Ought dialysis patients with atrial fibrillation be treated with oral anticoagulants?

Discontinuation of Anticoagulants and Occurrence of Bleeding and Thromboembolic Events in Vitamin K Antagonist Users with a Life-limiting Disease

Data on risks and benefits of long-term anticoagulants in patients with a life-limiting disease are limited. This cohort study aims to describe (dis)continuation of anticoagulants and incidences of bleeding and thromboembolic events in vitamin K antagonist (VKA) users with a life-limiting disease.Data from five Dutch anticoagulation clinics were linked to data from Statistics Netherlands and the Netherlands Cancer registry. Prevalent VKA users diagnosed with a pre-specified life-limiting disease between January 1, 2013 and December 31, 2019 were included and followed until December 31, 2019. Bleeding and thromboembolic events were identified by hospitalization data. Cumulative incidences of anticoagulant discontinuation, accounting for death as competing risk, and event rates for both anticoagulant exposed and unexposed person-years (PYs) were determined.Among 18,145 VKA users (median age 81 years [IQR: 74-86], 49% females, median survival time 2.03 years [95%CI: 1.97-2.10]), the most common life-limiting diseases were heart disease (60.0%), hip fracture (18.1%), and cancer (13.5%). One year after diagnosis, the cumulative incidence of anticoagulant discontinuation was 14.0% (95%CI: 13.5-14.6). Over 80% of patients continued anticoagulant therapy until the last month before death, with median 14 days between discontinuation and death. Event rates per 100 PYs (95%CI) were comparable during anticoagulant use and after discontinuation for bleeding 2.6 (2.4-2.8) versus 2.1 (1.5-2.8), venous thromboembolism 0.2 (0.1-0.2) versus 0.4 (0.2-0.7), and arterial thromboembolism 3.1 (2.9-3.3) versus 3.3 (2.6-4.2).Most VKA users with a life-limiting disease continued anticoagulant treatment during their last phase of life, with similar rates of bleeding and thromboembolic events during use and after discontinuation.

Safety and Efficacy of Apixaban Versus Warfarin in Patients With Advanced Chronic Kidney Disease

Background: Because of a lack of comparative data on anticoagulant use in the advanced chronic kidney disease (CKD) population, guidelines recommend warfarin for atrial fibrillation and venous thromboembolism (VTE) treatment in these patients. However, apixaban has specific dosing recommendations in CKD leading to use in clinical practice. Objective: To evaluate major bleeding, stroke, and thromboembolism rates in patients with CKD stage 4, stage 5, and dialysis on apixaban or warfarin therapy. Methods: This was a retrospective cohort study of patients with advanced CKD receiving apixaban or warfarin. The primary outcome was the occurrence of major bleeding at 3 months after enrollment. Secondary outcomes included occurrence of major bleeding, occurrence of ischemic stroke, and recurrence of VTE at 3 to 6 and 6 to 12 months. Results: A total of 604 patients were included in the analysis. The percentage of apixaban and warfarin patients with a major bleed at 0 to 3, 3 to 6, and 6 to 12 months were 8.3% versus 9.9% ( P=0.48), 1.4% versus 4% ( P=0.07), and 1.5% versus 8.4% ( P<0.001), respectively. There were no differences in rates of ischemic stroke or recurrent VTE at any time period. Conclusion and Relevance: Patients with advanced CKD taking apixaban had similar bleeding rates at 3 months compared with those taking warfarin. However, those who continued therapy had higher major bleeding rates with warfarin between 6 and 12 months. This study provides knowledge on the effects of a direct oral anticoagulant in a population that was excluded from all major trials.

Incidence and characteristics of major bleeding among rivaroxaban users with renal disease and nonvalvular atrial fibrillation

OBJECTIVE

Patients with nonvalvular atrial fibrillation (AF) and renal disease (RD) who receive anticoagulation therapy appear to be at greater risk of major bleeding (MB) than AF patients without RD. As observed in past studies, anticoagulants are frequently withheld from AF patients with RD due to concerns regarding bleeding. The objective of this study was to evaluate the incidence and pattern of MB in those with RD, as compared to those without RD, in a population of rivaroxaban users with nonvalvular AF.

METHODS

Electronic medical records of over 10 million patients from the Department of Defense Military Health System were queried to identify rivaroxaban users with nonvalvular AF. A validated algorithm was used to identify MB-related hospitalizations. RD was defined through diagnostic codes present within 6 months prior to the bleeding date for MB cases and end of study participation for non-MB patients. Data were collected on patient characteristics, comorbidities, MB management, and outcomes.

RESULTS

Overall, 44,793 rivaroxaban users with nonvalvular AF were identified. RD was present among 6,921 patients (15.5%). Patients with RD had a higher rate of MB than those without RD, 4.52 per 100 person-years versus 2.54 per 100 person-years, respectively. The fatal bleeding outcome rate (0.09 per 100 person-years) was identical between those with and without RD.

CONCLUSION

In this post-marketing study of 44,793 rivaroxaban users with nonvalvular AF, RD patients experienced a higher MB rate than those without RD. The higher rate of MB among those with RD may be due to the confounding effects of comorbidities.

Understanding and Managing Atrial Fibrillation in Patients with Kidney Disease

Chronic kidney disease (CKD) is on the rise due to the increased rate of related comorbidities such as diabetes and hypertension. Patients with CKD are at higher risk of cardiovascular events and atrial fibrillation is more common in this patient population. It is estimated that the prevalence of chronic atrial fibrillation in patients with CKD is two to three times higher than general population. Furthermore, patients with CKD are less likely to stay in sinus rhythm. Atrial fibrillation presents a major burden in this population due to difficult treatment decisions in the setting of a lack of evidence from randomized clinical trials. Patients with CKD have higher risk of stroke with more than half having a CHADS2 score ≥ 2. Anticoagulation have been shown to significantly decrease embolic stroke risk, however bleeding complications such as hemorrhagic stroke is twofold higher with warfarin. Although newer novel anticoagulation drugs have shown promise with lower intracranial hemorrhage risk in comparison to warfarin, lack clinical trial data in CKD and the unavailability of an antidote remains an issue. In this review, we discuss the treatment options available including anticoagulation and the evidence behind them in patients with chronic kidney disease suffering from atrial fibrillation.

Guidelines for the prevention of stroke in patients with stroke and transient ischemic attack: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

The aim of this updated guideline is to provide comprehensive and timely evidence-based recommendations on the prevention of future stroke among survivors of ischemic stroke or transient ischemic attack. The guideline is addressed to all clinicians who manage secondary prevention for these patients. Evidence-based recommendations are provided for control of risk factors, intervention for vascular obstruction, antithrombotic therapy for cardioembolism, and antiplatelet therapy for noncardioembolic stroke. Recommendations are also provided for the prevention of recurrent stroke in a variety of specific circumstances, including aortic arch atherosclerosis, arterial dissection, patent foramen ovale, hyperhomocysteinemia, hypercoagulable states, antiphospholipid antibody syndrome, sickle cell disease, cerebral venous sinus thrombosis, and pregnancy. Special sections address use of antithrombotic and anticoagulation therapy after an intracranial hemorrhage and implementation of guidelines.

Spontaneous and non-spontaneous bleeding complications in patients with oral vitamin K antagonist therapy

PURPOSE

The aim of the study was to evaluate potential differences between patients with spontaneous and non-spontaneous bleeding episodes during treatment with vitamin K antagonists which mainly resulted in compartment syndromes.

METHODS

The population in this study comprised 116 patients who suffered at least one bleeding complication which required surgical treatment during therapy with an oral vitamin K antagonist. The patients were treated between September 2001 and July 2008.

RESULTS

Significant differences were observed between the two patient groups with regard to the presence of renal failure, arterial hypertension, and diabetes mellitus, which occurred more frequently in patients with spontaneous bleeding. Also, significantly more patients with spontaneous bleedings developed compartment syndrome that needed emergency operation. Overall mortality was 9.6 %, was associated with multiorgan failure in all patients, and was not different between the two patient groups.

CONCLUSIONS

The identification of high-risk patients before treatment with an oral vitamin K antagonist is of major importance. The existence of over-anticoagulation syndrome and compartment syndrome is associated with significant mortality and morbidity and should not be underestimated.

Evaluation of atrial electromechanical coupling times in hemodialysis patients

BACKGROUND

There are no definite data about the atrial electromechanical coupling times (AEMCT) in patients with end stage renal failure (ESRF). The aim of this study was to investigate the AEMCT in ESRF patients without hypertension (HT) and diabetes mellitus.

METHODS

The study population consisted of 47 normotensive, nondiabetic ESRF patients and 41 healthy age/gender-matched control subjects. The time intervals from the onset of P-wave on the surface electrocardiogram to the beginning of late diastolic A-wave (PA) were obtained from the lateral mitral annulus (PA-lateral, maximum AEMCT), septal annulus (PA-septal), and tricuspid lateral annulus (PA-tricuspid). Time intervals were corrected according to the heart rate. The difference between PA-septal and PA-tricuspid (right AEMCT), PA-lateral and PA-septal (left AEMCT), and PA-lateral and PA-tricuspid (inter AEMCT) were calculated. Corrected time intervals were used for calculations.

RESULTS

Groups were similar for age (52 ± 12.3 vs. 49.9 ± 6 years, P > 0.05) and gender. Maximum (61 ± 20 vs. 47 ± 13 ms; P < 0.001) AEMCT was significantly higher in the patients compared with the control group, but septal and tricuspid EMCT were not different (P > 0.05). Both inter-atrial (37 ± 21 vs. 24 ± 16 ms, P = 0.002) and left atrial (25 ± 18 vs. 12 ± 9 ms; P < 0.001) EMCT were significantly higher in patients when compared with the controls but intra-right atrial EMCT was not different.

CONCLUSIONS

Atrial conduction parameters such as maximal EMCT, left atrial, and inter-atrial EMCTs were prolonged in ESRF patients. This prolongation is seen in ESRF patients even in the absence of factors that affect atrial coupling, such as HT.

Atrial Fibrillation and Renal Disease

Co-incidence of atrial fibrillation and renal dysfunction in general population is described in many epidemiological studies. Major issue is optimal anticoagulation in patients with atrial fibrillation and renal disease warranting balance between risks of ischemic stroke and hemorrhages. The second issue is catheter ablation of AF patients with renal dysfunction. Both issues are discussed in this paper.

Renal function and outcomes in anticoagulated patients with non-valvular atrial fibrillation: the AMADEUS trial

AIMS

Limited data are available on the impact of renal function on the outcome of patients with atrial fibrillation (AF).

METHODS AND RESULTS

AMADEUS was a multicentre, randomized, open-label non-inferiority study that compared fixed-dose idraparinux with conventional anticoagulation by dose-adjusted vitamin K antagonists. We performed a post hoc analysis to assess the impact of renal function on the outcomes of anticoagulated AF patients. The primary efficacy outcome was the composite of stroke/systemic embolism (SE). The principal safety outcome of this analysis was major bleeding. We calculated c-indexes, reflecting the ability for discriminating diseased vs. non-diseased patients, and the net reclassification improvement (NRI, an index of inferior/superior performance of risk estimation scores). Of 4576 patients, 45 strokes and 103 major bleeding events occurred following an average follow-up of 325 ± 164 days. Patients with CrCl >90 mL/min had an annual stroke/SE rate of 0.6% compared with 0.8% for those with CrCl 60-90 mL/min and 2.2% for those with CrCl <60 mL/min (P < 0.001 for linear association). After adjusting for stroke risk factors, patients with CrCl <60 mL/min had more than two-fold higher risk of stroke/SE and almost 60% higher risk of major bleeding compared with those with CrCl ≥60. In patients with the CHA2DS2VASc score 1-2, CrCl <60 mL/min was associated with eight-fold higher stroke risk. When added to the CHA2DS2VASc or CHADS2 scores, CrCl <60 mL/min did not improve the c-indexes for CHADS2 (P = 0.054) or CHA2DS2VASc (P = 0.63) but resulted in significant NRI (0.26, P = 0.02) in this anticoagulated trial cohort.

CONCLUSION

Renal impairment (CrCl <60 mL/min) doubles the risk of stroke and increased the risk of major bleeding by almost 60% in anticoagulated patients with AF. Renal impairment was additive to stroke risk prediction scores based on a significant NRI, but no significant improvement in discrimination ability (based on c-indexes) for CHA2DS2VASc or CHADS2 was observed.

Does Prophylactic Anticoagulation Reduce the Risk of Femoral Tunneled Dialysis Catheter-related Complications?

Purpose

To determine the incidence and predictors of femoral tunneled dialysis catheter (TDC)-related complications and whether prophylactic anticoagulation is associated with reduced catheter-related deep vein thrombosis (CRT) or prolonged patency.

Methods

A retrospective review of femoral TDCs inserted for maintenance hemodialysis in patients from two dialysis units that have used two different strategies to reduce thrombotic complications. One center routinely considered all femoral TDCs for prophylactic anticoagulation, whilst the other restricted anticoagulation to TDCs that had required repeated treatment with urokinase locks to maintain patency. Survival analyses were performed to establish complication rates, identify predictors of complications and assess the effect of prophylactic anticoagulation use.

Results

Of the 194 femoral TDCs identified, 178 (92%) were associated with at least one complication. Approximately three quarters did not provide adequate small solute clearance; one half were not in use by three months; one quarter had at least one catheter-related infection (2.3 per 1000 catheter days); and one in ten developed a CRT (1.1 per 1000 catheter days). Prophylactic anticoagulation was not associated with significant improvements in rates of catheter occlusion, CRT, catheter-related infection or dialysis adequacy. A previous ipsilateral femoral TDC was identified as a statistically significant predictor of a CRT (adjusted hazard ratio 3.7 [95% confidence interval 1.4-9.8]; P=.007).

Conclusions

Femoral TDCs are associated with poor patency rates and high complication rates; reusing femoral veins for TDCs should be avoided where possible, and this study provides no evidence to support routine prophylactic anticoagulation in all patients with femoral TDCs.

[Predilution online hemodiafiltration: which dose of anticoagulation?]

INTRODUCTION

Patients in end stage renal disease on hemodialysis are in higher risk of bleeding related to the anticoagulation used during a session, so only the lowest effective dose of anticoagulation must be used. The aim of this study was to evaluate the efficacy of predilution in hemodiafiltration with reduced dose of anticoagulation compared to hemodialysis in preventing coagulation of circuits.

PATIENTS AND METHODS

This study was conducted in stable hemodialysis patients without high bleeding risk. All patients were treated by two different treatments: (A) conventional hemodialysis, (B) predilution hemodiafiltration with the half dose of anticoagulation used during treatment (A). Other confounding parameters were kept constant during the study. The primary endpoint was the incidence of major thrombotic events judged on a subjective visual score.

RESULTS

Twenty-one patients were included (105 sessions for each treatment). Major incidents are occurring more frequently in predilution hemodiafiltration with reduced dose of anticoagulation (P=0.03). The premature discontinuation of sessions was more frequent in predilution hemodiafiltration, this difference was not significant (P=0.07). Duration of sessions was significantly shorter in predilution hemodiafiltration (P=0.03). The higher frequency of thrombotic events in predilution hemodiafiltration has no effect on net ultrafiltration volume achieved in both treatments.

CONCLUSION

Predilution hemodiafiltration with a lower dose of anticoagulation did not prevent major clotting of extracorporeal circuit manner at least equivalent to a reference method.

Prevalence of atrial fibrillation and warfarin use in older patients receiving hemodialysis

BACKGROUND

Little is known about the use of warfarin in hemodialysis (HD) patients with atrial fibrillation (AF). We studied temporal trends of AF among older HD patients, and of warfarin use among those with AF.

METHODS

We linked US Medicare and prescription claims from older patients undergoing HD in 2 Eastern US states. We established annual cohorts of prevalent HD patients; AF was ascertained from >2 claims (>7 days apart) in the same year, with a diagnosis code indicating AF. Among those with AF, we defined current and past warfarin use. Demographic and clinical characteristics were also ascertained for each cohort. We used repeated-measures logistic regression to define the odds of AF and of current or past versus absence of warfarin use.

RESULTS

Of 6,563 unique patients, 2,185 were determined to have AF. The prevalence of AF increased from 26% in 1998 to 32% in 2005. In 2005, current warfarin use was present in 24% of AF patients and past use in 25%; 51% had no evidence of any warfarin use. No significant trends in utilization were observed from 1998 through 2005. Patients aged =85 years and nonwhites were less likely to have received warfarin; most comorbidities were not associated with warfarin use except for patients with past pulmonary embolism or deep venous thrombosis who were more likely than those without such history.

CONCLUSION

While the prevalence of AF has been increasing among older HD patients, warfarin use was low and unchanged over time, perhaps reflecting the lack of evidence supporting its use.

Chronic Kidney Disease and Atrial Fibrillation: A Contemporary Overview

Chronic kidney disease (CKD) is associated with substantial cardiovascular morbidity, including myocardial infarction, heart failure and stroke. Similar to CKD, atrial fibrillation (AF) is a prevalent arrhythmia that increases risk for both stroke and overall mortality. Recent studies demonstrate that both prevalence and incidence of AF is higher in patient with versus without renal impairment and risk for developing AF increases as renal function worsens. Potential mechanisms for the higher burden of AF in CKD patients include but are not limited to augmented sympathetic tone, activation of the renin-angiotensin-aldosterone system and myocardial remodeling. Similar to the general population, AF confers an increased risk for both stroke and overall mortality in the CKD population. The safety and efficacy of antithrombotic therapy across the spectrum of CKD remains unknown, however, as patients with advanced renal failure are frequently excluded from randomized trials. While treatment with vitamin K antagonists appears to reduce ischemic complications without significant bleeding harm in patients with mild to moderate CKD and AF, the risk benefit ratio of anticoagulation among thosewith advanced renal failure on dialysis requires further investigation. Prospective, randomized trials are war ranted to define the impact of antithrombotic therapy on reducing stroke risk in patients with both AF and CKD.

Atrial Fibrillation and Oral Anticoagulation in Chronic Kidney Disease

Due to several unfavorable epidemiological changes, chronic kidney disease (CKD) and treatment of its associated cardiovascular morbidity have become a worldwide problem. Thus, atrial fibrillation (AF) is the most common arrhythmia and frequently associated with renal impairment: prevalence for AF is up to 27% in long-term hemodialysis patients and in general more than 25% in all CKD patients 70 years and older. Thromboembolism and stroke are the major complications of AF. Two-year death rates for CKD patients after stroke range between 55% and 74%. Although treatment of AF in the general population is well defined, patients with CKD and AF are often undertreated due to lack of studies and guidelines. In this review recent data concerning incidence and prevalence of AF, stroke, and major bleedings in CKD patients are presented. Particular attention is paid to the available data about the different types of oral anticoagulation therapy with regard to CKD stage, including the new oral anticoagulant drugs dabigatran, rivaroxaban, and apixaban. Stratification algorithms for stroke risk in general, and individualized risk stratification for oral anticoagulation in CKD patients are discussed in detail.

Preventative Measures of Stroke in Patients With Atrial Fibrillation

Atrial fibrillation (AF) is the commonest sustained cardiac arrhythmia and is associated with increased morbidity and mortality due to stroke and thrombo-embolism. In patients with AF, strokes are usually more severe, resulting in longer hospital stays, worse disability and considerable healthcare costs. The prevention of stroke therefore is crucial in the management of AF. Stroke risk stratification tools can be used to determine patients at higher risk of stroke, and if no contraindications are present oral anticoagulation (OAC) therapy can be initiated. Despite the strong evidence for the benefit of OAC in stroke prevention in patients with AF, the use of thromboprophylaxis remains inadequate. The key measures to prevent stroke in patients with AF include: adequate stroke risk assessment and thrombo-prophylaxis; prompt initiation of OAC and avoidance of interruptions; earlier detection of AF; and education to overcome the under-usage of OAC in elderly patients.

Utilization and costs of cardiovascular disease medications in dialysis patients in Medicare Part D

BACKGROUND

Cardiovascular disease (CVD) is a major source of mortality and morbidity in dialysis patients. Population-level descriptions of CVD medication use are lacking in this population.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Adult dialysis patients in the United States, alive on December 31, 2006, with Medicare Parts A and B and enrollment in Medicare Part D continuously in 2007.

PREDICTOR

CVDs and demographic characteristics.

OUTCOME

≥1 prescription fill during follow-up (2007).

MEASUREMENTS

Average out-of-pocket costs per user per month and average total drug costs per member per month were calculated.

RESULTS

Of 225,635 dialysis patients who met inclusion criteria during the entry period, 70% (n = 158,702) had continuous Part D coverage during follow-up. Of these, 76% received the low-income subsidy. β-Blockers were the most commonly used CVD medication (64%), followed by renin-angiotensin system inhibitors (52%), calcium channel blockers (51%), lipid-lowering agents (44%), and α-agonists (23%). Use varied by demographics, geographic region, and low-income subsidy status. For CVD medications, mean out-of-pocket costs per user per month were $3.44 and $49.59 and mean total costs per member per month were $124.02 and $110.32 for patients with and without the low-income subsidy, respectively.

LIMITATIONS

Information was available for only filled prescriptions under the Part D benefit; information for clinical contraindications was lacking, information for over-the-counter medications was unavailable, and medication adherence and persistence were not examined.

CONCLUSIONS

Most Medicare dialysis patients in 2007 were enrolled in Part D, and most enrollees received the low-income subsidy. β-Blockers were the most used CVD medication. Total costs of CVD medications were modestly higher for low-income subsidy patients, but out-of-pocket costs were much higher for patients not receiving the subsidy. Further study is warranted to delineate sources of variation in the use and costs of CVD medications across subgroups.

Clinical pharmacology basis of deriving dosing recommendations for dabigatran in patients with severe renal impairment

The objective of this work was to derive a dosing regimen for dabigatran in patients with severe renal impairment by modeling and simulation. Data from a dedicated renal impairment study were used to model the pharmacokinetics of dabigatran in normal and renal-impaired subjects. Model parameters were used to simulate the average concentration time-course of dabigatran following various dosing regimens. Pharmacokinetics of dabigatran in normal and renal-impaired subjects were best described by a 2-compartment open model with first-order absorption and elimination. Simulations were performed to select an appropriate regimen that reasonably matched the exposures on an average with those observed in subjects with moderate renal impairment who did not require a dose adjustment because of a favorable benefit-risk. Dabigatran 150 mg given once daily resulted in 35% higher average C(max, ss), whereas a 75 mg once daily regimen resulted in 42% lower average Cτ, relative to that observed with 150 mg administered twice daily in subjects with moderate renal impairment. A twice daily regimen of dabigatran 75 mg resulted in a reasonable matching of exposures and was selected as an appropriate dosing regimen in patients with severe renal impairment. This recommendation was incorporated in the dosing and recommendation section of dabigatran product insert.

Guidelines for the prevention of stroke in patients with stroke or transient ischemic attack: a guideline for healthcare professionals from the american heart association/american stroke association

The aim of this updated statement is to provide comprehensive and timely evidence-based recommendations on the prevention of ischemic stroke among survivors of ischemic stroke or transient ischemic attack. Evidence-based recommendations are included for the control of risk factors, interventional approaches for atherosclerotic disease, antithrombotic treatments for cardioembolism, and the use of antiplatelet agents for noncardioembolic stroke. Further recommendations are provided for the prevention of recurrent stroke in a variety of other specific circumstances, including arterial dissections; patent foramen ovale; hyperhomocysteinemia; hypercoagulable states; sickle cell disease; cerebral venous sinus thrombosis; stroke among women, particularly with regard to pregnancy and the use of postmenopausal hormones; the use of anticoagulation after cerebral hemorrhage; and special approaches to the implementation of guidelines and their use in high-risk populations.

Ischaemic stroke in incident dialysis patients

BACKGROUND

Despite the high frequency of cardiovascular disease among the population on dialysis, there are few studies on ischaemic stroke and associated factors. The objective of the present study is to assess the prevalence of ischaemic stroke at the start of dialysis, its incidence in the course of follow-up and possible factors associated in its presentation.

METHODS

All patients in our dialysis programme between 1 January 1999 and 31 December 2005 were included in the study and followed up until death, transplant, transfer out of our catchment area, or conclusion of the study on 31 December 2008. Factors analysed were age, gender, smoking habit, diabetes, hypertension, previous ischaemic stroke, ischaemic coronary disease, peripheral vascular disease and atrial fibrillation. Other factors measured in the first month of dialysis were haematocrit, urea, creatinine, lipids, calcium, phosphorus, parathyroid hormone and albumin.

RESULTS

Of 449 patients included in the study (age 64.4 ± 16 years), 30 commenced dialysis having had previous stroke (prevalence 6.7%). In a follow-up of 38.77 ± 29 months, 34 patients presented with one or more strokes; an incidence of 2.41/100 patient-years. Greater age [odds ratio (OR): 1.05; 95% confidence interval (CI): 1.01-1.09; P = 0.007], diabetes (OR: 2.29; 95% CI: 1.15-4.55; P = 0.018) and presence of atrial fibrillation (OR: 3.11; 95% CI: 1.53-6.32; P = 0.002) were independent predictors of stroke occurrence. Conclusions. The prevalence of ischaemic stroke is high at the commencement of dialysis, and its incidence is elevated in the course of follow-up. As with the general population, atrial fibrillation is an important factor predictive of ischaemic stroke, and as such, the clinical implication is that prophylactic anti-coagulation therapy needs to be considered for these individuals.

INR deviations in hemodialyzed patients under low dose oral anticoagulant therapy

The aim of this retrospective study was to evaluate the International Normalized Ratio (INR) in hemodialyzed uremic patients under treatment with oral anticoagulation drugs. Eleven out of one hundred and forty-two uremic hemodialyzed patients in our unit were included in the study. These 11 patients aged from 70 to 85 (mean: 76 years) were under oral anticoagulation treatment for protection from thromboembolic events. They received 1 mg acenocumarol daily with the therapeutic goal of achieving an INR between 2 and 2.5 units. During the last year, the number of total INR determinations was 129. Based on the INR levels, measurements were classified into three categories of anticoagulation, termed "under-anticoagulation", "target-anticoagulation", and "over-anticoagulation". The number, the percentage, and the mean value (+/-SD) of INR measurements for each category, respectively, were under-anticoagulation: 39, 30%, 1.78 +/- 0.14; target-anticoagulation: 48, 37.5%, 2.20 +/- 0.14; and over-anticoagulation: 42, 32.5%, 3.14 +/- 0.64. The mean value +/-SD of all INR determinations (n=129) was 2.34 +/-0.65. No thromboembolic or major bleeding events occurred in our patients with these INR. In conclusion, in elderly, hemodialyzed uremic patients with indications for oral anticoagulation treatment, adequate and safe INR levels can be achieved in a high proportion without serious deviations from the therapeutic goal by using low doses of drugs. Therefore, oral anticoagulation therapy should not be considered automatically contra-indicated in this patient group.

Incidence of thromboembolic stroke and of major bleeding in patients with atrial fibrillation and chronic kidney disease treated with and without warfarin

The objective was to investigate the incidence of thromboembolic stroke in patients with chronic kidney disease (CKD) and atrial fibrillation (AF) treated with and without warfarin. We investigated the incidence of thromboembolic stroke and of major bleeding in 399 unselected patients with CKD and AF treated with warfarin to maintain an international normalized ratio (INR) between 2.0 and 3.0 (N = 232) and without warfarin (N = 167). Of the 399 patients, 93 (23%) were receiving hemodialysis, and 132 (33%) had an estimated glomerular filtration rate (GFR) of <15 mL/min/1.73 m² At the 31-month follow-up of patients treated with warfarin and 23-month follow-up of patients not treated with warfarin, thromboembolic stroke developed in 21 of 232 patients (9%) treated with warfarin and in 43 of 167 patients (26%) not treated with warfarin (P < 0.001). Major bleeding occurred in 32 of 232 patients (14%) treated with warfarin and in 15 of 167 patients (9%) not treated with warfarin (P not significant). Stepwise Cox regression analysis showed that significant independent predictors of thromboembolic stroke were use of warfarin (odds ratio, 0.28; P < 0.0001) and prior stroke or transient ischemic attack (odds ratio, 2.9; P < 0.05). In conclusion, this observational study showed that CKD patients with AF treated with warfarin to maintain an INR between 2.0 and 3.0 had a significant reduction in thromboembolic stroke and an insignificant increase in major bleeding.

Oral anticoagulant therapy in hemodialysis patients: do the benefits outweigh the risks?

Managing oral anticoagulation may be difficult in hemodialysis patients because the antithrombotic effect can be counterbalanced by an increased risk of hemorrhagic complications. There is insufficient evidence to recommend the routine use of warfarin for thrombosis prophylaxis of the vascular access in all patients. If a decision for anticoagulation is made, dosing warfarin to a "therapeutic" level is suggested, although the most appropriate target INR range remains unclear. Many hemodialysis patients with atrial fibrillation have multiple risk factors for stroke and generally benefit from warfarin, with careful and frequent laboratory monitoring. Treatment with standard dose warfarin is also recommended in patients with venous thromboembolism provided that patients do not have contraindications to anticoagulation. For those with such contraindications, placement of an inferior vena cava filter is suggested. These recommendations are limited by the almost complete lack of data in dialysis patients. Sound randomized evidence of efficacy and harm for anticoagulation in these patients will likely never be available. Knowledge of the risk of bleeding and thrombosis in anticoagulated and nonanticoagulated dialysis patients could be provided by feasible, well-designed cohort studies.

Antiplatelet medications in hemodialysis patients: a systematic review of bleeding rates

BACKGROUND AND OBJECTIVES

Patients with end stage renal disease (ESRD) are often prescribed antiplatelet medications. However, these patients are also at increased risk of bleeding compared with the general population, and an aim was made to quantify this risk with antiplatelet agents.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A systematic review of the literature (Medline, EMBASE, Cochrane CENTRAL and Google Scholar databases) was done to determine the bleeding risk in ESRD patients prescribed antiplatelet therapy. The secondary outcome was the effect on access thrombosis. All case series, cohort studies and clinical trials were considered if they included ten or more ESRD patients, assessed bleeding risk with antiplatelet agents, and lasted for more than 3 mo.

RESULTS

Sixteen studies, including 40,676 patients, were identified that met predefined inclusion criteria. Due to study heterogeneity and weaknesses in methodology, bleeding rates were not pooled across studies. However, the bleeding risk appears to be increased for hemodialysis patients treated with combination antiplatelet therapy. The results are mixed for studies using a single antiplatelet agent. Antiplatelet agents appear to be effective in preventing shunt and central venous catheter thrombosis, but not for preventing thrombosis of arteriovenous grafts.

CONCLUSION

The risks and benefits of antiplatelet agents in ESRD patients remain poorly defined. Until a clinical trial addresses this in the dialysis population, individual risk stratification taking into account the increased risk of bleeding should be considered before initiating antiplatelet agents, especially in combination therapy.

Kidney function influences warfarin responsiveness and hemorrhagic complications

Although management of warfarin is challenging for patients with chronic kidney disease (CKD), no prospective studies have compared response to warfarin among patients with minimal, moderate, and severe CKD. This secondary analysis of a prospective cohort of 578 patients evaluated the influence of kidney function on warfarin dosage, anticoagulation control, and risk for hemorrhagic complications. We adjusted all multivariable regression and proportional hazard analyses for clinical and genetic factors. Patients with severe CKD (estimated GFR <30 ml/min per 1.73 kg/m2) required significantly lower warfarin dosages (P = 0.0002), spent less time with their international normalized ratio within the target range (P = 0.049), and were at a higher risk for overanticoagulation (international normalized ratio >4; P = 0.052), compared with patients with no, mild, or moderate CKD. Patients with severe CKD had a risk for major hemorrhage more than double that of patients with lesser degrees of renal dysfunction (hazard ratio 2.4, 95% confidence interval 1.1 to 5.3). In conclusion, patients with reduced kidney function require lower dosages of warfarin, have poorer control of anticoagulation, and are at a higher risk for major hemorrhage. These observations suggest that warfarin may need to be initiated at a lower dosage and monitored more closely in patients with moderate or severe CKD compared with the general population. Diminished renal function may have implications for a larger proportion of warfarin users than previously estimated.

Stroke in chronic renal failure

Chronic kidney diseases and cardiovascular diseases have several common risk factors like hypertension and diabetes. In chronic renal disease stroke risk is several times higher than in the average population. The combination of classical risk factors and those characteristic of chronic kidney disease might explain this increased risk. Among acute cerebrovascular diseases intracerebral hemorrhages are more frequent than in those with normal kidney function. The outcome of stroke is worse in chronic kidney disease. The treatment of stroke (thrombolysis, antiplatelet and anticoagulant treatment, statins, etc.) is an area of clinical research in this patient group. There are no reliable data on the application of thrombolysis in acute stroke in patients with chronic renal disease. Aspirin might be administered. Carefulness, individual considerations and lower doses might be appropriate when using other treatments. The condition of the kidney as well as other associated diseases should be considered during administration of antihypertensive and lipid lowering medications.

Atrial fibrillation in chronic non-cardiac disease: where do we stand?

Atrial fibrillation is the most common arrhythmia, and is associated with increased risk of stroke and death. Most of present knowledge is derived from studies in patients with cardiac disease whilst limited information is available for patients with several chronic non-cardiac conditions like cancer, chronic obstructive pulmonary disease and chronic kidney disease. Although millions of patients are affected and are at risk of adverse prognosis due to co-existent atrial fibrillation, we are left with very limited guidance for management of atrial fibrillation itself and prevention of complications in those patients. In this paper, we review data on incidence, prognostic importance and treatment modalities of atrial fibrillation in patients with cancer, chronic obstructive pulmonary disease, and chronic kidney disease.

Major bleeding in hemodialysis patients

BACKGROUND AND OBJECTIVES

Few studies have examined risk factors for hemorrhage in hemodialysis patients. The contribution of warfarin and antiplatelet agent exposure to the incidence of first major bleeding episodes in hemodialysis patients was determined.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Retrospective chart review was performed in eligible hemodialysis patients. Incidence rates were determined as the number of first major bleeding events divided by the total exposure time on each treatment combination. Time-dependent covariates and Cox proportional hazard models were used to determine the hazard rate of having a first major bleeding event.

RESULTS

A total of 1028 person-years of exposure were observed from 255 patients with a median follow-up time of 3.6 yr. The incidence rate of major bleeding episodes was 2.5% per person-year. The incidence of major bleeding episodes was 3.1% per person-year of warfarin exposure, 4.4% per person-year of aspirin exposure, and 6.3% per person-year of exposure to the combination of warfarin and aspirin. Compared with patients who were not prescribed warfarin or aspirin, the multivariable hazard ratio for time to first major bleeding event was 3.59 for warfarin, 5.24 for aspirin, and 6.19 for the combination of aspirin and warfarin.

CONCLUSIONS

The risk for major bleeding episodes in hemodialysis patients increases significantly while on aspirin and/or warfarin, although warfarin alone did not reach statistical significance. Future studies should evaluate the efficacy of these agents in the secondary prevention of cardiovascular events in this high-risk population.

Atrial fibrillation in end-stage renal disease

End-stage renal disease (ESRD) is associated with increased cardiovascular morbidity and mortality. Recent studies indicate that atrial fibrillation (AF) is prevalent among ESRD patients while it adversely affects the clinical outcome. Despite these considerations, AF management in this population is problematic. Notably, most ESRD patients with AF are deprived of the benefits of anticoagulation therapy because of the fear of hemorrhagic complications. This article provides a concise and critical overview of the complex pathophysiology, epidemiology, and discusses the clinical issues regarding the emerging association between ESRD and AF.

Atrial fibrillation in haemodialysis patients: Do the guidelines for anticoagulation apply?

AIM

Atrial fibrillation (AF) is common in haemodialysis patients, but the risks and benefits of anticoagulation in this group are not well characterized. We investigated the prevalence of AF, its associated risk factors, and the incidence of stroke and haemorrhage in a cohort of haemodialysis patients.

METHODS

We retrospectively reviewed 155 patients undergoing maintenance haemodialysis on 1 April 2003 (age 56.9 +/- 13.5 years; men 62.6%; mean duration of haemodialysis 39.3 +/- 37.5 months). Patients with paroxysmal or permanent AF were identified, and baseline clinical and echocardiographic data were obtained. The incidence of cerebrovascular accidents, major haemorrhage and all-cause mortality was assessed during the 26 month average follow-up period.

RESULTS

AF was present in 25.8% of patients, paroxysmal in 18.1%, and permanent in 7.7%. Patients with AF were more likely to be older (64.2 +/- 9.4 vs 54.4 +/- 13.8 years; P < 0.005), have underlying ischaemic heart disease or congestive heart failure, and have a lower serum albumin (P < 0.05 for all). Only 12.5% of AF patients were anticoagulated, although 47.5% had contraindications to warfarin. Cerebrovascular events occurred in 5.2% of all patients (30.4 episodes/1000 patient-years), and major haemorrhage in 20.0% (106.4 episodes/1000 patient-years). All-cause mortality was 29.7%. The endpoints for the AF group did not significantly differ from the non-AF group.

CONCLUSION

AF is common in haemodialysis patients. The incidence of major haemorrhage was over three times that of cerebrovascular accidents. Guideline recommendations for anticoagulation in AF in the general population may not be appropriate for the haemodialysis population.

Warfarin anticoagulation in hemodialysis patients: a systematic review of bleeding rates

BACKGROUND

Despite common use of warfarin, the bleeding risk associated with this treatment in hemodialysis (HD) patients is unknown.

STUDY DESIGN

Systematic review.

SELECTION CRITERIA FOR STUDIES

Inclusion criteria were case series, cohort studies, and randomized controlled trials in dialysis patients that examined the bleeding risk associated with warfarin use compared with no warfarin or subcutaneous heparin. Studies with fewer than 10 subjects, case reports, abstracts lacking complete data sets, review articles, and editorials were excluded.

PREDICTOR

Warfarin use compared with no warfarin or subcutaneous heparin.

OUTCOMES

Data for bleeding were reported as rates: number of bleeding episodes per number of patient-years of warfarin exposure or follow-up.

RESULTS

Of 79 articles and abstracts, 5 met inclusion criteria and 3 more could be added after investigators provided additional information. All studies were of HD patients, and 7 of 8 evaluated the use of warfarin for the prevention of HD access thrombosis. Intensity of anticoagulation varied. Meta-analysis was not possible because of study heterogeneity. Studies of full-intensity anticoagulation and the 1 randomized controlled trial of low-intensity anticoagulation showed major bleeding episode rates ranging from 0.1 to 0.54 events/patient-year of warfarin exposure. These rates are approximately twice as high as those of HD patients receiving either no warfarin or subcutaneous heparin.

LIMITATIONS

This review is based largely on data from observational studies in which bleeding rates may be confounded by comorbidity. Relatively small sample sizes may provide imprecise estimates of rates.

CONCLUSION

Low- and full-intensity anticoagulation use in HD patients is associated with a significant bleeding risk, which has to be balanced against any potential benefit of therapy. This has to be considered carefully when prescribing warfarin to HD patients.

Should Hemodialysis Patients With Atrial Fibrillation Undergo Systemic Anticoagulation? A Cost-Utility Analysis

BACKGROUND

Approximately 14% of hemodialysis patients have atrial fibrillation. Hemodialysis patients with atrial fibrillation appear to be at increased risk of both thromboembolic complications and bleeding. Furthermore, there is uncertainty regarding the efficacy of warfarin or acetylsalicylic acid (ASA) therapy for preventing strokes in this subgroup because they were excluded from relevant trials.

STUDY DESIGN

We performed a cost-utility analysis. Probabilistic sensitivity analysis was used to incorporate parameter uncertainty into the model. Expected value of perfect information and scenario analyses were performed to identify the important drivers of the decision and focus future research.

SETTING & POPULATION

Base case was a 60-year-old male hemodialysis patient in the United States.

MODEL, PERSPECTIVE, & TIME FRAME

A Markov Monte Carlo microsimulation model was constructed from the perspective of the health care payer, and patients were followed up during their lifetime.

INTERVENTION

We compared 3 alternative treatment strategies for permanent atrial fibrillation in hemodialysis patients: warfarin, ASA, or no treatment.

OUTCOMES

Quality-adjusted survival and cost.

RESULTS

ASA and warfarin both prolonged survival compared with no treatment (0.06 and 0.15 quality-adjusted life-years [QALYs], respectively). ASA was associated with an incremental cost-effectiveness ratio of $82,100/QALY. Warfarin provided additional benefits at a cost of $88,400 for each QALY gained relative to ASA. At a threshold of $100,000/QALY, the probabilities that no treatment, warfarin, and ASA were the most efficient therapy were 20%, 58%, and 23%, respectively.

LIMITATIONS

Parameterization data and costs were taken from US studies and may not be generalizable to other countries. Peritoneal dialysis patients were not included in the analysis.

CONCLUSIONS

The high future cost of hemodialysis constrains incremental cost-effectiveness ratios to values greater than commonly cited thresholds ($50,000/QALY). Based on available evidence, warfarin appears to be the optimal therapy to prevent thromboembolic stroke in hemodialysis patients with atrial fibrillation. Additional study is required to determine the efficacy of warfarin and risk of bleeding complications in this population so that patients can make a more informed choice.

Guidelines for Prevention of Stroke in Patients With Ischemic Stroke or Transient Ischemic Attack

The aim of this new statement is to provide comprehensive and timely evidence-based recommendations on the prevention of ischemic stroke among survivors of ischemic stroke or transient ischemic attack. Evidence-based recommendations are included for the control of risk factors, interventional approaches for atherosclerotic disease, antithrombotic treatments for cardioembolism, and the use of antiplatelet agents for noncardioembolic stroke. Further recommendations are provided for the prevention of recurrent stroke in a variety of other specific circumstances, including arterial dissections; patent foramen ovale; hyperhomocysteinemia; hypercoagulable states; sickle cell disease; cerebral venous sinus thrombosis; stroke among women, particularly with regard to pregnancy and the use of postmenopausal hormones; the use of anticoagulation after cerebral hemorrhage; and special approaches for the implementation of guidelines and their use in high-risk populations.

The effect of oral anticoagulation on clotting during hemodialysis

BACKGROUND

Between 5% and 10% of hemodialysis patients are treated with oral anticoagulants. It is currently unknown whether additional anticoagulation with heparin or low-molecular-weight heparin (LMWH) is needed to prevent clotting during hemodialysis.

METHODS

In this prospective, randomized, cross-over study 10 patients treated with oral anticoagulants (phenprocoumon) received either no additional anticoagulation or low dose dalteparin (bolus of 40 IU/kg body weight) before dialysis. Efficacy of hemodialysis was measured by normalized weekly Kt/V and urea reduction rate (URR). Thrombus formation was evaluated by measurement of D-dimer and inspection of air traps and dialyser.

RESULTS

The median international normalized ratio (INR) did not differ between both observation periods (phenprocoumon 2.2(2 to 3) vs. dalteparin 2.1(2 to 2.9). The anti-Xa level in dalteparin patients was 0.33 (0.27 to 0.38) IU/mL after 2 hours and 0.16 (0.03 to 0.23) IU/mL after 4 hours of hemodialysis. The median increase of D-dimer was significantly higher in patients without additional dalteparin therapy during hemodialysis (DeltaD-dimer 0.23 microg/mL vs. 0.03 mug/mL) (P= 0.0004). Complete thrombosis of the dialyser membrane occurred in one patient in the phenprocoumon group but in none with combined treatment. The extent of thrombosis in the arterial and venous air trap and dialyser was significantly less in patients with additional dalteparin therapy (P= 0.0014, P= 0.0002, and P= 0.0005, respectively). Weekly Kt/V and URR was similar in both groups.

CONCLUSION

Standard oral anticoagulation with an INR between 2 and 3 is insufficient to prevent clotting during hemodialysis. Additional low dose anticoagulation with a LMWH or heparin is necessary to facilitate treatment.