Intradialytic Blood Pressure Abnormalities: The Highs, The Lows and All That Lies Between

The Association Among Post-hemodialysis Blood Pressure, Nocturnal Hypertension, and Cardiovascular Risk Factors

Background

Most hemodialysis (HD) patients suffer from hypertension and have a heightened cardiovascular risk. While blood pressure (BP) control is essential to end-stage kidney disease (ESKD) patients, overly stringent control can lead to intradialytic hypotension (IDH). This study aimed to examine BP variations during and after HD to determine whether these variations correlate with IDH risk.

Methods

BP measurements during dialysis were taken from 28 ESKD patients, and ambulatory BP monitoring was applied post-dialysis. Laboratory parameters and risk factors, including diabetes, coronary disease, and LV mass index, were compared between IDH and non-IDH groups using an independent t-test.

Results

Of the 28 patients with an average age of 57.4 years, 16 (57.1%) had diabetes, 5 (17.9%) had coronary artery disease, and 1 (3.6%) had cerebrovascular disease. The mean systolic blood pressure (SBP) during and post-HD was 142.26 mmHg and 156.05 mmHg, respectively (p=0.0003). Similarly, the mean diastolic blood pressure (DBP) also demonstrated a significant increase, from 74.59 mmHg during HD to 86.82 mmHg post-HD (p<0.0001). Patients with IDH exhibited a more substantial SBP difference (delta SBP, 36.38 vs. 15.07 mmHg, p=0.0033; age-adjusted OR=1.58, p=0.0168) and a lower post-dialysis BUN level (12.75 vs. 18.77 mg/dL, p=0.0015; age-adjusted OR=0.76, p=0.0242). No significant variations were observed in daytime and nocturnal BP between the IDH and non-IDH groups.

Conclusion

Hemodialysis patients exhibited a marked increase in post-dialysis BP and lacked a nocturnal BP dip, suggesting augmented cardiovascular risks. This highlights the importance of more stringent BP control after hemodialysis.

Real-time dual prediction of intradialytic hypotension and hypertension using an explainable deep learning model

Both intradialytic hypotension (IDH) and hypertension (IDHTN) are associated with poor outcomes in hemodialysis patients, but a model predicting dual outcomes in real-time has never been developed. Herein, we developed an explainable deep learning model with a sequence-to-sequence-based attention network to predict both of these events simultaneously. We retrieved 302,774 hemodialysis sessions from the electronic health records of 11,110 patients, and these sessions were split into training (70%), validation (10%), and test (20%) datasets through patient randomization. The outcomes were defined when nadir systolic blood pressure (BP) < 90 mmHg (termed IDH-1), a decrease in systolic BP ≥ 20 mmHg and/or a decrease in mean arterial pressure ≥ 10 mmHg (termed IDH-2), or an increase in systolic BP ≥ 10 mmHg (i.e., IDHTN) occurred within 1 h. We developed a temporal fusion transformer (TFT)-based model and compared its performance in the test dataset, including receiver operating characteristic curve (AUROC) and area under the precision-recall curves (AUPRC), with those of other machine learning models, such as recurrent neural network, light gradient boosting machine, random forest, and logistic regression. Among all models, the TFT-based model achieved the highest AUROCs of 0.953 (0.952-0.954), 0.892 (0.891-0.893), and 0.889 (0.888-0.890) in predicting IDH-1, IDH-2, and IDHTN, respectively. The AUPRCs in the TFT-based model for these outcomes were higher than the other models. The factors that contributed the most to the prediction were age and previous session, which were time-invariant variables, as well as systolic BP and elapsed time, which were time-varying variables. The present TFT-based model predicts both IDH and IDHTN in real time and offers explainable variable importance.

Posterior reversible encephalopathy syndrome (PRES) associated with SARS-CoV-2 infection in a patient under maintenance haemodialysis: a case report

BACKGROUND

Endothelial dysfunction is common in patients undergoing chronic haemodialysis, and is a major cause of posterior reversible encephalopathy syndrome (PRES). Recently, Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been shown to cause endothelial dysfunction by infecting vascular endothelial cells. Several cases of neurological complications in patients without kidney dysfunction, and only a few cases in patients with chronic kidney disease, have been reported in the literature. However, no previous report has yet described PRES associated with SARS-CoV-2 infection among patients undergoing maintenance dialysis.

CASE PRESENTATION

A 54-year-old woman undergoing maintenance haemodialysis was admitted to our hospital for status epilepticus. She had developed end-stage kidney disease (ESKD) secondary to diabetic nephropathy. Seven days prior to admission, she had developed fever and was diagnosed with COVID-19. Subsequently her blood pressure increased from 160/90 mmHg to 190/100 mmHg. On admission, she presented with severe hypertension (> 220/150 mmHg), unconsciousness, and epilepticus. CT tomography revealed no signs of brain haemorrhage. Cranio-spinal fluid (CSF) examination revealed no signs of encephalitis, and CSF polymerase chain reaction (PCR) for SARS-CoV-2 was negative. MRI findings revealed focal T2/FLAIR hyperintensity in the bilateral parietooccipital regions, leading to the diagnosis of PRES. Deep sedation and strict blood pressure control resulted in a rapid improvement of her symptoms, and she was discharged without sequelae.

CONCLUSIONS

We report the first case of PRES associated with SARS-CoV-2 infection in a patient undergoing maintenance haemodialysis. Patients undergoing maintenance haemodialysis are at high risk of PRES because of several risk factors. SARS-CoV-2 infection causes direct invasion of endothelial cells by binding to angiotensin-converting enzyme 2 (ACE2), initiating cytokine release, and hypercoagulation, leading to vascular endothelial cell injury and increased vascular leakage. In the present case, SARS-CoV-2 infection possibly be associated with the development of PRES.

Current status of stroke in hemodialysis patients on a remote island

OBJECTIVES

Hemodialysis patients have a higher incidence of stroke than healthy individuals. Hemodialysis patients living on remote islands are subject to additional distance and transportation difficulties. Therefore, we aimed to study the association between stroke and hemodialysis in patients living on remote islands.

MATERIALS AND METHODS

We conducted a retrospective cohort study based on the medical records of maintenance hemodialysis patients in Shinkamigoto-Cho, Nagasaki, Japan, between June 1, 2005, and June 31, 2022. The clinical characteristics, probability of hemorrhagic stroke, acute ischemic stroke-free rate, and survival probability with or without a history of anticoagulant/antiplatelet use were evaluated. The survival probability among the hemorrhagic stroke, acute ischemic stroke, and non-stroke groups was also evaluated.

RESULTS

This study involved 142 patients. Nine patients (6.3%) had intracerebral hemorrhage, one (0.7%) had subarachnoid hemorrhage, eight (5.6%) had acute ischemic stroke, and 124 (87.3%) had no stroke. The number of patients with severe disabilities (modified Rankin Scale 5/6) was significantly higher in the hemorrhagic stroke group. The probability of hemorrhagic stroke and acute ischemic stroke-free rate, or survival probability with or without a history of anticoagulant/antiplatelet use, were not significantly different. The acute ischemic stroke group was not associated with a lower survival probability than the other groups. The hemorrhagic stroke group had a significantly lower survival probability than the acute ischemic stroke group.

CONCLUSIONS

This is the first study to report the status of stroke in hemodialysis patients living on remote islands, thus providing valuable information for improved stroke management in such patients.

The role of venous pressure variability during hemodialysis in the prediction of impending arteriovenous graft occlusion

BACKGROUND

Elevated venous pressure during hemodialysis (VPHD) is associated with arteriovenous graft (AVG) stenosis. This study investigated the role of VPHD variations in the prediction of impending AVG occlusion.

METHODS

Data were retrieved from 118 operations to treat AVG occlusion (occlusion group) and 149 operations to treat significant AVG stenosis (stenosis group). In addition to analyzing the VPHD values for the three hemodialysis (HD) sessions prior to the intervention, VPHD values were normalized to mean blood pressure (MBP), blood flow rate (BFR), BFR × MBP, and BFR2 × MBP to yield ratios for analysis. The coefficient of variation (CV) was used to measure relative variations.

RESULTS

The within-group comparisons for both groups revealed no significant differences in the VPHD mean and CV values among the three HD sessions prior to intervention. However, the CVs for VPHD/MBP, VPHD/(BFR × MBP), and VPHD/(BFR2 × MBP) exhibited significant elevation in the occlusion group during the last HD session prior to intervention compared with both the penultimate and antepenultimate within-group HD data (p < 0.05). In the receiver operating characteristic curve analysis, the CV for VPHD/(BFR2 × MBP) was the only parameter able to discriminate between the last and the penultimate HD outcomes (p < 0.001). According to a multivariate analysis, after controlling for covariates, CV for VPHD/(BFR2 × MBP) >8.76% was associated with a higher risk of AVG thrombosis (odds ratio: 3.17, p < 0.001).

CONCLUSIONS

Increasing the variation in VPHD/(BFR2 × MBP) may increase the probability of AVG occlusion.

Intra-dialytic blood pressure variability is a greater predictor of cardiovascular events in hemodialysis patients

BACKGROUND

Short-term and long-term blood pressure variability (BPV) in hemodialysis (HD) population are risk factors of cardiovascular diseases (CVD) and all-cause mortality. There is no full consensus on the best BPV metric. We compared the prognostic role of intra-dialytic and visit-to-visit BPV metrics for CVD morbidity and all-cause mortality in HD patients.

METHODS

A retrospective cohort of 120 patients on HD was followed up for 44 months. Systolic blood pressure (SBP) and baseline characteristics were collected for 3 months. We calculated intra-dialytic and visit-to-visit BPV metrics, including standard deviation (SD), coefficient of variation (CV), variability independent of the mean (VIM), average real variability (ARV) and residual. The primary outcomes were CVD events and all-cause mortality.

RESULTS

In Cox regression analysis, both intra-dialytic and visit-to-visit BPV metrics were associated with increased CVD events (intra-dialytic CV: HR 1.70, 95% CI 1.28-2.27, p < 0.01; visit-to-visit CV: HR 1.55, 95% CI 1.12-2.16, p < 0.01), but not associated with increased all-cause mortality (intra-dialytic CV: HR 1.32, 95% CI 0.99-1.76, p = 0.06; visit-to-visit CV: HR 1.22, 95% CI 0.91-1.63, p = 0.18). Overall, intra-dialytic BPV showed greater prognostic ability than visit-to-visit BPV for both CVD event (AUC of intra-dialytic BPV and visit-to-visit BPV metrics respectively: SD 0.686, 0.606; CV 0.672, 0.425; VIM 0.677, 0.581; ARV 0.684, 0.618; residual 0.652, 0.586) and all-cause mortality (SD 0.671, 0.608; CV 0.662, 0.575; VIM 0.669, 0.581; ARV 0.529, 0.588; residual 0.651, 0.602).

CONCLUSION

Compared to visit-to-visit BPV, intra-dialytic BPV is a greater predictor of CVD event in HD patients. No obvious priority was found among various BPV metrics.

The effect of food intake during hemodialysis on blood pressure: A nonrandomized experimental trial

BACKGROUND

Intradialytic hypotension (IDH) is one of the most important intradialytic complications and is thought to be associated with intradialytic food intake. Allowing intradialytic feeding is still unclear. This study aimed to determine the relationship between IDH and intradialytic food intake.

METHODS

A nonrandomized experimental study was conducted to determine the effect of intradialytic food intake on blood pressure (BP) in hemodialysis patients. Each patient was assessed twice using an ambulatory BP monitor with and without intradialytic food intake.

RESULTS

The study was completed with 54 patients. Intradialytic hypotension developed in 40 patients (74.1%) during the food intake session, while intradialytic hypotension developed in 22 participants (40%) in the no-food session. Repeated BP readings showed that eating 2 h or more after the start of hemodialysis significantly reduced BP.

CONCLUSIONS

Intradialytic food intake affects the development of IDH. Patients who ate during hemodialysis had a trend of higher of IDH than those who ate nothing during hemodialysis. Eating during dialysis is not recommended.

Sodium First Approach, to Reset Our Mind for Improving Management of Sodium, Water, Volume and Pressure in Hemodialysis Patients, and to Reduce Cardiovascular Burden and Improve Outcomes

New physiologic findings related to sodium homeostasis and pathophysiologic associations require a new vision for sodium, fluid and blood pressure management in dialysis-dependent chronic kidney disease patients. The traditional dry weight probing approach that has prevailed for many years must be reviewed in light of these findings and enriched by availability of new tools for monitoring and handling sodium and water imbalances. A comprehensive and integrated approach is needed to improve further cardiac health in hemodialysis (HD) patients. Adequate management of sodium, water, volume and hemodynamic control of HD patients relies on a stepwise approach: the first entails assessment and monitoring of fluid status and relies on clinical judgement supported by specific tools that are online embedded in the HD machine or devices used offline; the second consists of acting on correcting fluid imbalance mainly through dialysis prescription (treatment time, active tools embedded on HD machine) but also on guidance related to diet and thirst management; the third consist of fine tuning treatment prescription to patient responses and tolerance with the support of innovative tools such as artificial intelligence and remote pervasive health trackers. It is time to come back to sodium and water imbalance as the root cause of the problem and not to act primarily on their consequences (fluid overload, hypertension) or organ damage (heart; atherosclerosis, brain). We know the problem and have the tools to assess and manage in a more precise way sodium and fluid in HD patients. We strongly call for a sodium first approach to reduce disease burden and improve cardiac health in dialysis-dependent chronic kidney disease patients.

Using the Intelligent System to Improve the Delivered Adequacy of Dialysis by Preventing Intradialytic Complications

Acute kidney failure patients while detoxificated by hemodialysis (HD) mostly or continuously faced regular problems such as low blood pressure (hypotension), muscle cramps, nausea, or vomiting. Higher intradialytic symptom leads to low-quality HD treatment. Although more known therapeutic interventions are used to relieve the HD side effects, this study was designed to investigate how intelligent systems can make highly beneficial alterations in dialysis facilities and equipment to ease intradialytic complications and help the staff deliver high-quality treatment. A search was performed among relevant research articles based on nonpharmacological intervention methods considered to prevent adverse effects of renal replacement therapy until 2020 in the PubMed databases using the terms “intradialytic complications,” “intradialytic complication interventions,” “nonpharmacological interventions,” “intradialytic exercises,” and “adequacy calculation methods.” Studies included the prevalence of intradialytic complications, different strategies with the aim of preventing complications, the outcome of intradialytic exercises on dialysis symptoms, and dialysis dose calculation methods. The results showed the incidence of hypotension varying between 5% and 30%, fatigue, muscular cramps, and vomiting as the most common complications during dialysis, which greatly affect the outcome of HD sessions. To prevent hypotension, ultrafiltration profiling, sodium modeling, low dialysate temperature, and changing the position to Trendelenburg are some strategies. Urea reduction ratio (URR), formal urea kinetic modeling (FUKM), formal single-pool urea kinetics, and online clearance monitoring (OCM) are methods for calculating the delivered dose of dialysis in which OCM is a low-cost and accessible way to monitor regularly the quality of dialysis delivered. Integration of the chair and HD machine which is in direct contact with the patient provides an intelligent system that improves the management of the dialysis session to enhance the quality of healthcare service.

Comparison of hemodynamic instability among continuous, intermittent and hybrid renal replacement therapy in acute kidney injury: A systematic review of randomized clinical trials

PURPOSE

To compare hemodynamic instability during continuous, intermittent and hybrid renal replacement therapy (RRT) in critically ill patients, and its association with renal recovery and mortality.

MATERIALS AND METHODS

The search was conducted in accordance with the PRISMA guidelines which was registered at the PROSPERO Database (CRD42018086504). Randomized clinical trials (RCTs) involving critically ill patients with acute kidney injury (AKI) treated with continuous, intermittent or hybrid RRT were included. The search was performed using PubMed, Embase and Cochrane databases.

RESULTS

Out of 3442 citations retrieved, 12 RCTs were included in the systematic analysis, representing 1419 patients. Most studies (n = 8) did not report differences in hemodynamic parameters across different RTT modalities. The incidence of hypotensive episodes varied from 5 to 60% among the studies. Punctual differences on heart rate and blood pressure were observed among studies. However, studies presented high heterogeneity in terms of outcome definitions and measurement, thus making the conduction of meta-analysis impossible.

CONCLUSIONS

There is very few information available regarding hemodynamic tolerance of renal replacement therapy methods. A better standardization of hemodynamic tolerance and further reports are needed before conclusions can be drawn.

Reconsidering the Trendelenburg position during intradialytic hypotension

ABSTRACT

Intradialytic hypotension (IDH) is the most common complication that patients experience during hemodialysis. This article discusses IDH and its emergency management, focusing on Trendelenburg position, which may create more risks than benefits.

Dialysis-Associated Nonarteritic Anterior Ischemic Optic Neuropathy: A Case Series and Review

BACKGROUND

Dialysis-associated nonarteritic ischemic optic neuropathy (DA-NAION) occurs secondary to intradialytic hypotension often with catastrophic consequences and is one of the rare situations where NAION can recur in the same eye. We describe 3 cases of DA-NAION associated with hypotension, review the current literature on DA-NAION, and provide recommendations for decreasing the risk of intradialytic hypotension.

METHODS

In addition to describing 3 cases of DA-NAION, PubMed was searched for all reports of DA-NAION in adults with documented episodes of hypotension preceding the onset of NAION. A total of 50 eyes of 31 patients were included. Age, visual acuity at presentation, rate of bilateral involvement at presentation, sequential involvement of the fellow eye, and recurrence of NAION in the same eye were analyzed.

RESULTS

We found that most cases of DA-NAION occur in relatively young patients (47.7 ± 14.7 years) with a high rate of bilateral involvement at presentation (23%) and bilateral sequential involvement (39%). Vision loss is severe with 64% of patients presenting with 20/200 acuity or worse in the involved eye and 19% of patients with final visual acuity of 20/200 or worse in both eyes. 3 patients (9.7%) had recurrence of NAION in the previously affected eye.

CONCLUSIONS

Neuro-ophthalmologists have an important role in identifying patients who have suffered DA-NAION and communicating their findings to nephrologists to minimize the chance of involvement of the fellow eye and recurrence in the same eye. Intradialytic blood pressure must be closely monitored, and fluid balance, dialysate composition, and dialysis protocol must be optimized to prevent occurrence of intradialytic hypotension, which is the culprit for DA-NAION.

Association of Different Definitions of Intradialytic Hypertension With Long-Term Mortality in Hemodialysis

BACKGROUND

Hypertension is common in hemodialysis patients. A subset of patients experience systolic blood pressure increases from prehemodialysis to posthemodialysis (intradialytic hypertension), which are associated with adverse outcomes. However, little consensus exists on an evidence-based definition.

METHODS

In 3198 hemodialysis patients, Cox models were fit to examine the association of various definitions of intradialytic hypertension (≥30% of baseline sessions with an increase in prehemodialysis to posthemodialysis systolic blood pressure of (1) ≥0 mm Hg [Hyper0]; (2) ≥10 mm Hg [Hyper10], or (3) ≥20 mm Hg increase [Hyper20]) with all-cause mortality. Effect modification was assessed using interaction terms according to prespecified variables.

RESULTS

At baseline, mean age was 62±15 years, 57% were male, and 14% were Black. During the baseline period, 47% of individuals met the Hyper0 definition and experienced 32% (hazard ratio, 1.32 [95% CI, 1.05-1.66]) higher adjusted risk of death, compared with no systolic blood pressure increase. Hyper10 was present in 21.2% and associated with 18% higher adjusted risk of death (hazard ratio, 1.18 [95% CI, 0.94-1.48]). Hyper20 was present in 6.8% and associated with 3% higher adjusted risk of death (hazard ratio 1.03 [95% CI, 0.74-1.44]). Effect modification by age and peripheral vascular disease was observed (P interaction=0.04 for age and 0.02 for peripheral vascular disease), with higher associated risk of death for those aged 45 to 70 years and those without peripheral vascular disease.

CONCLUSIONS

Individuals with any systolic blood pressure increase from prehemodialysis to posthemodialysis had the highest adjusted risk of mortality, compared with other threshold-based definitions.

Pre-dialytic Systolic Blood Pressure is an Independent Predictor of Intradialytic Hypertension

BACKGROUND: Since endothelial dysfunction and activation of renin-angiotensin aldosterone system are the primary mechanism of intradialytic hypertension (IDHT), the assessment of pre dialytic blood pressure might provide an important information for the prediction of IDHT. OBJECTIVES: To assess the association between pre dialytic blood pressure and the risk of IDHT. METHODS: We conducted a cross-sectional study in Universitas Muhammadiyah Malang Hospital. The inclusion criteria were all hemodialysis patients aged more than 18 years, and the exclusion criteria were patients with hemodialysis duration of less than three months, patients with poor compliance to consume antihypertensive drugs, and hemodynamically unstable. The predictor variable was pre dialytic systolic blood pressure and the outcome was the incidence of IDHT. The association between pre dialytic blood pressure and the risk of IDHT was assessed using multiple logistic regression. RESULTS: A total of 36 patients with IDHT and 60 patients without IDHT was enrolled in our study. Our study identified that pre dialytic systolic blood pressure was associated with the risk of IDHT, with mean difference was 10.90 mmHg between patients with IDHT and without IDHT. Our study confirmed that the levels of pre dialytic systolic blood pressure 135 mmHg was the optimal cut off, and we found that patients with pre dialytic systolic blood pressure ≥ 135 mmHg had 4.60-fold to develop IDHT compared to patients with pre dialytic systolic blood pressure < 135 mmHg. CONCLUSION: Our study reveals that pre dialytic systolic blood pressure is an important predictor of IDHT.

Predicting factors of intradialytic hypotension in the last half of hemodialysis therapy

Background

Intradialytic hypotension (IDH) is one of the most frequent complications of hemodialysis. IDH alters a patient’s quality of life and has a strong association with mortality. IDH mainly occurs when ultrafiltration during hemodialysis exceeds the pace of the plasma refill. Ultrasonography has been used to evaluate the intravascular volume status. We evaluated the association between IDH and baseline laboratory data or ultrasound findings during IDH during the latter half of a hemodialysis session.

Methods

Sixty-two patients who underwent hemodialysis were enrolled in this study. The peak early mitral inflow wave velocity (peak E-velocity), the inferior vena cava (IVC) dimensions, and number of B-lines were estimated at two time points (just after the start and at the midpoint of the hemodialysis session). We compared the parameters between the patients without IDH throughout the hemodialysis session (non-IDH group) and patients with IDH only during the latter half of the hemodialysis session (IDH in the latter half group).

Results

Of the 62 study participants, 28 patients were in non-IDH group, and 16 patients were in IDH in the latter half group. The serum sodium level was significantly lower in the IDH in the latter half group (135 ± 4 mEq/L) than in the non-IDH group (138 ± 4 mEq/L) (P = 0.015). The rate of decrease of the peak E-velocity was significantly higher in the IDH in the latter half group (0.33 ± 0.13) than in the non-IDH group (0.24 ± 0.14) (P = 0.037). The best cutoff point of the serum level of sodium was 137 mEq/L, with a sensitivity of 68.8% and specificity of 64.3%. The area under the receiver operating characteristic (ROC) curve was 0.71. The best cutoff point of the rate of decrease of the peak E-velocity was 0.295, with a sensitivity of 73.3% and a specificity of 71.4%. The area under the ROC curve was 0.71.

Conclusions

A low serum level of sodium at baseline and an early decrease in the peak E-velocity during hemodialysis may be related to intradialytic hypotension in the latter half of a hemodialysis session. Careful observation may be needed in the hemodialysis patients in whom the serum level of sodium is below 137 mEq/L or the rate of decrease of the peak E-velocity is over 0.295.

High ultrafiltration rate induced intradialytic hypotension is a predictor for cardiac remodeling: a 5-year cohort study

BACKGROUND

Intradialytic-hypotension (IDH) is a common complication of hemodialysis. High ultrafiltration rate (UFR) might lead to IDH. However, the relationships between UFR, IDH, and cardiac remodeling among hemodialysis patients in the long-term have not been deeply explored.

METHODS

This retrospective cohort study collected clinical and echocardiographic data. Patients were enrolled from 1 January 2014 to 31 March 2014 and were followed-up for 5-year. Those who suffered from more than four hypotensive events during three months (10% of dialysis treatments) were defined as the IDH group. Subgroup analysis was done according to the UFR of 10 ml/h/kg. Associations between UFR, IDH, and alterations of cardiac structure/function were analyzed.

RESULTS

Among 209 patients, 96 were identified with IDH (45.9%). The survival rate of IDH patients was lower than that of no-IDH patients (65.5% vs. 81.4%, p = .005). In IDH group, decreased ejection fraction (EF), larger left atrium diameter index (LADI), and left ventricular mass index (LVMI) (p < .05) were observed at the end of the follow-up. In multivariate logistic model, the interaction between UFR and IDH was notably associated with LVMI variation (OR = 1.37). After adjusting covariates, UFR was still an independent risk factor of LVMI variation (OR = 1.52) in IDH group. In subsequent analysis, we divided patients according to UFR 10 ml/h/kg. For IDH-prone patients, decreased EF, larger LADI, and LVMI (p < .05) were observed at the end of the study only in high-UFR group.

CONCLUSIONS

UFR and IDH have interactions on cardiac remodeling. High ultrafiltration rate induced IDH is a predictor for cardiac remodeling in long-term follow-up.

Assessment of cerebral oxygenation response to hemodialysis using near-infrared spectroscopy (NIRS): Challenges and solutions

To date, the clinical use of functional near-infrared spectroscopy (NIRS) to detect cerebral ischemia has been largely limited to surgical settings, where motion artifacts are minimal. In this study, we present novel techniques to address the challenges of using NIRS to monitor ambulatory patients with kidney disease during approximately eight hours of hemodialysis (HD) treatment. People with end-stage kidney disease who require HD are at higher risk for cognitive impairment and dementia than age-matched controls. Recent studies have suggested that HD-related declines in cerebral blood flow might explain some of the adverse outcomes of HD treatment. However, there are currently no established paradigms for monitoring cerebral perfusion in real-time during HD treatment. In this study, we used NIRS to assess cerebral hemodynamic responses among 95 prevalent HD patients during two consecutive HD treatments. We observed substantial signal attenuation in our predominantly Black patient cohort that required probe modifications. We also observed consistent motion artifacts that we addressed by developing a novel NIRS methodology, called the HD cerebral oxygen demand algorithm (HD-CODA), to identify episodes when cerebral oxygen demand might be outpacing supply during HD treatment. We then examined the association between a summary measure of time spent in cerebral deoxygenation, derived using the HD-CODA, and hemodynamic and treatment-related variables. We found that this summary measure was associated with intradialytic mean arterial pressure, heart rate, and volume removal. Future studies should use the HD-CODA to implement studies of real-time NIRS monitoring for incident dialysis patients, over longer time frames, and in other dialysis modalities.

A maintenance hemodialysis mortality prediction model based on anomaly detection using longitudinal hemodialysis data

BACKGROUND

Most end-stage renal disease patients rely on hemodialysis (HD) to maintain their life, and they face a serious financial burden and high risk of mortality. Due to the current situation of the health care system in China, a large number of patients on HD are lost to follow-up, making the identification of patients with high mortality risks an intractable problem.

OBJECTIVE

This paper aims to propose a maintenance HD mortality prediction approach using longitudinal HD data under the situation of data imbalance caused by follow-up losses.

METHODS

A long short-term memory autoencoder (LSTM AE) based model is proposed to capture the physical condition changes of HD patients and distinguish between surviving and nonsurviving patients. The approach adopts anomaly detection theory, using only the surviving samples in the model training and identifying dead samples based on autoencoder reconstruction errors. The data are from a Chinese hospital electronic health record system between July 30, 2007, and August 25, 2016, and 36/72/108 continuous HD sessions were used to predict mortality within prediction windows of 90/180/365 days. Furthermore, the model performance is compared to that of logistic regression, support vector machine, random forest, LSTM classifier, isolation forest, and stacked autoencoder models.

RESULTS

Data for 1200 patients (survival: 1055, death: 145) were used to predict mortality during the next 90 days using 36 continuous HD sessions. The area under the PR curve for the LSTM AE was 0.57, the Recall_macro was 0.86, and the F1-score_macro was 0.87, outperforming the other models. Upon varying the observation window or prediction window length, LSTM AE continued to outperform the other models. According to the variable importance analysis, the dialysis session length was the feature that contributed the most to the prediction model.

CONCLUSIONS

The proposed approach was able to detect patients on maintenance HD with high mortality risk from an imbalanced dataset using anomaly detection theory and leveraging longitudinal HD data.

Pro-inflammatory cytokines as potential predictors for intradialytic hypotension

Background

Intradialytic hypotension (IDH) is a common complication in maintaining hemodialysis (MHD) patients. Immune activation might be part of the mechanisms. However, the association between pro-inflammatory cytokines and blood pressure (BP) has not been deeply explored. So we aim to evaluate the potential role of pro-inflammatory cytokines in IDH.

Methods

MHD patients starting hemodialysis before January 2016 were enrolled in our retrospective study. Patients' characteristics, laboratory results, and intradialytic BP were collected. IDH was defined as nadir systolic BP ≤ 90 mmHg during hemodialysis. The definition of IDH group was that those who suffered from more than one hypotensive event during one month after the enrollment (10% of dialysis treatments). Spearman correlation analysis and logistic regression were employed to explore the relationship between pro-inflammatory cytokines and IDH.

Results

Among 390 patients, 72 were identified with IDH (18.5%). High levels of serum tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were observed in the IDH group (p < 0.001). Both TNF-α and IL-1β positively correlated with predialysis BP (p < 0.01). Receiver operating characteristic curve (ROC) analysis was used to evaluate the diagnostic accuracy of serum IL-1β and TNF-α for IDH. The area under the curve of IL-1β was 0.772 (95% CI: 0.708-0.836, p < 0.01), and that of TNF-α was 0.701 (95% CI: 0.620-0.781, p < 0.01). After adjusting for patients' characteristics, biochemical parameters, comorbid conditions, predialysis BP, and medications, elevated TNF-α and IL-1β were still risk factors for IDH.

Conclusion

Pro-inflammatory cytokines (TNF-α and IL-1β) could be potential predictors for IDH.

Endothelin-1 and Parameters of Systolic Blood Pressure in Hemodialysis

BACKGROUND

Hypertension is common in hemodialysis (HD) patients. Increased blood pressure (BP) variability, particularly higher and lower extremes, is associated with adverse outcomes. We explored the association of endothelin-1 (ET-1), a potent vasoconstrictor, with different BP parameters (pre-HD, intra-HD, and post-HD) during HD in a contemporary patient cohort.

METHODS

This study uses the DaVita Biorepository, a longitudinal prospective cohort study with quarterly collection of clinical data and biospecimens. Unadjusted and adjusted linear mixed effects regression models were fit to determine association of pre-HD ET-1 (log-transformed and quartiles) with HD-related systolic BP (SBP) parameters (pre-HD, nadir intra-HD, and post-HD). As ET-1 was measured at baseline, analyses were restricted to 1 year of follow-up.

RESULTS

Among 769 participants, mean age was 52 years, 42% were females, and 41% were Black. Mean pre-HD SBP was 152 (±28) mm Hg and mean ET-1 concentration was 2.3 (±1.2) ng/ml. In fully adjusted models, each unit increase in SD of log-transformed ET-1 was associated with a 2.7 (95% confidence interval [CI] 1.5, 4.0) mm Hg higher pre-SBP; 1.6 (95% CI 0.9, 2.3) mm Hg higher nadir SBP; and 2.0 (95% CI 1.1, 2.9) mm Hg higher post-SBP. Each SD increase in log-transformed ET-1 was associated with 21% higher odds of experiencing intradialytic hypertension (odds ratio 1.21; 95% CI 1.10-1.34).

CONCLUSIONS

Higher baseline ET-1 levels are independently associated with higher SBP and higher odds of intradialytic hypertension. These results highlight a potential role for ET-1 in BP control in HD patients and raise the possibility of ET-1 antagonism as a therapeutic target.

Intravenous Albumin for Mitigating Hypotension and Augmenting Ultrafiltration during Kidney Replacement Therapy

Among its many functions, owing to its oversized effect on colloid oncotic pressure, intravascular albumin helps preserve the effective circulatory volume. Hypoalbuminemia is common in hospitalized patients and is found especially frequently in patients who require KRT either for AKI or as maintenance hemodialysis. In such patients, hypoalbuminemia is strongly associated with morbidity, intradialytic hypotension, and mortality. Intravenous albumin may be administered in an effort to prevent or treat hypotension or to augment fluid removal, but this practice is controversial. Theoretically, intravenous albumin administration might prevent or treat hypotension by promoting plasma refilling in response to ultrafiltration. However, clinical trials have demonstrated that albumin administration is not nearly as effective a volume expander as might be assumed according to its oncotic properties. Although intravenous albumin is generally considered to be safe, it is also very expensive. In addition, there are potential risks to using it to prevent or treat intradialytic hypotension. Some recent studies have suggested that hyperoncotic albumin solutions may precipitate or worsen AKI in patients with sepsis or shock; however, the overall evidence supporting this effect is weak. In this review, we explore the theoretical benefits and risks of using intravenous albumin to mitigate intradialytic hypotension and/or enhance ultrafiltration and summarize the current evidence relating to this practice. This includes studies relevant to its use in patients on maintenance hemodialysis and critically ill patients with AKI who require KRT in the intensive care unit. Despite evidence of its frequent use and high costs, at present, there are minimal data that support the routine use of intravenous albumin during KRT. As such, adequately powered trials to evaluate the efficacy of intravenous albumin in this setting are clearly needed.

Dialysis unit blood pressure two hours after hemodialysis is useful for predicting home blood pressure and ambulatory blood pressure in maintenance hemodialysis patients

This study aimed to determine which BP measurement obtained in the HD unit correlated best with home BP and ambulatory BP monitoring (ABPM). We retrospectively analyzed data from 40 patients that received maintenance HD who had available home BP and ABPM data. Dialysis unit BPs were the averages of pre-, 2hr- (2 h after starting HD), and post-HD BP during a 9-month study. Home BP was defined as the average of morning and evening home BPs. Dialysis unit BP and home BP were compared over the 9-month study period. ABPM was performed once for 24 h in the absence of dialysis during the final 2 weeks of the study period and was compared to the 2-week dialysis unit BP and home BP. There was a significant difference between dialysis unit systolic blood pressure (SBP) and home SBP over the 9-month period. No significant difference was observed between the 2hr-HD SBP and home SBP. When analyzing 2 weeks of dialysis unit BP and home BP, including ABPM, SBPs were significantly different (dialysis unit BP > home BP > ABPM; P = 0.009). Consistent with the 9-month study period, no significant difference was observed between 2hr-HD SBP and home SBP (P = 0.809). The difference between 2hr-HD SBP and ambulatory SBP was not significant (P = 0.113). In conclusion, the 2hr-HD SBP might be useful for predicting home BP and ABPM in HD patients.

Intradialytic systolic blood pressure variation can predict long-term mortality in patients on maintenance hemodialysis

PURPOSE

It is unclear which time-points of intradialytic blood pressure (BP) best predict prognosis. Thus, it is important to assess the association between different time-points of intradialytic BP and prognosis in clinical practice.

METHODS

We recruited patients who underwent hemodialysis from January 2014 to June 2014. Data about dialysis were collected, including intradialytic BP. Cox regression analysis was performed to examine the association between different time-points of intradialytic BP and clinical events, with a follow-up through December 31, 2019. The primary endpoint was all-cause mortality.

RESULTS

A total of 216 patients were recruited and 62 (30.7%) patients died (6.1 per 100-person year) during the follow-up. Intradialytic SBP varied greatly in fatalities. Univariate and multivariate Cox regression models indicated that the adjusted hazard ratio for death was 1.80 and 5.06 when intradialytic systolic blood pressure (SBP) variation was analyzed in increments of 20 mmHg. Furthermore, we divided intradialytic SBP variation into three categories: < 15 mmHg, 15 ~ 30 mmHg,  ≥ 30 mmHg. Kaplan-Meier analysis indicated that both all-cause mortality and cardiovascular mortality increased significantly for patients with intradialytic SBP variation over 30 mmHg (P = 0.006 and 0.021). Univariate and multivariate Cox regression models indicated that the adjusted hazard ratio for death was 3.78 and 12.62 as intradialytic SBP variation ≥ 30 mmHg vs. intradialytic SBP variation < 15 mmHg.

CONCLUSION

Intradialytic SBP variation, rather than BP of specific intradialytic time-points, has the potential to predict long-term mortality in hemodialysis patients. BP stability is crucial for patients' prognosis.

Treating Home Versus Predialysis Blood Pressure Among In-Center Hemodialysis Patients: A Pilot Randomized Trial

RATIONALE & OBJECTIVE

Observational studies have reported a U-shaped association between blood pressure (BP) before a hemodialysis session and death. In contrast, because a linear association between out-of-dialysis-unit BP and death has been reported, home BP may be a better target for treatment. To test the feasibility of this approach, we conducted a pilot trial of treating home versus predialysis BP in hemodialysis patients.

STUDY DESIGN

A 4-month, parallel, randomized, controlled trial.

SETTINGS & PARTICIPANTS

50 prevalent hemodialysis patients in San Francisco and Seattle. Participants were randomly assigned using 1:1 block randomization, stratified by site.

INTERVENTIONS

To target home systolic BP (SBP) of 100-<140 mm Hg versus predialysis SBP of 100-<140mm Hg. Home and predialysis SBPs were ascertained every 2 weeks. Dry weight and BP medications were adjusted to reach the target SBP.

OUTCOMES

Primary outcomes were feasibility, adherence, safety. and tolerability.

RESULTS

50 of 70 (71%) patients who were approached agreed to participate. All enrollees completed the study except for 1 who received a kidney transplant. In the home BP treatment group, adherence to obtaining/reporting home BP was 97.4% (and consistent over the 4 months). There was no increased frequency of high (defined as SBP>200mm Hg; 0.2% vs 0%) or low (defined as<90mm Hg; 1.8% vs 1.2%) predialysis BP readings in the home versus predialysis treatment arms, respectively. However, participants in the home BP arm had higher frequency of fatigue (32% vs 16%).

LIMITATIONS

Small sample size.

CONCLUSIONS

This pilot trial demonstrates feasibility and high adherence to home BP measurement and treatment in hemodialysis patients. Larger trials to test the long-term feasibility, efficacy, and safety of home BP treatment in hemodialysis patients should be conducted.

FUNDERS

National Institutes of Health, Satellite Healthcare, and Northwest Kidney Centers.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov with study number NCT03459807.

A Feasibility Study of Non-Invasive Continuous Estimation of Brachial Pressure Derived From Arterial and Venous Lines During Dialysis

Objective: Intradialytic haemodynamic instability is a significant clinical problem, leading to end-organ ischaemia and contributing to morbidity and mortality in haemodialysis patients. Non-invasive continuous blood pressure monitoring is not currently part of routine practice but may aid detection and prevention of significant falls in blood pressure during dialysis. Brachial blood pressure is currently recorded intermittently during haemodialysis via a sphygmomanometer. Current methods of continuous non-invasive blood pressure monitoring tend to restrict movement, can be sensitive to external disturbances and patient movement, and can be uncomfortable for the wearer. Additionally, poor patient blood circulation can lead to unreliable measurements. In this feasibility study we performed an initial validation of a novel method and associated technology to continuously estimate blood pressure using pressure sensors in the extra-corporeal dialysis circuit, which does not require any direct contact with the person receiving dialysis treatment. Method: The paper describes the development of the measurement system and subsequent in vivo patient feasibility study with concurrent measurement validation by Finapres Nova physiological measurement device. Real-time physiological data is collected over the entire period of (typically 4-hour) dialysis treatment. Results: We identify a quasi-linear mathematical function to describe the relationship between arterial line pressure and brachial artery BP, which is confirmed in a patient study. The results from this observational study suggest that it is feasible to derive a continuous measurement of brachial pressure from continuous measurements of arterial and venous line pressures via an empirically based and updated mathematical model. Conclusion: The methodology presented requires no interfacing to proprietary dialysis machine systems, no sensors to be attached to the patient directly, and is robust to patient movement during treatment and also to the effects of the cyclical pressure waveforms induced by the hemodialysis peristaltic blood pump. This represents a key enabling factor to the development of a practical continuous blood pressure monitoring device for dialysis patients.

Predictive modeling of blood pressure during hemodialysis: a comparison of linear model, random forest, support vector regression, XGBoost, LASSO regression and ensemble method

BACKGROUND

Intradialytic hypotension (IDH) is commonly occurred and links to higher mortality among patients undergoing hemodialysis (HD). Its early prediction and prevention will dramatically improve the quality of life. However, predicting the occurrence of IDH clinically is not simple. The aims of this study are to develop an intelligent system with capability of predicting blood pressure (BP) during HD, and to further compare different machine learning algorithms for next systolic BP (SBP) prediction.

METHODS

This study presented comprehensive comparisons among linear regression model, least absolute shrinkage and selection operator (LASSO), tree-based ensemble machine learning models (random forest [RF] and extreme gradient boosting [XGBoost]), and support vector regression to predict the BP during HD treatment based on 200 and 48 maintenance HD patients containing a total of 7,180 and 2,065 BP records for the training and test dataset, respectively. Ensemble method also was computed to obtain better predictive performance. We compared the developed models based on R², root mean square error (RMSE) and mean absolute error (MAE).

RESULTS

We found that RF (R²=0.95, RMSE=6.64, MAE=4.90) and XGBoost (R²=1.00, RMSE=1.83, MAE=1.29) had comparable predictive performance on the training dataset. However, RF (R²=0.49, RMSE=16.24, MAE=12.14) had more accurate than XGBoost (R²=0.41, RMSE=17.65, MAE=13.47) on testing dataset. Among these models, the ensemble method (R²=0.50, RMSE=16.01, MAE=11.97) had the best performance on testing dataset for next SBP prediction.

CONCLUSIONS

We compared five machine learning and an ensemble method for next SBP prediction. Among all studied algorithms, the RF and the ensemble method have the better predictive performance. The prediction models using ensemble method for intradialytic BP profiling may be able to assist the HD staff or physicians in individualized care and prompt intervention for patients' safety and improve care of HD patients.

Intradialytic hypotension and associated factors among patients on maintenance hemodialysis: A single-center study in cameroon

Intradialytic hypotension (IDH), one of the most frequent acute complications of hemodialysis (HD), is associated with increased patient's morbidity and mortality. The aim of this study was to determine its prevalence and associated factors among patients on maintenance HD in Cameroon. This was a prospective longitudinal study carried out from June 20, to July 30, 2016 (5 weeks), including adult patients on HD >3 months at a tertiary hospital in Douala. During this period, patients were followed up at each HD session, and their blood pressure and occurrence of clinical events possibly related to IDH were recorded. In this study, IDH was defined as a decrease in systolic BP by >20 mm Hg or a decrease in mean arterial pressure by >10 mm Hg, associated to a clinical event. Logistic regression analysis was used to determine associated factors. We included 104 patients (69 males) with a mean age of 50.74 ± 15.18 years and a median duration on HD of 30.5 (interquartile range: 12.25-58.75) years. Hypertension 99/104 (95.2%) and diabetes 32/104 (30.8%) were the main comorbidities encountered. A total of 1032 HD sessions were followed up with an average of 9.88 ± 1.57 sessions per patient. IDH occurred in 11.6% of HD sessions. Associated factors were age, female sex, HIV infection, feeding during dialysis, and use of antihypertensive drug during or within 2 h before dialysis. The prevalence of IDH in our study was low. Associated factors were mainly related to patient's characteristics and comorbidities.

Impacts of Coronary Artery Calcification on Intradialytic Blood Pressure Patterns in Patients Receiving Maintenance Hemodialysis

Intradialytic blood pressure abnormalities are associated with adverse outcomes in patients with end-stage renal disease on dialysis. Vascular calcification is a common complicating feature, but whether this complication results in intradialytic blood pressure abnormalities remains uncertain. Therefore, this study investigated the relationship between coronary artery calcium score and intradialytic blood pressure abnormalities in patients with end-stage renal disease on maintenance hemodialysis. Thirty-six patients who received nongated chest computed tomography scans were included. Intradialytic hypotension was defined as a minimum intradialytic systolic blood pressure of <100 mmHg or a pre-dialysis blood pressure – minimum intradialytic systolic blood pressure >30 mmHg. Intradialytic hypertension was defined as >10 mmHg increase in systolic blood pressure (pre- to post-dialysis). Patients were classified as 22 (61.1%) with coronary artery calcium score <400 and 14 (38.9%) with coronary artery calcium score ≥400. Median systolic and diastolic blood pressures were equivalent, but median pulse pressure was higher in patients with coronary artery calcium score ≥400 than in those with scores <400. Coronary artery calcium score was comparable according to both intradialytic hypotension and hypertension, and had no correlation with systolic blood pressure fall and nadir systolic blood pressure. Coronary artery calcium score predicted the occurrence of cardiovascular events and all-cause mortality (hazard ratio 1.001 and 1.001; p=0.058 and 0.010). Coronary vascular calcification could be irrelevant to intradialytic blood pressure abnormalities in patients with end-stage renal disease on dialysis.

Association between Mean Heart Rate and Recurrence Quantification Analysis of Heart Rate Variability in End-Stage Renal Disease

Linear heart rate variability (HRV) indices are dependent on the mean heart rate, which has been demonstrated in different models (from sinoatrial cells to humans). The association between nonlinear HRV indices, including those provided by recurrence plot quantitative analysis (RQA), and the mean heart rate (or the mean cardiac period, also called meanNN) has been scarcely studied. For this purpose, we analyzed RQA indices of five minute-long HRV time series obtained in the supine position and during active standing from 30 healthy subjects and 29 end-stage renal disease (ESRD) patients (before and after hemodialysis). In the supine position, ESRD patients showed shorter meanNN (i.e., faster heart rate) and decreased variability compared to healthy subjects. The healthy subjects responded to active standing by shortening the meanNN and decreasing HRV indices to reach similar values of ESRD patients. Bivariate correlations between all RQA indices and meanNN were significant in healthy subjects and ESRD after hemodialysis and for most RQA indices in ESRD patients before hemodialysis. Multiple linear regression analyses showed that RQA indices were also dependent on the position and the ESRD condition. Then, future studies should consider the association among RQA indices, meanNN, and these other factors for a correct interpretation of HRV.

Intradialytic Symptoms and Recovery Time in Patients on Thrice-Weekly In-Center Hemodialysis: A Cross-sectional Online Survey

Rationale & Objective

Patients experience various symptoms during hemodialysis. We aimed to assess the frequency and severity of symptoms during hemodialysis and whether intradialytic symptoms are associated with recovery time postdialysis.

Study Design

An online questionnaire was sent to 10,000 patients in a National Kidney Foundation database.

Setting & Participants

Adult patients receiving in-center hemodialysis 3 times weekly for 3 or more months.

Exposure

Online questionnaire.

Analytic Approach

Tabulation of frequency and severity of events and recovery time as percent of respondents, construction of a total symptom score, followed by rank correlation analysis of symptom characteristics with total recovery time.

Outcomes

Patient-reported intradialytic symptoms and recovery time postdialysis.

Results

359 patients met screening criteria and completed the questionnaire. Mean age was 62.5 ± 13.8 years, 207 (58%) were men, 74 (21%) were black/African American, 132 (37%) had diabetes, 252 (70%) had hypertension, and 102 (28%) had a history of myocardial infarction, heart surgery, or stent placement. 311 (87%) patients had symptoms during dialysis in the previous week, with mean severity of 2.7 (range for each symptom, 1-5). The most common symptoms were fatigue/feeling washed out (62%), cramps (44%), and symptoms of low blood pressure (42%). Median time to recovery was 3 (range, 0-24) hours, and this correlated with the incidence and severity of intradialytic symptoms (P < 0.0001). 40% of patients had time to recovery times of 4 hours or longer. 1 in 3 patients reported having stopped dialysis early for intradialytic symptoms and 6% reported skipping dialysis at least once because of intradialytic symptoms.

Limitations

Recall-based self-reported data with a relatively low response rate.

Conclusions

A majority of patients receiving in-center hemodialysis experience symptoms such as feeling washed out, fatigue, and cramping; these may be severe and are correlated with longer recovery time following hemodialysis, as well as shortened and skipped hemodialysis sessions.

The relationship of volume overload and its control to hypertension in hemodialysis patients

Hypertension is highly prevalent and associated with poor clinical outcomes among individuals receiving maintenance hemodialysis (HD). Volume overload is a key modifiable contributor to hypertension and cardiovascular disease in the HD population. Despite their importance, assessment and treatment of volume overload and hypertension remain major clinical challenges and have substantial implications for both clinical outcomes and patient experiences of care. This review will summarize current data on the diagnosis, epidemiology, pathophysiology, and clinical consequences of hypertension and volume overload in HD patients. We will also identify priorities for future research studies.

Feeding during dialysis-risks and uncertainties

Allowing dialysis patients to eat during the treatment is controversial. It is, therefore, no surprise that practices and policies with respect to intradialytic food consumption vary considerably from unit to unit and from country to country. Those who defend the position of feeding during dialysis reason that intradialytic meals offer a supervised and effective therapy for protein-energy wasting. Those who take the opposite view argue that intradialytic food intake should be avoided for the following three reasons. First, interventional studies show that eating during dialysis causes a clinically significant reduction in systemic blood pressure during the postprandial period and elevates the risk of symptomatic intradialytic hypotension; the latter is associated with increased mortality risk. Second, clinical studies have shown that eating during dialysis interferes with the adequacy of the delivered dialysis, whereas eating 2-3 h before the dialysis session has no impact on the efficiency of the subsequent dialysis treatment. And third, randomized studies show that eating during dialysis focus on the positive outcomes but do not adequately balance this potential benefit against the risk of intradialytic hemodynamic instability and poor quality of delivered dialysis. Even after half a century of providing long-term dialysis, definitive randomized trials that balance risks and benefits of eating during dialysis are missing. These knowledge gaps require randomized trials. Since there is a real possibility of harm with eating during dialysis, we caution that instead of encouraging the widespread use of intradialytic meals, practices and policies should focus on adequate nutrient intake during the interdialytic interval.

Intradialytic hypertension is associated with low intradialytic arterial oxygen saturation

Background

The pathophysiology of a paradoxical systolic blood pressure (SBP) rise during hemodialysis (HD) is not yet fully understood. Recent research indicated that 10% of chronic HD patients suffer from prolonged intradialytic hypoxemia. Since hypoxemia induces a sympathetic response we entertained the hypothesis that peridialytic SBP change is associated with arterial oxygen saturation (SaO2).

Methods

We retrospectively analyzed intradialytic SaO2 and peridialytic SBP change in chronic HD patients with arteriovenous vascular access. Patients were followed for 6 months. We defined persistent intradialytic hypertension (piHTN) as average peridialytic SBP increase ≥10 mmHg over 6 months. Linear mixed effects (LME) models were used to explore associations between peridialytic SBP change and intradialytic SaO2 in univariate and adjusted analyses.

Results

We assessed 982 patients (29 872 HD treatments; 59% males; 53% whites). Pre-dialysis SBP was 146.7 ± 26.5 mmHg and decreased on average by 10.1 ± 24.5 mmHg. Fifty-three (5.7%) patients had piHTN. piHTN patients had lower intradialytic SaO2, body weight and interdialytic weight gain. LME models revealed that with every percentage point lower mean SaO2, the peridialytic SBP change increased by 0.46 mmHg (P < 0.001). This finding was corroborated in multivariate analyses.

Conclusion

We observed an inverse relationship between intradialytic SaO2 and the blood pressure response to HD. These findings support the notion that hypoxemia activates mechanisms that partially blunt the intradialytic blood pressure decline, possibly by sympathetic activation and endothelin-1 secretion. To further explore that hypothesis, specifically designed prospective studies are required.

Intradialysis blood pressure changes among chronic kidney disease patients on maintenance haemodialysis in a tertiary hospital south - south Nigeria: a 2 year retrospective study

Introduction

Haemodialysis (HD) which is a form of renal replacement therapy commonly prescribed for patients with chronic kidney disease (CKD). However, it is not without deleterious haemodynamic responses which may occur either during or immediately after the termination of the procedure. These may include hypotension or hypertension.

Methods

This was a retrospective study that reviewed chronic kidney disease (CKD) patients on maintenance haemodialysis at the renal unit of University of Calabar Teaching Hospital, Calabar, Nigeria. In all, 71 patients were reviewed but only 64 patients had complete data for analysis. Socio-demographic, clinical and biochemical data were obtained from the records in the dialysis unit.

Results

There were more males 38 (59.4%) than females 26 (40.6%) in the study. The mean age was 51.71±15.43 years and 43.04±14.03years for males and females respectively. The prevalence of intradialysis hypertension 29 (45.3%) was higher than that of intradialysis hypotension 20 (31.3%) and the commonest cause of CKD requiring haemodialysis was diabetic nephropathy. The factors associated with intradialysis hypotension were lower post-dialysis systolic blood pressure (PDSBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and less number of antihypertensive medications; while the factors associated with intradialysis hypertension were higher post-dialysis systolic blood pressure (SBP), MAP, greater number of antihypertensive medications and longer duration of haemodialysis.

Conclusion

Our study shows that there are several modifiable factors associated with blood pressure fluctuations among CKD patients on maintenance haemodialysis in the renal unit of the University of Calabar Teaching Hospital, Calabar.

The Prevalence of Intradialytic Hypotension in Patients on Conventional Hemodialysis: A Systematic Review with Meta-Analysis

BACKGROUND

Intradialytic hypotension (IDH) is considered to be a frequent complication of hemodialysis (HD) and is associated with symptom burden, increased incidence of access failure, cardiovascular events, and higher mortality. This systematic literature review aims to analyse studies that investigated the prevalence of IDH. A complicating factor herein is that many different definitions of IDH are used in literature.

METHODS

A systematic literature search from databases, Medline, Cinahl, EMBASE, and the Cochrane library to identify studies reporting on the actual prevalence of IDH was conducted. Studies were categorized by the type of definition used for the prevalence of IDH. A meta-analysis of the prevalence of IDH was performed.

RESULTS

In a meta-analysis comprising 4 studies including 1,694 patients and 4 studies including 13,189 patients, the prevalence of HD sessions complicated by IDH was 10.1 and 11.6% for the European Best Practice Guideline (EBPG) definition and the Nadir <90 definition, respectively. The proportion of patients with frequent IDH could not reliably be established because of the wide range in cutoff values that were used to identify patients with frequent IDH. There was a large variety in the prevalence of symptoms and interventions. Major risk factors associated with IDH across studies were diabetes, a higher interdialytic weight gain, female gender, and lower body weight.

CONCLUSION

Our meta-analysis suggests that the prevalence of IDH is lower than 12% for both the EBPG and the Nadir <90 definition which is much lower than stated in most reviews.

Timing of blood pressure medications and intradialytic hypotension

Intradialytic hypotension (IDH) is a prevalent yet serious complication of hemodialysis, associated with decreased quality of life, inadequate dialysis, vascular access thrombosis, global hypoperfusion, and increased cardiovascular and all-cause mortality. Current guidelines recommend antihypertensive medications be given at night and held the morning of dialysis for affected patients. Despite little evidence to support this recommendation, more than half of patients on dialysis may employ some form of this method. In this article, we will review the available evidence and clinical considerations regarding timing of blood pressure medications and occurrence of IDH, and conclude that witholding BP medications before hemodialysis should not be a routine practice.

Intradialytic hypotension, blood pressure changes and mortality risk in incident hemodialysis patients

Background

Intradialytic hypotension (IDH) occurs frequently in maintenance hemodialysis (HD) patients and may be associated with higher mortality. We hypothesize that nadir intradialytic systolic blood pressure (niSBP) is inversely related to death risk while iSBP change (Δ) and IDH frequency are incrementally associated with all-cause mortality.

Methods

In a US-based cohort of 112 013 incident HD patients over a 5-year period (2007-11), using niSBP, ΔiSBP (pre-HD SBP minus niSBP) and IDH frequency (proportion of HD treatments with niSBP <90 mmHg) within the first 91 days of HD, we examined mortality-predictability at 1, 2 and 5 years using Cox models and restricted cubic splines adjusted for case-mix, comorbidities and laboratory covariates.

Results

We observed that niSBP of <90 and ≥140 mmHg had a 5-year mortality hazard ratio (HR) (95% confidence interval) of 1.57 (1.47-1.67) and 1.25 (1.18-1.33), respectively, compared with niSBP 110 to <120 mmHg. ΔiSBP of <15 and ≥50 compared with 21-30 mmHg had mortality HR of 1.31 (1.26-1.37) and 1.32 (1.24-1.39), respectively. Among patients with >40% IDH frequency, we observed a mortality HR of 1.49 (1.42-1.57) compared with 0% IDH frequency in fully adjusted models. These associations were robust at 1 and 2 years of follow-up.

Conclusion

In conclusion, we observed a U-shaped association between niSBP and ΔiSBP and mortality and a direct linear relationship between IDH frequency and mortality. Our findings lend some prognostic insight of HD blood pressure and hemodynamics, and have the potential to guide blood pressure management strategies among the HD population.

Cycles, Arrows and Turbulence: Time Patterns in Renal Disease, a Path from Epidemiology to Personalized Medicine?

Patients with end-stage renal disease (ESRD) experience unique patterns in their lifetime, such as the start of dialysis and renal transplantation. In addition, there is also an intricate link between ESRD and biological time patterns. In terms of cyclic patterns, the circadian blood pressure (BP) rhythm can be flattened, contributing to allostatic load, whereas the circadian temperature rhythm is related to the decline in BP during hemodialysis (HD). Seasonal variations in BP and interdialytic-weight gain have been observed in ESRD patients in addition to a profound relative increase in mortality during the winter period. Moreover, nonphysiological treatment patters are imposed in HD patients, leading to an excess mortality at the end of the long interdialytic interval. Recently, new evidence has emerged on the prognostic impact of trajectories of common clinical and laboratory parameters such as BP, body temperature, and serum albumin, in addition to single point in time measurements. Backward analysis of changes in cardiovascular, nutritional, and inflammatory parameters before the occurrence as hospitalization or death has shown that changes may already occur within months to even 1-2 years before the event, possibly providing a window of opportunity for earlier interventions. Disturbances in physiological variability, such as in heart rate, characterized by a loss of fractal patterns, are associated with increased mortality. In addition, an increase in random variability in different parameters such as BP and sodium is also associated with adverse outcomes. Novel techniques, based on time-dependent analysis of variability and trends and interactions of multiple physiological and laboratory parameters, for which machine-learning -approaches may be necessary, are likely of help to the clinician in the future. However, upcoming research should also evaluate whether dynamic patterns observed in large epidemiological studies have relevance for the individual risk profile of the patient.

Effects of acute intradialytic exercise on cardiovascular responses in hemodialysis patients

BACKGROUND

In patients with kidney failure requiring hemodialysis (HD) treatment, intradialytic exercise (IDEX) has been advocated for its feasibility and effectiveness in improving important health outcomes. However, IDEX as an adjunct therapeutic strategy is infrequently implemented, in part due to potential risks of IDEX, especially in patients with chronic volume overload. This study was performed to evaluate the safety of IDEX performed at different time points by examining its effect on intradialytic cardiovascular hemodynamics.

METHODS

In a randomized cross-over study (n = 12), intradialytic changes in brachial, aortic, and cardiac hemodynamics and autonomic function were examined during a HD session; (1) without exercise; (2) with 30 min of IDEX performed in the first hour of treatment; or (3) with 30 min of IDEX in the third hour of treatment.

RESULTS

IDEX during either the first or third hour did not exacerbate hemodynamic instability during treatment regardless of patient's hydrations status. While there were transient increases in stroke volume, cardiac output, and heart rate during IDEX, intradialytic changes in brachial and aortic blood pressure, cardiac hemodynamics, and autonomic function were similar on days with and without IDEX.

CONCLUSION

These results indicate that IDEX does not exacerbate hemodynamic instability during HD, regardless of a patient's hydration status or the timing of exercise.

Impact of intradialytic blood pressure changes on cardiovascular outcomes is independent of the volume status of maintenance hemodialysis patients

Intradialytic systolic blood pressure (SBP) changes are related to the volume status; however, whether SBP change impacts on adverse outcomes depends on the volume status remains uncertain. We retrospectively investigated the relationship among intradialytic changes in SBP, cardiovascular outcomes, and volume status in maintenance hemodialysis patients. We determined SBP changes (ΔSBP) as postdialysis SBP minus predialysis SBP and volume status as the ratio of extracellular water to total body water (ECW/TBW) using bioelectrical impedance analysis. There were 82 (60.3%) with ΔSBP -20 to 10 mm Hg, 21 (15.4%) with ΔSBP ≤ -20 mm Hg, and 33 (24.3%) with ΔSBP ≥ 10 mm Hg, and they were followed up for a median of 34 months. Cardiovascular events more frequently occurred in the patients with ΔSBP ≤ -20 mm Hg and ≥ 10 mm Hg (hazard ratio: 2.3 and 3.0; P = .062 and .006); these associations persisted even after adjusting for postdialysis ECW/TBW (P = .056 and .028). Moreover, ΔSBP ≥ 10 mm Hg was associated with increased cardiovascular mortalities independent of postdialysis ECW/TBW (P = .043). There was an independent association of volume status between considerable SBP decrease or increase during hemodialysis and adverse cardiovascular outcomes. Besides appropriate volume control, other factors related to BP changes during hemodialysis must be investigated.

The Association between Intradialytic Hypertension and Metabolic Disorders in End Stage Renal Disease

Background

Intradialytic hypertension was associated with a high mortality risk. We examined the relationship between intradialytic hypertension and metabolic disorders in hemodialysis treatment patients.

Methods

We studied 76 patients in online hemodiafiltration. Dialysis adequacy was defined by Kt/V for urea. Normalized protein catabolic rate (nPCR), as a marker of protein intake, was calculated. Sodium removal was determined as percent sodium removal. Metabolic acidosis was determined by serum bicarbonate less than 22 mmol/L. Interdialytic urine volume more than 100 ml was recorded. Intradialytic hypertension was defined by an increase in systolic blood pressure equal to 10 mmHg from pre- to posthemodialysis. Arterial stiffness was assessed as carotid-femoral pulse wave velocity (c-fPWV) and carotid augmentation index (AIx). Chi-square tests and logistic regression analysis were applied for intradialytic hypertension prediction.

Results

Patients with intradialytic hypertension were older and had significantly lower hemoglobin, nPCR, urine output, and serum bicarbonate and significantly higher c-fPWV, though similar Kt/V for urea, than patients without intradialytic hypertension. They also had increased sodium removal and pulse pressure related to less urine output. Serum bicarbonate was inversely associated with c-fPWV (r = -0.377, p = 0.001). Chi-square test showed significant association between intradialytic hypertension and serum bicarbonate < 22 mmol/L (x² = 5.6, p = 0.01), which was supported by an adjusted model.

Conclusion

The intradialytic hypertension was significantly associated with metabolic disorders including malnutrition/inflammation and uncontrolled metabolic acidosis in hemodialysis treatment patients. Severe metabolic acidosis may reflect sodium imbalance and hemodynamic instability of these patients resulting in volume overload and increased vascular resistance.

Intradialytic blood pressure pattern recognition based on density peak clustering

End-stage renal disease (ESRD) is the final stage of chronic kidney disease (CKD) and requires hemodialysis (HD) for survival. Intradialytic blood pressure (IBP) measurements are necessary to ensure patient safety during HD treatments and have critical clinical and prognostic significance. Studies on IBP measurements, especially IBP patterns, are limited. All related studies have been based on a priori knowledge and artificially classified IBP patterns. Therefore, the results were influenced by subjective concepts. In this study, we proposed a new approach to identify IBP patterns to classify ESRD patients. We used the dynamic time warping (DTW) algorithm to measure the similarity between two series of IBP data. Five blood pressure (BP) patterns were identified by applying the density peak clustering algorithm (DPCA) to the IBP data. To illustrate the association between BP patterns and prognosis, we constructed three random survival forest (RSF) models with different covariates. Model accuracy was improved 3.7-6.3% by the inclusion of BP patterns. The results suggest that BP patterns have critical clinical and prognostic significance regarding the risk of cerebrovascular events. We can also apply this clustering approach to other time series data from electronic health records (EHRs). This work is generalizable to analyses of dense EHR data.

Treatment of intradialytic hypotension with an herbal acupoint therapy in hemodialysis patients: A randomized pilot study

OBJECTIVE

Hypotension during hemodialysis (HD) is the most common complication that negatively affects the quality of life of patients. The objective of the current study was to evaluate the preliminary efficacy and safety of herbal acupoint therapy (HAT) for intradialytic hypotension (IDH).

METHODS

A randomized, placebo-controlled trial was performed in 32 HD patients to determine whether HAT was more effective than a sham treatment for the treatment of IDH. The outcomes were frequency of IDH episodes and number of nursing interventions during HD sessions, pre- and post-dialysis BP, subjective change in fatigue as measured by the Visual Analogue Scale (VAS), and recovery time from fatigue after dialysis at the 0th and 4th week. Data analyses were performed using per-protocol population.

RESULTS

In all, 27 patients (84%) completed the entire study. At the end of the intervention, the patients in the HAT group were found to have a significantly lower frequency of IDH episodes, fewer nursing interventions, a lower intervention failure rate, and earlier discontinuation of dialysis than those in the sham group (p < .05). The improvement in degree of fatigue (p = .001) was greater and recovery time from fatigue after dialysis (p = .03) was shorter in the group treated with HAT than in the sham group. HAT was safe, with 2 withdrawal cases due to local erythema caused by the patch.

CONCLUSIONS

HAT appears to be safe and efficacious for improving IDH-related symptoms and intervention in HD patients. Larger studies are needed to confirm the benefit of this technique for IDH.

Pathophysiology and implications of intradialytic hypertension

PURPOSE OF REVIEW

Intradialytic hypertension occurs regularly in 10--15% of hemodialysis patients. A large observational study recently showed that intradialytic hypertension of any magnitude increased mortality risk comparable to the most severe degrees of intradialytic hypotension. The present review review discusses the most recent evidence underlying the pathophysiology of intradialytic hypertension and implications for its management.

RECENT FINDINGS

Patients with intradialytic hypertension typically have small interdialytic weight gains, but bioimpedance spectroscopy shows these patients have significant chronic extracellular volume excess. Intradialytic hypertension patients have lower albumin and predialysis urea nitrogen levels, which may contribute to small reductions in osmolarity that prevents blood pressure decreases. Intradialytic vascular resistance surges remain implicated as the driving force for blood pressure increases, but mediators other than endothelin-1 may be responsible. Beyond dry weight reduction, the only controlled intervention shown to interrupt the blood pressure increase is lowering dialysate sodium.

SUMMARY

Patients with recurrent intradialytic hypertension should be identified as high-risk patients. Dry weight should be re-evaluated, even if patients do not clinically appear volume overloaded. Antihypertensive drugs should be prescribed because of the persistently elevated ambulatory blood pressure. Dialysate sodium reduction should be considered, although the long term effects of this intervention are uncertain.

Intradialytic Hypertension Frequency and Short-Term Clinical Outcomes Among Individuals Receiving Maintenance Hemodialysis

BACKGROUND

Intradialytic hypertension occurs in 5-20% of hemodialysis treatments. Observational data support an association between intradialytic hypertension and long-term mortality. However, the short-term consequences of recurrent intradialytic hypertension are unknown.

METHODS

Data were taken from a cohort of prevalent hemodialysis patients receiving treatment at a large United States dialysis organization on 1 January 2010. A retrospective cohort design with a 180-day baseline, 30-day exposure assessment, and 30-day follow-up period was used to estimate the associations between intradialytic hypertension frequency and 30-day outcomes. Intradialytic hypertension frequency was defined as the proportion of exposure period hemodialysis treatments with a predialysis to postdialysis systolic blood pressure rise >0 mm Hg. Multivariable Cox proportional hazards regression, adjusted for baseline clinical, laboratory, and dialysis treatment covariates, was used to estimate hazard ratios and 95% confidence intervals.

RESULTS

Of the 37,094 study patients, 5,242 (14.1%), 17,965 (48.4%), 10,821 (29.2%), 3,066 (8.3%) had intradialytic hypertension in 0%, 1-32%, 33-66%, and ≥67% of exposure period treatments, respectively. More frequent intradialytic hypertension was associated with incremental increases in 30-day mortality and hospitalizations. Patients with intradialytic hypertension in ≥67% (vs. 0%) of exposure period treatments had the highest risk of all-cause death, hazard ratio [95% confidence interval]: 2.57 [1.68, 3.94]; cardiovascular (CV) death, 3.68 [1.89, 7.15]; all-cause hospitalizations, 1.42 [1.26, 1.62]; CV hospitalizations, 1.71 [1.36, 2.15]; and volume-related hospitalizations, 2.25 [1.25, 4.04].

CONCLUSIONS

Among prevalent hemodialysis patients, more frequent intradialytic hypertension was incrementally associated with increased 30-day morbidity and mortality. Intradialytic hypertension may be an important short-term risk marker in the hemodialysis population.