Survival pattern of hemodialysis patients in Kumasi, Ghana: A summary of forty patients initiated on hemodialysis at a new hemodialysis unit

To evaluate the survival pattern of hemodialysis patients at a dialysis unit in Kumasi, Ghana, through a retrospective (observational) study. Patients who were placed on hemodialysis at the dialysis unit at Komfo Anokye teaching hospital from October 25, 2006 to December 2007. The patients were followed from initiation of dialysis until December 31, 2007. The overall mortality was 14 (35.9%) on the incident population for the period and that for the first 90 days was 12 (32.4%) patients. Chronic glomerulonephritis was the underlying kidney disease in 35.9%. This was followed by hypertension (19.1%) and diabetes mellitus (15.4%), respectively. Cardiovascular diseases accounted for 42% of mortality. This was followed by septicemia (25%) from the access site and anemia (25%). Fifty percent of the patients were able to afford 20 sessions of hemodialysis before stopping. The most powerful predictors of survival were the duration of hemodialysis (P=0.05) and the number of hemodialysis sessions (P=0.02). Age at initiation of hemodialysis was not significant. First 90-day mortality of patients on hemodialysis is high in poor African countries. This is due partially to the late referral of patients and also the cost of the dialysis treatment. Efforts will have to be made to reduce the cost of the dialysis treatment. Reuse technology (of dialyzer, etc.) should be introduced to cut down the cost of hemodialysis. Peritoneal dialysis should also be introduced for highly motivated patients. Efforts should also be made to reduce the increasing incidence of kidney disease, and finally third-world countries should consider establishing kidney transplantation, that is cost effective.     

Patient preferences for in-center intense hemodialysis

There is a lack of data on patient preferences for intense hemodialysis (IHD). In this study, we conducted a cross-sectional survey to identify patient preferences and patient-centered barriers for IHD. A questionnaire on preferences and anticipated barriers, anticipated benefits, and quality of life for three in-center IHD schedules (daytime 2 hr six times/week [DHD], nocturnal 8 hr three times/week [ND3], and nocturnal 8 hr six times/week [ND6]) was administered to 100 chronic hemodialysis patients. A majority of patients (68%) were willing to undergo DHD for symptomatic benefits or increase in survival. An increase in energy level (94%) and improvement in sleep (57%) were the most common potential benefits that would justify DHD, but only 19% would undergo DHD for an increase in survival of < or =3 years. Only 20% and 7% would consider ND3 and ND6, respectively. The most common reported barriers were inadequate time for self (50%) and family (53%), followed by transportation difficulties (53%). Most patients would undergo DHD for symptomatic or survival benefits, but not ND3 or ND6. Disruption of personal time, however, is an important consideration. Success of DHD program would depend on arrangements for transportation to dialysis unit.     

Determinants of hemodialysis‐induced segmental wall motion abnormalities

Patients who demonstrate worsening of cardiac wall motion (WM) during hemodialysis have higher 1‐year mortality. We sought to identify risk factors for dialysis‐induced WM abnormalities. Additionally, we examined the effects of hemodialysis on other parameters of cardiac function. Forty patients underwent echocardiography directly before dialysis and during the last hour of dialysis (79 dialysis sessions). Candidate predictors for intradialytic worsening of WM included age, a history of heart failure (HF) or coronary artery disease, changes in blood pressure or heart rate, high sensitivity cardiac troponin T and N‐terminal brain natriuretic peptide. Among 40 patients, WM worsened segmentally in eight patients (20%), worsened globally in one patient (3%), and improved segmentally in four patients (10%). Diastolic function worsened in 44% of patients, and left ventricular ejection fraction was largely unchanged during dialysis. The case of globally worsened WM occurred in the setting of intradialytic hypertension in a patient without HF. Surprisingly, history of coronary artery disease, hemodynamics, and serologic factors were not associated with worsened segmental WM during dialysis. After adjustment for history of coronary artery disease and other cardiac risk factors, patients with a history of HF had a threefold higher risk of worsening segmental WM during dialysis (RR 3.1, 95% CI [1.1, 9], p = 0.04). In conclusion, patients with a history of clinical HF were at higher risk of intradialytic worsening of segmental WM. Further studies are needed to determine the mechanism of this association and whether cardioprotective medications could ameliorate this adverse cardiac effect of hemodialysis.     

Fallacies of High‐Speed Hemodialysis

Chronic hemodialysis sessions, as developed in Seattle in the 1960s, were long procedures with minimal intra‐ and interdialytic symptoms. Financial and logistical pressures related to the overwhelming number of patients requiring hemodialysis created an incentive to shorten dialysis time to four, three, and even two hours per session in a thrice weekly schedule. This method spread rapidly, particularly in the United States, after the National Cooperative Dialysis Study suggested that time of dialysis is of minor importance as long as urea clearance multiplied by dialysis time and scaled to total body water (Kt/V_urea) equals 0.95–1.0. This number was later increased to 1.3, but the assumption remained unchanged that hemodialysis time is of minimal importance as long as it is compensated by increased urea clearance. Patients accepted short dialysis as a godsend, believing that it would not be detrimental to their well‐being and longevity. However, Kt/V_urea measures only removal of low molecular weight substances and does not consider removal of larger molecules. Besides, it does not correlate with the other important function of hemodialysis, namely ultrafiltration. Whereas patients with substantial residual renal function may tolerate short dialysis sessions, the patients with little or no urine output tolerate short dialyses poorly because the ultrafiltration rate at the same interdialytic weight gain is inversely proportional to dialysis time. Rapid ultrafiltration is associated with cramps, nausea, vomiting, headache, fatigue, hypotensive episodes during dialysis, and hangover after dialysis; patients remain fluid overloaded with subsequent poor blood pressure control, left ventricular hypertrophy, diastolic dysfunction, and high cardiovascular mortality. Short, high‐efficiency dialysis requires high blood flow, which increases demands on blood access. The classic wrist arteriovenous fistula, the access with the best longevity and lowest complication rates, provides “insufficient” blood flow and is replaced with an arteriovenous graft fistula or an intravenous catheter. Moreover, to achieve high blood flows, large diameter intravenous catheters are used; these fit veins “too tightly,” so predispose the patient to central‐vein thrombosis. Longer hemodialysis sessions (5–8 hrs, thrice weekly), as practiced in some centers, are associated with lower complication rates and better outcomes. Frequent dialyses (four or more sessions per week) provide better clinical results, but are associated with increased cost. It is my strong belief that a wide acceptance of longer, gentler dialysis sessions, even in a thrice weekly schedule, would improve overall hemodialysis results and decrease access complications, hospitalizations, and mortality, particularly in anuric patients.     

The advantages and disadvantages of home hemodialysis

In Australia, 12% of the hemodialysis population dialyze at home. Until recently, the majority of these patients dialyzed for similar hours to those in satellite dialysis. However, in the past 5 years there has been a new departure such that in many centers the concept of home hemodialysis is now synonymous with extended hours dialysis. Registry data supports the concept that increased frequency and duration of dialysis may result in improved patient survival and a reduction in cardiovascular risk profile. It is hoped, therefore, that the long recognized survival benefit observed in home hemodialysis patients may be further augmented by the swing to extended hours dialysis in this patient population. In addition to the physiological benefits of extended hours home dialysis, there are clear quality of life, social, and economic advantages associated with dialyzing at home. There are however a number of perceived disadvantages to home hemodialysis including the application and time commitment required for training, the potential for relationship strain or "burnout," and reluctance to "hospitalize" the home. Overall, however, in this new era of extended hours dialysis, the advantages both physiological and lifestyle of home hemodialysis far outweigh the disadvantages.     

Survival Advantage of Tailored Dialysis

Survival has been defined as an index of adequacy of dialysis. These hard data are the basis for comparing results obtained by different schedules or policies. The aim of the study was to assess mortality rate recorded within a system of tailored dialysis (1–6 dialysis per week in out‐of‐hospital settings: home hemodialysis, self‐ and limited care dialysis). Data recorded in a single center (1998–2003) were compared with data gathered in the Registry of Dialysis and Transplantation in the whole Region (1998–2000). Methods: Out‐of‐hospital dialysis unit is active since 1971, in which a new program integrating self‐ and limited care and home dialysis started since 1998. Patients: Incident dialysis patients starting renal replacement therapy within the program and all further patients starting dialysis in the Region in the same period were compared in an historical prospective cohort study. Results: 55 patients in the Unit and further 1443 patients in the whole Region started RRT since 1998. Main features of 55 patients were 32 males 23 females; median age 51 years, range 20–76; 72.7% displaying at least 1 comorbid factor. Throughout the period gross mortality rate was 4/125 patient‐years in the Center. Kaplan–Meier curves showed a 1‐year survival of 100% vs. 91%, respectively, in the Center and in the whole Region, and a 2‐year survival of 95.5% vs. 76.6%, respectively, in the Center and in the whole Region (p = 0.001). The main demographic features were remarkably different in both settings (for the whole Region median age 66 years, range 2.2–101, at least 1 comorbidity in 56.9% of patients). In an attempt to correct for the different baseline characteristics, a multivariate Cox regression analysis was performed. The whole model resulted in statistically significant value (p = 0.000) and an increasing mortality risk resulted for age at starting dialysis, diabetes, and collagenopathy. In conclusion, tailored, high‐efficiency dialysis policy may allow superior survival results. A longer follow up is needed to confirm our approach; in larger cohorts, the finding of a low mortality rate in a relatively young population with high comorbidity may underline the need to review our current concepts on dialysis adequacy.     

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.     

Role of bicarbonate dialysis in prevention of serious arrhythmias in high‐risk cardiac patients undergoing regular hemodialysis

Background: Cardiac arrhythmias are considered as one of the most important causes of mortality in patients on hemodialysis. Arrhythmias frequently occur in patients with chronic renal failure on regular hemodialysis with reported incidences varying from 30–48% of patients. These abnormalities can span from supraventricular to severe ventricular arrhythmia. There is an increased frequency of occurrence and clustering of arrhythmias around the dialysis time. Aim of the study: To detect the difference between acetate and bicarbonate dialysis as regard to the type and frequency of arrhythmia in those patients. Study design: This study was done on 20 male patients age 51–73, all have history of heart disease. Patients were divided into 2 equal groups using acetate in group 1 and bicarbonate in group 2. All patients were on regular hemodialysis (4 hours, thrice weekly). Careful history and clinical examination were done. Pre‐dialysis investigations included serum creatinine, blood urea nitrogen, serum sodium, potassium, calcium and phosphorus, serum albumin, hemoglobin, and arterial blood gases. Post‐dialysis serum potassium and arterial blood gases were measured. ECG and forty‐eight hours ambulatory monitor (Holter monitor)(before, during, and after hemodialysis, till the end of the dialysis day and throughout the following day) were performed. Results: Group 1 showed significantly less post‐dialysis supraventricular arrhythmias than in dialysis day (210.9 ± 236 and 62.3 ± 14.4), respectively. Significantly less ventricular arrhythmias in post‐dialysis than in dialysis day (30.7 ± 50.4, and 106.2 ± 128.4), respectively. While in Group 2 there were insignificant differences regarding supraventricular arrhythmias (21.9 ± 28.9 and 16.6 ± 36.3) and ventricular arrhythmias (22.9 + 7.8 and 29.6 + 12.8) in dialysis day than in post‐dialysis day. There was significantly higher frequency of supraventricular and ventricular arrhythmias in the dialysis day in acetate hemodialysis in comparison to bicarbonate hemodialysis. Conclusion: Bicarbonate hemodialysis is less arrhythmogenic in comparison to acetate hemodialysis and has better effect on the blood pH and greater degree of base repletion. Continuous ambulatory ECG recording (Holter) is a useful tool in detecting arrhythmias in dialysis patients.     

Modifiable variables affecting interdialytic weight gain include dialysis time,frequency, and dialysate sodium

Interdialytic weight gain (IDWG) is associated with hypertension, left ventricular hypertrophy, and all‐cause mortality. Dialysate sodium concentration may cause diffusion gradients with plasma sodium and influence subsequent IDWG. Dialysis time and frequency may also influence the outcomes of this Na⁺ gradient; these have been overlooked. Our objective was to identify modifiable factors influencing IDWG. We performed a retrospective multivariable regression analyses of data from 86 home hemodialysis patients treated by hemodialysis modalities differing in frequency and session duration to determine factors involved that predict IDWG. Age, diabetic status, and residual renal function did not correlate with IDWG in the univariable analysis. However, using a combination of backwards selection and Akaike information criterion to build our model, we created an equation that predicted IDWG on the basis of serum albumin, age, patient sex, dialysis frequency, and the diffusive balance of sodium, represented by the product of the duration of dialysis and the patient plasma to dialysate Na⁺ gradient. This equation was internally validated using bootstrapping, and externally validated in a temporally distinct patient population. We have created an equation to predict IDWG on the basis of independent factors readily available before a dialysis session. The modifiable factors include dialysis time and frequency, and dialysate sodium. Patient sex, age, and serum albumin are also correlated with IDWG. Further work is required to establish how improvements in IDWG influence cardiovascular and other clinical outcomes.     

The Middle Molecule Hypothesis Revisited. Should Short,Three Times Weekly Hemodialysis Be Abandoned?

When the middle molecule (MM) hypothesis was formulated in 1975, no MM had yet been identified as a uremic toxin. Meanwhile, the birth and implementation of the Kt/V_urea concept gained wide acceptance and has remained the world standard for assessing dialysis adequacy. However, over the past 20 years, accumulating evidence has made it clear that MM's are important uremic toxins, and that the dose of dialysis based on removal of small molecular substances does not protect against excessive hemodialysis mortality, morbidity, or the presence of uremic signs and symptoms. These poor results are, in one way or another, linked to the accumulation of MM's and other substances behaving like MM's, such as phosphate. Dialysis schedules yielding the best clinical results, such as longer dialysis and more frequent dialysis, favor increased removal of middle molecular substances. The observation that short daily dialysis is giving results similar to long nocturnal quotidian dialysis supports early observations that the volume from which middle molecular substances are extracted mainly by hemodialysis is small (about as large as the extracellular volume), and that transfer of MM's from cells to extracellular fluid is very slow. This behavior of MM's is markedly different from that of small molecular substances, which are more rapidly transferred from intracellular to extracellular compartments and are more readily extracted from total body water during hemodialysis. In order to achieve even minimum adequate dialysis, it is now scientifically validated that toxic MM's must be removed in larger amounts than currently attained. This can only be accomplished by long dialysis sessions with a 3‐times per week schedule or more frequent dialyses. Five hours 3 times per week represents the absolute minimum treatment. Dialy sis 6 to 7 times per week is the ideal schedule for patients who are willing to commit the time and effort in exchange for maximum well‐being and long survival.     

We Should Strive for Optimal Hemodialysis: A Criticism of the Hemodialysis Adequacy Concept

Adequacy of hemodialysis is frequently equated with Kt/V_urea , the amount of urea clearance (K) multiplied by time (t) and divided by urea distribution volume (V). Several formulas have been developed to calculate Kt/V_urea from the pre‐ and post‐dialysis urea concentrations. In three‐times‐weekly hemodialysis, a single pool (spKt/V_urea) value of 1.3 per treatment is commonly considered to indicate adequate therapy.
Despite providing the recommended spKt/V_urea of 1.3 per treatment, short dialysis with rapid ultrafiltration is associated with multiple intradialytic and interdialytic complications. Patients experience cramps, nausea, vomiting, headaches, fatigue, hypotensive episodes during dialysis, and hangover after dialysis; patients remain fluid overloaded with subsequent poor blood pressure control, left ventricular hypertrophy, diastolic dysfunction, and high cardiovascular mortality.
According to Webster's dictionary, "optimal" means most desirable or satisfactory; "adequate" means sufficient for a specific requirement or barely sufficient or satisfactory. Optimal dialysis is the method of dialysis yielding results that cannot be further improved. New approaches, including hemeral quotidian or long nocturnal dialysis, provide opportunities to abandon the notion that adequate dialysis is "good enough" for our patients. Optimal dialysis should be our goal. Dialysis sessions should be long and frequent enough to provide excellent intra‐ and interdialytic tolerance of hemodialysis, normalization of serum calcium and phosphorus, blood pressure control, normal myocardial morphology and function, and hormonal balance, and to eliminate all, even subtle, uremic symptoms.     

Length of Dialysis Session Is More Important Than Large Kt/V in Hemodialysis

Long, slow hemodialysis (3 × 8 hours/week) has been used without significant modification in Tassin, France, for 30 years with excellent morbidity and mortality rates. A long dialysis session easily provides high Kt/V_urea and allows for good control of nutrition and correction of anemia with a limited need for erythropoietin (EPO). Control of serum phosphate and potassium is usually achieved with low-dose medication. The good survival achieved by long hemodialysis sessions is essentially due to lower cardiovascular morbidity and mortality than in short dialysis sessions. This, in turn, is mainly explained by good blood pressure (BP) control without the need for antihypertensive medication. Normotension in this setting is due to the gentle but powerful ultrafiltration provided by the long sessions, associated with a low salt diet and moderate interdialytic weight gains. These allow for adequate control of extracellular volume (dry weight) in most patients without important intradialytic morbidity. Therefore, increasing the length of the dialysis session seems to be the best way of achieving satisfactory long-term clinical results.     

Safety analysis of intermittent hemodialysis in patients with continuous flow left ventricular assist devices

Dialysis centers adopt a cautious approach when it comes to performing intermittent hemodialysis (HD) on patients with continuous flow (CF) left ventricular assist devices (LVADs) because of the potential for volume flux‐related complications and absence of pulsatile blood pressure for monitoring. Many patients have to remain hospitalized because of the inability of the dialysis centers to accept them for outpatient dialysis. In this study, the effect of HD was observed in such patients. Between June 2009 and October 2012, 139 patients received LVADs, of which 10 patients (7%) required intermittent HD postoperatively. The mean age of the patients was 53 ± 14 years and 90% were men. A total of 281 dialysis sessions were administered amounting to 1025 hours of dialysis. The mean systolic blood pressure monitored with Doppler device was 97 ± 18 mmHg. Dialysis durations averaged 218 ± 18 minutes. Mean blood flow rate was 334 ± 38 cc/min, and 2.6 ± 1.1 L was ultrafiltrated during each session. Only 15 (5.3%) sessions were interrupted or terminated in six patients. The reasons for termination were symptomatic hypotension—6 (2.1%), asymptomatic hypotension—3 (1%), ventricular tachycardia—1 (0.36%), dialysis machine malfunction—2 (0.7%), low phosphorus—2 (0.7%), and abdominal cramps—1 (0.36%). Volume expansion was necessary on three occasions. Low‐flow device alarms were registered during two (0.71%) sessions. The results showed no serious adverse effects or deaths.     

On‐line hemodiafiltration at home

Survival with online hemodiafiltration (OL‐HDF) is higher than with hemodialysis; frequent hemodialysis has also improved survival and quality of life. Home hemodialysis facilitates frequent therapy. We report our experience with 2 patients with stage 5 CKD who started home hemodialysis with OL‐HDF in November 2016. After a training period at the hospital, they started home hemodialysis with OL‐HDF after learning how to manage dialysis monitors and how to administer water treatment. We used the “5008‐home” (FMC^©) monitor, and the Acqua C^© (Fresenius Medical Care) for water treatment. Water conductivity was always checked before and during dialysis sessions and was always 2.5 to 3 mS/cm. Water cultures always fulfilled the criteria for ultrapurity. As far as we know, this is the first report on patients receiving OL‐HDF at home. The technique proved to be safe and valid for renal replacement therapy and transfers the benefits of hospital convective therapy to the home setting. Future data will enable us to determine whether survival has also improved.     

Obstructive sleep apnea in incremental hemodialysis: Determinants,consequences, and impact on survival

Sleep disorders are common in hemodialysis patients, although causes and consequences remain unclear. We sought to establish prevalence, determinants, and outcomes of sleep disturbances in patients receiving incremental dialysis. One hundred two unselected patients undergoing incremental high‐flux hemodialysis or hemodiafiltration underwent limited overnight sleep study. Large subsets underwent echocardiography, interdialytic ambulatory blood pressure monitoring, and brain natriuretic peptide measurements. Patients were followed up to 44 months. Full sleep data were obtained in 91 patients. All had sleep disturbance as evidenced by an apnea–hypopnea index >5/min. We defined major obstructive sleep apnea (MOSA) as an apnea–hypopnea index ≥15, together with either significant oxygen desaturation or symptoms of daytime sleepiness. Forty patients met these criteria. Significant independent predictors of MOSA were age <65 years, male gender, has diabetes, and has a brain natriuretic peptide >2500 pg/mL. Mean ambulatory blood pressure and left ventricular mass index were significantly higher in these patients. In a model controlling for body mass index, high C‐reactive protein, and the presence of cancer, MOSA was associated with a twofold increased risk of mortality, although this did not reach statistical significance. MOSA was common, and was associated with hypertension and high left ventricular mass index. Whether obstructive sleep apnea contributes to the high mortality remains to be firmly established.     

Daily (quotidian) nocturnal home hemodialysis: Nine years later

Daily nocturnal home hemodialysis was developed to satisfy the need for a highly effective, smooth, and cost‐effective home dialysis therapy. It combines the benefits of the following dialysis methods: long, frequent, and home hemodialysis. It provides a high dialysis dose for small, as well as large, molecules including β₂‐microglobulin; improves quality if life; and leads to control of hyperphosphatemia without the need for phosphate binders, as well as dissolution for extraosseous calcifications. Furthermore, it controls blood pressure often without medications, is associated with regression of left ventricular hypertrophy, improves cardiac function, improves anemia as well as nutrition, allows an unrestricted diet, and corrects sleep apnea. Finally, it decreases the overall cost of patient care and improves cost utility when compared to conventional hemodialysis. The main obstacle to its wider utilization is the structure of the current reimbursement system. Along with short daily hemodialysis, long intermittent dialysis, and the convective dialysis techniques, daily nocturnal hemodialysis promises to improve dialysis outcomes.     

Effect of acetate-free biofiltration with a potassium-profiled dialysate on the control of cardiac arrhythmias in patients at risk: a pilot study

Cardiac arrhythmias are a frequent event in chronic hemodialysis patients. The aim of this study was to evaluate the efficacy and safety of acetate-free hemofiltration with potassium-profiled dialysate (AFB-K) dialysis compared with constant potassium acetate-free biofiltration (AFB). Twelve patients (mean age 79 years) affected by cardiac arrhythmias or at a high risk for arrhythmia (advanced age, hypertension, left ventricular hypertrophy, heart valve disease, coronary artery disease, diabetes, paroxysmal atrial fibrillation) participated in a single-center, sequential cohort study. All were treated with hemodialysis 3 times per week, using constant potassium AFB for the first 3 weeks, followed by an AFB-K dialysate for the subsequent 3 weeks. The hemofilter, duration of dialysis, and electrolyte concentration were the same in both treatments. Both AFB-K and constant potassium AFB dialytic techniques were safe and well tolerated. The results of biochemical tests were similar, except for serum potassium levels after 2 hr of dialysis, which were significantly higher in the AFB-K group (4.0 mmol/L) than in the constant potassium AFB group (3.6 mmol/L) (p<0.001). All cardiac variables improved during AFB-K dialysis. There was a significant reduction of postdialysis QT intervals corrected for heart rate in the AFB-K group (448.8 ms) compared with the constant potassium AFB group (456.8 ms) (p=0.039). The severity and mean number of ventricular extasystoles also decreased (163.5 vs. 444.5/24 hr). Potassium profiling during hemodialysis treatment may be beneficial for patients with arrhythmias or at those risk of arrhythmias, particularly those with predialysis hyperkalemia.     

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.