Warfarin Initiation, Atrial Fibrillation, and Kidney Function: Comparative Effectiveness and Safety of Warfarin in Older Adults With Newly Diagnosed Atrial Fibrillation

Oral Anticoagulation in Patients With Advanced Chronic Kidney Disease and Atrial Fibrillation: Beyond Anticoagulation

The optimal approach to prevent stroke and systemic embolism in patients with advanced chronic kidney disease (CKD) and atrial fibrillation remains unresolved. We conducted a narrative review to explore areas of uncertainty and opportunities for future research. First, the relationship between atrial fibrillation and stroke is more complex in patients with advanced CKD than in the general population. The currently employed risk stratification tools do not adequately discriminate between patients deriving a net benefit and those suffering a net harm from oral anticoagulation. Anticoagulation initiation should probably be more restrictive than is currently advocated by official guidelines. Recent evidence reveals that the superior benefit-risk profile of non-vitamin K antagonist oral anticoagulants (NOACs) vs vitamin K antagonists (VKAs) observed in the general population and in moderate CKD can be extended to advanced CKD. The NOACs yield better protection against stroke, cause less major bleeding, are associated with less acute kidney injury and a slower decline of CKD, and are associated with a lower incidence of cardiovascular events than VKAs. The VKAs may be harmful in CKD patients, in particular in patients with a high bleeding risk and labile international normalized ratio. The better safety and efficacy of NOACs as opposed to VKAs may be particularly evident in advanced CKD as a result of better on-target anticoagulation with NOACs, harmful off-target vascular effects of VKAs, and beneficial off-target vascular effects of NOACs. The intrinsic vasculoprotective effects of NOACs are supported by animal experimental evidence as well as by findings of large clinical trials and may result in use of NOACs beyond their anticoagulant properties.

A systematic review of the efficacy and safety of anticoagulants in advanced chronic kidney disease

BACKGROUND

Patients with chronic kidney disease (CKD) have an increased risk of venous thromboembolism (VTE) and atrial fibrillation (AF). Anticoagulants have not been studied in randomised controlled trials with CrCl < 30 ml/min. The objective of this review was to identify the impact of different anticoagulant strategies in patients with advanced CKD including dialysis.

METHODS

We conducted a systematic review of randomized controlled trials and cohort studies, searching electronic databases from 1946 to 2022. Studies that evaluated both thrombotic and bleeding outcomes with anticoagulant use in CrCl < 50 ml/min were included.

RESULTS

Our initial search yielded 14,503 papers with 53 suitable for inclusion. RCTs comparing direct oral anticoagulants (DOACs) versus warfarin for patients with VTE and CrCl 30-50 ml/min found no difference in recurrent VTE events (RR 0.68(95% CI 0.42-1.11)) with reduced bleeding (RR 0.65 (95% CI 0.45-0.94)). Observational data in haemodialysis suggest lower risk of recurrent VTE and major bleeding with apixaban versus warfarin. Very few studies examining outcomes were available for therapeutic and prophylactic dose low molecular weight heparin for CrCl < 30 ml/min. Findings for patients with AF on dialysis were that warfarin or DOACs had a similar or higher risk of stroke compared to no anticoagulation. For patients with AF and CrCl < 30 ml/min not on dialysis, anticoagulation should be considered on an individual basis, with limited studies suggesting DOACs may have a preferable safety profile.

CONCLUSION

Further studies are still required, some ongoing, in patients with advanced CKD (CrCl < 30 ml/min) to identify the safest and most effective treatment options for VTE and AF.

Oral Anticoagulant Agents in Patients With Atrial Fibrillation and CKD: A Systematic Review and Pairwise Network Meta-analysis

OBJECTIVE

To evaluate the relative efficacy and safety of different oral anticoagulant agents (OACs) for patients with atrial fibrillation (AF) and chronic kidney disease (CKD).

STUDY DESIGN

Systematic review and pairwise and Bayesian network meta-analysis.

SETTING & STUDY POPULATIONS

Adult patients with AF and CKD stages 3-5D who received OACs.

SELECTION CRITERIA FOR STUDIES

Randomized controlled trials (RCTs) and observational studies that reported the efficacy and safety outcomes of subgroups with a glomerular filtration rate (GFR)<60mL/min.

DATA EXTRACTION

Two reviewers independently abstracted data, assessed study quality, and rated the strength of evidence (SOE).

ANALYTICAL APPROACH

Random-effects models using restricted maximum-likelihood methods were fit for the pairwise meta-analyses as well as a network meta-analysis within a Bayesian framework.

RESULTS

Pairwise meta-analysis including 8 RCTs and 46 observational studies showed that direct OACs (DOACs) were superior to warfarin in preventing thromboembolic events (hazard ratio [HR], 0.86 [95% CI, 0.78-0.95]), without heterogeneity (I²=10.5%), and in reducing the risk of bleeding events (HR, 0.81 [95% CI, 0.66-0.99]), with substantial heterogeneity (I²=69.8%), in patients with AF and a GFR of 15-60mL/min. Bayesian network meta-analysis including 8 RCTs showed that dose-adjusted apixaban and a 15-mg dose of edoxaban were superior to the other OAC regimens in reducing bleeding events. Dose-adjusted apixaban was more effective than edoxaban in preventing thromboembolic events for patients with AF and GFR in the range of 25-50 or 30-50mL/min. In dialysis recipients with AF, the use of OACs increased the risk of bleeding events by 28% (HR, 1.28 [95% CI, 1.03-1.60]) without significant beneficial effects versus not using anticoagulants.

LIMITATIONS

Low SOE and heterogeneity in most comparisons.

CONCLUSIONS

This study suggests that DOACs are superior to warfarin for the prevention of thromboembolic events and reduction in bleeding risk in patients with AF and mild to moderate kidney disease. However, the low SOE limits the conclusions that can be drawn about the preferred DOAC. Notably, the use of OACs may increase bleeding risk without significant benefits in dialysis recipients with AF.

REGISTRATION

Registered at PROSPERO with identification number CRD42018090896.

Ischemic stroke, hemorrhage, and mortality in patients with non-valvular atrial fibrillation and renal dysfunction treated with rivaroxaban: sub-analysis of the EXPAND study

The EXPAND Study demonstrated the effectiveness and safety of rivaroxaban in patients with non-valvular atrial fibrillation (NVAF) in routine clinical practice in Japan. This sub-analysis was conducted to reveal the effectiveness and safety of rivaroxaban in Japanese NVAF patients according to baseline creatinine clearance (CrCl) levels and rivaroxaban doses in the EXPAND Study. We examined 6806 patients whose baseline CrCl data were available and classified them into 2 groups: normal renal function group with CrCl ≥ 50 mL/min (n = 5326, 78%) and renal dysfunction group with CrCl < 50 mL/min (n = 1480, 22%). In the normal renal function group, 1609 (30%) received 10 mg/day (under-dose), while in the renal dysfunction group, 108 (7%) received 15 mg/day (over-dose). In the normal renal function group, under-dose of rivaroxaban was associated with higher all-cause mortality, while in the renal dysfunction group, over-dose was associated with higher incidence of major bleeding. In contrast, the incidence of stroke or systemic embolism was not different between the 2 groups regardless of the dose of rivaroxaban. In the propensity score matched analysis to adjust the difference in characteristics according to doses of rivaroxaban, the incidences of clinical outcomes were comparable between the 2 dose groups in both renal function groups. These results indicate that the dose of rivaroxaban should be reduced depending on the renal function, considering the balance between risks of bleeding and ischemia.

Influence of renal insufficiency on anticoagulant effects and safety of warfarin in Chinese patients: analysis from a randomized controlled trial

This study aimed to analyze the influence of renal insufficiency on the anticoagulant effects and safety of warfarin in Chinese patients. Data on the creatinine levels of participants enrolled in a randomized controlled study were screened and divided into the non-renal insufficiency group, mild renal insufficiency group, and moderate renal insufficiency group, according to the creatinine clearance rate. The primary outcome measures were stable dose and average daily dose of warfarin. Secondary outcome measures were percentage of time in the therapeutic international normalized ratio (INR) (%TTR), and the first time to reach the therapeutic INR. Adverse events included bleeding events, thromboembolic events, and mortality. All participants with renal function test results and a baseline INR of less than 1.5 were included in the primary and secondary outcome analysis. The SPSS Statistics 21.0 software was used for statistical analysis. The randomized controlled trial was registered in Clinicaltrials.gov (NCT02211326). A total of 571 patients were included in this analysis. Multiple regression analysis showed that the renal function was correlated with stable dose, average daily dose, and the first time to reach therapeutic INR after adjusting for confounding factors. However, no correlation was noted between kidney function and %TTR. No significant differences were observed across the various safety parameters among the three groups. Renal function is an important consideration in patients using warfarin.

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.

Pathophysiology of atrial fibrillation and chronic kidney disease

Atrial fibrillation (AF) and chronic kidney disease (CKD) are closely related conditions with shared risk factors. The growing prevalence of both AF and CKD indicates that more patients will suffer from concurrent conditions. There are various complex interlinking mechanisms with important implications for the management of these patients. Furthermore, there is uncertainty regarding the use of oral anticoagulation (OAC) in AF and CKD that is reflected by a lack of consensus between international guidelines. Therefore, the importance of understanding the implications of co-existing AF and CKD should not be underestimated. In this review, we discuss the pathophysiology and association between AF and CKD, including the underlying mechanisms, risk of thrombo-embolic and bleeding complications, influence on stroke management, and evidence surrounding the use of OAC for stroke prevention.

Anticoagulation in Concomitant Chronic Kidney Disease and Atrial Fibrillation: JACC Review Topic of the Week

Atrial fibrillation (AF) and chronic kidney disease (CKD) often coexist as they share multiple risk factors, including hypertension, diabetes mellitus, and coronary artery disease. Although there is irrefutable evidence supporting anticoagulation in AF in the general population, these data may not be transferable to the setting of advanced CKD, where the decision to commence anticoagulation poses a conundrum. In this cohort, there is a progressively increased risk of both ischemic stroke and hemorrhage as renal function declines, complicating the decision to initiate anticoagulation. No definitive clinical guidelines derived from randomized controlled trials exist to aid clinical decision-making, and the findings from observational studies are conflicting. In this review, the authors outline the pathophysiological mechanisms at play and summarize the limited existing data related to anticoagulation in those with concomitant CKD and AF. Finally, the authors suggest how to approach the decision of whether and how to use oral anticoagulation in these patients.

Haemorrhagic stroke and major bleeding after intervention with biological aortic valve prosthesis: risk factors and antithrombotic treatment

The majority of patients with severe aortic stenosis are recommended intervention with a surgical biological prosthesis (bioSAVR) or a transcatheter aortic valve intervention (TAVI). The antithrombotic strategies after aortic valve intervention vary and include drugs targeting both platelets and the coagulation cascade. Long-term exposure and changes of antithrombotic treatment influence the risk of both bleeding and thromboembolic events.The aim was to describe an unselected sample of patients who have experienced haemorrhagic stroke and other major bleeding events after biological aortic prosthesis, their antithrombotic treatment and changes of treatments in relation to the bleeding event.All patients performing an bioSAVR or a TAVI 2008–2014 were identified in the SWEDEHEART registry and included in the study (n = 10 711). The outcome events were haemorrhagic stroke and other major bleeding event. Information of drug exposure was collected from the dispensed drug registry.The incidence rate of any bleeding event was 2.85/100 patient-years the first year after aortic valve intervention. Heart failure and atrial fibrillation were present more often in patients with a first haemorrhagic stroke or other major bleeding event compared to without. The proportion of exposure to warfarin was 28.7% vs. 21.3% in patients with and without a haemorrhagic stroke. Comparable figures were 31.2% vs. 19.0% in patients with and without other major bleeding event. During 1 month prior a haemorrhagic stroke or other major bleeding event 39.4% and 38.0%, respectively, of the patients not previously exposed to antithrombotic treatment started warfarin or single antiplatelet therapy.Major bleeding events are not uncommon after aortic valve intervention with a biological prosthesis. Evaluation of comorbidities and previous bleeding might improve risk stratification for bleeding in these elderly patients. The pattern of change of antithrombotic treatment was similar in the groups with and without a bleeding event and in most patients the antithrombotic regime was unchanged the month before an event.

Pros and cons of antithrombotic therapy in end-stage kidney disease: a 2019 update

Dialysis patients manifest both an increased thrombotic risk and a haemorrhagic tendency. A great number of patients with chronic kidney disease requiring dialysis have cardiovascular comorbidities (coronary artery disease, atrial fibrillation or venous thromboembolism) and different indications for treatment with antithrombotics (primary or secondary prevention). Unfortunately, few randomized controlled trials deal with antiplatelet and/or anticoagulant therapy in dialysis. Therefore cardiology and nephrology guidelines offer ambiguous recommendations and often exclude or ignore these patients. In our opinion, there is a need for an expert consensus that provides physicians with useful information to make correct decisions in different situations requiring antithrombotics. Herein the European Dialysis Working Group presents up-to-date evidence about the topic and encourages practitioners to choose among alternatives in order to limit bleeding and minimize atherothrombotic and cardioembolic risks. In the absence of clear evidence, these clinical settings and consequent therapeutic strategies will be discussed by highlighting data from observational studies for and against the use of antiplatelet and anticoagulant drugs alone or in combination. Until new studies shed light on unclear clinical situations, one should keep in mind that the objective of treatment is to minimize thrombotic risk while reducing bleeding events.

Systematic DOACs oral anticoagulation in patients with atrial fibrillation and chronic kidney disease: the nephrologist's perspective

Atrial fibrillation (AF) is highly prevalent among patients with chronic kidney disease (CKD), and also associated with unfavorable outcome. Anticoagulant therapy is the mainstep of management in such patients, aimed at reducing the high risk of systemic thromboembolism and especially of ischemic stroke, which is reportedly associated with increased mortality in CKD patients. Even though new direct oral anticoagulant agents (DOACs) proved to be effective in patients with non valvular chronic AF, and are therefore recommended by recent guidelines for their treatment, warfarin is currently used in more than one-half of subjects needing oral anticoagulation, and only 30% of them are converted from a vitamin K antagonist- to a DOAC-based regimen. The main reason for not prescribing DOACs is often a reduction in renal function, even if mild. Aim of this review was therefore to evaluate the impact of DOAC therapy in the setting of CKD, from a nephrological perspective, by comparing available evidence on the role of DOACs in patients with CKD and AF with that emerging from traditional warfarin-based therapy. Both the pathogenesis of AF in CKD, and available findings of renal, cardiovascular and bone effects of DOACs in CKD are discussed, leading to the conclusion that DOAC therapy should be considered as the first line therapy for non valvular AF in patients with mild and moderate reduction of renal function, and could also be adopted for patients with severe CKD not on hemodialysis treatment, whereas there is insufficient evidence for ESRD patients on dialysis.

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.

Effect of anticoagulation therapy in older patients with chronic kidney disease and atrial fibrillation: A meta-analysis

BACKGROUND

The role of anticoagulation therapy for stroke prevention in older atrial fibrillation (AF) patients with chronic kidney disease (CKD) remains unclear. Therefore, we conducted a meta-analysis to explore the efficacy and safety of anticoagulation therapy in this population.

METHODS

The Cochrane Library, PubMed, and Embase databases were systematically searched for studies reporting the effect of anticoagulation therapy in older patients with AF and CKD. The risk ratios (RRs) and 95% confidence intervals (CIs) were regarded as the risk estimates. A random-effects model selected was to evaluate the treatment outcomes. The presentations were based on the Preferred Reporting Items for reporting systematic reviews and meta-analyses statement.

RESULTS

A total of 7 studies with 24,794 older patients with AF and CKD were included. The follow-up of the included studies ranged from 0.9 to 9.0 years. In older patients with no dialysis, compared with nonanticoagulants, anticoagulants reduced the risk of all-cause death (RR 0.66, 95% CI 0.54-0.79), but had comparable risks of ischemic stroke/transient ischemic attack (TIA, RR 0.91, 95% CI 0.46-1.79) and bleeding (RR 1.17, 95% CI 0.86-1.60). In older patients with dialysis, compared with nonanticoagulants, anticoagulants increased the risk of bleeding (RR 1.37, 95% CI 1.09-1.74), but had similar risks of ischemic stroke/TIA (RR 1.18, 95% CI 0.88-1.58) and death (RR 0.87, 95% CI 0.60-1.27).

CONCLUSION

Compared with nonanticoagulation, anticoagulation therapy is associated with a reduced risk of death in older AF patients with nondialysis, but an increased risk of bleeding in older patients with dialysis.

Anti-androgenic therapy with finasteride in patients with chronic heart failure - a retrospective propensity score based analysis

Sex hormones influence the prevalence and the outcome of heart diseases. The conversion of testosterone to its more active metabolite dihydrotestosterone drives cardiac growth and dysfunction, while inhibition of this step by the anti-androgenic drug finasteride counteracts these pathological processes in preclinical models. In this retrospective, observational study, we aim to investigate whether finasteride, which is in clinical use mainly for prostate disease, might ameliorate cardiac hypertrophy and heart failure in patients. Retrospective chart review of 1041 medical cases with heart failure between 1995 and 2015 was conducted. Stratification was performed by concomitant prostate treatment status (tamsulosin versus finasteride). A propensity score analysis yielded a total of 328 matched medical cases without residual differences in the baseline patient characteristics. In this propensity score matched samples, anti-androgenic therapy with finasteride was associated with significantly reduced left ventricular hypertrophy (interventricular septal thickness 13.3 ± 2.4 mm control vs. 12.6 ± 2.1 mm finasteride group (p = 0.029); estimated average treatment effects on the treated: −0.7 mm, 95% CI mean difference −1.3 to −0.1). In this retrospective analysis anti-androgenic therapy with finasteride for prostate disease was associated with attenuated cardiac hypertrophy in patients with heart failure. Therefore, our data encourage further analysis of this approach in larger heart failure patient cohorts.

Warfarin use increases bleeding risk in hemodialysis patients with atrial fibrillation: A meta-analysis of cohort studies

BACKGROUND AND AIM

Atrial fibrillation is one of the most common comorbid conditions in hemodialysis patients, and warfarin is widely prescribed anticoagulant to prevent thromboembolic complications in such patients. In the last decade, several epidemiological studies pointed out the risk of bleeding with the use of warfarin. So, this meta-analysis is aimed to assess the bleeding risk associated with the use of warfarin.

METHODS

This meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-analysis guidelines. PubMed, Embase, Scopus, and Cochrane central databases were searched from inception to June 10, 2018. The primary outcome was to quantify the bleeding risk associated with warfarin use. The secondary outcome was to assess the bleeding risk based on different subgroups. Review Manager (RevMan) version 5.3 was used for performing statistical analysis.

RESULTS

A total of 15 studies, constituting a pooled sample of 53 581 patients (37.14% female), were included. Of these, 17 469 were warfarin users. We found that warfarin use had a significant association with the bleeding risk. The pooled relative risk (RR) of bleeding was estimated to be 1.35 (95% CI: 1.18-1.53, P = < 0.00001), and the pooled RR of major bleeding (five studies) was estimated to be 1.32 (95% CI: 1.07-1.63, P = 0.009). Subgroup analysis revealed a significant association of warfarin use with the intracranial hemorrhage/hemorrhagic stroke (nine studies) (pooled RR: 1.43 [95% CI: 1.20-1.71, P = < 0.0001]).

CONCLUSIONS

The results indicate that warfarin use increases the risk of bleeding in hemodialysis patients with atrial fibrillation.

Management and 1-Year Outcomes of Patients With Newly Diagnosed Atrial Fibrillation and Chronic Kidney Disease: Results From the Prospective GARFIELD - AF Registry

Background Using data from the GARFIELD - AF (Global Anticoagulant Registry in the FIELD -Atrial Fibrillation), we evaluated the impact of chronic kidney disease ( CKD ) stage on clinical outcomes in patients with newly diagnosed atrial fibrillation ( AF ). Methods and Results GARFIELD - AF is a prospective registry of patients from 35 countries, including patients from Asia (China, India, Japan, Singapore, South Korea, and Thailand). Consecutive patients enrolled (2013-2016) were classified with no, mild, or moderate-to-severe CKD , based on the National Kidney Foundation's Kidney Disease Outcomes Quality Initiative guidelines. Data on CKD status and outcomes were available for 33 024 of 34 854 patients (including 9491 patients from Asia); 10.9% (n=3613) had moderate-to-severe CKD , 16.9% (n=5595) mild CKD , and 72.1% (n=23 816) no CKD . The use of oral anticoagulants was influenced by stroke risk (ie, post hoc assessment of CHA 2 DS 2- VAS c score), but not by CKD stage. The quality of anticoagulant control with vitamin K antagonists did not differ with CKD stage. After adjusting for baseline characteristics and antithrombotic use, both mild and moderate-to-severe CKD were independent risk factors for all-cause mortality. Moderate-to-severe CKD was independently associated with a higher risk of stroke/systemic embolism, major bleeding, new-onset acute coronary syndrome, and new or worsening heart failure. The impact of moderate-to-severe CKD on mortality was significantly greater in patients from Asia than the rest of the world ( P=0.001). Conclusions In GARFIELD - AF , moderate-to-severe CKD was independently associated with stroke/systemic embolism, major bleeding, and mortality. The effect of moderate-to-severe CKD on mortality was even greater in patients from Asia than the rest of the world. Clinical Trial Registration URL : http://www.clinicaltrials.gov . Unique identifier: NCT 01090362.

Demystifying the Benefits and Harms of Anticoagulation for Atrial Fibrillation in Chronic Kidney Disease

Patients with CKD represent a vulnerable population where the risks of atrial fibrillation, ischemic stroke, and bleeding are all heightened. Although large randomized, controlled trials in the general population clearly demonstrate that the benefits of warfarin and direct-acting oral anticoagulants outweigh the risks of bleeding, no such studies have been conducted in patients when their creatinine clearance falls below 25-30 ml/min. Without randomized, controlled trial data, the role of anticoagulation in patients with CKD with atrial fibrillation remains unclear and our practice is informed by a growing body of imperfect literature such as observational and pharmacokinetic studies. This article aims to present a contemporary literature review of the benefits versus harms of anticoagulation in atrial fibrillation for patients with CKD stages 3, 4, 5, and 5 on dialysis. Although unanswered questions and areas of clinical equipoise remain, this piece serves to assist physicians in interpreting the complex body of literature and applying it to their clinical care.

Predicting Thromboembolic and Bleeding Event Risk in Patients with Non-Valvular Atrial Fibrillation: A Systematic Review

BACKGROUND

 Atrial fibrillation (AF) is a common cardiac arrhythmia that increases the risk of stroke. Medical therapy for decreasing stroke risk involves anticoagulation, which may increase bleeding risk for certain patients. In determining the optimal therapy for stroke prevention for patients with AF, clinicians use tools with various clinical, imaging and patient characteristics to weigh stroke risk against therapy-associated bleeding risk.

AIM

 This article reviews published literature and summarizes available risk stratification tools for stroke and bleeding prediction in patients with AF.

METHODS

 We searched for English-language studies in PubMed, Embase and the Cochrane Database of Systematic Reviews published between 1 January 2000 and 14 February 2018. Two reviewers screened citations for studies that examined tools for predicting thromboembolic and bleeding risks in patients with AF. Data regarding study design, patient characteristics, interventions, outcomes, quality, and applicability were extracted.

RESULTS

 Sixty-one studies were relevant to predicting thromboembolic risk and 38 to predicting bleeding risk. Data suggest that CHADS₂, CHA₂DS₂-VASc and the age, biomarkers, and clinical history (ABC) risk scores have the best evidence for predicting thromboembolic risk (moderate strength of evidence for limited prediction ability of each score) and that HAS-BLED has the best evidence for predicting bleeding risk (moderate strength of evidence).

LIMITATIONS

 Studies were heterogeneous in methodology and populations of interest, setting, interventions and outcomes analysed.

CONCLUSION

 CHADS₂, CHA₂DS₂-VASc and ABC scores have the best prediction for stroke events, and HAS-BLED provides the best prediction for bleeding risk. Future studies should define the role of imaging tools and biomarkers in enhancing the accuracy of risk prediction tools.

PRIMARY FUNDING SOURCE

 Patient-Centered Outcomes Research Institute (PROSPERO #CRD42017069999).

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.

Cause-Specific Mortality in Patients with Chronic Kidney Disease and Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is associated with death in patients with chronic kidney disease (CKD). We examined the associations between AF and cause-specific mortality in a large CKD population.

METHODS

We included 62,459 patients with estimated glomerular filtration rate 15-59 mL/min/1.73 m2 (6,639 patients with AF and 55,820 without AF) followed in a large health care system. Outcomes included overall and cause-specific deaths (a) cardiovascular; (b) malignancy; and (c) non-cardiovascular/non-malignancy causes. Cox regression models for overall mortality and separate competing risk models for each major cause of death category were used to evaluate their respective associations with AF.

RESULTS

During a median follow-up of 4.1 years, 19,094 patients died; cause of death was known for 18,854 patients. After multivariable adjustment (demographics, comorbidities, relevant laboratory data, medication use, and kidney function), AF was associated with 23% (95% CI 18-29%) higher risk of all-cause mortality, 45% (95% CI 31-61%) higher risk of cardiovascular mortality and 13% (95% CI 3-22%) lower risk of malignancy-related mortality. Exclusion of patients with malignancy yielded similar results except for a lack of association between AF and malignancy-related deaths. Results were consistent across various stages of CKD.

CONCLUSIONS

In a non-dialysis-dependent CKD population, the presence of AF was associated with higher all-cause and cardiovascular mortality. These data suggest that patients with both CKD and AF are at high cardiovascular risk, and thus clinical practice (or trials) should aim at reducing the overall excess cardiovascular mortality (not stroke alone) in patients with AF and CKD.

Oral Anticoagulation in Chronic Kidney Disease and Atrial Fibrillation

BACKGROUND

Cardiological societies recommend, in their guidelines, that patients with atrial fibrillation and an intermediate (or higher) risk of stroke and systemic embolization should be treated with oral anticoagulant drugs. For patients who do not have mitral valve stenosis or a mechanical valve prosthesis, non-vitamin-K dependent oral anticoagulants (NOAC) are preferred over vitamin K antagonists (VKA) for this purpose. It is unclear, however, whether patients with chronic kidney disease and atrial fibrillation benefit from oral anticoagulation to the same extent as those with normal kidney function. It is also unclear which of the two types of anti - coagulant drug is preferable for patients with chronic kidney disease; NOAC are, in part, renally eliminated.

METHODS

This review is based on pertinent publications retrieved by a selective literature search, and on international guidelines.

RESULTS

Current evidence suggests that patients with atrial fibrillation who have chronic kidney disease with a glomerular filtration rate (GFR) above 15 mL/ min/1.73 m² should be treated with an oral anticoagulant drug if they have an at least intermediate risk of embolization, as assessed with the CHA2DS2-VASc score. For patients with advanced chronic kidney disease (GFR from 15 to 29 mL/ min/1.73 m²), however, this recommendation is based only on registry studies. For dialysis patients with atrial fibrillation, decisions whether to give oral anticoagulant drugs should be taken on an individual basis, in view of the elevated risk of hemorrhage and the unclear efficacy of such drugs in these patients. The subgroup analyses of the NOAC approval studies show that, for patients with atrial fibrillation and chronic kidney disease with a creatinine clearance of >25-30 mL/min, NOAC should be given in preference to VKA, as long as the patient does not have mitral valve stenosis or a mechanical valve prosthesis. For those whose creatinine clearance is less than 25 mL/min, the relative merits of NOAC versus VKA are still debated.

CONCLUSION

The cardiological societies' recommendation that patients with atrial fibrillation should be given oral anticoagulant drugs applies to the majority of such patients who also have chronic kidney disease.

Comparative safety of direct oral anticoagulants and warfarin in venous thromboembolism: multicentre, population based, observational study

Objective To determine the safety of direct oral anticoagulant (DOAC) use compared with warfarin use for the treatment of venous thromboembolism.Design Retrospective matched cohort study conducted between 1 January 2009 and 31 March 2016.Setting Community based, using healthcare data from six jurisdictions in Canada and the United States.Participants 59 525 adults (12 489 DOAC users; 47 036 warfarin users) with a new diagnosis of venous thromboembolism and a prescription for a DOAC or warfarin within 30 days of diagnosis.Main outcome measures Outcomes included hospital admission or emergency department visit for major bleeding and all cause mortality within 90 days after starting treatment. Propensity score matching and shared frailty models were used to estimate adjusted hazard ratios of the outcomes comparing DOACs with warfarin. Analyses were conducted independently at each site, with meta-analytical methods used to estimate pooled hazard ratios across sites.Results Of the 59 525 participants, 1967 (3.3%) had a major bleed and 1029 (1.7%) died over a mean follow-up of 85.2 days. The risk of major bleeding was similar for DOAC compared with warfarin use (pooled hazard ratio 0.92, 95% confidence interval 0.82 to 1.03), with the overall direction of the association favouring DOAC use. No difference was found in the risk of death (pooled hazard ratio 0.99, 0.84 to 1.16) for DOACs compared with warfarin use. There was no evidence of heterogeneity across centres, between patients with and without chronic kidney disease, across age groups, or between male and female patients.Conclusions In this analysis of adults with incident venous thromboembolism, treatment with DOACs, compared with warfarin, was not associated with an increased risk of major bleeding or all cause mortality in the first 90 days of treatment.Trial registration Clinical trials NCT02833987.

Direct oral anticoagulants in patients with chronic kidney disease: patient selection and special considerations

Many patients with chronic kidney disease (CKD) receive anticoagulation or antiplatelet therapy due to atrial fibrillation, coronary artery disease, thromboembolic disease, or peripheral artery disease. The treatment usually includes vitamin K antagonists (VKAs) and/or platelet aggregation inhibitors. The direct oral anticoagulants (DOAC) inhibiting factor Xa or thrombin represent an alternative for VKAs. In patients with acute and chronic kidney disease, caution is warranted, as DOACs can accumulate as they are partly eliminated by the kidneys. Thus, they can potentially increase the bleeding risk in patients with CKD. In patients with an estimated glomerular filtration rate (eGFR) above 60 mL/min, DOACs can be used safely with greater efficacy and safety as compared to VKAs. In patients with CKD 3, DOACs are as effective as VKAs with a lower bleeding rate. The more the renal function declines, the lower is the advantage of DOACs over VKAs. Thus, use of DOACs should be avoided in patients with an eGFR below 30 mL/min, particularly, the compounds with a high renal elimination. Available data suggest that DOACs can also be used safely in older patients. In this review, use of DOACs in comparison with VKAs, heparins, and heparinoids, together with special considerations in patients with impaired renal function will be discussed.