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

When anticoagulation management in atrial fibrillation becomes difficult: Focus on chronic kidney disease, coagulation disorders, and cancer

Anticoagulation therapy (AT) is fundamental in atrial fibrillation (AF) treatment but poses challenges in implementation, especially in AF populations with elevated thromboembolic and bleeding risks. Current guidelines emphasize the need to estimate and balance thrombosis and bleeding risks for all potential candidates of antithrombotic therapy. However, administering oral AT raises concerns in specific populations, such as those with chronic kidney disease (CKD), coagulation disorders, and cancer due to lack of robust data. These groups, excluded from large direct oral anticoagulants trials, rely on observational studies, prompting physicians to adopt individualized management strategies based on case-specific evaluations. The scarcity of evidence and specific guidelines underline the need for a tailored approach, emphasizing regular reassessment of risk factors and anticoagulation drug doses. This narrative review aims to summarize evidence and recommendations for challenging AF clinical scenarios, particularly in the long-term management of AT for patients with CKD, coagulation disorders, and cancer.

Feasibility of Outpatient Hemodialysis for Patients With Total Artificial Heart: A Case Series

Total artificial hearts (TAH) are used in patients with end-stage heart failure as a bridge-to-transplant. AKI is a common postoperative complication associated with TAH implant. Patients requiring temporary dialysis are denied implantation of TAH due to the inability to provide outpatient (OP) dialysis in the long term. Here we discuss four cases of TAH patients from a single center who were successfully maintained on OP hemodialysis (HD). All four patients were implanted with a 70cc Syncardia TM TAH for NICM. Two patients were implanted as bridge-to-transplant (BTT); one received a heart/kidney transplant and the other received a heart transplant. Two patients were implanted as destination therapy; one was maintained on OP HD until end-of-life, and the other received a heart transplant after becoming transplant eligible. These cases confirm that OP HD is a feasible option for TAH patients with post-implant chronic renal dysfunction provided that the dialysis centers are trained and supported by the implanting program.

Clinical benefits and risks of anticoagulation therapy according to the degree of chronic kidney disease in patients with atrial fibrillation

BACKGROUND

The clinical benefits and risks of anticoagulation therapy in patients with chronic kidney disease (CKD) are still inconclusive. We describe the outcomes of patients with atrial fibrillation (AF) after anticoagulation therapy according to differences in creatinine clearance (CrCl). We also aimed to determine the patients who could benefit from anticoagulation therapy.

METHODS

This is a retrospective observational review of patients with AF who were managed at Asan Medical Center (Seoul, Korea) between January 1, 2006, and December 31, 2018. Patients were categorized into groups according to their baseline CrCl by Cockcroft-Gault equation and their outcomes were evaluated (CKD 1, ≥ 90 mL/min; CKD2, 60-89 mL/min; CKD3, 30-59 mL/min; CKD4, 15-29 mL/min; CKD 5, < 15 mL/min). The primary outcome was NACE (net adverse clinical events), defined as a composite of all-cause mortality, thromboembolic events, and major bleeding.

RESULTS

We identified 12,714 consecutive patients with AF (mean 64.6 ± 11.9 years, 65.3% male, mean CHA₂DS₂-VASc score 2.4 ± 1.6 points) between 2006 and 2017. In patients receiving anticoagulation therapy (n = 4447, 35.0%), warfarin (N = 3768, 84.7%) was used more frequently than NOACs (N = 673, 15.3%). There was a higher 3-year rate of NACE with renal function deterioration (14.8%, 18.6%, 30.3%, 44.0%, and 48.8% for CKD stages 1-5, respectively).The clinical benefit of anticoagulation therapy was most prominent in patients with CKD 1 (hazard ratio [HR] 0.49, 95% confidence interval [CI] 0.37-0.67), 2 (HR 0.64 CI 0.54-0.76), and 3 (HR 0.64 CI 0.54-0.76), but not in CKD 4 (HR 0.86, CI 0.57-1.28) and 5 (HR 0.81, CI 0.47-1.40). Among patients with CKD, the benefit of anticoagulation therapy was only evident in those with a high risk of embolism (CHA₂DS₂-VASc score ≥ 4, HR 0.25, CI 0.08-0.80).

CONCLUSION

Advanced CKD is associated with a higher risk of NACE. The clinical benefit of anticoagulation therapy was reduced with the increasing CKD stage.

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.

Anticoagulation for Stroke Prevention of Concomitant Atrial Fibrillation and End-Stage Renal Disease: Insights of Cardiologists and Nephrologists From India

Introduction Patients with concomitant atrial fibrillation (AF) and end-stage renal disease (ESRD) are at increased risk of thrombosis and bleeding. Diligent anticoagulant therapy that prevents major bleeding is essential for stroke prevention. There is a dearth of evidence and guidance on anticoagulation in this patient subset. Methods A validated questionnaire was sent to 500 physicians across India. Anonymized responses from 353 consenting physicians (275 cardiologists and 78 nephrologists) were analyzed. Results Most physicians opined that the risk of progression of chronic kidney disease (CKD) stages 2-4 to ESRD was 1-5%, and that >10% of patients with ESRD had concomitant AF. Most physicians perceived that the risk of ischemic stroke, major bleeding, and mortality was 30-40%, <15%, and >40% respectively in patients with concomitant AF and ESRD. The first critical goal for the management of these patients was 'reduction of thrombotic risk', followed by 'prevention of bleeding' and finally 'prevention of ESRD progression' (72.0%, 68.0%, and 67.1% participants, respectively). Most participating physicians (93.8%) preferred non-vitamin K antagonist oral anticoagulants (NOACs) over warfarin for stroke prevention, and most of the participating physicians (94.9%) preferred an adjusted dose rather than the standard dose of the NOAC. Most of the responses were similar between cardiologists and nephrologists. Conclusion According to the survey response, patients with concomitant AF and ESRD have an increased risk of thrombosis, bleeding, and mortality. NOACs with dose adjustment are the preferred modality for stroke prevention among cardiologists and nephrologists in India, with the primary goal of preventing thrombotic events.

Stroke Prevention in Atrial Fibrillation: A Scientific Statement of JACC: Asia (Part 2)

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is associated with substantial increases in the risk for stroke and systemic thromboembolism. With the successful introduction of the first non-vitamin K antagonistdirect oral anticoagulant agent (NOAC) in 2009, the role of vitamin K antagonists has been replaced in most clinical settings except in a few conditions for which NOACs are contraindicated. Data for the use of NOACs in different clinical scenarios have been accumulating in the past decade, and a more sophisticated strategy for patients with AF is now warranted. JACC: Asia recently appointed a working group to summarize the most updated information regarding stroke prevention in AF. The aim of this statement is to provide possible treatment options in daily practice. Local availability, cost, and patient comorbidities should also be considered. Final decisions may still need to be individualized and based on clinicians' discretion. This is part 2 of the statement.

Insights into Concomitant Atrial Fibrillation and Chronic Kidney Disease

Chronic kidney disease (CKD) shows a high prevalence and is characterized by progressive and irreversible loss of renal function. It is also associated with a high risk of cardiovascular disease. The CKD population often suffers from atrial fibrillation (AF), which is associated with cardiovascular and all-cause mortality. There is a pernicious bidirectional relationship between CKD and AF: renal dysfunction can help promote AF initiation and maintenance, while unmanageable AF often accelerates kidney function deterioration. Therefore, it is necessary to determine the interactive mechanisms between CKD and AF for optimal management of patients. However, due to renal function impairment and changes in the pharmacokinetics of anticoagulants, it is still elusive to formulate a normative therapeutic schedule for the AF population concomitant with CKD especially those with end-stage kidney failure. This review describes the possible molecular mechanisms linking CKD to AF and existing therapeutic options.

Epidemiology of cardiovascular death in kidney failure: An Australian and New Zealand cohort study using data linkage

Aim

Cardiovascular mortality risk evolves over the lifespan of kidney failure (KF), as patients develop comorbid disease and transition between treatment modalities. Absolute cardiovascular death rates would help inform clinical practice and health‐care provision, but are not well understood across a continuum of dialysis and transplant states. We aimed to characterize cardiovascular death across the natural history of KF using a lifespan approach.

Methods

We performed a population‐based cohort study of incident patients commencing kidney replacement therapy in Australia and New Zealand. Cardiovascular deaths were identified using data linkage to national death registers. We estimated the probability of death and kidney transplant using multi‐state models, and calculated rates of graft failure and cardiovascular death across demographic factors and comorbidities.

Results

Among 60 823 incident patients followed over 381 874 person‐years, 25% (8492) of deaths were from cardiovascular disease. At 15 years from treatment initiation, patients had a 15.2% probability of cardiovascular death without being transplanted, but only 2.3% probability of cardiovascular death post‐transplant. Females had a 3% lower probability of cardiovascular death at 15 years (15.3% vs. 18.6%) but 4% higher probability of non‐cardiovascular death (54.5% vs. 50.8%). Within the first year of dialysis, cardiovascular mortality peaked in the second month and showed little improvement across treatment era.

Conclusion

Despite improvements over time, cardiovascular death remains common in KF, particularly among the dialysis population and in the first few months of treatment. Multi‐state models can provide absolute measures of cardiovascular mortality across both dialysis and transplant states.

In this population‐based cohort study using multi‐state models (alive without kidney transplant [KT], CV death without KT, non‐CV death without KT, alive after first KT, CV death after first KT and non‐CV death after first KT), the probability of CV death was higher in non‐KT than KT patients at 15 years from treatment. In patients on dialysis, CV mortality was highest from the second month after commencing dialysis and remained high thereafter. Thus, the use of multi‐state models provides helpful information on impacts of different treatments with respect to serious outcomes.

Warfarin Usage in Patients with Atrial Fibrillation Undergoing Hemodialysis in Indonesian Population

The data about the efficacy and safety of warfarin usage in atrial fibrillation (AF) in hemodialysis patients is still limited, especially in the Asia population. The population of this study was end-stage renal disease patients with AF who underwent hemodialysis. The design of the study was a retrospective observational cohort that collected the patient data from 2016 to 2019. The Cox regression model was applied to assess the effect of warfarin on the outcomes. We conducted a survival analysis by comparing Kaplan-Meier curves using the log-rank test. We also measured the time in therapeutic range as a quality indicator of warfarin usage. Among 444 hemodialysis patients, 126 patients with AF matched the inclusion criteria, 88 patients completely followed up. Half patients used warfarin. The mean age was 52.2 ± 12.97 years, the mean follow-up duration was 11 ± 10 months. We observed all-cause death in 86.4% of patients, ischemic stroke in 10.2%, and hemorrhagic stroke in 2.3% of patients. There were no significant differences in all-cause death, ischemic stroke, and hemorrhagic stroke. Warfarin use was not associated with a lower rate for death (HR 0.782; 95% CI, 0.494-1.237, P = 0.293) or ischemic stroke (HR 0.435; 95% CI, 0.103-1.846, P = 0.259) or hemorrhagic stroke (HR 0.564; 95% CI, 0.034-9.386, P = 0.689). None of the patients reach the time in the therapeutic range >65%. Our findings suggest that warfarin has no association with mortality, ischemic stroke, and hemorrhagic stroke events rate in atrial fibrillation patients who underwent hemodialysis in the Indonesian population.

A Review of Direct Oral Anticoagulants in Patients With Stage 5 or End-Stage Kidney Disease

OBJECTIVE

To evaluate the role of oral anticoagulation in patients with stage 5 chronic kidney disease (CKD-5) or end-stage kidney disease (ESKD).

DATA SOURCES

A literature search of PubMed (January 2000 to July 1, 2021), the Cochrane Library, and Google Scholar databases (through April 1, 2021) was performed with keywords DOAC (direct-acting oral anticoagulant) OR NOAC or dabigatran OR rivaroxaban OR apixaban OR edoxaban AND end-stage kidney disease combined with atrial fibrillation (AF) or venous thromboembolism (VTE) OR pulmonary embolism OR deep-vein thrombosis.

STUDY SELECTION AND DATA EXTRACTION

Case-control, cohort, and randomized controlled trials comparing DOACs to an active control for AF or VTE in patients with CKD-5 or ESKD and reporting outcomes of stroke, recurrent thromboembolism, or major bleeding were included.

DATA SYNTHESIS

Nine studies were included. Efficacy data supporting routine use of warfarin or DOACs in CKD-5 or ESKD are limited. Rivaroxaban and apixaban may provide enhanced safety compared to warfarin in patients with AF. Data for VTE are limited to 1 retrospective study.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Because of the paucity of rigorous, prospective studies in CKD-5 or ESKD, OACs should not be broadly used in this population. It is clear that data regarding efficacy of DOACs cannot be reliably and safely extrapolated from the non-ESKD population. Therefore, use of OACs in this population should be individualized.

CONCLUSIONS

If OACs for stroke prevention with AF are deemed necessary, apixaban or rivaroxaban can be considered. DOACs cannot currently be recommended over warfarin in patients with CKD-5 or ESKD and VTE.

A retrospective study of antithrombotic therapy use in an outpatient haemodialysis unit

WHAT IS KNOWN AND OBJECTIVE

Patients on haemodialysis (HD) are at increased risk of both bleeding and thrombotic events, due to comorbidities and nature of dialysis treatment. However, there is a lack of research on evidence-based treatment strategies and prescribing patterns for antithrombotic therapies (ATT) in this population. To characterize ATT use and its main indications in an outpatient HD unit.

METHODS

A single-centre retrospective chart review was conducted in a Toronto outpatient HD unit (n = 329). Medical histories, number of ATTs and corresponding indications were collected from adult patients prescribed at least one ATT from 1 October 2019 to 31 December 2019, inclusive.

RESULTS AND DISCUSSION

Of 329 patients in the unit, a total of 135 (41%) patients were on at least one ATT. Of these 135 patients, 80% were on monotherapy (55% antiplatelet, 25.1% anticoagulant), 12.6% were on dual antiplatelet therapy (DAPT), and 7.4% were on a antiplatelet and anticoagulant combination. Primary indications for ATT in our cohort were coronary artery disease (CAD; 55%), atrial fibrillation (18.5%) and venous thromboembolism (VTE; 17%). Described ATT use was in-line with current clinical guidelines. Monotherapy was primarily used in our HD cohort, whereas few patients were on dual therapy. Low-dose aspirin was the most common antiplatelet prescribed for secondary prevention of cardiovascular events. Warfarin monotherapy was primarily indicated for VTE, and DAPT aspirin/clopidogrel was the most commonly prescribed for CAD.

WHAT IS NEW AND CONCLUSION

Our characterization of ATT use in this HD cohort demonstrates that ATT is often prescribed for a number of different CVD reasons. Overlapping and confounding indications for prescribing ATTs, lack of randomized controlled trials and unclear clinical guidelines mean that individualized risk-benefit assessments for ATT use are still needed to provide care for these high-risk patients. More research to address the safety and efficacy of ATTs is warranted to develop more robust evidence-based treatment guidelines for the HD population.

Effectiveness and safety of rivaroxaban versus warfarin in Taiwanese patients with end-stage renal disease and nonvalvular atrial fibrillation: A real-world nationwide cohort study

BACKGROUND

The optimal anticoagulant for end-stage renal disease patients for stroke prophylaxis is unknown. The efficacy and safety of warfarin in this population are debatable. In addition, real-world evidence of direct oral anticoagulants in patients with end-stage renal disease is limited. The aim of this study was to evaluate the clinical outcomes of rivaroxaban compared with warfarin in Taiwanese patients with end-stage renal disease with nonvalvular atrial fibrillation in a real-world setting.

METHODS AND RESULTS

This was a retrospective population-based cohort study conducted using Taiwan's National Health Insurance Research Database. Patients with nonvalvular atrial fibrillation and end-stage renal disease who started on rivaroxaban or warfarin between February 2013 and September 2017 were eligible to participate in the study. The inverse probability of treatment weighting approach was used to balance baseline characteristics. Bleeding and thromboembolic outcomes were compared using competing risk analyses. The study population consisted of 3358 patients (173 and 3185 patients on rivaroxaban and warfarin, respectively). In the rivaroxaban group, 50.8%, 38.7%, and 10.4% of the patients received 10, 15, and 20 mg of the drug, respectively. The cumulative incidence of major bleeding was similar between the two groups; however, the gastrointestinal bleeding rate was lower in the rivaroxaban group (adjusted subdistribution hazard ratio [SHR]: 0.56, 95% confidence interval [CI]: 0.34-0.91) than in the warfarin group. Furthermore, the composite risk of ischemic stroke or systemic embolism was significantly lower in the rivaroxaban group (adjusted SHR: 0.36, 95% CI: 0.17-0.79). Similar findings were observed for patients who received 10 mg of rivaroxaban.

CONCLUSIONS

In Taiwanese patients with end-stage renal disease and nonvalvular atrial fibrillation, rivaroxaban may be associated with a similar risk of major bleeding but a lower risk of thromboembolism compared with warfarin. The potential benefit of 10 mg of rivaroxaban in this population requires further investigation.

Clinical Outcomes of Warfarin Initiation in Advanced Chronic Kidney Disease Patients With Incident Atrial Fibrillation

OBJECTIVES

The aim of this study was to examine the efficacy and safety of warfarin initiation following the diagnosis of atrial fibrillation (AF) in patients with late-stage chronic kidney disease (CKD) who transitioned to dialysis.

BACKGROUND

The clinical benefit of warfarin therapy for thromboprophylaxis after incident AF diagnosis in patients with late-stage CKD who are transitioning to dialysis is unknown.

METHODS

In this retrospective cohort analysis, the study population was a national cohort of 22,771 U.S. veterans with incident end-stage renal disease who developed incident AF before initiating renal replacement therapy. This study examined the association of warfarin therapy following the diagnosis of incident AF with ischemic cerebrovascular accidents (CVAs) (ischemic stroke or transient ischemic attack), ischemic CVA-related hospitalization, major bleeding events (gastrointestinal or intracranial bleeding), bleeding event-related hospitalizations, and post-dialysis, all-cause mortality in multivariable adjusted Cox regression analyses that adjusted for demographic characteristics and comorbidities.

RESULTS

The mean ± SD age of the cohort was 73.5 ± 8.8 years, 13% were African American, and the mean CHA₂DS₂-VASc score was 5.7 ± 2.1. Of the overall cohort, 6,682 (29.3%) patients were started on warfarin during the follow-up period. The hazard ratios (95% confidence intervals) for ischemic CVA, bleeding events, and death for those started on warfarin were 1.23 (1.16 to 1.30), 1.36 (1.29 to 1.44), and 0.94 (0.90 to 0.97), respectively, compared with those who received no anticoagulation. Warfarin exposure was associated with higher risk for ischemic CVA and bleeding event-related hospitalizations.

CONCLUSIONS

In patients with late-stage CKD who transitioned to dialysis, warfarin use was associated with higher risk of ischemic and bleeding events but a lower risk of mortality. Future studies such as those comparing warfarin with newer oral anticoagulant agents are needed to granularly define the net clinical benefit of anticoagulation therapy in patients with advanced CKD with incident AF.

Association Between Use of Warfarin for Atrial Fibrillation and Outcomes Among Patients With End-Stage Renal Disease: A Systematic Review and Meta-analysis

IMPORTANCE

Several studies have examined the role of warfarin in preventing strokes in patients with atrial fibrillation and end-stage renal disease; however, the results remain inconclusive.

OBJECTIVE

To assess recently published studies to examine the outcomes of the use of warfarin among patients with atrial fibrillation and end-stage renal disease.

DATA SOURCES

A literature search was performed using the terms warfarin and atrial fibrillation and end-stage renal disease and warfarin and atrial fibrillation and dialysis in the MEDLINE, Embase, and Google Scholar databases from January 1, 2008, to February 28, 2019.

STUDY SELECTION

The studies included were those with patients with end-stage renal disease and atrial fibrillation who were receiving warfarin and with hazard ratios (HRs) of at least 1 primary outcome. The studies excluded were those with a lack of information on outcomes and unreliable 95% CIs of the results.

DATA EXTRACTION AND SYNTHESIS

The Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines were followed in selecting studies. Collected data were also scrutinized for reliable 95% CIs. Finally, studies were examined for perceived biases, their limitations, and the definitions of the outcomes.

MAIN OUTCOMES AND MEASURES

The HRs and 95% CIs were calculated for the incidence of ischemic stroke, hemorrhagic stroke, major bleeding, and mortality among patients receiving anticoagulants and those not receiving anticoagulants.

RESULTS

Study selection yielded 15 studies with a total of 47 480 patients with atrial fibrillation and end-stage renal disease. Of these patients, 10 445 (22.0%) were taking warfarin. With a mean (SD) follow-up period of 2.6 (1.4) years, warfarin use was associated with no significant change for the risk of ischemic stroke (HR, 0.96; 95% CI, 0.82-1.13), with a significantly higher risk of hemorrhagic stroke (HR, 1.49; 95% CI, 1.03-1.94), with no significant difference in the risk of major bleeding (HR, 1.20; 95% CI, 0.99-1.47), and with no change in overall mortality (HR, 0.95; 95% CI, 0.83-1.09).

CONCLUSIONS AND RELEVANCE

In the studies reviewed, warfarin use appears to have been associated with no change in the incidence of ischemic stroke in patients with atrial fibrillation and end-stage renal disease. However, from the studies reviewed, it does appear to be associated with a significantly higher risk of hemorrhagic stroke, with no significant difference in the risk of major bleeding, and with no change in mortality.

Racial/Ethnic Disparities in Atrial Fibrillation Treatment and Outcomes among Dialysis Patients in the United States

BACKGROUND

Because stroke prevention is a major goal in the management of ESKD hemodialysis patients with atrial fibrillation, investigating racial/ethnic disparities in stroke among such patients is important to those who could benefit from strategies to maximize preventive measures.

METHODS

We used the United States Renal Data System to identify ESKD patients who initiated hemodialysis from 2006 to 2013 and then identified those with a subsequent atrial fibrillation diagnosis and Medicare Part A/B/D. Patients were followed for 1 year for all-cause stroke, mortality, prescription medications, and cardiovascular disease procedures. The survival mediational g-formula quantified the percentage of excess strokes attributable to lower use of atrial fibrillation treatments by race/ethnicity.

RESULTS

The study included 56,587 ESKD hemodialysis patients with atrial fibrillation. Black, white, Hispanic, and Asian patients accounted for 19%, 69%, 8%, and 3% of the population, respectively. Compared with white patients, black, Hispanic, or Asian patients were more likely to experience stroke (13%, 15%, and 16%, respectively) but less likely to fill a warfarin prescription (10%, 17%, and 28%, respectively). Warfarin prescription was associated with decreased stroke rates. Analyses suggested that equalizing the warfarin distribution to that in the white population would prevent 7%, 10%, and 12% of excess strokes among black, Hispanic, and Asian patients, respectively. We found no racial/ethnic disparities in all-cause mortality or use of cardiovascular disease procedures.

CONCLUSIONS

Racial/ethnic disparities in all-cause stroke among hemodialysis patients with atrial fibrillation are partially mediated by lower use of anticoagulants among black, Hispanic, and Asian patients. The reasons for these disparities are unknown, but strategies to maximize stroke prevention in minority hemodialysis populations should be further investigated.

Stroke Prophylaxis in Patients with Atrial Fibrillation and End-Stage Renal Disease

Atrial fibrillation (AF) is an important comorbidity in patients with end-stage renal disease (ESRD) undergoing dialysis that portends increased health care utilization, morbidity, and mortality in this already high-risk population. Patients with ESRD have a particularly high stroke risk, which is further compounded by AF. However, the role of anticoagulation for stroke prophylaxis in ESRD and AF is debated. The ESRD population presents a unique challenge because of the combination of elevated stroke and bleeding risks. Warfarin has been traditionally used in this population, but it is associated with significant risks of minor and major bleeding, particularly intracranial, thus leading many clinicians to forgo anticoagulation altogether. When anticoagulation is prescribed, rates of adherence and persistence are poor, leaving many patients untreated. The direct oral anticoagulants (DOACs) may offer an alternative to warfarin in ESRD patients, but these agents have not been extensively studied in this population and uncertainties regarding comparative effectiveness (versus warfarin, each other, and no treatment) remain. In this review, we discuss the current evidence on the risk and benefits of anticoagulants in this challenging population and comparisons between warfarin and DOACs, and review future directions including options for non-pharmacologic stroke prevention.

[Atrial Fibrillation in Patients on Dialysis Therapy: Epidemiology, Prognosis and Choice of Anticoagulant Therapy]

The review presents data on the prevalence of atrial fibrillation in patients on dialysis therapy. It is shown that dialysis-dependent patients with non-valve atrial fibrillation prognosis is extremely unfavorable, significantly increased risk of death due to both ischemic and hemorrhagic complications. Scales to assess the risk of thromboembolic and hemorrhagic complications in patients with atrial fibrillation on program dialysis are not validated. The lack of data from randomized clinical trials makes it much more difficult to choose anticoagulant therapy in patients with terminal stage of chronic kidney disease on dialysis who have undergone kidney transplantation. Therefore, the need for anticoagulant therapy and the choice of drugs in patients in this category should be made on the basis of a personalized multidisciplinary approach, taking into account comorbid pathology and the patient's preferences.

Efficacy and safety of direct oral anticoagulants in patients with atrial fibrillation and chronic kidney disease

BACKGROUND

Direct oral anticoagulants (DOACs) are effective alternatives to warfarin for stroke prevention in patients with atrial fibrillation (AF) including patients with CKD III. However, data on patient outcomes with DOACs for advanced CKD are limited, while warfarin use is controversial.

METHODS

A retrospective study of patients with AF using DOACs and CKD stages III-V was conducted. The primary outcomes were stroke or systemic embolism and major bleeding while on DOAC therapy among CKD IV and V patients. Rates of outcomes from the DOAC trials and from previous studies of warfarin in CKD were referenced.

RESULTS

Of 316 patients reviewed, 152 were included with mean CrCl of 38.8 mL/min. Stroke and systemic embolism occurred at a rate of 1.17 per 100 person-years, with no significant difference between CKD IV/V and CKD III (P = .567). Rates were comparable to DOAC use from the DOAC trials, and lower than rates in studies of warfarin in CKD IV/V patients. There was a nonstatistically significant trend toward increased major bleeding in CKD IV/V patients. Rates of major bleeding in CKD III to V subjects were comparable to published rates for warfarin users with similar levels of renal impairment.

CONCLUSIONS

In our study, DOACs appeared to be as efficacious and safe in CKD IV and V as in CKD III. In addition, DOACs appeared to be more effective than, and as safe as warfarin when compared with reference studies of patients with advanced CKD. Our findings support the use of DOACs for thromboembolism prevention in patients with advanced CKD and AF.

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.

Warfarin Dosing and Outcomes in Chronic Kidney Disease: A Closer Look at Warfarin Disposition

BACKGROUND

Chronic Kidney Disease (CKD) is a prevalent worldwide health problem. Patients with CKD are more prone to developing cardiovascular complications such as atrial fibrillation and stroke. This warrants the use of oral anticoagulants, such as warfarin, in this population. While the efficacy and safety of warfarin in this setting remain controversial, a growing body of evidence emphasizes that warfarin use in CKD can be problematic. This review discusses 1) warfarin use, dosing and outcomes in CKD patients; and 2) possible pharmacokinetic mechanisms for altered warfarin dosing and response in CKD.

METHODS

Structured search and review of literature articles evaluating warfarin dosing and outcomes in CKD. Data and information about warfarin metabolism, transport, and pharmacokinetics in CKD were also analyzed and summarized.

RESULTS

The literature data suggest that changes in warfarin pharmacokinetics such as protein binding, nonrenal clearance, the disposition of warfarin metabolites may partially contribute to altered warfarin dosing and response in CKD.

CONCLUSION

Although the evidence to support warfarin use in advanced CKD is still unclear, this synthesis of previous findings may help in improving optimized warfarin therapy in CKD settings.

Warfarin and the Risk of Death, Stroke, and Major Bleeding in Patients With Atrial Fibrillation Receiving Hemodialysis: A Systematic Review and Meta-Analysis

Background: Up to date, the efficacy and safety of warfarin treatment in atrial fibrillation patients receiving hemodialysis remain controversial. So we performed this meta-analysis to try to offer recommendations regarding warfarin management in this population.

Methods: We searched Pubmed, Embase, and Cochrane library and reviewed relevant reference lists from 1980 to March 2018. Studies were included if they described the risks of mortality, stroke, and bleeding events with or without warfarin in atrial fibrillation patients receiving hemodialysis.

Results: Overall, the use of warfarin was not associated with mortality (OR = 0.95, 95%CI = 0.89–1.02), stroke (OR = 1.06, 95% CI = 0.87–1.30) and ischemic stroke (OR = 0.85, 95% CI = 0.68–1.05), but its use could increase the risks of hemorrhagic stroke (OR = 1.34, 95% CI = 1.13–1.59) and major bleeding (OR = 1.24, 95% CI = 1.14, 1.35). In subgroup analyses, when analyses were mainly restricted to atrial fibrillation patients who were undergoing hemodialysis and taking other anticoagulation agents, warfarin therapy didn't reduce the risks for mortality (OR = 0.98, 95% CI = 0.68–1.42) and ischemic stroke (OR = 1.03, 95% CI = 0.89–1.19), but significantly increased the risks of stroke (OR:1.14, 95% CI = 1.01–1.29) and bleeding events such as hemorrhagic stroke (OR = 1.42, 95% CI = 1.14–1.77) and major bleeding (OR = 1.24, 95% CI = 1.14–1.35). While in patients who didn't take other anticoagulation agents or aspirin, warfarin use was not associated with all-cause mortality (OR = 0.90, 95% CI = 0.78–1.04), or any stroke (OR = 1.00, 95% CI = 0.71–1.40). Its use was associated with significantly decreased risk of ischemic stroke (OR = 0.71, 95% CI = 0.60–0.85), but not associated with hemorrhagic stroke (OR = 1.45, 95% CI = 0.83–2.55). Besides, another subgroup analysis showed that warfarin therapy didn't exert a protective role in patients with normal serum lipid levels (OR = 1.04, 95% CI = 0.85–1.26), but seemed to decrease the risk of ischemic stroke in patients with hyperlipidemia (OR = 0.38, 95% CI = 0.11–1.29).

Conclusion: Our results suggested that it was necessary to prescribe warfarin for the prevention of ischemic events in hemodialysis patients with atrial fibrillation, but if these patients were already prescribed with other anticoagulants for the treatment of other co-existing diseases, then warfarin was not recommended.

Atrial fibrillation and chronic kidney disease: A review of options for therapeutic anticoagulation to reduce thromboembolism risk

Atrial fibrillation and chronic kidney disease (CKD) commonly occur together, which poses a therapeutic dilemma due to increased risk of both systemic thromboembolism and bleeding. Chronic kidney disease also has implications for medication selection. The objective of this review is to evaluate the options for anticoagulation for thromboembolism prevention in patients with atrial fibrillation and chronic kidney disease. We searched PubMed for studies of patients with atrial fibrillation and CKD on warfarin or a direct oral anticoagulant (DOAC) for thromboembolism prevention through January 1 2018, in addition to evaluating major trials evaluating DOACs and warfarin use as well as society guidelines. For patients with mild to moderate chronic kidney disease, primarily observational data supports the use of warfarin, and high quality trial data and meta-analyses support the use and possible superiority of DOACs. For patients with severe chronic kidney disease, there are limited data on warfarin which supports its use, and data for DOACs is limited primarily to pharmacologic studies which support dose reductions but lack information on patient outcomes. For patients with end-stage renal disease, studies on warfarin are conflicting, but the majority suggest a lack of benefit and possible harm; studies in DOACs are very limited, but apixaban is the least renally cleared and may be both safe and effective. In conclusion, warfarin or DOACs may be used based on the degree of severity of chronic kidney disease, but further study in needed in patients with end-stage renal disease.

Is anticoagulating haemodialysis patients with non-valvular atrial fibrillation too risky?

There is an increasing understanding of the risks from atrial fibrillation (AF) in the current era. In patients with end-stage renal disease (ESRD) on dialysis, the prevalence of AF is significantly higher compared to the general population and those with earlier stages of CKD. Although anticoagulation of these patients may seem appropriate, there is a lack of conclusive evidence that it provides the same protection from thromboembolic complications as it does in patients not on dialysis. In addition, the increased risk of bleeding in patients requiring dialysis makes the use of anticoagulants less favourable. This article aims to discuss the problem of AF in dialysis patients, summarise the current evidence around the use of oral anticoagulants for AF in ESRD and provide some practical suggestions on management of AF in the haemodialysis 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.

2017 Scientific Sessions Sol Sherry Distinguished Lecture in Thrombosis: Factor XI as a Target for New Anticoagulants

The goal of anticoagulant therapy is to attenuate thrombosis without compromising hemostasis. Although the direct oral anticoagulants are associated with less intracranial hemorrhage than vitamin K antagonists, bleeding remains their major side effect. Factor XI has emerged as a promising target for anticoagulants that may be safer than those currently available. The focus on factor XI stems from epidemiological evidence of its role in thrombosis, the observation of attenuated thrombosis in factor XI-deficient mice, identification of novel activators, and the fact that factor XI deficiency is associated with only a mild bleeding diathesis. Proof-of-concept comes from the demonstration that compared with enoxaparin, factor XI knockdown reduces venous thromboembolism without increasing bleeding after elective knee arthroplasty. This article rationalizes the selection of factor XI as a target for new anticoagulants, reviews the agents under development, and outlines a potential path forward for their development.

Warfarin Use in Hemodialysis Patients With Atrial Fibrillation: A Systematic Review of Stroke and Bleeding Outcomes

Background:

Given the lack of clear indications for the use of warfarin in the treatment of atrial fibrillation (AF) in patients on hemodialysis and the potential risks that accompany warfarin use in these patients, we systematically reviewed stroke and bleeding outcomes in hemodialysis patients treated with warfarin for AF.

Objective:

To systematically review the stroke and bleeding outcomes associated with warfarin use in the hemodialysis population to treat AF.

Design:

Systematic review.

Setting:

All adult hemodialysis patients.

Patients:

Patients on hemodialysis receiving warfarin for the management of AF.

Measurements:

Any type of stroke and/or bleeding outcomes.

Methods:

MEDLINE(R) In-Process & Other Non-Indexed Citations and MEDLINE(R) via OVID (1946 to January 11, 2017), and EMBASE via OVID (1974 to January 11, 2017) were searched for relevant literature. Inclusion criteria were randomized controlled trials, observational studies, and case series in English that examined stroke and bleeding outcomes in adult population of patients (over 18 years old) who are on hemodialysis and taking warfarin for AF. Studies with less than 10 subjects, case reports, review articles, and editorials were excluded. Quality of selected articles was assessed using Newcastle-Ottawa Scale (NOS).

Results:

Of the 2340 titles and abstracts screened, 7 met the inclusion criteria. Two studies showed an association between warfarin use and an increased risk of stroke (Hazard Ratio: 1.93-3.36) but no association with an increased risk of bleed (HR: 0.85-1.04), while 4 studies showed no association between warfarin and stroke outcomes (HR: 0.12-1.17) but identified an association between warfarin and increased bleeding outcome (HR: 1.41-3.96). And 1 study reported neither beneficial nor harmful effects associated with warfarin use.

Limitations:

The major limitation to this review is that the 7 included studies were observational cohort studies, and thus the outcome measures were not specified and predetermined in a research protocol.

Conclusion:

Our systematic review demonstrated that for patients with AF who are on hemodialysis, warfarin was not associated with reduced outcomes of stroke but was rather associated with increased bleeding events.