Evidence for the prevention and treatment of stroke in dialysis patients

Research progress on the kidney-gut-brain axis in brain dysfunction in maintenance hemodialysis patients

Maintenance hemodialysis (MHD) has become the primary renal replacement therapy for patients with end-stage renal disease. The kidney-gut-brain axis represents a communication network connecting the kidney, intestine and brain. In MHD patients, factors such as uremic toxins, hemodynamic changes, vascular damage, inflammation, oxidative stress, and intestinal dysbiosis in MHD patients refers to a range of clinical syndromes, including brain injury, and is manifested by conditions such as white matter disease, brain atrophy, cerebrovascular disease, cognitive impairment, depression, anxiety, and other behavioral or consciousness abnormalities. Numerous studies have demonstrated the prevalence of these brain disorders in MHD patients. Understanding the mechanisms of brain disorders in MHD patients, particularly through the lens of kidney-gut-brain axis dysfunction, offers valuable insights for future research and the development of targeted therapies. This article reviews the brain dysfunction associated with MHD, the impact of the kidney-brain axis, intestinal barrier damage, gut microbiota dysbiosis caused by MHD, and the role of the gut-brain axis in brain dysfunction.

Mediatory role of the serum mineral level and discharge disability of stroke survivors

Background

Possible association between minerals contributing and mortality related to stroke were seen, but prospective data on the relation of vitamin D, magnesium and calcium serum levels with stroke were inconsistent. Consideration about the potential health effects of minerals and nutrients, the current study was conducted.

Methods

This analytical cross-sectional study was conducted on 216 stroke survivors who were referred to the Ayatollah Rouhani Hospital of Babol, Iran. Demographic characteristics, clinical variables, and serum mineral levels were completed in the checklist. Admit score and discharge scale of these patients were determined according to the National Institute of Health Stroke Scale. A path model was constructed to explore the interrelationship between variables and to verify the relationship between variables and disability discharges.

Results

Of 216 stroke patients, 185 (85.6%) cases were ischemic. The discharge status of 29 (12.9%) cases were severe or expired. The patients with moderate and severe admit scores, hemorrhagic stroke type, diabetes mellitus, hypertension and live in the village significantly had a poor discharge disability scale (all of p<0.05). Of all direct paths, Mg (β=-2.85), and among indirect paths, calcium(β=-3.59) had the highest effect on the discharge scale. Only mg had affected the discharge scale through direct and indirect (β=-2.45) paths and had the greatest reverse effect on the discharge scale (β=-5.30; totally).

Conclusion

Hypomagnesemia and hypocalcemia play a mediatory role in poor outcomes. Especially, hypomagnesemia was the direct parameter for poor outcomes. The independent role of each mineral in this issue is difficult to define and suggested for future study.

Stroke Subtype Among Individuals With Chronic Kidney Disease

Background

It is widely accepted that there is a stepwise increase in the risk of acute ischemic stroke with chronic kidney disease (CKD). However, whether the risk of specific ischemic stroke subtypes varies with CKD remains unclear.

Objective

To assess the association between ischemic stroke subtypes (cardioembolic, arterial, lacunar, and other) classified using the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) and CKD stage.

Design

retrospective cohort study.

Setting

Ontario, Canada.

Patients

A total of 17 434 adults with an acute ischemic stroke in Ontario, Canada between April 1, 2002 and March 31, 2013, with an estimated glomerular filtration rate (eGFR) measurement or receipt of maintenance dialysis captured in a stroke registry were included.

Measurements

Kidney function categorized as an eGFR of ≥60, 30-59, <30 mL/min/1.73 m2, or maintenance dialysis. Ischemic stroke classified by TOAST included arterial, cardioembolic, lacunar, and other (dissection, prothrombotic state, cortical vein/sinus thrombosis, and vasculitis) types of strokes.

Methods

Adjusted regression models.

Results

In our cohort, 58.9% had an eGFR of ≥60, 34.7% an eGFR of 30-59, 6.0% an eGFR of <30 and 0.5% were on maintenance dialysis (mean age of 73 years; 48% women). Cardioembolic stroke was more common in patients with non-dialysis-dependant CKD (eGFR 30-59: 50.4%, adjusted odds ratio [OR] 1.20, 95% confidence interval [CI]: 1.02, 1.44; eGFR<30: 50.6%, OR 1.21, 95% CI: 1.02, 1.44), whereas lacunar stroke was less common (eGFR 30-59: 22.7% OR 0.85, 95% CI: 0.77, 0.93; eGFR <30: 0.73, 95% CI: 0.61, 0.88) compared with those with an eGFR ≥60. In stratified analyses by age and CKD, lacunar strokes were more frequent in those aged less than 65 years, whereas cardioembolic was higher in those aged 65 years and above.

Limitations

TOAST classification was not captured for all patients.

Conclusion

Non-dialysis CKD was associated with a higher risk of cardioembolic stroke, whereas an eGFR ≥60 mL/min/1.73 m2 was associated with a higher risk of lacunar stroke. Detailed stroke subtyping in CKD may therefore provide mechanistic insights and refocus treatment strategies in this high-risk population.

Implementation of a coagulation component into a phosphate kinetics model in haemodialysis therapy: A tool for detection of clotting problems?

A coagulation component should be considered in phosphate kinetics modelling because intradialytic coagulation of the extracorporeal circuit and dialyser might reduce phosphate removal in haemodialysis. Thus, the objective of this study was to add and evaluate coagulation as an individual linear clearance reduction component to a promising three-compartment model assuming progressive intradialytic clotting. The model was modified and validated on intradialytic plasma and dialysate phosphate samples from 12 haemodialysis patients collected during two treatments (HD1 and HD2) at a Danish hospital ward. The most suitable clearance reduction in each treatment was identified by minimizing the root mean square error (RMSE). The model simulations with and without clearance reduction were compared based on RMSE and coefficient of determination (R2 ) values. Improvements were found for 17 of the 24 model simulations when clearance reduction was added to the model. The slopes of the clearance reduction were in the range of 0.011-0.632/h. Three improvements were found to be statistically significant (|observed z value| > 1.96). A very significant correlation (R2  = 0.708) between the slopes for HD1 and HD2 was found. Adding the clearance reduction component to the model seems promising in phosphate kinetics modelling and might be explained, at least in part, by intradialytic coagulation. In future studies, the model might be developed further to serve as a potentially useful tool for the quantitative detection of clotting problems in haemodialysis. NEW FINDINGS: What is the central question of this study? The aim was to add an intradialytic coagulation component to a modified version of a promising three-compartment phosphate kinetics model. The hypothesis was that circuit and dialyser clotting can be modelled by an individual linear phosphate clearance reduction component during haemodialysis treatment. What is the main finding and its importance? Improvements were found for 17 of 24 model simulations when clearance reduction was added to the model. Thus, the kinetics model seems promising and could be a useful tool for the quantitative detection of clotting problems in haemodialysis patients.

Left atrial appendage closure in end-stage renal disease and hemodialysis: Data from a German multicenter registry

BACKGROUND

Left atrial appendage closure (LAAC) has emerged as an alternative to oral anticoagulation (OAC) for stroke prevention in patients with atrial fibrillation (AF). OAC treatment has been proven feasible in mild-to-moderate chronic kidney disease (CKD). In contrast, the optimal antithrombotic management of AF patients with end-stage renal disease (ESRD) is unknown and LAAC has not been proven in these patients in prospective randomized clinical trials.

OBJECTIVES

The objective of this study is to evaluate safety and efficacy of LAAC in patients with ESRD.

METHODS

Patients undergoing LAAC were collected in a German multicenter real-world observational registry. A composite endpoint consisting of the occurrence of ischemic stroke/transient ischemic attack, systemic embolism, and/or major clinical bleeding was assessed. Patients with ESRD were compared with propensity score-matched patients without severe CKD. ESRD was defined as a glomerular filtration rate < 15 ml/min/1.73 m² or chronic hemodialysis treatment.

RESULTS

A total of 604 patients were analyzed, including 57 with ESRD and 57 propensity-matched patients. Overall, 596 endocardial and 8 epicardial LAAC procedures were performed. Frequency of major complications was 7.0% (42/604 patients) in the overall cohort, 8.8% (5/57 patients) in patients with ESRD, and 10.5% (6/57 patients) in matched controls (p = 0.75). The estimated event-free survival of the combined endpoint after 500 days was 90.7 ± 4.5% in patients with ESRD and 90.2 ± 5.5% in matched controls (p = 0.33).

CONCLUSIONS

LAAC had comparable procedural safety and clinical efficacy in patients with ESRD and patients without severe CKD.

Risk factors for intracerebral hemorrhage in patients undergoing maintenance hemodialysis

Background

In patients undergoing hemodialysis, intracerebral hemorrhage (ICH) is the main cause of mortality among stroke subtypes. It is unclear whether, along with traditional cardiovascular risk factors, the risk factors unique to the uraemic environment, such as the abnormal metabolism of intact parathyroid hormone (iPTH), can contribute to the risk of ICH in these patients.

Methods

This retrospective case-control study included 25 patients undergoing hemodialysis with ICH at a single center between 30 June 2015 and 10 October 2022. The controls were 95 patients undergoing maintenance hemodialysis treated at the same dialysis center in July 2020. We compared the characteristics of patients with ICH with those of the control group to identify factors that contributed to the development of ICH.

Results

Intracerebral hemorrhage (ICH) was located in the basal ganglia (14/25), cerebellum (6/25), and brainstem (6/25) in 25 patients. A total of 17 patients died in the first 16 days due to neurological complications. Univariate analysis showed significant differences in systolic BP, diastolic BP, iPTH, and alkaline phosphatase between the two groups (p < 0.05). Multivariate logistic regression analysis showed that higher systolic BP (OR, 1.053; 95% CI, 1.018-1.090; p = 0.003) and higher iPTH (OR, 1.007; 95% CI, 1.003-1.012; p = 0.001) were associated with the onset of ICH. ICH was predicted by systolic BP and iPTH by receiver operating characteristic (ROC) curve analysis, with areas under the curve (AUCs) of 0.732 and 0.624, respectively. The optimal cutoffs for systolic BP and iPTH were 151.9 mmHg and 295.4 pg./ml, respectively. Restricted cubic spline showed that the shape of the association of iPTH with the risk of ICH was approximately J-shaped (P for non-linearity <0.05).

Conclusion

Higher systolic BP and abnormal iPTH metabolism might be associated with ICH in patients undergoing hemodialysis. Comprehensive control of hypertension and iPTH may be a fundamental preventive strategy for ICH in these patients.

Endovascular salvage of thrombosed haemodialysis vascular access

Background: Haemodialysis access thrombosis is associated with significant morbidity and access abandonment rates, for which endovascular salvage is a well described treatment option. This study aimed to evaluate the outcomes of endovascular salvage procedures of thrombosed vascular access circuits and identify factors influencing outcomes. Patients and methods: Retrospective review of 328 consecutive procedures performed over 10 years at our institution between January 2010 and December 2019. Patient demographics, access circuit characteristics, procedure details and outcome data were collected. Kaplan-Meier survival curves were used to estimate patency rates and Cox multivariate regression analysis to identify factors affecting outcomes. Results: Technical and clinical success rates were 87.8% and 75.9% respectively. The primary, primary assisted and secondary patency rates at 6 months were 42.2%, 46.7% and 59.1%; and at 12 months were 23.4%, 28.3% and 41.8% respectively. Median access circuit survival was 9.2 months. Major complication rate was 5.2% including 3 procedure-related deaths. Native AVF, lower time from thrombosis to intervention and pharmacomechanical thrombectomy using AngioJet^TM predicted positive outcomes. Previous thrombectomy within 3 months and residual thrombus at completion were associated with poorer outcomes. Age and hypertension predicted higher complication rates. Conclusions: This is one of the largest single center series of endovascular salvage of thrombosed haemodialysis access and demonstrates that endovascular treatment is effective and provides durable access circuit survival. Careful patient screening is essential to optimize outcomes.

Cerebrovascular Disease, Cardiovascular Disease, and Chronic Kidney Disease: Interplays and Influences

PURPOSE OF REVIEW

We reviewed reasons for the high cardiovascular risk (CVD) of patients with chronic kidney disease (CKD), and explored alternatives to treatment of traditional risk factors to reduce CVD in CKD.

RECENT FINDINGS

Besides traditional risk factors, patients with CKD are exposed to uremic toxins of two kinds: systemically derived toxins include asymmetric dimethylarginine (ADMA), total homocysteine (tHcy), thiocyanate, tumor necrosis factor alpha, and interleukin 6. Gut-derived uremic toxins (GDUT), products of the intestinal microbiome, include hippuric acid, indoxyl sulfate, p-cresyl sulfate, p-cresyl glucuronide, phenylacetylglutamine, and trimethylamine N-oxide (TMAO). Cyanocobalamin is toxic in patients with CKD. Approaches to reducing plasma levels of these uremic toxins would include diet to reduce GDUT, kidney transplantation, more intensive dialysis, and vitamin therapy to lower tHcy with methylcobalamin rather than cyanocobalamin. The high CVD risk in CKD requires consideration of therapies beyond treatment of traditional risk factors.

Characteristics and Prognosis of Stroke in Living Donor Renal Transplant Recipients

Aims: We aimed to determine the characteristics and vascular outcomes of stroke in renal transplant (RT) recipients and compare them with those in patients on hemodialysis (HD) and those with no renal replacement therapy (RRT).

Methods: In this prospective observational study, 717 patients (mean age, 70.8 years; male, 60.5%) with acute ischemic stroke within one week of onset were consecutively enrolled and followed for one year. The patients were classified into three groups: (1) living donor RT recipients (n=27); (2) patients on maintenance HD before the index stroke (n=39); and (3) those with no history of RRT (n=651). The primary outcome was a composite of major adverse cardiovascular events (MACE).

Results: Diabetic nephropathy was the most common reason for RRT in both RT and HD patients. RT patients were more likely to have embolic stroke of undetermined source (33.3%) than others, whereas HD patients more often had cardioembolism (51.3%). No difference was observed in the MACE risk between the patients in RT and non-RRT groups (annual rate, 11.3% vs. 13.1%; log-rankP=0.82; hazard ratio [95% confidence interval], 0.92 [0.29-2.98]). In contrast, HD patients had a greater risk of MACE than those with no RRT (annual rate, 28.2% vs. 13.1%; log-rankP=0.019; hazard ratio [95% confidence interval], 2.24 [1.16-4.3]).

Conclusions: The underlying etiologies of stroke differed in RT and HD patients. The one-year risk of MACE for stroke patients who had received an RT was lower than that for patients undergoing HD and comparable with that of patients with no RRT.

Stroke in Hemodialysis Patients Randomized to Different Intravenous Iron Strategies: A Prespecified Analysis from the PIVOTAL Trial

Background

People with kidney failure treated with hemodialysis (HD) are at increased risk of stroke compared with similarly aged people with normal kidney function. One concern is that treatment of renal anemia might increase stroke risk. We studied risk factors for stroke in a prespecified secondary analysis of a randomized, controlled trial of intravenous iron treatment strategies in HD.

Methods

We analyzed data from the Proactive IV Iron Therapy in Haemodialysis Patients (PIVOTAL) trial, focusing on variables associated with risk of stroke. The trial randomized 2141 adults who had started HD <12 months earlier and who were receiving an erythropoiesis-stimulating agent (ESA) to high-dose IV iron administered proactively or low-dose IV iron administered reactively in a 1:1 ratio. Possible stroke events were independently adjudicated. We performed analyses to identify variables associated with stroke during follow-up and assessed survival following stroke.

Results

During a median 2.1 years of follow-up, 69 (3.2%) patients experienced a first postrandomization stroke. Fifty-seven (82.6%) were ischemic strokes, and 12 (17.4%) were hemorrhagic strokes. There were 34 postrandomization strokes in the proactive arm and 35 postrandomization strokes in the reactive arm (hazard ratio, 0.90; 95% confidence interval, 0.56 to 1.44; P=0.66). In multivariable models, women, diabetes, history of prior stroke at baseline, higher baseline systolic BP, lower serum albumin, and higher C-reactive protein were independently associated with stroke events during follow-up. Hemoglobin, total iron, and ESA dose were not associated with risk of stroke. Fifty-eight percent of patients with a stroke event died during follow-up compared with 23% without a stroke.

Conclusions

In patients on HD, stroke risk is broadly associated with risk factors previously described to increase cardiovascular risk in this population. Proactive intravenous iron does not increase stroke risk.Clinical Trial registry name and registration number: Proactive IV Iron Therapy in Haemodialysis Patients (PIVOTAL), 2013-002267-25.

Controversies: Stroke Prevention in Chronic Kidney Disease

Risk of both ischemic and hemorrhagic stroke is increased in the chronic kidney disease (CKD) population, particularly in end-stage kidney disease patients. Uremic factors that contribute to stroke risk include blood pressure variability, vascular calcification, build-up of vascular toxins, chronic inflammation, platelet dysfunction and increased brain microbleeds. This paper discusses the controversial evidence for stroke prevention strategies including blood pressure control, statins, antiplatelet agents, and anticoagulation in the CKD population. Only a few randomized clinical trials included patients with advanced CKD, thus evidence is derived mostly from observational cohorts and real-world data. Overall, targeting a lower systolic blood pressure below 120 mmHg and statin prescription do not appear to decrease stroke risk in CKD. Antiplatelet agents have not shown a clear benefit for secondary stroke prevention, but aspirin may reduce incident stroke in hypertensive CKD stage 3B-5 patients. Observational data suggests that the factor Xa inhibitor apixaban has a favorable profile over warfarin in dialysis patients with atrial fibrillation; apixaban being associated with lower stroke risk and fewer major bleeding events.

Predictive value of ankle-brachial index for long-term events of ischemic stroke in hemodialysis patients

OBJECTIVES

The ankle-brachial index is a noninvasive modality to evaluate atherosclerosis and is a predictive role for future cardiovascular events and mortality. However, few studies have evaluated its relation to long-term future ischemic stroke in hemodialysis patients. Therefore, we examined the relationship between ankle-brachial index and ischemic stroke events among hemodialysis patients in a seven-year follow-up.

METHODS

A total of 84 patients were enrolled. Ankle-brachial index was assessed in January 2009. Primary outcomes included ischemic stroke. An ankle-brachial index < 0.9 was considered abnormal and 1.4 ≥ ankle-brachial index ≥ 0.9 to be normal ankle-brachial index.

RESULTS

Mean values for ankle-brachial index were 0.98 ± 0.21at study entrance. In addition, 28 patients encountered ischemic stroke in the seven-year follow-up. In univariate Cox regression analysis, old age (hazard ratio (HR): 1.065, 95% confidence interval (CI): 1.030-1.102, p < 0.001), low seven-year averaged serum phosphate levels (HR: 0.473, 95% CI: 0.306-0.730, p = 0.001), and abnormal ankle-brachial index (HR: 0.035, 95% CI: 0.009-0.145, p < 0.001) were risk factors for ischemic stroke. In multivariate Cox regression analysis for significant variables in univariate analysis, abnormal ankle-brachial index (HR: 0.058, 95% CI: 0.012-0.279, p < 0.001) and low seven-year averaged serum phosphate levels (HR: 0.625, 95% CI: 0.404-0.968, p = 0.035) remained the risk factors for ischemic stroke. The risk of ischemic stroke was 3.783-fold in patients with abnormal ankle-brachial index compared with patients with normal ankle-brachial index (HR: 3.783, 95% CI: 1.731-8.269, p = 0.001).

CONCLUSIONS

These findings suggest that ankle-brachial index is an impressive predictor of future ischemic stroke among hemodialysis patients.

The efficacy of rehabilitation for elderly hemodialysis patients: a retrospective, single center study

INTRODUCTION

Chronic kidney disease is associated with an increased risk of vascular events and bone fractures, and its prevalence is increasing. Despite the high frequency of strokes and bone fractures in the hemodialysis (HD) population, the few studies on rehabilitation outcomes in this population are controversial. The current study assessed the efficacy of inpatient rehabilitation for hemodialysis patients.

METHODS

This is a retrospective, observational review of medical records of all chronic HD patients who underwent rehabilitation in Meir Medical Center, from 2008 to 2018. The primary endpoint was functional independence measure (FIM) score at discharge. Secondary endpoints were all-cause mortality, efficiency of rehabilitation and discharge destination from rehabilitation.

RESULTS

During the study period, 162 patients were included in the analysis. 76/81 (93.8%) hemodialysis patients had improvement FIM scores. There were no significant differences in FIM scores at discharge between hemodialysis patients and controls. However, the efficiency of rehabilitation expressed by FIM efficiency (progress measured as FIM gain/length of stay in rehabilitation) was higher in hemodialysis vs. controls. 73% of hemodialysis patients were discharged home. There was no significant difference in discharge destinations between groups. Both 30-day and 1-year mortality after admission to rehabilitation was higher in HD vs. controls (OR 4.97, 95% CI 1.4-18.2, p = 0.008 and OR 4.98, 95% CI 1.8-14.1, p value = 0.001, respectively).

CONCLUSION

Hemodialysis patients may benefit from inpatient rehabilitation. Although mortality was higher, efficacy of rehabilitation for hemodialysis patients is comparable to non-dialysis patients and is no less effective.

[Clinical characteristics and treatment outcomes of first peritonitis in patients receiving long-term peritoneal dialysis: a multicenter study]

OBJECTIVE

To analyze the clinical characteristics and treatment outcomes of the first episode of peritoneal dialysis-associated peritonitis (PDAP) in patients receiving long-term peritoneal dialysis.

METHODS

The clinical data of patients with the first episode of PDAP in 4 general hospitals in Jilin Province from 2013 to 2019 were collected retrospectively. According to the duration of dialysis, the patients were divided into long-term (≥36 months) and short-term (< 36 months) dialysis groups for comparison of the clinical data, treatment outcomes and long-term prognostic events.

RESULTS

A total of 625 patients with PDAP were enrolled, including 93 on long-term and 532 on short-term dialysis. Compared with those on short-term dialysis, the patients on long-term dialysis had significantly higher hemoglobin levels and lower glomerular filtration rates when the first episode of PDAP occurred (P < 0.05), were more susceptible to gram-negative bacterial infections (P < 0.05), and had significantly lower initial treatment response rate (P=0.009) and complete cure rate (P=0.018) and higher extubation rate (P=0.017). Multivariate logistic regression analysis showed that in patients on long-term dialysis, the risks of extubation and treatment failure for the first episode of PDAP were 3.05 times (OR: 3.05, 95%CI: 1.35-6.91, P=0.008) and 2.81 times (OR: 2.81, 95%CI: 1.45-5.44, P=0.002) those in patients with short-term dialysis, respectively. Fungal infection (OR: 45.40, 95%CI: 1.488-1385.5, P=0.029) and mixed bacterial infection (OR: 16.50, 95%CI: 1.106-246.123, P=0.042) were independent risk factors for treatment failure of the first episode of PDAP in patients on long-term dialysis. Maintenance peritoneal dialysis, technical failure, or all-cause mortality did not differ significantly between the two groups. Multivariate Cox regression analysis suggested that long-term dialysis was not an independent risk factor for technical failure (OR: 1.36, 95%CI: 0.84-2.19, P=0.206) or all-cause mortality (OR: 1.51, 95%CI: 0.97-2.35, P=0.068) in patients with PDAP.

CONCLUSIONS

Compared with those on short-term dialysis, patients on long-term dialysis are prone to gram-negative bacterial infection when the first episode of PDAP occurs with worse treatment outcomes but similar long-term outcomes. Long-term dialysis is an independent risk factor of extubation and treatment failure for the first episode of PDAP, and fungal and mixed bacterial infections are independent risk factors for treatment failure of the first PDAP in patients with long-term dialysis.

Impact of atrial fibrillation on the risk of ischemic stroke in patients on hemodialysis: BOREAS-HD3 Study

BACKGROUND

Atrial fibrillation (AF) is an established risk factor for ischemic stroke in a general population. However, its impact in patients on hemodialysis (HD), a group with a high risk for stroke, is still controversial. Here we examined this issue in a Japanese cohort.

METHODS

This study was designed as a multicenter cohort study. HD patients (n = 1,067) were enrolled from 22 institutes in January 2009 and followed up for 3 years. Patients with missing data (n = 196) or kidney transplantation (n = 4) were excluded, and 867 patients contributed to the analysis of the risk of new-onset of ischemic stroke.

RESULTS

At baseline, AF was observed in 123 patients (14.2%, AF group) and not in the others (n = 744: 85.8%, non-AF group). During a follow-up period of 31.3 months, the cumulative incidence rate for ischemic stroke was significantly higher in the AF group than in the non-AF group (6.5% vs. 2.9%, p < 0.05). In Cox regression analysis, AF was a significant independent risk factor for new-onset of ischemic stroke after adjustment for age, sex, prior history of ischemic stroke, use of warfarin, dialysis vintage, comorbidity of diabetic nephropathy, and interdialytic weight gain (hazard ratio 2.17-2.68).

CONCLUSION

Present analyses using comprehensive adjustment for multiple confounders, including prior history of ischemic stroke, indicated that AF independently increases the risk of new-onset of ischemic stroke by more than twofold in Japanese HD patients.

Questionnaire survey on the prescription of renal replacement therapy for acute phase patients on maintenance dialysis who developed cerebrovascular disease

BACKGROUND

There is limited information about acute phase renal replacement therapy (RRT) for maintenance hemodialysis patients after the onset of cerebrovascular disease. This study aimed to investigate which modality of renal replacement therapy is currently selected in practice.

METHODS

We conducted a mail-based survey in 317 dialysis facilities that were certified by three academic societies that focus on dialysis, neurology, and neurosurgery in Japan.

RESULTS

We received responses from 103 facilities (32.5%). In cases of cerebral infarction (CI) and intracerebral hemorrhage (ICH), more than 80% of the facilities selected only intermittent RRT, and 22.3% (CI)/8.7% (ICH) of the facilities selected intermittent HD which is the same setting in normal conditions. Although continuous hemodiafiltration and peritoneal dialysis are recommended in the Japanese guidelines, these were selected in only a few facilities: 16.5% and 0% in CI, 16.5% and 1% in ICH, respectively. RRT on the day of onset tended to be avoided, irrespective of the duration following the last HD session. Furthermore, physicians preferred to modify anticoagulants and reduce dialysis performance in the acute phase.

CONCLUSION

This questionnaire survey uncovered a gap between guidelines and actual practice, even in hospitals accredited as educational facility, which is a novel and important finding. Further studies with larger sample sizes are needed to determine the optimal modality of RRT for the acute phase of cerebrovascular disease.

Endovascular therapy for hemodialysis patients with atrial fibrillation and cerebral thromboembolism: A case series

INTRODUCTION

Hemodialysis patients with atrial fibrillation are at high risk for stroke. Intravenous recombinant tissue plasminogen activator is considered for acute ischemic stroke. However, recombinant tissue plasminogen activator therapy is contraindicated for some hemodialysis patients with atrial fibrillation. These patients and those who have received recombinant tissue plasminogen activator therapy without blood flow recovery are candidates for endovascular therapy.

METHODS AND RESULTS

Three hemodialysis patients with atrial fibrillation received endovascular therapy for acute cerebral infarction. Cerebrovascular incident occurred during or after hemodialysis in two of these patients. All three patients achieved successful recanalization after endovascular therapy.

CONCLUSION

In this series, endovascular therapy showed good results without complications. More cases should be investigated to obtain more evidence of successful endovascular therapy for hemodialysis patients.

The Association of Atrial Fibrillation and Ischemic Stroke in Patients on Hemodialysis: A Competing Risk Analysis

Background

Stroke is common in patients with end-stage renal disease (ESRD) treated with hemodialysis (HD) and associated with high mortality rate. In the general population, atrial fibrillation (AF) is a major risk factor for stroke and therapeutic anticoagulation is associated with risk reduction, whereas in ESRD the relationship is less clear.

Objective

The purpose of this study is to demonstrate the influence of AF on stroke rates and probability in those on HD following competing risk analyses.

Design

A national record linkage cohort study.

Setting

All renal and stroke units in Scotland, UK.

Patients

All patients with ESRD receiving HD within Scotland from 2005 to 2013 (follow-up to 2015).

Measurements

Demographic, clinical, and laboratory data were linked between the Scottish Renal Registry, Scottish Stroke Care Audit, and hospital discharge data. Stroke was defined as a fatal or nonfatal event and mortality derived from national records.

Methods

Associations for stroke were determined using competing risk models: the cause-specific hazards model and the Fine and Gray subdistribution hazards model accounting for the competing risk of death in models of all stroke, ischemic stroke, and first-ever stroke.

Results

Of 5502 patients treated with HD with 12 348.6-year follow-up, 363 (6.6%) experienced stroke. The stroke incidence rate was 26.7 per 1000 patient-years. Multivariable regression on the cause-specific hazard for stroke demonstrated age, hazard ratio (HR) (95% confidence interval [CI]) = 1.04 (1.03-1.05); AF, HR (95% CI) = 1.88 (1.25-2.83); prior stroke, HR (95% CI) = 2.29 (1.48-3.54), and diabetes, HR (95% CI) = 1.92 (1.45-2.53); serum phosphate, HR (95% CI) = 2.15 (1.56-2.99); lower body weight, HR (95% CI) = 0.99 (0.98-1.00); lower hemoglobin, HR (95% CI) = 0.88 (0.77-0.99); and systolic blood pressure (BP), HR (95% CI) = 1.01 (1.00-1.02), to be associated with an increased stroke rate. In contrast, the subdistribution HRs obtained following Fine and Gray regression demonstrated that AF, weight, and hemoglobin were not associated with stroke risk. In both models, AF was significantly associated with nonstroke death.

Limitations

Our analyses derive from retrospective data sets and thus can only describe association not causation. Data on anticoagulant use are not available.

Conclusions

The incidence of stroke in HD patients is high. The competing risk of "prestroke" mortality affects the relationship between AF and risk of future stroke. Trial designs for interventions to reduce stroke risk in HD patients, such as anticoagulation for AF, should take account of competing risks affecting associations between risk factors and outcomes.

Clinical outcomes of stroke in hemodialysis patients: a retrospective single-center study

PURPOSE

The incidence of stroke in patients undergoing hemodialysis (HD) is eight-to-ten times greater than that of the general population. However, data on the outcome of stroke in these patients are limited.

METHODS

In this retrospective observational cohort study, electronic medical records of all patients undergoing HD from 1.1.2014 to 31.12.2017 at Meir Medical Center, Israel, were reviewed. Stroke was defined as a focal neurological deficit of cerebrovascular origin, and confirmed as ischemic or hemorrhagic by computed tomography. Age- and sex-matched HD patients who did not experience a stroke (HD-NS) and hospitalized stroke patients with normal kidney function (NRF-S) served as the two control groups. Baseline demographic, clinical, and laboratory data were collected. Thrombolytic therapy, duration of hospital stay, and mortality were recorded. Functional status at discharge was assessed by the Modified Rankin Scale.

RESULTS

In the cohort study group (HD-S), 52 strokes occurred during 248.3 patient years, an incidence rate of 8.13%, and a stroke rate of 0.19% patients/month. Most strokes in HD patients were ischemic, and only four patients were administered tissue plasminogen activator. HD-S had longer hospitalization than did NRF-S (10.6 ± 9.9 vs. 5.96 ± 5.3 days, p = 0.004) and lower functional status at discharge (Rankin score 3.75 ± 1.57 vs. 2.29 ± 1.89, p < 0.001). HD-S patients had a higher mortality than both HD-NS and NRF-S patients.

CONCLUSIONS

Stroke outcome in these patients is dismal with prolonged hospital stay, poor functional status at discharge, very limited response to rehabilitation, and increased mortality.

Association between serum calcium levels and prognosis, hematoma volume, and onset of cerebral hemorrhage in patients undergoing hemodialysis

BACKGROUND

High serum calcium levels should be avoided in patients on hemodialysis (HD) because they can induce cardiovascular diseases and worsen the patient's prognosis. In contrast, low serum calcium levels worsen the prognosis of patients with cerebral hemorrhage in the general population. So far, whether serum calcium levels in patients on HD are associated with cerebral hemorrhage remains unknown. This study aimed to reveal the association between serum calcium and cerebral hemorrhage in patients on HD, including in-hospital death, volume of hematoma, and onset of cerebral hemorrhage.

METHODS

This cross-sectional case-control study included 99 patients on HD with cerebral hemorrhage at a single center between July 1, 2007 and December 31, 2017. Controls included 339 patients on HD at a single HD center between July 1, 2011 and June 30, 2012. Data on serum calcium level, patient demographics, and comorbid conditions were collected, and associations between cerebral hemorrhage and subsequent death were evaluated by multivariate logistic regression analysis. Further, the association of these backgrounds and hematoma volume was evaluated by multiple regression analysis.

RESULTS

Of the 99 patients, 32 (32%) died from cerebral hemorrhage. The corrected serum calcium level (odds ratio [OR], 2.49; 95% confidence interval [CI], 1.43-4.35; P < 0.001) and antiplatelet drug use (OR, 3.95; 95% CI, 1.50-10.4; P = 0.005) had significant effects on the prognosis. Moreover, the corrected serum calcium (P = 0.003) and antiplatelet drug use (P = 0.01) were significantly correlated with hematoma volume. In the patients, the corrected serum calcium level (OR, 1.54; 95% CI, 1.07-2.22; P = 0.02) was associated with the onset of cerebral hemorrhage, as was pre-hemodialysis systolic blood pressure (per 10 mmHg) (OR, 1.40; 95% CI, 1.23-1.59; P < 0.001).

CONCLUSIONS

Although the precise mechanisms remain unknown, a high serum calcium level is associated with cerebral hemorrhage in patients on HD. Thus, we should pay attentions to a patient's calcium level.

Absolute risk and risk factors for stroke mortality in patients with end-stage kidney disease (ESKD): population-based cohort study using data linkage

INTRODUCTION

People with end-stage kidney disease (ESKD) have up to 30-fold higher risk of stroke than the general population.

OBJECTIVE

To determine risk factors associated with stroke death in the ESKD population.

METHODS

We identified all patients with incident ESKD in Australia (1980-2013) and New Zealand (1988-2012) from the Australian and New Zealand Dialysis and Transplant Registry (ANZDATA) registry. We ascertained underlying cause of death from data linkage with national death registries and risk factors from ANZDATA. Using a competing risks multivariable regression model, we estimated cumulative incidence of stroke and non-stroke deaths, and risk factors for stroke deaths (adjusted sub-HR, SHR).

RESULTS

We included 60 823 people with ESKD. There were 941 stroke deaths and 33 377 non-stroke deaths during 381 874 person-years of follow-up. Overall, the cumulative incidence of stroke death was 0.9% and non-stroke death was 36.8% 5 years after starting ESKD treatment. The risk of stroke death was higher at older ages (SHR 1.92, 95% CI 1.45 to 2.55), in females (SHR 1.41, 95% CI 1.21 to 1.64), in people with cerebrovascular disease (SHR 2.39, 95% CI 1.99 to 2.87), with ESKD caused by hypertensive/renovascular disease (SHR 1.39, 95% CI 1.09 to 1.78) or polycystic kidney disease (SHR 1.38, 95% CI 1.00 to 1.90), with earlier year of ESKD treatment initiation (SHR 1.93, 95% CI 1.56 to 2.39) and receiving dialysis (transplant vs haemodialysis SHR 0.27, 95% CI 0.09 to 0.84).

CONCLUSION

Patients with ESKD with higher risk of stroke death are older, women, with cerebrovascular disease, with hypertensive/renovascular or polycystic kidney disease cause of ESKD, with earlier year of ESKD treatment and receiving dialysis. These groups may benefit from targeted stroke prevention interventions.

Predictors of atherosclerotic events in patients on haemodialysis: post hoc analyses from the AURORA study

Background

Patients on haemodialysis (HD) are at high risk for cardiovascular events, but heart failure and sudden death are more common than atherosclerotic events. The A Study to Evaluate the Use of Rosuvastatinin in Subjects on Regular Hemodialysis: An Assessment of Survival and Cardiovascular Events (AURORA) trial was designed to assess the effect of rosuvastatin on myocardial infarction and death from any cardiac cause in 2773 HD patients. We studied predictors of the atherosclerotic cardiovascular events in AURORA.

Methods

We readjudicated all deaths and presumed myocardial infarctions according to the criteria used in the Study of Heart and Renal Protection (SHARP); these were specifically developed to separate atherosclerotic from non-atherosclerotic cardiovascular events. The readjudicated atherosclerotic end point included the first event of the following: non-fatal myocardial infarction, fatal coronary heart disease, non-fatal and fatal non-haemorrhagic stroke, coronary revascularization procedures and death from ischaemic limb disease. Stepwise Cox regression analysis was used to identify the predictors of such events.

Results

During a mean follow-up of 3.2 years, 506 patients experienced the new composite atherosclerotic outcome. Age, male sex, prevalent diabetes, prior cardiovascular disease, weekly dialysis duration, baseline albumin [hazard ratio (HR) 0.96; 95% confidence interval (CI) 0.94-0.99 per g/L increase], high-sensitivity C-reactive protein (HR 1.13; 95% CI 1.04-1.22 per mg/L increase) and oxidized low-density lipoprotein (LDL) cholesterol (HR 1.09; 95% CI 1.03-1.17 per 10 U/L increase) were selected as significant predictors in the model. Neither LDL cholesterol nor allocation to placebo/rosuvastatin therapy predicted the outcome.

Conclusions

Even with the use of strict criteria for end point definition, non-traditional risk factors, but not lipid disturbances, predicted atherosclerotic events in HD patients.

Favourable renal outcomes after intravenous thrombolytic therapy for acute ischemic stroke: Clinical implication of kidney-brain axis

AIM

Recombinant tissue plasminogen activator (rt-PA) administration is the most prevalent treatment for acute ischemic within golden time. However, the effects of rt-PA on the kidney function in such patients remain unknown. This study determined long-term renal outcomes in patients with acute ischemic stroke receiving systemic rt-PA.

METHODS

We enroled patients who were hospitalized for acute ischemic stroke from January 2001 to January 2017. We applied 1:2 propensity score matching to eliminate various confounding variables. We defined surrogate renal outcomes as declining of estimated glomerular filtration rate (eGFR) greater than 30% and 50%, and chronic kidney disease (CKD) with eGFR less than 60 mL/min. We then compared the 1-year eGFR with paired t-test in patients treated with or without rt-PA.

RESULTS

Overall, 343 of 1739 patients received rt-PA within golden time. After 1:2 propensity score matching, their baseline characteristics were grouped as treated with rt-PA (n = 235) or not (n = 394). rt-PA-treated patients exhibited slower renal progression, including the risk of eGFR declining greater than 30% (hazard ratio (HR), 0.72; P = 0.03), risk of declining eGFR greater than 50% (HR, 0.63; P = 0.046) and risk of CKD (HR, 0.61; P = 0.005). After 1-year cohort, the rt-PA group exhibited an improved renal outcome by the paired t-test (propensity match: ΔGFR = 9.1 (95% confidence interval: 6.3, 11.8), P < 0.001 in rt-PA group; ΔGFR = -1.1 (95% confidence interval: -2.9, 0.7), P = 0.23 in non-rt-PA group). In patients with eGFR less than 45 mL/min (n = 34), intracerebral haemorrhage was not reported.

CONCLUSION

Patients receiving rt-PA for acute ischemic stroke exhibit favourable renal outcomes, and no increased incidence of intracerebral haemorrhage occurs in rt-PA patients with advanced CKD.

The comparison of risk of stroke in patients with peritoneal dialysis and hemodialysis: A systematic review and meta-analysis

OBJECTIVE

Several studies have demonstrated that end-stage renal disease (ESRD) patients on dialysis are at higher risk for cerebrovascular events, especially those on hemodialysis. However, the risk of stroke in patients on peritoneal dialysis (PD) compared to those on hemodialysis (HD) remains unclear. We performed this meta-analysis to assess the risks of stroke in ESRD patients on PD compared to HD.

METHODS

A systematic review was conducted using MEDLINE, EMBASE, Cochrane databases from inception through January 2018 to identify studies that evaluated the risks of stroke (all types of stroke, ischemic stroke or hemorrhagic stroke) in ESRD patients on different dialysis modalities. Effect estimates from the individual study were extracted and combined using random-effect, generic inverse variance method of DerSimonian and Laird.

RESULTS

Fifteen cohort studies with a total of 1 289 572 ESRD patients (over 1 140 942 on HD and 122 534 on PD) were enrolled. Compared with HD, PD was associated with a significantly decreased risk of hemorrhagic stroke with pooled OR of 0.84 (95% CI: 0.76-0.92). However, there were no differences in risks of all types of stroke or ischemic stroke in those on PD compared to HD with pooled ORs of 1.06 (95% CI: 0.91-1.22) and 1.01 (95% CI: 0.80-1.18,), respectively.

CONCLUSIONS

PD status is associated with 16% lower risk of hemorrhagic stroke compared to HD, but the risks of all types of stroke and hemorrhagic stroke are not statistically different in PD patients when compared to HD patients.

Temporal Trends in the Outcomes of Dialysis Patients Admitted With Acute Ischemic Stroke

BACKGROUND

There is a paucity of contemporary data on the characteristics and outcomes of acute ischemic stroke (AIS) in patients on maintenance dialysis.

METHODS AND RESULTS

We used the nationwide inpatient sample to examine contemporary trends in the incidence, management patterns, and outcomes of AIS in dialysis patients. A total of 930 010 patients were admitted with AIS between 2003 and 2014, of whom 13 642 (1.5%) were on dialysis. Overall, the incidence of AIS among dialysis patients decreased significantly (Ptrend<0.001), while it remained stable in non-dialysis patients (Ptrend=0.78). Compared with non-dialysis patients, those on dialysis were younger (67±13 years versus 71±15 years, P<0.001), and had higher prevalence of major comorbidities. Black patients constituted 35.2% of dialysis patients admitted with AIS compared with 16.7% of patients in the non-dialysis group (P<0.001). After propensity score matching, in-hospital mortality was higher in the dialysis group (7.6% versus 5.2%, P<0.001), but this mortality gap narrowed overtime (Ptrend<0.001). Hemorrhagic conversion and gastrointestinal bleeding rates were similar, but blood transfusion was more common in the dialysis group. Rates of severe disability surrogates (tracheostomy, gastrostomy, mechanical ventilation and non-home discharge) were also similar in both groups. However, dialysis patients had longer hospitalizations, and accrued a 25% higher total cost of acute care.

CONCLUSIONS

Dialysis patients have 8-folds higher incidence of AIS compared withnon-dialysis patients. They also have higher risk-adjusted in-hospital mortality, sepsis and blood transfusion, longer hospitalizations, and higher cost. There is a need to identify preventative strategies to reduce the risk of AIS in the dialysis population.

Long-term prognostic impact of anticoagulation on patients with atrial fibrillation undergoing hemodialysis

INTRODUCTION AND OBJECTIVES

Evidence for the efficacy and safety of oral anticoagulation with dicumarines in patients with atrial fibrillation (AF) on hemodialysis is controversial. The aim of our study is to evaluate the long-term prognostic implications of anticoagulation with dicumarines in a cohort of patients with non-valvular AF on a hemodialysis program due to end-stage renal disease.

METHODS

Retrospective, observational study with consecutive inclusion of 74 patients with AF on hemodialysis. The inclusion period was from January 2005 to October 2016. The primary variables were all-cause mortality, non-scheduled readmissions and bleeding during follow-up.

RESULTS

Mean age was 75±10 years; 66.2% were men and 43 patients (58.1%) received acenocoumarol. During a median follow-up of 2.40 years (IQR=0.88-4.15), acenocoumarol showed no survival benefit [HR=0.76, 95% CI (0.35-1.66), p=0.494]. However, anticoagulated patients were at increased risk of recurrent cardiovascular hospitalizations [IRR=3.94, 95% CI (1.06-14.69), p=0.041]. There was a trend towards an increase in repeated hospitalizations of ischemic cause in anticoagulated patients [IRR=5.80, 95% CI (0.86-39.0), p=0.071]. There was a statistical trend towards a higher risk of recurrent total bleeding in patients treated with acenocoumarol [IRR=4.43, 95% CI (0.94-20.81), p=0.059].

CONCLUSIONS

In this study, oral anticoagulation with acenocoumarol in patients with AF on hemodialysis did not increase survival. However, it was associated with an increased risk of hospitalizations of cardiovascular causes and a tendency to an increased risk of total bleeding.

Association Between Stroke Risk and Metformin Use in Hemodialysis Patients With Diabetes Mellitus: A Nested Case-Control Study

BACKGROUND

Metformin use reduces the incidence and severity of stroke in patients with type 2 diabetes mellitus (DM). The benefits of metformin for stroke have not been examined in hemodialysis patients with DM.

METHODS AND RESULTS

Using the National Health Insurance Research Database, we identified 17 760 patients with DM and new-onset hemodialysis between 2001 and 2013. Of these, 1898 patients hospitalized for either ischemic or hemorrhagic stroke were matched to 7592 control patients according to sex, age, and year of initial hemodialysis therapy by using incidence sampling. The association between metformin use and stroke risk was estimated using conditional logistic regression after adjustment for hemodialysis frequency, comorbidity, and prescribed medications. Metformin use was recorded before the date of stroke admission and the date of pseudostroke of the case and control patients, respectively. Results showed that hemodialysis patients with ischemic stroke were more likely to use metformin than the controls 1 year before the date of stroke admission (adjusted odds ratio: 1.64; 95% confidence interval, 1.32-2.04). The association was evident within 90 days before the index date (adjusted odds ratio: 1.81; 95% confidence interval, 1.27-2.60). The results were consistent with those of hemodialysis patients with hemorrhagic stroke. Metformin use remained a risk factor for stroke in patients treated with antihypertensive, sulfonylurea, and antiplatelet drugs.

CONCLUSIONS

This nested case-control study is the first to show that metformin use is associated with stroke risk in hemodialysis patients with DM. We suggest that metformin should not be used by hemodialysis patients with DM.

Impact of the Number of Anti-Thrombosis Agents in Hemodialysis Patients: BOREAS-HD2 Study

BACKGROUND/AIMS

Relationships between the number of anti-thrombosis agents, clinical benefits and adverse events in hemodialysis (HD) patients are unclear.

METHODS

All patients on HD in 22 institutes (n = 1,071) were enrolled and followed up for 3 years. After exclusion of patients with missing data, kidney transplantation or retraction of consent during the follow-up period (n = 204), mortality rate and ischemic and hemorrhagic events were compared between different regimens of anti-thrombosis agents.

RESULTS

The use of dual or triple antiplatelet (AP) agents (HR:2.03, 95% CI:1.01-4.13, p = 0.04) and the combination of an AP agent and warfarin (WF) (HR:4.84, 95%CI 1.96-11.96, p < 0.001) were associated with an increase in hemorrhagic events compared with no use of anti-thrombosis agents. No anti-thrombosis regimen was associated with a significant change in risk of ischemic stroke. The use of dual or triple AP agents, but not WF, was associated with an increase in cardiovascular mortality (HR:2.48, 95% CI:1.24-4.76, p = 0.01).

CONCLUSION

A significant increase in hemorrhagic events by the use of dual or more AP agents and by co-administration of an AP agent and WF in patients on HD should be considered in planning their anti-thrombosis regimen.

Reverse epidemiology of elevated blood pressure among chronic hemodialysis black patients with stroke: a historical cohort study

Background

Stroke is the third leading cause of cardiovascular mortality in dialysis patients. The objective of this study was to assess the extent of stroke in chronic hemodialysis patients.

Methods

Historical cohort of patients enrolled in two hemodialysis (HD) centers from January 1, 2010 to December 31, 2011, including 191 patients (mean age 52 years, 68% men). Incidence curves and survival time analysis between the first day of HD and the end of the study were described by the Kaplan-Meier method. Independent stroke predictors were identified by multiple logistic regression analysis. P < 0.05 defined the level of statistical significance.

Results

12 incident stroke were recorded during the study period, with 1622.1 person-months (PM), a stroke incidence rate of 7.4 cases per 1000 PM (95% CI = 7.35–7.44) at the point date. The incidence of stroke at 6 months, 12 months and 24 months was 9.8%, 11.9% and 13%, respectively. Only the absence of arterial hypertension (RR = 5.7, 95% CI: 1.52–21.42) emerged as an independent determinant of stroke.

Conclusion

The high incidence of stroke in Kinshasa HD centers is partially explained by reverse epidemiology. Efforts must be made to understand this phenomenon in order to reduce its impact.

Repetitive Transcranial Magnetic Stimulation Ameliorates Cognitive Impairment by Enhancing Neurogenesis and Suppressing Apoptosis in the Hippocampus in Rats with Ischemic Stroke

Cognitive impairment is a serious mental deficit caused by stroke that can severely affect the quality of a survivor's life. Repetitive transcranial magnetic stimulation (rTMS) is a well-known rehabilitation modality that has been reported to exert neuroprotective effects after cerebral ischemic injury. In the present study, we evaluated the therapeutic efficacy of rTMS against post-stroke cognitive impairment (PSCI) and investigated the mechanisms underlying its effects in a middle cerebral artery occlusion (MCAO) rat model. The results showed that rTMS ameliorated cognitive deficits and tended to reduce the sizes of cerebral lesions. In addition, rTMS significantly improved cognitive function via a mechanism involving increased neurogenesis and decreased apoptosis in the ipsilateral hippocampus. Moreover, brain-derived neurotrophic factor (BDNF) and its receptor, tropomyosin-related kinase B (TrkB), were clearly upregulated in ischemic hippocampi after treatment with rTMS. Additionally, further studies demonstrated that rTMS markedly enhanced the expression of the apoptosis-related B cell lymphoma/leukemia gene 2 (Bcl-2) and decreased the expression of the Bcl-2-associated protein X (Bax) and the number of TUNEL-positive cells in the ischemic hippocampus. Both protein levels and mRNA levels were investigated. Our findings suggest that after ischemic stroke, treatment with rTMS promoted the functional recovery of cognitive impairments by inhibiting apoptosis and enhancing neurogenesis in the hippocampus and that this mechanism might be mediated by the BDNF signaling pathway.

Predicting in a predicament: Stroke and hemorrhage risk prediction in dialysis patients with atrial fibrillation

Whether to anticoagulate dialysis patients with atrial fibrillation is a common clinical dilemma with limited high-quality data to inform decision-making. While the efficacy and safety of anticoagulation for stroke prevention in dialysis patients with atrial fibrillation has long been debated and remains unclear, the more upstream issue of stroke risk assessment from atrial fibrillation has received relatively little attention. In the general population, a handful of risk scores to help predict stroke and hemorrhage risk in the setting of atrial fibrillation are widely validated and applied in clinical practice. But are they applicable to the dialysis population? The most commonly used stroke risk scores, CHADS2 and CHA2DS2-VASC, have limited validation in the dialysis population, and when validated, have shown poor performance (c-statistics <0.70). Stroke risk scores derived in the general atrial fibrillation population may perform poorly in dialysis patients for a number of reasons. Dialysis patients have unique stroke risk factors, such as chronic inflammation and vascular calcification, and a much higher competing risk of death, none of which are accounted for in current risk scores. Further complicating the dilemma of anticoagulation is hemorrhage risk, which is known to be exceedingly high in dialysis patients. Currently available hemorrhage risk scores, such as HAS-BLED, have not been validated in dialysis patients and will likely underestimate hemorrhage risk. Moving forward, risk tools specific to the dialysis population are needed to accurately assess and balance stroke and hemorrhage risks in dialysis patients with atrial fibrillation.

Vitamin K antagonists for stroke prevention in hemodialysis patients with atrial fibrillation: A systematic review and meta-analysis

BACKGROUND

The use of vitamin K antagonists (VKAs) in hemodialysis patients with atrial fibrillation (AF) is controversial. No randomized trials are available and observational studies have yielded conflicting results, engendering a large clinical practice variability and physician uncertainty. An unresolved but highly relevant question is whether AF poses a true risk of ischemic stroke in hemodialysis and whether any form of oral anticoagulation is therefore warranted.

METHODS

We conducted a systematic review of studies that compared the incidence of ischemic stroke and bleeding in hemodialysis patients with AF taking VKA and those not taking VKA. When hemodialysis patients had been pooled with peritoneal dialysis, kidney transplant, or stage V chronic kidney disease patients, unpublished outcome data of the hemodialysis subgroup were obtained through personal communication. The main outcome measures were ischemic stroke/thromboembolic events, all-cause mortality, major bleeding, and hemorrhagic stroke. Combined hazard ratios (HRs) and 95% CIs were calculated using a random-effects model.

RESULTS

Twelve prospective or retrospective cohort studies were included in the meta-analysis, totaling 17,380 hemodialysis patients of whom 4,010 (23.1%) received VKA. In VKA-treated patients, mean CHADS₂ or CHA₂DS₂VASc score was low (range 1.7-2.75) or a sizeable proportion of patients had scores <2 (range 2%-23%). Time in the therapeutic range or mean international normalized ratio was generally low. Treatment with VKA was associated with a nonsignificant 26% reduction of the risk of ischemic stroke (HR 0.74; 0.51-1.06), a 21% increase in total bleeding risk (HR 1.21; 1.03-1.43), and no effect on mortality (HR 1.00; 0.92-1.09). Vitamin K antagonist almost doubled the risk of hemorrhagic stroke, but this did not reach the limit of statistical significance (4 studies, n = 16.365; HR 1.93; 0.93-3.98).

CONCLUSION

Our meta-analysis revealed a trend for a reduction of the risk of ischemic stroke in hemodialysis patients with AF treated with VKA. The true protective effect may have been underestimated, owing to inclusion of low-risk patients not expected to benefit from anticoagulation and to suboptimal anticoagulation. However, assessment of the overall effect of VKA in hemodialysis patients should also take into account the increased risk of bleeding, in particular of hemorrhagic stroke. Whether new oral anticoagulants provide a better benefit-risk ratio in hemodialysis patients should be the subject of future trials.

Association Between Serum Phosphate Levels and Stroke Risk in Patients Undergoing Hemodialysis: The Q-Cohort Study

BACKGROUND AND PURPOSE

The contribution of serum phosphate levels to stroke risk in dialysis patients remains unclear. The present study aimed to elucidate the respective association between serum phosphate levels and the risk of brain hemorrhage or infarction in patients undergoing hemodialysis.

METHODS

A total of 3437 patients undergoing hemodialysis were followed up for a median of 3.9 years. The primary outcome was the occurrence of brain hemorrhage or infarction. Patients were divided into 4 groups based on their baseline serum phosphate levels (Q1-Q4). Stroke risk was estimated using a Cox proportional hazards model.

RESULTS

During the follow-up period, 75 patients experienced brain hemorrhage and 139 experienced brain infarction. The risk of brain hemorrhage was significantly higher in the highest (Q4) compared with the lowest quartile (Q1) as the reference value (multivariate-adjusted hazard ratio [95% confidence intervals]: Q1, 1.00; Q2, 1.76 [0.79-4.18]; Q3, 1.99 [0.92-4.67]; and Q4, 2.74 [1.27-6.47]; P=0.077 for trend; hazard ratio for every 1 mmol/L increase in serum phosphate level, 2.07 [1.10-3.81]; P=0.025). In contrast, the risk of brain infarction was significantly higher in Q1 (P=0.045) compared with Q3 as the reference value (Q1, 1.65 [1.01-2.73]; Q2, 1.35 [0.82-2.25]; Q3, 1.00; and Q4, 1.30 [0.77-2.20]).

CONCLUSIONS

Higher serum phosphate levels were associated with an increased risk of brain hemorrhage, whereas low levels were associated with an increased risk of brain infarction in hemodialysis patients. These results suggest the importance of managing serum phosphate levels within an appropriate range in hemodialysis patients.

CLINICAL TRIAL REGISTRATION

URL: http://www.umin.ac.jp/. Unique identifier: UMIN000000556.

Factors affecting outcomes in patients reaching end-stage kidney disease worldwide: differences in access to renal replacement therapy, modality use, and haemodialysis practices

More than 2 million people worldwide are being treated for end-stage kidney disease (ESKD). This Series paper provides an overview of incidence, modality use (in-centre haemodialysis, home dialysis, or transplantation), and mortality for patients with ESKD based on national registry data. We also present data from an international cohort study to highlight differences in haemodialysis practices that affect survival and the experience of patients who rely on this therapy, which is both life-sustaining and profoundly disruptive to their quality of life. Data illustrate disparities in access to renal replacement therapy of any kind and in the use of transplantation or home dialysis, both of which are widely considered preferable to in-centre haemodialysis for many patients with ESKD in settings where infrastructure permits. For most patients with ESKD worldwide who are treated with in-centre haemodialysis, overall survival is poor, but longer in some Asian countries than elsewhere in the world, and longer in Europe than in the USA, although this gap has reduced. Commendable haemodialysis practice includes exceptionally high use of surgical vascular access in Japan and in some European countries, and the use of longer or more frequent dialysis sessions in some countries, allowing for more effective volume management. Mortality is especially high soon after ESKD onset, and improved preparation for ESKD is needed including alignment of decision making with the wishes of patients and families.

Efficacy and safety of warfarin in dialysis patients with atrial fibrillation: a systematic review and meta-analysis

Objective

To systematically review and meta-analyse the risk–benefit ratio of warfarin users compared with non-warfarin users in patients with atrial fibrillation (AF), who are undergoing dialysis.

Methods

We searched PubMed/MEDLINE, EMBASE, SCOPUS, Web of Science, Cochrane Library, grey literature, conference proceedings, trial registrations and also did handsearch. Cohort studies without language restrictions were included. Two investigators independently conducted a full abstraction of data, risk of bias and graded evidence. Effect estimates were pooled using random-effect models.

Main outcome measure

All-cause mortality, total stroke/thromboembolism and bleeding complications.

Results

14 studies included 37 349 dialysis patients with AF, of whom 12 529 (33.5%) were warfarin users. For all-cause mortality: adjusted HR=0.99 (95% CI 0.89 to 1.10; p=0.825), unadjusted risk ratio (RR)=1.00 (95% CI 0.96 to 1.04; p=0.847). For stroke/thromboembolism: adjusted HR=1.06 (95% CI 0.82 to 1.36; p=0.676), unadjusted incidence rate ratio (IRR)=1.23 (95% CI 0.94 to 1.61; p=0.133). For ischaemic stroke/transient ischaemic attack, adjusted HR=0.91 (95% CI 0.57 to 1.45; p=0.698), unadjusted IRR=1.16 (95% CI 0.84 to 1.62; p=0.370). For haemorrhagic stroke, adjusted HR=1.60 (95% CI 0.91 to 2.81; p=0.100), unadjusted IRR=1.48 (95% CI 0.92 to 2.36; p=0.102). Major bleeding was increased among warfarin users; adjusted HR=1.35 (95% CI 1.11 to 1.64; p=0.003) and unadjusted IRR=1.22 (95% CI 1.07 to 1.40; p=0.003).

Conclusions

Among dialysis patients with AF, warfarin therapy was not associated with mortality and stroke/thromboembolism, but significantly increased the risk of major bleeding. More rigorous studies are essential to demonstrate the effect of warfarin for stroke prophylaxis in dialysis patients with AF.

Meta-Analysis of Anticoagulation Use, Stroke, Thromboembolism, Bleeding, and Mortality in Patients With Atrial Fibrillation on Dialysis

Atrial fibrillation (AF) is common in patients on dialysis. Although randomized trials of anticoagulation for AF have demonstrated striking reductions in stroke, these trials did not recruit patients on dialysis. We thus undertook this systematic review and meta-analysis of observational studies including patients with AF on dialysis that reported associations of anticoagulation use. Twenty studies involving 529,741 subjects and 31,321 patients with AF on dialysis were identified. Anticoagulation was associated with a 45% (95% CI 13% to 88%) increased risk of any stroke, reflecting a nonsignificant 13% (95% CI -4% to 34%) increased ischemic stroke risk and 38% (95% CI 3% to 85%) increased hemorrhagic stroke risk. There was also a 44% (95% CI 38% to 56%) lower risk of any thromboembolism, and a 31% (95% CI 12% to 53%) increased risk of any bleeding but no clear association with cardiovascular death (relative risk 0.99, 95% CI 0.86 to 1.15) or all-cause mortality (relative risk 0.97, 95% CI 0.90 to 1.04). Incident event rates were similar or worse in patients on anticoagulation. In conclusion, these observational analyses provide little supporting evidence of benefit, and instead suggest harm, from anticoagulation in patients on dialysis with AF. These results raise the possibility that the effects of anticoagulation in patients with AF on dialysis may not be similar to the clear benefit of anticoagulation seen in patients with AF without end-stage renal disease. Randomized trials are required to definitively evaluate the safety and efficacy of anticoagulation for AF in the dialysis setting.

The atrial fibrillation conundrum in dialysis patients

The burden of atrial fibrillation (AF) and the risk of stroke are high in dialysis patients. The decision to use anticoagulation rests heavily on effective risk stratification. Because both the pathophysiology of the disease and the response to therapy differ in dialysis, data from the general population cannot be extrapolated. The effect of vitamin K antagonists (VKAs) on the risk of stroke in dialysis patients with AF has not been studied in randomized trials. The available observational data provide contradictory results, reflecting differences in the degree of residual confounding, quality of international normalized ratio control, and stroke characterization. Dialysis patients have a high baseline bleeding risk. It remains unclear to what extent VKAs affect the overall bleeding propensity, but they may significantly increase the risk of intracerebral hemorrhage. Vascular calcifications are extremely prevalent in dialysis patients and independently associated with an adverse outcome. Vitamin K antagonists inhibit the activity of key anticalcifying proteins and may thus compound the risk of vascular calcification progression in dialysis. In the absence of evidence-based guidelines for anticoagulation in dialysis patients with AF, we provide recommendations to assist clinicians in individualized risk stratification. We further propose that new oral anticoagulants may have a better benefit-risk profile in dialysis patients than VKA, provided appropriate dose reductions are made. New oral anticoagulant may yield more on-target anticoagulation, reduce the risk of intracerebral bleeding, and not interfere with vascular calcification biology. Clinical trials with new oral anticoagulant in dialysis patients are eagerly awaited, to reveal whether these assumptions can be confirmed.

Modulation of stroke risk in chronic kidney disease

Stroke is the second most common cause of death and the leading cause of neurological disability worldwide, with huge economic costs and tragic human consequences. Both chronic kidney disease (CKD) and end-stage kidney disease are associated with a significantly increased risk of stroke. However, to date this has generated far less interest compared with the better-recognized links between cardiac and renal disease. Common risk factors for stroke, such as hypertension, hypercholesterolaemia, smoking and atrial fibrillation, are shared with the general population but are more prevalent in renal patients. In addition, factors unique to these patients, such as disorders of mineral and bone metabolism, anaemia and its treatments as well as the process of dialysis itself, are all also postulated to further increase the risk of stroke. In the general population, advances in medical therapies mean that effective primary and secondary prevention therapies are available for many patients. The development of specialist stroke clinics and acute stroke units has also improved outcomes after a stroke. Emerging therapies such as thrombolysis and thrombectomy are showing increasingly beneficial results. However, patients with CKD and on dialysis have different risk profiles that must be taken into account when considering the potential benefits and risks of these treatments. Unfortunately, these patients are either not recruited or formally excluded from major clinical trials. There is still much work to be done to harness effective stroke treatments with an acceptable safety profile for patients with CKD and those on dialysis.