorporeal blood temperature in the disparate cardiovascular response between isolated ultrafiltration and combined ultrafiltration-haemodialysis. METHODS: In twelve stable dialysis patients (21-77 years), blood pressure and heart rate (Finapres) as well as forearm vascular resistance and venous tone (strain-gauge plethysmography) were measured during 1-h isolated ultrafiltration and 1-h combined ultrafiltration-haemodialysis (bicarbonate, sodium 141 mmol/l) at a fixed ultrafiltration rate of 0.91 l/h. The sequence of both treatment modalities was randomly defined within each patient. Serving as his or her own control, each patient was studied at two different dialysate temperatures: 37.5 and 35.0 degrees C. RESULTS: At a dialysate temperature of 35.0 degrees C extracorporeal blood cooling during combined ultrafiltration-haemodialysis was comparable to isolated ultrafiltration. The cardiovascular response in isolated ultrafiltration was characterized by a significant increase in both forearm vascular resistance and venous tone, while heart rate even decreased. As a result, blood pressure remained unchanged or even increased. In contrast, during combined ultrafiltration-haemodialysis at a dialysate temperature of 37.5 degrees C the increase in forearm vascular resistance was only small and insignificant, while venous tone decreased significantly. Heart rate tended to increase. Combined ultrafiltration-haemodialysis at a dialysate temperature of 35.0 degrees C was also associated with a small increase in forearm vascular resistance. However, venous tone remained stable while heart rate decreased. At both dialysate temperatures, blood pressure was well maintained. CONCLUSIONS: We conclude that differences in cardiovascular reactivity between isolated ultrafiltration and combined ultrafiltration-haemodialysis are only partially explained by differences in the extracorporeal blood temperature. In addition, especially venous reactivity is improved by lowering the dialysate temperature.

Influence of interdialytic weight gain on blood pressure in hemodialysis patients.

The role of fluid overload in the pathogenesis of hypertension in hemodialysis patients is not clear. One problem is the lack of techniques to determine the fluid state. Recent new noninvasive techniques have become available which make it possible to accurately determine the dry weight in these patients. Therefore, we studied the influence of interdialytic weight gain on interdialytic blood pressure in 10 normotensive and 10 hypertensive hemodialysis patients without antihypertensive medication. The dry weight was determined with echography of the vena cava. The blood pressure was measured during 2-day and 3-day interdialytic periods using Spacelabs 90207 ambulatory blood pressure monitors. Mean systolic and diastolic blood pressures of the last day of the interdialytic period were compared with mean systolic and diastolic blood pressures of the 1st day of the interdialytic period. Although the interdialytic weight gain in the normotensive and hypertensive patients was greater during the 3-day than during the 2-day interdialytic period, the interdialytic systolic and diastolic blood pressure changes were not greater during the 3-day period. Also, the interdialytic blood pressure rise did not correlate significantly with weight gain, neither in the normotensive nor in hypertensive patients. No significant interdialytic blood pressure changes were found between the normotensive and the hypertensive patients. We conclude that fluid overload does not seem to play a major role in interdialytic blood pressure control in normotensive and hypertensive hemodialysis patients.

Diurnal blood-pressure variations in haemodialysis and CAPD patients.

The influence of variations in fluid state on diurnal blood pressure was studied by measuring day-time and night-time blood pressure during a 3-day interdialytic period in 10 normotensive and 10 hypertensive haemodialysis patients using Spacelab 90207 Monitors. Ambulatory blood pressure was also measured during 24 h in 11 normotensive and nine hypertensive CAPD patients, and in nine normotensive and 11 hypertensive control patients with a normal renal function. Antihypertensive drugs had been discontinued for at least 3 weeks before the study period. Optimal dry weight in the haemodialysis patients was estimated by echography of the inferior vena cava and in the CAPD patients on clinical grounds. Although in the dialysis patients and controls a significant nocturnal blood pressure reduction was found, day-night blood pressure difference in the dialysis patients was blunted when compared with the control patients. No significant differences in diurnal blood pressure variation was found between the normotensive and the hypertensive patients. Day-night blood pressure differences in the haemodialysis patients did not change during the 3-day interdialytic period. Also the more stable fluid state of the CAPD patients was not associated with significant different diurnal blood pressure variation compared to the haemodialysis patients. We conclude that factors other than changes in extracellular fluid volume are responsible for a blunted day-night difference in blood pressure in dialysis patients.

Blood pressure during the interdialytic period in haemodialysis patients: estimation of representative blood pressure values.

The estimation of representative blood pressure (BP) levels is difficult in haemodialysis (HD) patients as it is not known whether pre- or postdialytic blood pressure are predictive for the average interdialytic BP. Furthermore, the day-night BP rhythm can be disturbed in HD patients. Therefore, in this study, BP was measured during the interdialytic period using non-invasive ambulatory BP measurements in four hypotensive, six normotensive, and 12 hypertensive HD patients. It was assessed whether pre- or postdialytic BP was representative for the average interdialytic BP. Furthermore, the nocturnal BP reduction was compared between HD patients, seven normotensive controls and eight treated subjects with essential hypertension. Postdialytic BP was superior to predialytic BP in predicting the average BP during the interdialytic period. BP did not differ significantly between day 1 and day 2 of the interdialytic period but increased rapidly in the hours before dialysis. Weight gain (corrected for actual body-weight) did not correlate significantly with the increment in systolic BP (r = 0.21; P = 0.2) or diastolic BP (r = -0.02; P = 0.5) during the interdialytic period. The nocturnal decline in systolic BP was significantly attenuated (P less than 0.001) in hypertensive HD patients compared with normotensive controls. The nocturnal reduction in diastolic BP was significantly less in hypotensive (P less than 0.001) and normotensive (P less than 0.001) HD patients compared with normotensive controls and in hypertensive HD patients compared with normotensive (P less than 0.001) and hypertensive (P less than 0.001) controls.(ABSTRACT TRUNCATED AT 250 WORDS)