Characteristics of hypotension-prone haemodialysis patients: is there a critical relative blood volume?

BACKGROUND: Intradialytic morbid events (IME, mostly hypotension) mainly due to ultrafiltration-induced hypovolaemia still are the most frequent complication during haemodialysis (HD). This study was performed to test the hypothesis that there is an individual critical relative blood volume (RBV(crit)) in IME-prone HD patients. METHODS: In this prospective international multicentre study, 60 IME-prone patients from nine dialysis centres were observed during up to 21 standard HD sessions without trial-specific intervention. The RBV was monitored continuously by an ultrasonic method (BVM; blood volume monitor). Also, the ultrafiltration rate was registered continuously. Blood pressure was measured at regular intervals, and more frequently during IME. All IME and specific therapeutic interventions were noted. RESULTS: In total, 537 IME, some with more than one symptom, were documented during 585 HD sessions. The occurrence of IME increased up to 10-fold from the start to the end of the HD session. RBV(crit) showed a wide inter-individual range, varying from 71 to 98%. However, the intra-individual RBV limit was relatively stable, with an SD of <5% in three-quarters of the patients. In patients with congestive heart failure, cardiac arrhythmia, advanced age, low ultrafiltration volume and low diastolic blood pressure, higher values of RBV(crit) were observed. While all correlations between RBV(crit) and patient characteristics alone were found to be of weak or medium strength, the combination of diastolic blood pressure, ultrafiltration volume and age resulted in a strong correlation with RBV(crit): the linear equation with these parameters allows an estimation of RBV(crit) in patients not yet monitored with a BVM. CONCLUSIONS: An individual RBV limit exists for nearly all patients. In most IME-prone patients, these RBV values were stable with only narrow variability, thus making it a useful indicator to mark the individual window of haemodynamic instabilities.     

Reduction of hypotensive side effects during online-haemodiafiltration and low temperature haemodialysis.

BACKGROUND: This study compares the effect of online-haemodiafiltration (o-HDF, post-dilution mode) with conventional haemodialysis (HD) and 'temperature-controlled' HD (Temp-HD) on the haemodynamic stability of hypotension-prone patients. METHODS: Seventeen patients with a history of frequent hypotensive episodes during dialysis sessions were studied, each patient serving as his or her own control. The first 25 HD treatments in comparison with 25 o-HDF sessions were evaluated using identical dialysate temperature. In the second part of the study, o-HDF (n = 25) was compared with Temp-HD (n = 25). In the latter method, the temperature of the dialysate was adjusted to result in identical energy transfer rates to those in the corresponding o-HDF. The number of hypotensive episodes, blood temperature and blood volume regulation were assessed. RESULTS: Symptomatic hypotension was much more frequent during HD (40%) than during o-HDF (4%) (P < 0.001). During o-HDF, an enhanced energy loss within the extracorporeal system occurred (o-HDF, 16.6 +/- 4.0 W; HD, 5.4 +/- 5.1 W; P < 0.0001), despite identical temperature settings for dialysate and substitution fluid. As a result, the blood returning to the patient was cooler during o-HDF than during HD (o-HDF 35 +/- 0.2 degrees C vs HD 36.5 +/- 0.3 degrees C; P < 0.0001). In o-HDF, even in the patients' circulation, the mean blood temperature was lower (o-HDF 36.7 +/- 0.2 degrees C vs HD 36.9 +/- 0.3 degrees C; P < 0.0001) and blood volume was significantly more reduced (o-HDF, 91.8 +/- 3.1%; HD, 94.0 +/- 3.2%; P < 0.05). Energy transfer rates and blood temperature did not differ significantly between o-HDF and Temp-HD. The rate of hypotensive episodes was low and not different between o-HDF (4%) and Temp-HD (4%). Neither was there any significant difference in blood volume reduction. CONCLUSIONS: O-HDF showed a significant reduction of hypotensive episodes compared with HD. Surprisingly, o-HDF resulted in cooling of the blood via enhanced thermal energy losses within the extracorporeal system, despite use of replacement fluid prepared from pre-warmed dialysate. The incidence of symptomatic hypotension was reduced to that of o-HDF by using cooler Temp-HD. Thus, unexpected blood cooling appears to be the main blood pressure-stabilizing factor in o-HDF.     

Unexpected haemodynamic instability associated with standard bicarbonate haemodialysis.

BACKGROUND: The bicarbonate concentration in dialysis fluids for intermittent haemodialysis usually is between 32 and 35 mmol/l. The severity of chronic metabolic acidosis secondary to end-stage renal failure is very variable, however, so that in some patients pre-dialysis acidosis is overcorrected. This study aimed to analyse haemodynamic tolerances to metabolic alkalosis during intermittent haemodialysis. METHODS: In this randomized controlled trial with a single blind, cross-over design, we used dialysis liquids with two different bicarbonate concentrations, 32 (modality A) and 26 (modality B) mmol/l, and in 26 patients, 468 dialysis sessions, compared blood pressure, heart rate, incidence of hypotension and the frequency of corrections required with saline or hypertonic glucose infusions. RESULTS: The results of intradialytic haemodynamic monitoring for modalities A and B, respectively, were: lowest systolic blood pressure 120.8+/-20.8 vs 124.3+/-20.6 mmHg (P < 0.01); mean systolic blood pressure 138.5+/-23.8 vs 144.6+/-24.8 mmHg (P < 0.001); and highest heart rate 73.5+/-12.0 vs 75.8 +/- 12.9 (NS); with modality A, patients had more dialysis sessions with hypotensive episodes (5.55 vs 1.7%, P < 0.05) and required more saline or hypertonic glucose infusions (20.9 vs 13.7% of the dialysis sessions, P < 0.05). CONCLUSIONS: Mild metabolic alkalosis resulting from standard bicarbonate haemodialysis (32 mmol/l) may induce symptomatic hypotension. While normalizing chronic metabolic acidosis is desirable, reducing bicarbonate concentrations should be considered in cases of significant alkalaemia or otherwise untreatable haemodynamic instability.     

Relationship between blood pressure during haemodialysis and ambulatory blood pressure in between dialyses

BACKGROUND.: Ambulatory blood pressure measurements in haemodialysis patientsare relevant in view of the high cardiovascular morbidity andmortality in chronic haemodialysis patients. METHODS.: Twelve normotensive patients were studied from the beginningof one dialysis until the end of the next (mean 64 h, SD 19h) using a Spacelabs oscillometric blood-pressure recorder. RESULTS.: A circadian blood pressure rhythm was present in six of the12 patients. In seven patients the lowest pressure recorded(including the dialysis sessions) occurred 5–6 h afterdialysis (late post-dialysis dip). Blood pressure did not increasesharply in the hours before dialysis although it increased slightlyin the interdialytic interval as a whole, at a mean rate of5.6 mmHg per 24 h (SD 4.1, P<0.001). We could not find ablood pressure measurement during dialysis (or combination ofmeasurements) which reliably reflects interdialytic blood pressure:the 95% confidence intervals were 25 mmHg or higher. CONCLUSION.: Ambulatory blood pressure measurements are needed for adequatemonitoring of the control of blood pressure in haemodialysispatients.     

Assessment of refill and hypovolaemia by continuous surveillance of blood volume and extracellular fluid volume

During renal replacement therapy hypovolaemia due to ultrafiltration(UF) may, when not sufficiently counteracted by refill fromthe interstitium, result in hypotension. Combining two recentlydeveloped methods the haemodynamic process of refill was studiedin order to find characteristics featuring hypotension. Relativeblood volume (BV) and extracellular fluid volume (EFV) weremeasured continuously in 40 stable haemodialysis patients bymeans of an optical and a conductivity technique respectively.Regarding their postdialytic (PD) EFV the patients were dividedinto three groups: normohydrated (N, n=20), dehydrated (D, n=11) and overhydrated (O, n=9). Significant differences betweenthe groups were assessed in BV decrease (after 2 h until theend of treatment P<0.05 and after 3 h P<0.01), EFV decrease(after 3 h P<0.05) and occurrence of hypotensive episodes(N,5; D,7; O,none; P<0.01). During the entire session thespeed of BV decrease was significantly higher in hypotensivepatients (H) than in non-hypotensive patients (non-H). At themoment of hypotension (after 141±49 min) residual BVwas less (P<0.0005) in H (87.7±5.2%) than at the correspondingmoment in non-H patients (96.5±4.0%). PD BV and PD EFV,both expressed as a percentage of the starting value, correlatedsignificantly (r=0.63, p<0.005) and UF-volume (differencesbetween the groups were not significant) correlated to EFV decrease(r=0.45, P<0.005). In conclusion, the combination of bothnon-invasive methods elucidates the pathophysiology of UF-inducedhypotension and provides a means of reducing dialysis morbidity.The influence of tissue hydration state on these variables hasbeen shown.     

Intra-dialytic hypotension and blood volume and blood temperature monitoring

Intra-dialytic hypotension (IDH) is a common problem affecting haemodialysis patients. Its aetiology is complex and influenced by multiple patient and dialysis factors. IDH occurs when the normal cardiovascular response cannot compensate for volume loss associated with ultrafiltration, and is exacerbated by a myriad of factors including intra-dialytic fluid gains, cardiovascular disease, antihypertensive medications and the physiological demands placed on patients by conventional haemodialysis. The use of blood volume monitoring and blood temperature monitoring technologies is advocated as a tool to predict and therefore prevent episodes of IDH. We review the clinical utility of these technologies and summarize the current evidence of their effect on reducing the incidence of IDH in haemodialysis population.     

Comparison of volume of blood processed on haemodialysis adequacy measurement sessions vs regular non-adequacy sessions.

BACKGROUND: Knowledge that adequacy measures such as the urea reduction ratio (URR) or Kt/V(urea) are being measured on haemodialysis may influence the behaviour of patients or staff such that the treatment may be better on those days. This study therefore tested the hypothesis that mean volume of blood processed (VBP), utilized as a surrogate for adequacy, is higher on adequacy measurement days than non-measurement days. METHODS: Patients were identified who had been on haemodialysis over the preceding 8 months. Primary outcome was the difference in the mean VBP (in litres) on URR measurement compared with non-URR measurement days (DeltaVBP(U)(-N)). Univariate and multivariate correlates of mean VBP and DeltaVBP(U)(-N) were also determined. RESULTS: Eighty-nine patients were identified who met inclusion and exclusion criteria. Linear regression demonstrated a weak relationship between VBP and URR (r=0.24, P<0.02). This relationship was much stronger when VBP was adjusted for patient weight (mean VBP/weight; r=0.78, P<0.0001). The overall mean VBP was 87.4 l (+/-1.2 l) and the average DeltaVBP(U)(-N) was 1.1 l (+/-0.3 l) (P=0.001). Twenty per cent of patients had a clinically relevant DeltaVBP(U)(-N) of >3.6 l. Patients with a graft or fistula had a significantly higher DeltaVBP(U)(-N) than patients with a tunnelled catheter. CONCLUSIONS: This study demonstrates that the average VBP is less on non-URR than on URR measurement days; this difference was clinically important in >20% of patients. Univariate analysis indicated that the use of a fistula or graft correlated with a higher DeltaVBP(U)(-N). This implies that our current method of assessing dialysis adequacy does systematically overestimate the average delivered dose of dialysis in a subset of patients.     

Predictors of haemodynamic instability and heart rate variability during haemodialysis.

BACKGROUND: The pathogenesis of haemodialysis-induced hypotension is multifactorial and may include autonomic nervous system dysfunction. The present study was undertaken to (i) determine heart rate variability (HRV) in chronic haemodialysis patients without and with haemodynamic instability (hypotension-prone) during ultrafiltration and (ii) identify patients at risk and the predictors of dialysis-related hypotension. METHODS: HRV was evaluated in 56 chronic haemodialysis patients without (stable; n = 27) and with symptomatic hypotension episodes (unstable; n = 29) during daytime, haemodialysis and night-time periods. Logistic regression analysis was performed in a model that included clinical and biochemical data and HRV measurements. RESULTS: HRV was significantly reduced in haemodynamically unstable as compared with the stable patients. LF/HF ratio, an index representative of sympathovagal balance, was significantly lower in unstable patients, especially in those with ischaemic heart disease and diabetes mellitus. In a logistic regression model including clinical data and HRV measurements, ischaemic heart disease and left ventricular systolic dysfunction were found to be the main predictors of haemodynamic instability. CONCLUSIONS: These data suggest that haemodynamic instability is strongly associated with a decreased HRV and an impaired sympathovagal balance, suggesting disturbed autonomic control in uraemic patients with cardiac damage. Patients with ischaemic heart disease, reduced left ventricular systolic function and decreased HRV may be at the highest risk to be haemodynamically unstable during haemodialysis. The role of early detection and treatment of ischaemic heart disease in preventing symptomatic hypotensive episodes in these patients remains to be determined.     

Norepinephrine-induced vasoconstriction results in decreased blood volume in dialysis patients.

BACKGROUND: Hypotension during haemodialysis results from an inadequate cardiovascular response to ultrafiltration-induced hypovolaemia. It has been suggested that plasma volume could be increased as a result of systemic vasoconstriction. METHODS: We studied the effect of a norepinephrine (NOR) infusion (30 min), compared with no infusion, on relative blood volume (RBV) in six haemodialysis patients. During infusion we measured RBV, systolic blood pressure (SAP), heart rate (HR), stroke volume index (SI), total peripheral resistance (TPRI), ejection fraction (EF), inferior vena cava diameter (VCD) and core temperature. RESULTS: At the end of the NOR infusion, we observed a significant increase in TPRI (47+/-47% vs 4+/-17%; P<0.01) and SAP (27+/-12% vs 0+/-8%; P<0.01). Norepinephrine-induced vasoconstriction resulted in a significant decrease in RBV (-9+/-3% vs 0+/-1%; P<0.01). No significant changes were seen in SI (-4+/-21% vs 0+/-8%), HR (-5+/-19% vs -4+/-5%), EF (7+/-14% vs -2+/-10%), VCD or temperature. CONCLUSIONS: We conclude that norepinephrine-induced vasoconstriction results in a decrease in RBV. This indicates that improved haemodynamic stability during haemodialysis through vasoconstriction can be accompanied by a decrease in RBV and that part of the variability in blood volume may be due to changes in arterial tone. Such changes must be taken into account if RBV measurements are used to improve the haemodynamic tolerance of dialysis.     

Specific effect of the infusion of glucose on blood volume during haemodialysis.

BACKGROUND: Intradialytic morbid events such as hypotension and cramps during haemodialysis are generally treated by infusion of iso- or hypertonic solutions. However, differences may exist between solutions with respect to plasma refilling and vascular reactivity. METHODS: We compared the effect of no infusion (NI) with isovolumetric infusion of isotonic saline 0.9% (IS), saline 3% (HS), isotonic glucose 5% (IG), glucose 20% (HG) and mannitol 20% (HM), in six patients during the first hour of six standardized haemodialysis sessions with ultrafiltration. Relative blood volume was monitored continuously by measurement of the intravascular amount of protein. Blood pressure was measured by an oscillometric method, while cardiac output was measured by a thoracic impedance technique. RESULTS: At baseline, no differences in serum urea, sodium, potassium, glucose and osmolarity were found between the various infusion experiments. The maximum increase in relative blood volume directly after infusion was significantly greater with HG (5.1+/-0.7%) than with all other infusions (P<0.05). Stroke volume increased (21.0+/-19.2%, P<0.05) and total peripheral resistance decreased significantly (15.4+/-16.4%, P<0.05) after HG infusions. CONCLUSIONS: Infusion of hypertonic glucose during dialysis results in a greater increase in relative blood volume (RBV) than equal volumes of other solutions. As mannitol has the same osmolarity, molecule mass and charge, the greater increase in RBV following hypertonic glucose appears to be a specific effect, possibly related to a decline in vascular tone. It is therefore uncertain whether the observed increase in plasma volume during hypertonic glucose infusions will be of clinical benefit.     

血液透析中相对血容量与血压的相关性

目的 观察血液透析低血压倾向患者血液透析时相对血容量的改变,并与血压进行相关性分析,以研究相对血容量对预测低血压发生的价值.方法 挑选维持性血液透析者61例（透析龄≥1个月）,持续在线监测相对血容量,每30分钟测定血液和心率.记录140次血液透析过程中低血压的发生次数及相对血容量的数值.采用线性相关分析进行数据统计.结果 相对血容量与收缩压之间无相关性（相关系数r为0.17）.发生低血压时,患者相对血容量变化差异显著.在21例患者中,49例次相对血容量与收缩压呈线形相关.结论 在透析过程中,患者所能耐受的血容量下降程度存在明显的个体差异,但个体内变异不大,患者临床表现结合血容量监测有助于防治透析过程中低血压的发生以及确定合适的超滤量、调整干体质量.     

Long-term survival rates in haemodialysis patients treated with strict volume control.

METHODS: We analysed the survival of 218 patients (132 male, 86 female, age 48 +/- 15 years) who were treated in our dialysis units since we adopted the strategy of strict volume control without antihypertensive drugs. The mean observation period was 47 +/- 34 (6-140) months. Follow-up was ended because of death (57 patients), transfer to another center (35 patients), continous ambulatory peritoneal dialysis (CAPD) (15 patients) or transplantation (23 patients), while 88 were still under our treatment at the time of writing. RESULTS: Blood pressure (BP) decreased from a mean of 150 +/- 31/89 +/- 16 at the start to 121 +/- 14/75 +/- 8 mmHg at the end of observation (P < 0.001). Only nine patients needed a drug (enalapril) to reach this goal. Cardiothoracic index (CTI) dropped from 0.50 +/- 0.06 to 0.46 +/- 0.05 (P < 0.001). Interdialytic weight gain decreased from 1440 +/- 360 to 930 +/- 240 g/day (P < 0.001). Mortality rate was 68, 2 per 1000 patient-years, better than in most published series. There was a striking influence of age, but also of CTI and systolic BP on survival rate. Patients with CTI > or = 0.48 showed mortality 3.8 times higher than CTI < 0.48 (log rank P < 0.001). Consequently, the mean CTI of the deceased patients was much higher (0.50) than the average of the group (0.46) while their mean BP (123 +/- 16/75 +/- 9 mmHg) was not significantly different from the other patients. We found no increased mortality at low-normal pressure levels (systolic BP between 100 and 130 mmHg), but mortality was increased in small groups of patients whose pressures were lower or higher than these values. Thus, the curve, relating mortality to blood pressure was shifted markedly to the left. CONCLUSIONS: These results strongly suggest that the strategy of 'volume control', also when applied with conventional dialysis times, normalizes BP and increases survival of dialysis patients. Cardiomegaly, as evidenced on the chest X-ray despite normal BP, had a strong negative influence on survival. The large majority of the patients had low-normal BP after long periods of treatment and showed the lowest mortality, favouring the view that target BP should be lower than advised by most authors.     

Efficacy and safety of haemodialysis treatment with the Hemocontrol biofeedback system: a prospective medium-term study.

BACKGROUND: Hypovolaemia has been implicated as a major causal factor of morbidity during haemodialysis (HD). A model biofeedback control system for intra-HD blood volume (BV) changes modelling has been developed (Hemocontrol), Hospal Italy) to prevent destabilizing hypovolaemia. It is based on an adaptive controller incorporated in a HD machine (Integra), Hospal Italy). The Hemocontrol biofeedback system (HBS) monitors BV contraction during HD with an optical device. HBS modulates BV contraction rates by adjusting the ultrafiltration rate (UFR) and the refilling rate by adjusting dialysate conductivity (DC) in order to obtain the desired pre-determined BV trajectories. METHODS: Nineteen hypotension-prone uraemic patients (seven males, 12 females; mean age 64.5+/-3.0 SEM years; on maintenance HD for 80.5+/-13.2 months) volunteered for the present prospective study that compared the efficacy and safety of bicarbonate HD treatment equipped with HBS, as a whole, with the gold-standard bicarbonate treatment equipped with a constant UFR and DC (BD). The study included three phases: Medium-term studies started with one period of 6 months of BD and always had a follow-up period of HBS treatment ranging from 14 to 30 months (mean 24.0+/-1.6); short-term studies started in September 1999, when all patients went back to BD treatment for a wash-out period of 4 weeks and a short-term study period of a further 3 weeks (phase A). Afterwards, they once again started HBS treatment for a wash-out period of 4 weeks and a short-term study period of a further 3 weeks (phase B). Every patient underwent acute studies during a single HD run, once during phase A and once in phase B. Resistance (R) and reactance (Xc) measurements were obtained utilizing a single-frequency (50 kHz) tetrapolar bioimpedance analysis (BIA). Extracellular fluid volume (ECV) was calculated from R, Xc, and height and body weight measurements using the conventional BIA regression equations. RESULTS: The overall occurrence of symptomatic hypotension and muscle cramps was significantly less in HBS treatment in both medium- and short-term studies. Self-evaluation of intra- and inter-HD symptoms (worst score=0, best score=10) revealed a statistically significant difference, as far as post-HD asthenia was concerned (6.2+/-0.2 in HBS treatment vs 4.3+/-0.1 in BD treatment, P<0.0001). No difference was observed between the two treatments when comparing pre- and post-HD lying blood pressure, heart rate, body weights and body weight changes in medium- and short-term studies. The residual BV%/ Delta ECV% ratio, expression of the vascular refilling, was significantly higher during HBS treatment in acute studies. CONCLUSIONS: HBS treatment is effective in lowering hypovolaemia-associated morbidity compared with BD treatment; this could be related to a greater ECV stability. Furthermore, HBS is a safe treatment in the medium-term because these results are not achieved through potentially harmful changes in blood pressure, body weight, and serum sodium concentration.     

The haemodynamic response to submaximal exercise during isovolaemic haemodialysis.

INTRODUCTION: Exercise during haemodialysis has potential benefits but may compromise cardiovascular stability. We studied its acute effects on relative blood volume (RBV) and other haemodynamic parameters. METHODS: Two groups of 10 patients were exercised submaximally using a stationary cycle during isovolaemic dialysis whilst RBV was monitored continuously. In study 1, patients exercised for two 10 min periods separated by 10 min rest. Cardiac output (CO), peripheral vascular resistance (PVR), central blood volume (CBV) and stroke volume were measured using ultrasound dilution immediately before and after each exercise session. In study 2, haemoglobin, serum total protein and albumin levels were measured before and immediately after the exercise session and at the nadir of the RBV trace. RESULTS: RBV fell immediately on exercise initiation, the maximum reduction being 2.0+/-1.1% (after 5.9+/-1.4 min of exercise 1: P<0.001) and 2.0+/-1.2% (after 4.7+/-2.3 min of exercise 2: P<0.001). CO increased significantly after both periods of exercise (4.5+/-0.96 and 5.1+/-1.1 to 7.2+/-2.1 and 7.9+/-2.4 l/min, P<0.001 in both). Stroke volume increased significantly and PVR fell significantly during exercise. CBV increased in absolute terms but fell as a proportion of CO. Mean haemoglobin level at the RBV nadir was significantly higher than baseline (12.3+/-1.8 vs 11.8+/-1.7 g/dl: P<0.05: mean change 4.4+/-2.3%), as was mean total protein concentration (66.0+/-6.9 vs 62.0+/-8.1 g/l: P = 0.001: mean change 6.8+/-5.9%) and mean serum albumin concentration (36.0+/-3.9 vs 34.1+/-3.9 g/l: P<0.001: mean change 5.8+/-3.5%). CONCLUSION: The haemodynamic response to exercise during haemodialysis is comparable with that in normal individuals. The rapid reduction in RBV on exercise occurs in spite of a significant increase in CO, mainly as a consequence of fluid shifts from the microvasculature to the interstitium.     

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)     

Relationships between blood pressure variability and left ventricular parameters in haemodialysis and renal transplant patients

SUMMARY: Blood pressure (BP) elevation and left ventricular hypertrophy (LVH) are important factors in the high cardiovascular mortality on the renal replacement programme. the relationship between these, predictable in essential hypertension, is less well defined in uraemia. We wished to examine the contribution of abnormal blood pressure variability (BPV) to the cardiovascular changes seen in uraemia and after renal transplantation. Twenty-four hour ambulatory blood pressure monitoring (ABPM), and simultaneous echocardiography, on a cohort of 35 long-term, long-hours haemodialysis survivors and 28 patients with stable renal transplants was undertaken. We also retrospectively compiled biochemical and clinical data. There were strong relationships between both diurnal and standard deviation measures of BPV and left ventricular cavity size and function: per cent fall in awake to asleep diastolic BP with fractional shortening index (FSI), r =0.28, P =0.039; with left ventricular mass index (LVMI), r =−0.35, P =0.011. This study suggests that reduced diurnal and short-term BP variability is cross-sectionally associated with a dilated, heavier left ventricle (LV) with worse systolic function. Thus, BPV may independently contribute to the abnormal LV structure and function commonly seen in uraemia.     

Relationships between blood pressure variability and left ventricular parameters in haemodialysis and renal transplant patients

Blood pressure (BP) elevation and left ventricular hypertrophy (LVH) are important factors in the high cardiovascular mortality on the renal replacement programme. The relationship between these, predictable in essential hypertension, is less well defined in uraemia. We wished to examine the contribution of abnormal blood pressure variability (BPV) to the cardiovascular changes seen in uraemia and after renal transplantation. Twenty-four hour ambulatory blood pressure monitoring (ABPM), and simultaneous echocardiography, on a cohort of 35 long-term, long-hours haemodialysis survivors and 28 patients with stable renal transplants was undertaken. We also retrospectively compiled biochemical and clinical data. There were strong relationships between both diurnal and standard deviation measures of BPV and left ventricular cavity size and function: per cent fall in awake to asleep diastolic BP with fractional shortening index (FSI), r =0.28, P =0.039; with left ventricular mass index (LVMI), r =−0.35, P =0.011. This study suggests that reduced diurnal and short-term BP variability is cross-sectionally associated with a dilated, heavier left ventricle (LV) with worse systolic function. Thus, BPV may independently contribute to the abnormal LV structure and function commonly seen in uraemia.