The risk of anticoagulation in hemodialysis patients

The risk of bleeding for antiplatelet agents in Haemodialysis patients: a Meta-analysis

Background

The safety of antiplatelet therapy in haemodialysis (HD) patients remains controversial. we conducted the first meta-analysis to evaluate the bleeding risk with antiplatelet agents in these populations.

Methods

The relevant literature was searched using the following electronic databases without any language restrictions: the Cochrane Library, EMBASE, Global Health, MEDLINE, PubMed, and the Chinese Biomedical Database.

Results

Seven randomized controlled trials (RCTs) and 2 prospective cohort studies, consisting of 1131 patients, were identified for detailed evaluation. The meta-analysis suggested that the use of double antiplatelet agents increased the risk of bleeding in HD patients [odds ratio (OR) = 2.78; 95% confidence interval (CI) 1.63 to 4.76; I² = 0], and antiplatelet agents increased the risk of bleeding in 7 RCTs [odds ratio (RR) = 1.40, 95% CI 1.08 to 1.79; I² = 23%,]; however, the use of a single antiplatelet agent was not found to significantly increase the risk of bleeding (RR = 0.88; 95% CI 0.51 to 1.50; I² = 0).

Conclusion

The results suggested that the use of double antiplatelet agents increased the risk of bleeding in HD patients.

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.

2017 consensus of the Asia Pacific Heart Rhythm Society on stroke prevention in atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia, causing a 2-fold increase in mortality and a 5-fold increase in stroke. The Asian population is rapidly aging, and in 2050, the estimated population with AF will reach 72 million, of whom 2.9 million may suffer from AF-associated stroke. Therefore, stroke prevention in AF is an urgent issue in Asia. Many innovative advances in the management of AF-associated stroke have emerged recently, including new scoring systems for predicting stroke and bleeding risks, the development of non-vitamin K antagonist oral anticoagulants (NOACs), knowledge of their special benefits in Asians, and new techniques. The Asia Pacific Heart Rhythm Society (APHRS) aimed to update the available information, and appointed the Practice Guideline sub-committee to write a consensus statement regarding stroke prevention in AF. The Practice Guidelines sub-committee members comprehensively reviewed updated information on stroke prevention in AF, emphasizing data on NOACs from the Asia Pacific region, and summarized them in this 2017 Consensus of the Asia Pacific Heart Rhythm Society on Stroke Prevention in AF. This consensus includes details of the updated recommendations, along with their background and rationale, focusing on data from the Asia Pacific region. We hope this consensus can be a practical tool for cardiologists, neurologists, geriatricians, and general practitioners in this region. We fully realize that there are gaps, unaddressed questions, and many areas of uncertainty and debate in the current knowledge of AF, and the physician׳s decision remains the most important factor in the management of AF.

Anticoagulation and dialysis access practice in home haemodialysis in the UK

Anticoagulation is an important component of haemodialysis treatment in all settings. The therapeutic options available for anticoagulation of home haemodialysis are similar to those for haemodialysis in other settings. However, dialysis sessions with a wide range of treatment durations are undertaken at home, which can require different approaches to anticoagulation. Conference delegates were asked about the types of anticoagulation used in home dialysis and about surveillance strategies for monitoring vascular access, and the results are presented and discussed.

Bleeding and thrombotic complications of kidney disease

With the rising prevalence of kidney disease, clinicians are increasingly faced with concerns about potential thrombotic and bleeding complications. Thrombotic risk, both arterial and venous, predominates with all severities of kidney disease but bleeding manifestations become an additional concern particularly with uraemia. This article reviews these contrasting problems and discusses strategies for prevention and management in the context of renal impairment, renal replacement therapy and renal transplantation.

Warfarin in haemodialysis patients with atrial fibrillation: what benefit?

Warfarin is commonly used to prevent stroke in patients with atrial fibrillation; however, patients on haemodialysis may not derive the same benefit from warfarin as the general population. There are no randomized controlled studies in dialysis patients which demonstrate the efficacy of warfarin in preventing stroke. In fact, warfarin places the dialysis patient at increased risk for haemorrhagic stroke and possibly ischaemic stroke. Additionally, warfarin increases the risk of major bleeding and has been associated with vascular calcification. Routine use of warfarin in dialysis for stroke prevention should be discouraged, and therapy should only be reserved for dialysis patients at high risk for thrombo-embolic stroke and carefully monitored if implemented.

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.

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 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.

Primary Vascular Access

Primary vascular access is usually achievable by a distal autogenous arterio-venous fistula (AVF). This article describes the approach to vascular access planning, the usual surgical options and the factors affecting patency.

Uremic bleeding: pathophysiology and clinical risk factors

Renal insufficiency appears clinically to be associated with a bleeding tendency. This has been documented in clinical settings including as a complication of medical interventions such as surgery and also in spontaneous bleeding events at gastrointestinal and intracranial sites. The pathophysiology that underlies this tendency appears to involve platelet dysfunction and an imbalance of mediators of normal endothelial function. It is also may be complicated by the co-morbidities in this population, such as vascular disease, hypertension and anemia, and the medical interventions required to treat such co-morbidities. This article reviews the evidence, the pathophysiology and the risk factors for increased bleeding in patients with chronic renal insufficiency.

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

BACKGROUND

Dialysis patients with atrial fibrillation have an increased thrombolic risk. Dicoumarin anticoagulant therapy is often considered contra-indicated in chronic renal insufficiency in which the risk of haemorrhage, though not defined, is perceived to be high. We assessed haemorrhage complications in dialysis patients receiving dicoumarin anticoagulant therapy to establish whether the haemorrhage risk justifies the contra-indication of anticoagulant therapy in patients with atrial fibrillation.

PATIENTS AND METHODS

Over a period of a decade in our dialysis centre, 29 patients receiving anticoagulant therapy over a protracted period presented haemorrhage complications. These were classified with respect to severity and location and compared with 211 patients not receiving anticoagulant therapy. The relative risk of haemorrhage was calculated and was compared to risk of thrombo-embolism in dialysis patients with atrial fibrillation.

RESULTS

Of the 29 patients, nine had 13 episodes of haemorrhage complications (26 episodes/100 patient-years). None was fatal, nor intra-cranial nor with serious clinical sequelae. In the group without anticoagulants, 29 patients had 39 haemorrhage complications (11 episodes/100 patient-years); four (10.2%) intra-cranial and all fatal. The relative risk of bleeding with anticoagulant therapy was 2.36 (95% confidence interval=1.19-4.27).

CONCLUSIONS

(1) Dialysis patients with anticoagulant therapy presented with a higher risk of haemorrhage; (2) the relative risk of bleeding was double that of the dialysis population without anticoagulant therapy; (3) despite the high risk of haemorrhage that we observed, the high risk of thrombo-embolism and the attendant serious sequelae to which dialysis patients with atrial fibrillation are predisposed indicates that oral anticoagulation therapy ought not to be considered automatically contra-indicated in this patient group but that an exhaustive evaluation of the risk-benefit needs to be conducted on an individual patient basis.

Low-intensity warfarin is ineffective for the prevention of PTFE graft failure in patients on hemodialysis: a randomized controlled trial

Polytetrafluoroethylene (PTFE) dialysis grafts in patients with end-stage renal disease (ESRD) are prone to thrombotic failure. The objective of this multicenter, randomized, double-blind, placebo-controlled clinical trial was to determine if warfarin reduces the risk of failure of PTFE dialysis grafts. Patients with ESRD and newly placed PTFE grafts were studied at community and academic dialysis centers in Southwestern Ontario. Patients were allocated to receive warfarin or matching placebo, with the warfarin administered to achieve a target INR of 1.4 to 1.9. Time to graft failure was the main outcome measure. A total of 107 patients (56 allocated to warfarin) were randomized. The time-to-event analysis revealed no significant difference in the likelihood of graft survival between the two groups (odds ratio, 1.76 in favor of placebo; 95% confidence interval, 0.72 to 4.34). Six major bleeds occurred in five patients allocated to warfarin compared with none in the patients who received placebo (P = 0.03). In conclusion, low-dose warfarin was associated with an excess of clinically important major bleeding in patients with ESRD enrolled in this study. Furthermore, low-intensity, monitored-dose warfarin does not appear to prolong PTFE graft survival.

Influence of atrial fibrillation on the morbido-mortality of patients on hemodialysis

BACKGROUND

The consequences of atrial fibrillation (AF) on morbido-mortality of patients on hemodialysis have not been fully explored. The objective of this study was to determine the prevalence of AF in patients on hemodialysis and to evaluate its influence on the development of thromboembolic phenomena (TEP).

METHODS

The incidence of AF in 190 patients in our hemodialysis program was assessed, and the patients were followed up for 1 year. Pertinent demographic and biochemical parameters were entered into univariate and multivariate statistical analyses to evaluate associations with overall mortality and TEP such as cerebrovascular accident, transitory ischemic accident, or peripheral embolism.

RESULTS

In 13.6% of patients, AF was found; 9.4% of these were of the permanent type. In the multivariate analysis, only increased age was associated with a higher probability of having arrhythmia (odds ratio, 1.10; 95% confidence interval, 1.03-1.17; P =.003). During follow-up, 23% of the patients with AF died compared with 6% of those in sinus rhythm (P <.05), although AF did not appear to be an independent predictive factor for death. Thirty-five percent of the patients with AF and 4% with sinus rhythm had TEP (P <.01). In the multivariate analysis, AF was identified as the only independent predictor for TEP (odds ratio, 8; 95% CI, 2.3-27; P =.0008).

CONCLUSIONS

AF is a frequent arrhythmia in patients on hemodialysis, and approximately 1 in 3 hemodialysis patients with AF had thromboembolic complications within 1 year of follow-up. These findings suggest that the consensus contraindication of prophylactic anticoagulation therapy for this group of patients may need to be redefined.

Anticardiolipin antibody in patients on maintenance hemodialysis and its association with recurrent arteriovenous graft thrombosis

To investigate the relationship between dialysis access thrombosis (arteriovenous grafts [AVG] and arteriovenous fistulas [AVF]) and the presence of elevated concentration of immunoglobulin G-anticardiolipin antibody (IgG-ACA), we conducted a cross-sectional study of all patients, in a single dialysis facility, who had a minimum of 6 months of uninterrupted hemodialysis. Episodes of thrombosis of AVGs and AVFs in the preceding 30 months were documented and each patient's IgG-ACA titer was determined. Sixteen of 74 patients with AVGs (22%) had a raised titer of IgG-ACA compared with only one of 17 patients (6%) with AVFs. In the patients with AVGs the odds ratio for patients with raised IgG-ACA titer to have experienced two or more episodes of thrombosis, compared with none or only one episode, was 3.7 (95% confidence interval, 1.2 to 11.8; P < 0.04). No events of AVF thrombosis were encountered during the same period. We conclude that in end-stage renal disease patients undergoing hemodialysis, there is a greater prevalence of elevated IgG-ACA titer in patients with AVGs than in patients with AVFs, and this in turn is associated with increased odds of having had recurrent AVG thrombosis.

Frequent hemodialysis graft thrombosis: association with antiphospholipid antibodies

We present two cases of patients with systemic lupus erythematosus and end-stage renal disease. Both were on hemodialysis and had multiple arteriovenous graft thromboses associated with the presence of antiphospholipid antibodies. A review of patients with end-stage renal disease secondary to systemic lupus erythematosus reveals that all had borderline or frankly elevated antiphospholipid antibody titers, and four of the seven patients had multiple graft thromboses. Possible etiologic and pathophysiologic mechanisms are discussed.

Nontraumatic subdural hematoma in a patient with osteogenesis imperfecta and renal failure

Intracranial hematomas in patients with osteogenesis imperfecta rarely are reported despite an increased incidence of skull fractures. We present a case of a patient with osteogenesis imperfecta but without any history of trauma or chronic anticoagulation in whom a subdural hematoma occurred during hemodialysis. Despite operative intervention, the patient died. We could find no other cases in the medical literature of a patient with osteogenesis imperfecta who had an intracranial hematoma in the absence of a skull fracture. Patients with osteogenesis imperfecta may be at high risk for intracranial bleeding from coagulation abnormalities or otherwise trivial injuries.