Effect of mineralocorticoids on interdialytic weight gain in hemodialysis patients with perdialytic hypotension

Fludrocortisone is recommended in patients with orthostatic hypotension and a benefit has been suggested in hemodialysis patients with severe hypokaliemia. We report 2 patients who suffered from chronic severe perdialytic hypotension resistant to midodrine and who were treated in a long-term period with fludrocortisone. A rise of post-dialytic BP was observed with a decrease of the interdialytic weight gain (IWG). We suggest that the IWG decrease is induced by a lessening of the renin angiotensin aldosterone system that could be less stimulated at the end of the dialysis session because of a better-preserved arterial pressure. The decrease of angiotensin could lessen the feeling of thirst.     

Does Blood Pressure Control by Gentle Ultrafiltration Improve Survival in Hemodialysis Patients?

Agentle ultrafiltration can be achieved using a long and slow hemodialysis. It is easier to achieve gentle ultrafiltration if the interdialytic weight intake is moderate ( i.e., if the patient maintains a low sodium diet) and if diffusion allows for a negative or nil sodium balance during the session ( i.e., dialysate sodium < 140 mmol/L). A gentle ultrafiltration allows control of blood pressure by reducing the extracellular volume to its ideal level, the “dry weight,” at the end of the session. Controlling blood pressure reduces cardiovascular mortality, which is by far the foremost cause of death in hemodialysis. Controlling blood pressure means reducing the occurrence of both hypertension and hypotension. Hypotension has been reported to correlate with mortality in hemodialysis as much as or more than hypertension itself. This “U‐curve” phenomenon is not paradoxical. It displays two distinct facts on the same figure: an increased early mortality in hypotensive patients (hypotension is a marker of frailty or congestive heart failure, both of which cause increased mortality) and, on the other hand, the well‐established, long‐term increased mortality in hypertensive patients. Hypotension is not a mandate to undertreat hypertension.     

Is there an association between intradialytic hypotension and serum magnesium changes?

Intradialytic hypotension (IDH) is the most common complication of hemodialysis (HD). The aim of this study was to investigate the significance of intradialytic changes of serum magnesium (sMg) and its relation to IDH. We considered 58 patients undergoing HD. Serum magnesium was measured at start, after 2 hours, and at the end of the HD sessions. Total sMg concentration corrected for albumin was according to Krolles proposed formula. Blood pressure was measured every 30 min. Data were analyzed by SPSS.15. A P value of less than 0.05 was considered as significant. Occurrence of IDH among HD patients was 27.6% (16/58). Serum magnesium decreased significantly during HD session (P<0.05). Comparing corrected sMg in IDH group with non-IDH group showed that: corrected sMg was 0.66 ± 0.14 mmol/L vs. 0.84 ± 0.26 mmol/L at the start of dialysis (P=0.43), 0.62 ± 0.17 mmol/L vs. 0.74 ± 0.23 mmol/L (P=0.04) at 2 hours, and 0.61 ± 0.12 mmol/L vs. 0.72 ± 0.22 mmol/L (P=0.03) at the end of dialysis. Intradialytic hypotension episodes were significantly related to a decrease in sMg during dialysis (P=0.02). There was a significant decrease in sMg levels during dialysis. Intradialytic hypotension was significantly related to lowered sMg levels during dialysis.     

A meta‐analysis of sodium profiling techniques and the impact on intradialytic hypotension

Introduction Hemodialysis has improved in recent years, however, despite such improvements, intra‐dialytic hypotensive episodes still persist which can lead to a reduction in the overall effectiveness of the treatment. Profiling sodium levels during dialysis can improve vascular refilling and therefore may prevent hypotensive events. A number of profiling methods exist and this meta‐analysis set out to examine the effectiveness of these methods. Methods To assess the effectiveness of hemodialysis sodium profiling techniques. A review and meta‐analysis analytical framework was used. A search was conducted using Medline, Embase and CINAHL, Scopus and Web of Knowledge between 1946 and 2014 of published English‐language peer reviewed randomized control studies. In total 10 articles were retrieved and included in the review. All data was abstracted with a standardized data collection form. Stata 11.2 (Stata Corp) was used to analyse the data. Actual numbers of hypotensive events were pooled between studies. Analysis of subgroups was performed on sodium profile type. The data were further investigated using meta‐regression. Publication bias was also tested. Findings Stepwise profiling was shown to be statistically significantly effective in reducing intradialytic episodes. Results demonstrated that linear sodium profiling was not effective in reducing hypotensive events during dialysis. Discussion This review has shown that using stepwise profiling is more effective at reducing intra‐dialytic symptoms than other profiling methods. There was no evidence that linear profiling method was any more effective than conventional dialysis and in fact the results showed the reverse.     

Characteristics of heart rate variability entropy and blood pressure during hemodialysis in patients with end-stage renal disease

Entropy (ENT) is a newly developed measure of the complexity of heart rate variability (HRV). The aim of this study was to characterize the complexity of HRV in patients with end-stage renal disease (ESRD) and to find a possible clinical utility. Healthy subjects and patients with ESRD undergoing hemodialysis (HD) were recruited. The HD population consisted of patients with and without diabetes mellitus (DM). An electrocardiogram was recorded before HD, and blood pressure was measured during HD. The coefficients of variation of R-R intervals, high- and low-frequency components, and ratio of the low- to high-frequency components were measured as variables of HRV. The ENT was used to describe the complexity of HRV. Forty-six healthy subjects and 27 HD patients participated in this study. The ENT negatively correlated with the duration of DM (p = 0.001), systolic blood pressure (p = 0.003), and mean blood pressure (p = 0.004) before a HD session. ENT in HD patients was lower than that in healthy subjects (p < 0.01). ENT in HD patients with DM was lower than that in HD patients without DM (p < 0.01). The change in systolic blood pressure (DeltaSBP) during a HD session showed high correlations to ENT and ultrafiltration rate (UFR) of the dialyzer. The following equation was obtained: DeltaSBP = 2.25 x ENT - 2.28 x UFR - 21.27 (R2 = 0.805; p < 0.0001). ENT decreased with uremic and diabetic status. ENT also represents a possible prediction of hypotension during a HD session.     

Refractory orthostatic hypotension after creation of a brachio‐basilic arteriovenous fistula

Arteriovenous fistulas (AVFs) are preferred vascular access in patients with end‐stage renal disease (ESRD) undergoing hemodialysis (HD). However, AVFs, can occasionally lead to clinically significant complications. Of these, cardiovascular complications have been well described in the literature. In this report, we describe a case of a 78‐year‐old Caucasian male with ESRD who presented with severe debilitating dizziness and orthostatic hypotension that started soon after the creation of left brachiobasilic AVF. The patient had no significant cardiovascular history apart from essential hypertension. His symptoms persisted despite extensive evaluation and interventions, and abated only after banding of the AVF. This report describes the timeline of the patient's clinical course beginning from the day of creation of his AVF, through the course of his hospitalization leading to AVF banding and ending with postoperative recovery phase with resolution of symptoms. We will also review the pathophysiologic effects of AVF on cardiovascular system, as well as the potential causes of our patient's clinical presentation.     

Hypoalbuminemia is an important risk factor of hypotension during hemodialysis

Hypotension during hemodialysis (HD) is an important problem in patients on HD. To investigate the risk factors that contribute to the hypotension during HD, we compared background factors of hypotensive (HP) patients during HD. Among 58 patients undergoing HD in Tamura Memorial Hospital, 12 patients could not continue full HD because of hypotension. We compared the data of ultrafiltration volume, cardiothoracic ratio (CTR), total protein (TP), serum albumin, blood urea nitrogen (BUN), serum creatinine, total cholesterol (TC), hemoglobin (Hb), blood glucose (BS), brain natriuretic peptide (BNP), and cardiac function between HP patients (HP group; n=12) and sex- and age-matched control patients (NP group; n=12). There were no significant differences of age, sex, and duration of HD between the 2 groups. Cardiothoracic ratio is bigger and BNP is higher in the HP group compared with the NP group (CTR: HP 55.8+/-2.9% vs. NP 47.7+/-1.1%, p=0.0165; BNP: HP 602+/-171 vs. NP 147+/-38, p=0.0167). Serum albumin in the HP group is significantly lower compared with the NP group (HP 3.2+/-0.1 g/dL vs. NP 3.5+/-0.1 g/dL, p=0.0130). However, there were no significant differences of ultrafiltration rate (UFR), BS, TC, Hb, and cardiac function between the 2 groups. There is a significant negative correlation between changes of systolic blood pressure (delta systolic blood pressure) and serum albumin in these patients (r=-0.598, p=0.0016). From these data, we conclude that hypoalbuminemia is a major risk factor of hypotension during HD.     

Myocardial stunning in hemodialysis: What is the overall message?

Heart failure and cardiovascular events are common in chronic renal failure. Hemodialysis (HD) causes significant hemodynamic changes and hypotension. New evidence based on intradialytic echocardiography demonstrates transient cardiac dysfunction or stunning in majority of chronic HD patients. Over time, this group may progress to chronic heart failure and appears to predict higher cardiovascular events and mortality. Although the exact etiology is unclear, alterations in HD technique and cardiac medications may reduce this complication. We review the current understanding of acute cardiac stunning during HD and present a systematic management algorithm to optimizing overall outcomes in this high-risk population.     

Effects of secondary amyloidosis on arteriovenous hemodialysis fistula outcomes and intradialytic hypotension: a case-control study

Amyloid fibrils can affect vascular structure through deposition and by causing nitric oxide depletion and increase of asymmetric dimethyl arginine. Patients with amyloidosis are prone to development of hypotension. Hypotension may also affect the maturation of arteriovenous fistula (AVF) and may set the stage for formation of thrombosis and fistula failure. Thus, we aimed to evaluate effects of secondary amyloidosis on AVF outcomes and intradialytic hypotension. This is a case‐control study which included 20 hemodialysis patients with amyloidosis and 20 hemodialysis patients without amyloidosis as control group. All patients underwent Doppler ultrasound of AVF. A thorough fistula history and baseline laboratory values along with episodes of intradialytic hypotension and blood pressure measurements were recorded. There was no difference between the groups regarding age, gender, body mass index, presence of comorbidities, hypertension, and drug use. Systolic and diastolic blood pressures were similar (119 ± 28/75 ± 17 and 120 ± 14/75 ± 10 mmHg for patients with and without amyloidosis, respectively). Intradialytic hypotension episodes were also similar. Patients with amyloidosis had significantly lower serum albumin and higher C‐reactive protein values compared to control hemodialysis patients. AVF sites and total number of created fistulas were similar in both groups. Flow rates of current functional AVFs were not different between the groups (1084 ± 875 and 845 ± 466 mL/minute for patients with and without amyloidosis, respectively, p:0.67). Patency duration of first AVF was not different between the groups. Clinical fistula outcomes and rate of intradialytic hypotension episodes were not significantly different between patients with and without secondary systemic amyloidosis.     

The relationship between symptoms and blood pressure during maintenance hemodialysis

Intradialytic hypotension (IDH) is a detrimental complication of maintenance hemodialysis, but how it is defined and reported varies widely in the literature. European Best Practice Guideline and Kidney Disease Outcomes Quality Initiative guidelines require symptoms and a mitigating intervention to fulfill the diagnosis, but morbidity and mortality outcomes are largely based on blood pressure alone. Furthermore, little is known about the incidence of asymptomatic hypotension, which may be an important cause of hypoperfusion injury and impaired outcome. Seventy‐seven patients were studied over 456 dialysis sessions. Blood pressure was measured at 15‐minute intervals throughout the session and compared with post‐dialysis symptom questionnaire results using mixed modeling to adjust for repeated measures in the same patient. The frequency of asymptomatic hypotension was estimated by logistic regression using a variety of commonly cited blood pressure metrics that describe IDH. In 113 sessions (25%) where symptoms were recorded on the questionnaire, these appear not to have been reported to dialysis staff. When symptoms were reported (293 sessions [64%]), an intervention invariably followed. Dizziness and cramp were strongly associated with changes in systolic blood pressure (SBP), but not diastolic blood pressure. Nausea occurred more frequently in younger patients but was not associated with falls in blood pressure. Thresholds that maximized the probability of an intervention rather than a session remaining asymptomatic were SBP <100 mmHg or a 20% reduction in SBP from baseline. The probability of SBP falling to <100 mmHg in an asymptomatic session was 0.23. Symptoms are frequently not reported by patients who are hypotensive during hemodialysis, which leads to an underestimation of IDH if symptom‐based definitions are used. A revised definition of IDH excluding patient‐reported symptoms would be in line with literature reporting morbidity and mortality outcomes and include sessions in which potentially detrimental asymptomatic hypotension occurs.     

The source of net ultrafiltration during hemodialysis is mostly the extracellular space regardless of hydration status

Fluid shifts are common in patients undergoing chronic hemodialysis (HD) during the intradialytic periods, as several liters of fluid are removed during ultrafiltration (UF). Some patients have experienced frequent intradialytic hypotension (IDH). However, the characteristics of fluid shifts and which fluid space is affected remain controversial. Therefore, we designed this study to evaluate the fluid spaces most affected by UF and to determine whether hydration status influences the fluid shifts during HD. This was a prospective cohort study of 40 patients undergoing HD. We measured the patient's fluid spaces using a whole‐body bioimpedance apparatus to evaluate the changes in the fluid spaces before HD and 1–4 hours of HD and 30 minutes after HD. UF achieved during HD by the 40 patients (age, 60.0 ± 5.2 years; 50% men; 50% of patients with diabetes; body weight, 61.3 ± 10.5 kg) was 2.18 ± 0.78 L (measured fluid overload, 2.15 ± 1.24 L). 1) Mean relative reduction of total body water and extracellular water was reduced from the start to the end of HD. 2) However, mean relative reduction of intracellular water was not reduced from the start to the end of HD. 3) No significant differences in fluid shifts were observed according to hydration status. The source of net UF during HD is mostly the extracellular space regardless of hydration status. Thus, IDH may be related to differences in the interstitial fluid shift to the vascular space.     

A study of the extracorporeal rate of blood flow and blood pressure during hemodialysis

Hemodynamic instability is a common problem during hemodialysis (HD). The effect of blood flow rate (BFR) on blood pressure (BP) during HD has not been previously evaluated. Subjects receiving HD for the treatment of renal failure were enrolled (n=34). For each patient, during the last hour of 2 consecutive HD sessions the BFR was set at 200 mL/min for 30 min and at 400 mL/min for 30 min, during which period the fluid removal rate was kept constant. The order of the BFR alterations was randomized. The study procedure was repeated during the next HD session but with reversal of the order of the altered BFR. During each 30-min period, BP was recorded at baseline and subsequently every 10 min. During the BFR of 400 mL/min, subjects had a higher systolic BP by an average of 4.1 mmHg compared with the BFR of 200 mL/min (95% confidence interval [CI] 0.22-7.98; p=0.038). Similarly, during the BFR of 400 mL/min, subjects had a higher diastolic BP by an average of 3.04 mmHg compared with the BFR of 200 mL/min (95% CI 0.55-5.53; p=0.017). Likewise, during the BFR of 400 mL/min, subjects had a higher mean arterial pressure by an average of 3.44 mmHg (95% CI 0.77-6.11; p=0.012). The findings suggest that during HD, BPs are maintained higher at higher BFRs as compared with lower BFRs.     

Convection with conviction-online hemodiafiltration for all: single center clinical observations

Online hemodiafiltration (HDF) has recently become an alternative to conventional hemodialysis for treatment of end-stage renal disease with superior results. Clinical experience with HDF in unselected populations has not been widely published and a longitudinal study on such a group of patients is presented here.     

Pulse contour-derived cardiac output in hemodialysis patients

Reliable methods for cardiac output determination are essential for studying the pathophysiology of intradialytic hypotension. Use of the current gold standard, the Transonic^® monitor, requires an arteriovenous fistula. We wished to verify the accuracy of a method based on finger pulse contour analysis, namely the Finometer^® monitor (FNM) for further use on patients dialyzing on a central vascular catheter. Fifty simultaneous cardiac output measurements were obtained during hemodialysis sessions in 25 patients. The internal variability of the FNM measurements was assessed by comparing 24 pairs of immediately successive measurements. The variability of successive FNM measurements was small (bias 0.28%, SD ± 6.1%; NS). The absolute cardiac output values reported by the FNM were unreliable (bias 20.1%, SD ± 35.3%; P<0.001) as were the relative intradialytic changes (r²=0.01). Excluding participants from the analysis due to old age, high dialysis vintage or a suspicion of atherosclerosis did not improve the results. Our findings do not support the use of pulse contour analysis for measuring cardiac output in hemodialysis patients. Uremic vascular disease may be the cause of the observed inaccuracy.     

Intradialytic changes of serum magnesium and their relation to hypotensive episodes in hemodialysis patients on different dialysates

Magnesium is a crucial mineral, involved in many important physiological processes. Magnesium plays a role of maintaining myocardial electrical stability in hemodialysis patients. Intradialytic hypotension is a common complication of dialysis and it is more common with acetate dialysate. The significance of the intradialytic changes of magnesium and their relation to parathyroid hormone (PTH) level and calcium changes during dialysis, and their relation to hypotensive episodes during dialysis are interesting. The aim of this work is to investigate the intradialytic changes of serum magnesium in chronic hemodialysis patients with different hemodialysis modalities and the relation to other electrolytes and to PTH, and also the relation to intradialytic hypotension. The present study was conducted on 20 chronic renal failure patients. All patients were on regular hemodialysis thrice weekly 4 hr each using acetate dialysate (group I). To study the effect of an acetate-based dialysate vs. a bicarbonate-based dialysate on acute changes of magnesium, calcium, phosphorus, and PTH during a hemodialysis session, the same patients were shifted to bicarbonate dialysis (group II). All patients were subjected to full history and clinical examination, predialysis laboratory assessment of blood urea nitrogen (BUN), serum creatinine, albumin, and hemoglobin, serial assessment of magnesium, calcium, phosphorus, and parathyroid hormone at the start of the hemodialysis session, 2 hr later, and at the end of the session, blood pH, and electrocardiogram (ECG) presession and postsession. All patients were urged to fix their dry weight, diet, and current medications. None of the patients had diabetes, neoplasia, liver disease, or cachexia, nor had they been recently on magnesium-containing drugs or previously parathyroidectomized. Hemodialysis sessions were performed by volumetric dialysis machines using the same electrolyte composition. Magnesium level significantly increased in the bicarbonate group at the end of dialysis (0 hr: 2.73+/-0.87, 2 hr: 3.21+/-1.1, and at 4 hr: 5.73+/-1.45 mg/dL, p value <0.01), while it significantly decreased in the acetate group (0 hr: 3.00+/-0.58, 2 hr: 2.26+/-0.39, 4 hr: 1.97+/-0.33 mg/dL, p value <0.01). Calcium level significantly increased in the bicarbonate group (p=0.024) but not in the acetate group. Phosphorus level significantly decreased in both acetate and bicarbonate groups. PTH level did not significantly change in either group, p value > or =0.05. Blood pH significantly increased, changing from acidic to alkaline pH, with both modalities of hemodialysis. ECG showed no significant changes during sessions with either type of dialysate. Hypotension was significantly higher in group I compared with group II (p=0.01), and this hypotension was positively correlated with a decrease in serum magnesium level in group I. Intradialytic changes in serum magnesium have no correlation with intradialytic changes in serum calcium or with PTH level. However, it was significantly correlated with hypotension during the dialysis session, especially with acetate dialysate. Further investigations are needed to determine whether or not this is true in patients using bicarbonate dialysis.