Anticoagulants in atrial fibrillation patients with chronic kidney disease

The Cardio-Kidney Patient: Epidemiology, Clinical Characteristics and Therapy

Patients with chronic kidney disease (CKD) are at high risk to develop cardiovascular disease with its manifestations coronary artery disease, heart failure, arrhythmias, and sudden cardiac death. In addition, the presence of CKD has a major impact on the prognosis of patients with cardiovascular disease, leading to an increased morbidity and mortality if both comorbidities are present. Therapeutic options including medical therapy and interventional treatment are often limited in patients with advanced CKD, and in most cardiovascular outcome trials, patients with advanced CKD have been excluded. Thus, in many patients, treatment strategies for cardiovascular disease need to be extrapolated from trials conducted in patients without CKD. The current article summarizes the epidemiology, clinical presentation, and treatment options for the most prevalent manifestations of cardiovascular disease in CKD and discusses the currently available treatment options to reduce morbidity and mortality in this high-risk population.

Safety and Efficacy of DOACs in Patients with Advanced and End-Stage Renal Disease

The prevalence of chronic kidney disease (CKD) is increasing due to the aging of the population and multiplication of risk factors, such as hypertension, arteriosclerosis and obesity. Impaired renal function increases both the risk of bleeding and thrombosis. There are two groups of orally administered drugs to prevent thromboembolic events in patients with CKD who require anticoagulation: vitamin K antagonists (VKAs) and direct oral anticoagulants (DOACs). Although VKAs remain the first-line treatment in patients with advanced CKD, treatment with VKAs is challenging due to difficulties in maintaining the appropriate anticoagulation level, tendency to accelerate vascular calcification and faster progression of CKD in patients treated with VKAs. On the other hand, the pleiotropic effect of DOACs, including vascular protection and anti-inflammatory properties along with comparable efficacy and safety of treatment with DOACs, compared to VKAs observed in preliminary reports encourages the use of DOACs in patients with CKD. This review summarizes the available data on the efficacy and safety of DOACs in patients with CKD and provides recommendations regarding the choice of the optimal drug and dosage depending on the CKD stage.

Resolution of warfarin-induced alopecia with conversion to apixaban

Warfarin is frequently prescribed as a long-term anticoagulant in patients with end-stage kidney disease as direct oral anticoagulants undergo renal excretion. Anticoagulation is a rare cause of alopecia in adults and is thought to be due to the promotion of the 'resting phase' of hair follicles. In this case report, a prevalent haemodialysis female patient required long-term anticoagulation following a complex pulmonary embolus and dialysis access complications. After commencing warfarin therapy, the patient reported generalised loss and thinning of her hair. All other potential causes were excluded. Cessation of warfarin therapy and conversion to apixaban with close monitoring alleviated the hair loss. Warfarin therapy is a rare cause of alopecia but should be considered in patients on long-term anticoagulation when other diagnoses have been excluded. Hair loss has a profoundly negative impact on patient quality of life and should prompt investigation to determine the underlying cause.

Antiplatelets, anticoagulants, and colonoscopic polypectomy

The management of antiplatelet and anticoagulant (ie, antithrombotic) agents is challenging in the periendoscopic setting. In this state-of-the-art update, we review current best practice recommendations focusing on the risk of immediate and delayed postpolypectomy bleeding in the context of drug discontinuation (ie, temporary interruption) and drug continuation. The data regarding polypectomy technique (cold snare vs conventional thermal-based) and prophylactic placement of hemostatic clips are evaluated to assess whether these endoscopic techniques are beneficial in reducing postpolypectomy bleeding. Finally, clinical takeaways are provided to facilitate safer polypectomy among patients on antiplatelet and anticoagulant agents.

The impact of renal function on efficacy and safety of new oral anticoagulant in atrial fibrillation patients: A systemic review and meta-analysis

BACKGROUND AND OBJECTIVES

This meta-analysis was to investigate the efficacy and safety of new oral anticoagulant (NOAC) in atrial fibrillation (AF) patients with renal function insufficiency, and to explore whether renal decline occurs in AF patients with NOAC and its impact on outcomes.

METHODS AND RESULTS

In AF patients with mild renal insufficiency, the NOAC was associated with significantly lower rates of stroke (odds ratio [OR], 0.78; 95% confidence interval [CI], 0.67-0.91; P < .05). Lower rates of bleeding were significantly observed in NOAC group (OR, 0.85; 95% CI, 0.75-0.97; P < .05). In AF patients with moderate renal impairment, similar results were revealed (OR for stroke or systemic embolism, 0.80; 95% CI, 0.67-0.95, P < .05; OR for major bleeding, 0.78; 95% CI, 0.59-1.03; P = .07). During the follow-up, pooled data revealed that NOAC showed a less renal toxicity, but the difference did not reach statistical significance (creatinine clearance decline: -0.12 mL/min [-0.84, 0.61 mL/min]). We have revealed that the NOACs were associated with significantly lower rates of stroke or systemic embolism (hazard ratio [HR], 0.66; 95% CI, 0.42-0.89; P < .05) and lower rates of bleeding (HR, 0.93; 95% CI, 0.70-1.16; P = .153) in AF patients with worsening renal function.

CONCLUSIONS

NOAC may have the potentiality to be at least as effective as warfarin and may equal safety outcomes in AF patients with renal impairment. Renal decline during therapeutics may be less likely happened in NOAC than warfarin dose. NOAC may reveal good efficacy and safety outcomes in these scenarios. Further detailed research is needed to gain more clear profile on this new anticoagulant.

Cerebrovascular events, bleeding complications and device related thrombi in atrial fibrillation patients with chronic kidney disease and left atrial appendage closure with the WATCHMAN™ device

BACKGROUND

Impaired renal function increases the bleeding risk, leading to a conservative prescription and frequent discontinuation of oral anticoagulation in atrial fibrillation patients with chronic kidney disease (CKD). Interventional left atrial appendage closure (LAAC) might be an alternative therapeutic strategy for these patients.

METHODS

We aimed to prospectively assess cerebrovascular (CE) and bleeding events, as well as peri-procedural and long-term complications in a cohort of consecutive patients undergoing interventional LAAC using the WATCHMAN™ device, with focus on CKD patients.

RESULTS

One hundred and eighty-nine consecutive patients undergoing interventional LAAC were included in this analysis; 171 (90.5%) patients had a reduced estimated glomerular filtration rate (eGFR; patients for each CKD stage: II = 66; IIIa = 32; IIIb = 43; IV = 18; V = 12). During a follow-up of 310 patient years three (1.0%) patients suffered a CE (two strokes, one transitory ischemic attack) and five (1.6%) other ones a bleeding complication. The observed stroke rate was more than two-thirds and the bleeding risk more than half lower than expected. Device related thrombi (DRT) were detected in twelve (6.5%) patients; women had significantly more DRT than men (12.5% vs. 2.6%; p = 0.009). Patients with an eGFR< 30 ml/min/1.73m2 showed a trend to a higher DRT rate as compared to the opposite group (13.3% vs. 5.1%; p = 0.10). Thrombus resolved with temporary oral anticoagulation therapy in ten patients without sequelae; thrombus consolidation was confirmed by serial TEE controls in the remaining two patients.

CONCLUSIONS

Atrial fibrillation patients with CKD have low CE and bleeding rates after LAAC with the WATCHMAN™ device. DRT risk is higher in female and patients with severe CKD. More frequent post-interventional TEE controls might be justified for early DRT detection and safe management of patients at high DRT risk.

TRIAL REGISTRATION

(German Clinical Trials Register ID: DRKS00 010768 ; Registration Date 07.07.2016).

Antithrombotic treatment for secondary prevention of stroke and other thromboembolic events in patients with stroke or transient ischemic attack and non-valvular atrial fibrillation: A European Stroke Organisation guideline

Patients with ischemic stroke or transient ischemic attack and non-valvular atrial fibrillation have a high risk of recurrent stroke and other vascular events. The aim of this guideline is to provide recommendations on antithrombotic medication for secondary prevention of stroke and other vascular outcomes in these patients. The working group identified questions and outcomes, graded evidence, and developed recommendations according to the Grading of Recommendations Assessment, Development, and Evaluation approach and the European Stroke Organisation (ESO) standard operating procedure for guidelines. The guideline was reviewed and approved by the ESO guideline board and the ESO executive committee. In patients with atrial fibrillation and previous stroke or transient ischemic attack, oral anticoagulants reduce the risk of recurrence over antiplatelets or no antithrombotic treatment. Non-vitamin K antagonist oral anticoagulants are preferred over vitamin K antagonists because they have a lower risk of major bleeding and death. Recommendations are weak regarding timing of treatment, (re-)starting oral anticoagulants in patients with previous intracerebral haemorrhage, and treatment in specific patient subgroups of those of older age, with cognitive impairment, renal failure or small vessel disease, because of a lack of strong evidence. In conclusion, for patients with atrial fibrillation and ischemic stroke or transient ischemic attack, non-vitamin K antagonist oral anticoagulants are the preferred treatment for secondary prevention of recurrent stroke or thromboembolism. Further research is required to determine the best timing for initiating oral anticoagulants after an acute ischemic stroke, whether or not oral anticoagulants should be (re)started in patients with a history of intracerebral haemorrhage, and the best secondary preventive treatment in specific subgroups.

Association of Fibroblast Growth Factor 23 With Atrial Fibrillation in Chronic Kidney Disease, From the Chronic Renal Insufficiency Cohort Study

IMPORTANCE

Levels of fibroblast growth factor 23 (FGF23) are elevated in chronic kidney disease (CKD) and strongly associated with left ventricular hypertrophy, heart failure, and death. Whether FGF23 is an independent risk factor for atrial fibrillation in CKD is unknown.

OBJECTIVE

To investigate the association of FGF23 with atrial fibrillation in CKD.

DESIGN, SETTING, AND PARTICIPANTS

Prospective cohort study of 3876 individuals with mild to severe CKD who enrolled in the Chronic Renal Insufficiency Cohort Study between June 19, 2003, and September 3, 2008, and were followed up through March 31, 2013.

EXPOSURES

Baseline plasma FGF23 levels.

MAIN OUTCOMES AND MEASURES

Prevalent and incident atrial fibrillation.

RESULTS

The study cohort comprised 3876 participants. Their mean (SD) age was 57.7 (11.0) years, and 44.8% (1736 of 3876) were female. Elevated FGF23 levels were independently associated with increased odds of prevalent atrial fibrillation (n = 660) after adjustment for cardiovascular and CKD-specific factors (odds ratio of highest vs lowest FGF23 quartile, 2.30; 95% CI, 1.69-3.13; P < .001 for linear trend across quartiles). During a median follow-up of 7.6 years (interquartile range, 6.3-8.6 years), 247 of the 3216 participants who were at risk developed incident atrial fibrillation (11.9 events per 1000 person-years). In fully adjusted models, elevated FGF23 was independently associated with increased risk of incident atrial fibrillation after adjustment for demographic, cardiovascular, and CKD-specific factors, and other markers of mineral metabolism (hazard ratio of highest vs lowest FGF23 quartile, 1.59; 95% CI, 1.00-2.53; P = .02 for linear trend across quartiles). The results were unchanged when further adjusted for ejection fraction, but individual adjustments for left ventricular mass index, left atrial area, and interim heart failure events partially attenuated the association of elevated FGF23 with incident atrial fibrillation.

CONCLUSIONS AND RELEVANCE

Elevated FGF23 is independently associated with prevalent and incident atrial fibrillation in patients with mild to severe CKD. The effect may be partially mediated through a diastolic dysfunction pathway that includes left ventricular hypertrophy, atrial enlargement, and heart failure events.

Risks and Benefits of Direct Oral Anticoagulants across the Spectrum of GFR among Incident and Prevalent Patients with Atrial Fibrillation

BACKGROUND AND OBJECTIVES

All randomized trials of direct oral anticoagulants in atrial fibrillation excluded patients with severe kidney disease. The safety and effectiveness of direct oral anticoagulants across the range of eGFR in real-world settings is unknown. Our objective is to quantify the risk of bleeding and benefit of ischemic stroke prevention for direct oral anticoagulants compared with warfarin in patients with atrial fibrillation with and without CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We created a propensity score-matched cohort of 3206 patients with atrial fibrillation and direct oral anticoagulant use and 3206 patients with atrial fibrillation using warfarin from October of 2010 to February of 2017 in an electronic health record (Geisinger Health System). The risks of bleeding and ischemic stroke were compared between direct oral anticoagulant and warfarin users using Cox proportional hazards regression, stratified by eGFR (≥60 and <60 ml/min per 1.73 m2).

RESULTS

The mean (SD) age of the 6412 participants was 72 (12) years, 47% were women, and average eGFR was 69 (21) ml/min per 1.73 m2. There were 1181 bleeding events and 466 ischemic strokes over 7391 person-years of follow-up. Compared with warfarin use, the hazard ratios (HRs) (95% confidence interval [95% CI]) of bleeding associated with direct oral anticoagulant use were 1.01 (0.88 to 1.17) and 1.23 (1.02 to 1.48) for those with eGFR≥60 and eGFR<60 ml/min per 1.73 m2, respectively (P-interaction=0.10). There was no difference between direct oral anticoagulant and warfarin users in the risk of ischemic stroke: HRs (95% CI) of 0.94 (0.74 to 1.18) and 1.02 (0.76 to 1.37) for those with eGFR≥60 and eGFR<60 ml/min per 1.73 m2, respectively (P-interaction=0.70). Similar findings were observed with individual drugs.

CONCLUSIONS

In a large health care system, patients with eGFR<60 ml/min per 1.73 m2 who took direct oral anticoagulants for atrial fibrillation had slightly higher risk of bleeding compared with those on warfarin, but similar benefits from prevention of ischemic stroke.

Creatinine Versus Cystatin C: Differing Estimates of Renal Function in Hospitalized Veterans Receiving Anticoagulants

BACKGROUND

Current practice in anticoagulation dosing relies on kidney function estimated by serum creatinine using the Cockcroft-Gault equation. However, creatinine can be unreliable in patients with low or high muscle mass. Cystatin C provides an alternative estimation of glomerular filtration rate (eGFR) that is independent of muscle.

OBJECTIVE

We compared cystatin C-based eGFR (eGFR_cys) with multiple creatinine-based estimates of kidney function in hospitalized patients receiving anticoagulants, to assess for discordant results that could impact medication dosing.

DESIGN

Retrospective chart review of hospitalized patients over 1 year who received non-vitamin K antagonist anticoagulation, and who had same-day measurements of cystatin C and creatinine.

PARTICIPANTS

Seventy-five inpatient veterans (median age 68) at the San Francisco VA Medical Center (SFVAMC).

MAIN MEASURES

We compared the median difference between eGFR by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) study equation using cystatin C (eGFR_cys) and eGFRs using three creatinine-based equations: CKD-EPI (eGFR_EPI), Modified Diet in Renal Disease (eGFR_MDRD), and Cockcroft-Gault (eGFR_CG). We categorized patients into standard KDIGO kidney stages and into drug-dosing categories based on each creatinine equation and calculated proportions of patients reclassified across these categories based on cystatin C.

KEY RESULTS

Cystatin C predicted overall lower eGFR compared to creatinine-based equations, with a median difference of - 7.1 (IQR - 17.2, 2.6) mL/min/1.73 m² versus eGFR_EPI, - 21.2 (IQR - 43.7, - 8.1) mL/min/1.73 m² versus eGFR_MDRD, and - 25.9 (IQR - 46.8, - 8.7) mL/min/1.73 m² versus eGFR_CG. Thirty-one to 52% of patients were reclassified into lower drug-dosing categories using cystatin C compared to creatinine-based estimates.

CONCLUSIONS

We found substantial discordance in eGFR comparing cystatin C with creatinine in this group of anticoagulated inpatients. Our sample size was limited and included few women. Further investigation is needed to confirm these findings and evaluate implications for bleeding and other clinical outcomes.

NIH TRIAL REGISTRY NUMBER

Not applicable.

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.

[Anticoagulation in patients with chronic kidney disease : Recommendations from the working group "Heart-Kidney" of the German Cardiac Society and the German Society of Nephrology]

Indications for anticoagulation are thromboembolic events, prosthetic heart valves, and atrial fibrillation with a corresponding risk score. Clinical trials have excluded patients with advanced chronic kidney disease and these data cannot be always generalized to patients with chronic kidney disease. Non-vitamin K antagonist oral anticoagulants (NOACs) are mostly not recommended or are contraindicated in advanced stages of chronic kidney disease. Observational studies have shown that dialysis patients with atrial fibrillation do not profit from coumarin anticoagulants; prospective studies are lacking.

Chronic kidney disease and anticoagulation: from vitamin K antagonists and heparins to direct oral anticoagulant agents

Anticoagulation in patients with impaired kidney function can be challenging since drugs' pharmacokinetics and bioavailability are altered in this setting. Patients with chronic kidney disease (CKD) treated with conventional anticoagulant agents [vitamin K antagonist (VKA), low-molecular weight heparin (LMWH) or unfractionated heparin (UFH)] are at high risk of bleeding events (both non-major and major clinically relevant bleeding). While anticoagulation reduces the risk of thromboembolic events, the co-existing bleeding risk and the fact that the most commonly used anticoagulation agents are eliminated via the kidneys pose additional challenges. More recently, two classes of direct oral anticoagulant agents (DOACs) have been investigated for the prevention and management of venous thromboembolic events: the direct factor Xa inhibitors rivaroxaban, apixaban and edoxaban, and the direct thrombin inhibitor dabigatran. In this review, we discuss the complex challenges and the practical considerations associated with the management of anticoagulation treatment in patients with CKD, with a special focus on DOACs.

Meta-analysis of safety and efficacy for direct oral anticoagulation treatment of non-valvular atrial fibrillation in relation to renal function

INTRODUCTION

We performed a meta-analysis of the safety and efficacy of anticoagulation treatment for atrial fibrillation (AF) in relation to renal function. We also examined the change in estimated glomerular filtration rate (eGFR) from baseline and compared the outcomes for patients with stable and worsening renal function.

MATERIALS AND METHODS

We selected studies that used randomized controlled trials in which outcomes for direct oral anticoagulants (DOACs) (dabigatran, rivaroxaban, apixaban, or edoxaban) were compared with those for warfarin in AF patients with normal, mild or moderate renal function, except the severe one (creatinine clearance<30).

RESULTS

We assessed five clinical trials, involving 72,608 patients. Pooled analysis indicated that the risk of stroke was lower for DOACs than for warfarin among patients with mild renal impairment (Risk ratio, 0.79; 95% confidence interval, 0.68-0.91) and moderate renal impairment (0.80, 0.69-0.92). No major differences were found in patients with normal renal function. Additionally, DOACs were associated with fewer major bleeds among patients with normal (0.77, 0.70-0.84), mild (0.86, 0.77-0.95), and moderate renal impairment (0.73, 0.65-0.82). Among those treated with DOACs, a lower dosage was associated with lower risk of major bleeding (0.75, 0.68-0.83) and higher risk of stroke or systemic embolism (1.28, 1.12-1.47). Further, DOACs tended to be associated with a lower estimated glomerular filtration rate (eGFR) than warfarin even after 30months. Finally, we found significant differences in the risk of stroke (2.09, 1.64-2.68) and major bleeding (2.01, 1.66-2.42) between patients with stable and worsening renal function.

CONCLUSIONS

DOACs have a greater clinical benefit than warfarin with respect to renal function. They are associated with a comparatively lower risk of stroke and major bleeding, as well lower eGFR. This suggests these agents are a better choice in patients with renal disease.

Influence of renal function on anticoagulation control in patients with non-valvular atrial fibrillation taking vitamin K antagonists

BACKGROUND AND PURPOSE

Chronic kidney disease (CKD) has been related to poor anticoagulation control and an increased risk of bleeding. This study aims to evaluate the association between impaired renal function (eGFR <60 mL/min/1.73 m² ) and anticoagulation control in patients with non-valvular atrial fibrillation (AF) on vitamin K antagonists (VKA) therapy. We also assessed whether the predictive value of the SAMe-TT₂ R₂ score prevailed for subgroups both with and without CKD.

METHODS

This is an ancillary analysis of 1381 patients from the PAULA study, which was a cross-sectional, retrospective and nationwide multicenter study.

RESULTS

A total of 370 patients had eGFR <60 mL/min/1.73 m² . Anticoagulation control levels progressively worsened across each stage of CKD. Multiple linear regression analysis showed CKD as an independent predictor of time in therapeutic range (TTR). In the subgroup of patients with preserved renal function, female sex, diet affecting INR, polypharmacy and amiodarone were associated with poorer TTR. The SAMe-TT₂ R₂ score had a significant but modest predictive value for TTR<65% (AUC, area under the curve 0.558, P = .002). In the subgroup of patients with CKD, the SAMe-TT₂ R₂ (>2 points) showed no significant predictive capacity for TTR (AUC 0.528, P = .354). The average TTR was similar for both sexes (P = .255), but with a higher percentage of males subjects with TTR ≥65% (P = .013).

CONCLUSION

Chronic kidney disease is associated with poor anticoagulation control in patients with non-valvular AF taking VKA. The SAMe-TT₂ R₂ score was not predictive of poor TTR in the subgroup with CKD, although a modest predictive value for poor TTR was found in those without CKD.

Estimated glomerular filtration rate calculated using different creatinine and cystatin based formulas in prediction of trough plasma Dabigtran concentration

BACKGROUND

In this paper we evaluated the relationship between trough DAB concentration with eGFR calculated using CRE and CYS based formulas.

MATERIALS AND METHODS

We considered 100 patients. eGFR was calculated using CKD-EPIcreat, CG, MDRD, CKD-EPIcys and CKD-EPIcombined equations. DAB dosage was selected on the basis of CKD-EPIcreat and relationship between trough DAB concentration and eGFRs was evaluated.

RESULTS

Trough DAB concentration roughly correlates with eGFR calculated using various formulas. CKD-EPIcreat eGFR was higher than CKD-EPIcys. In patients receiving a DAB dosage considered adequate using CKD-EPIcreat eGFR but considered excessive using CKD-EPIcys, we observed higher DAB trough concentration and an increased prevalence of subjects with drug concentration >200ng/mL.

CONCLUSION

These results suggest that eGFR alone was unable to fully explain trough DAB plasma concentration. Therefore a drug's prescription schedule based on eGFR only should be inadequate. We observed a better correlation between trough DAB concentration and CKD-EPIcys rather than CKD-EPIcreat eGFR. Thus, in patients chronically treated with DAB for thromboprophylaxis in nonvalvular atrial fibrillation evaluation of eGFR using a cystatin base formula should be considered.

Non-vitamin K antagonist oral anticoagulants and heart failure

Thromboembolism contributes to morbidity and mortality in patients with heart failure (HF), and atrial fibrillation (AF) is one of the main factors promoting this complication. As they share many risk factors, HF and AF frequently coexist, and patients with both conditions are at a particularly high risk of thromboembolism. Non-vitamin K antagonist oral anticoagulants (NOACs) are direct antagonists of thrombin (dabigatran) and factor Xa (rivaroxaban, apixaban and edoxaban), and were designed to overcome the limitations of vitamin K antagonists. Compared with warfarin in non-valvular AF, NOACs demonstrated non-inferiority with better safety, most particularly for intracranial haemorrhages. Therefore, the European Society of Cardiology guidelines recommend NOACs for most patients with non-valvular AF. Subgroups of patients with both AF and HF from the pivotal studies investigating the safety and efficacy of NOACs have been analysed and, for each NOAC, results were similar to those of the total analysis population. A recent meta-analysis of these subgroups has confirmed the better efficacy and safety of NOACs in patients with AF and HF - particularly the 41% decrease in the incidence of intracranial haemorrhages. The prothrombotic state associated with HF suggests that patients with HF in sinus rhythm could also benefit from treatment with NOACs. However, in the absence of clinical trial data supporting this indication, current guidelines do not recommend anticoagulant treatment of patients with HF in sinus rhythm. In conclusion, recent analyses of pivotal studies support the use of NOACs in accordance with their indications in HF patients with non-valvular AF.

Phlegmasia cerulean dolens: complication of femoral vein catheterization

There are three less frequent manifestations of acute massive venous thrombosis and obstruction of the venous drainage of an extremity. They are phlegmasia alba dolens, phlegmasia cerulean dolens (PCD), and venous gangrene. The term PCD differentiates ischemia-associated massive venous thrombosis from phlegmasia alba dolens, which describes fulminant venous thrombosis without ischemia. We present a 55-year-old hypertensive, who presented with paedal oedema and breathlessness at rest. About a month prior to this admission, she suffered dislocation of left patella. She was treated with a plaster cast and immobilization for 3 weeks. Her serum creatinine was 8.8 mg/dL. She was initiated on haemodialysis via two single-lumen catheters placed in left femoral vein. The femoral vein catheters were removed after third session of haemodialysis. On fourth day, the patient complained pain and blue discolouration of left toes. On examination, the left lower limb was swollen, discoloured, and cold with blebs up to upper one-third of left leg. The left dorsalis pedis and posterior tibial arteries were not palpable. A Doppler of veins of lower limb revealed, thrombosis of deep, and superficial venous system of left lower limb. As there was no response to anticoagulation below, knee amputation was performed.

Use of direct oral anticoagulants in patients with nonvalvular atrial fibrillation according to clinical profile

The majority of patients with atrial fibrillation should receive oral anticoagulation to reduce the risk of stroke. The limitations of vitamin K antagonists have led to an underuse of anticoagulants in clinical practice which has been associated with a higher risk of stroke, hospitalizations and healthcare costs. Direct oral anticoagulants (DOACs) overcome some of the limitations of vitamin K antagonists and may therefore increase the use of oral anticoagulants in clinical practice. Since no head-to-head trials have been performed, only indirect comparisons can be made among them. In this review, the results of the Phase III randomized controlled trials with DOACs were analyzed, trying to determine whether one or more DOACs could be especially recommended according to different clinical conditions.

Should oral anticoagulant therapy be continued during dental extraction? A meta-analysis

Background

Oral anticoagulation therapy is widely used to reduce the risks of thromboembolism. However, the therapy increases the risk of hemorrhage during the surgical procedures. The aim of this meta-analysis was to evaluate the bleeding risk of patients continuing or discontinuing oral anticoagulant therapy while undergoing dental extractions.

Methods

Six electronic databases, including PubMed, Embase, Cochrane library, Web of Science, China Biology Medicine disc (CBM), and China National Knowledge Infrastructure (CNKI), were searched in March, 2016. Relevant articles were screened by two independent reviewers under our inclusion criteria. Quality was evaluated using the Cochrane Collaboration risk of bias tool. Meta-analyses were conducted with fixed and random effects models as appropriate.

Results

Six studies (with a total of 591 patients) were included in our meta-analysis. Our results showed that there was no significant difference in the bleeding risk between patients continuing or discontinuing oral anticoagulant therapy while undergoing dental extractions (risk ratio, 1.31; 95 % CI, 0.79, 2.14; P > 0.05). There was also no significant difference in bleeding risk 1 day (risk ratio, 0.91; 95 % CI, 0.35, 2.37; P > 0.05) and 7 days (risk ratio, 1.47; 95 % CI, 0.83, 2.59; P > 0.05) after the dental extraction.

Conclusion

Under current studies and evidence, it appears that patients continuing oral anticoagulant therapy do not have an increased risk of bleeding after dental extractions compared to patients who discontinue oral anticoagulant therapy.

Renal function in atrial fibrillation patients switched from warfarin to a direct oral anticoagulant

All available direct oral anticoagulants (DOACs) are at least partially eliminated by the kidneys. These agents are increasingly being used as alternatives to warfarin for stroke prevention in patients with atrial fibrillation. The aim of this study was to identify changes in renal function and associated DOAC dosing implications in a multicenter cohort of atrial fibrillation patients switched from warfarin to DOAC treatment. We included all patients in the Michigan Anticoagulation Quality Improvement Initiative cohort who switched from warfarin to a DOAC with atrial fibrillation as their anticoagulant indication between 2009 and 2014, and who had at least two creatinine values. Compliance with FDA-recommended dosing based on renal function was assessed. Of the 189 patients switched from warfarin to a DOAC, 34 (18.0 %) had a baseline creatinine clearance <50 mL/min and 23 (12.2 %) experienced important fluctuations in renal function. Of these 23 patients, 6 (26.1 %) should have impacted the DOAC dosing, but only 1 patient actually received an appropriate dose adjustment. Additionally, 15 (7.9 %) of patients on DOACs had a dose change performed, but only one patient demonstrated a change in renal function to justify the dose adjustment. Most atrial fibrillation patients who switched from warfarin to a DOAC had stable renal function. However, the majority of patients who had a change in renal function did not receive the indicated dose change. As the use of DOACs expands, monitoring of renal function and appropriate dose adjustments are critical.

Meta-Analysis of Renal Function on the Safety and Efficacy of Novel Oral Anticoagulants for Atrial Fibrillation

Novel oral anticoagulants (NOACs) are safe and effective for the prevention of stroke or systemic embolism (S/SE) in atrial fibrillation. The efficacy and safety of NOACs compared with warfarin has not been systematically assessed in subjects with mild or moderate renal dysfunction. We performed a meta-analysis of the randomized clinical trials that compared efficacy and safety (major bleeding) outcomes of NOACs compared to warfarin for the treatment of nonvalvular atrial fibrillation and had available data on renal function. We estimated the pooled relative risk (RR) of S/SE and major bleeding in relation to renal function (assessed by baseline estimated glomerular filtration rate divided in 3 groups: normal [estimated glomerular filtration rate >80 ml/min], mildly impaired [50 to 80 ml/min], and moderate impairment [<50 ml/min]). We included 4 randomized clinical trials enrolling a total of 58,338 subjects. The RRs of S/SE and major bleeding were higher in subjects with renal impairment compared to normal renal function, independent of type of anticoagulant therapy. In subjects with normal renal function, no difference in the risk of S/SE was observed, whereas the risk of major bleeding was slightly lower for subjects taking NOACs (RR 0.87, 95% confidence interval [CI] 0.76 to 0.99). In subjects with mild or moderate renal impairment, NOACs were associated with a reduced risk of S/SE (RR 0.75, 95% CI 0.66 to 0.85 and RR 0.80, 95% CI 0.68 to 0.94, respectively) and major bleeding (RR 0.87, 95% CI 0.79 to 0.95 and RR 0.80, 95% CI 0.71 to 0.91, respectively) compared to warfarin. The pooled analysis for major bleeding demonstrated significant heterogeneity. In conclusion, the use of NOACs was associated with a reduced risk of S/SE and reduced risk of major bleeding compared to warfarin in subjects with mild or moderate renal impairment suggesting a favorable risk profile of these agents in patients with renal disease.

Atrial fibrillation and chronic kidney disease: focus on rivaroxaban

Renal insufficiency increases the risk of stroke and bleeding in atrial fibrillation patients. Although vitamin K antagonists reduce the risk of stroke in patients with moderate renal dysfunction, this observation is less clear in patients with renal impairment. Moreover, the risk of bleeding with vitamin K antagonists increases as renal function worsens. Maintaining international normalized ratio values within therapeutic targets is more difficult in patients with renal dysfunction, and those agents may cause warfarin-related nephropathy and vascular calcification. Rivaroxaban is the only nonvitamin K oral anticoagulant with a dose specifically tested in patients with moderate renal insufficiency. Rivaroxaban is effective for the prevention of stroke in atrial fibrillation patients with moderate renal dysfunction, with a lower risk of intracranial and fatal bleeding.

Meta-analysis on risk of bleeding with apixaban in patients with renal impairment

Apixaban is a novel oral anticoagulant which is approved for the management of atrial fibrillation and venous thromboembolism prophylaxis. There have been concerns regarding bleeding risks with apixaban in patients with renal impairment. We performed a systematic review and meta-analysis to evaluate the risk of bleeding with apixaban in these patients. Relevant studies were identified through electronic literature searches of MEDLINE, EMBASE, Cochrane library, and clinicaltrials.gov (from inception to February 24, 2014). Phase III randomized controlled trials that compared apixaban with conventional agents (vitamin K antagonist and/or warfarin, low molecular weight heparin, aspirin, and placebo) were included. We defined mild renal impairment as creatinine clearance of 50 to 80 ml/min and moderate to severe renal impairment as creatinine clearance <50 ml/min. Study-specific risk ratios were calculated, and between-study heterogeneity was assessed using the I(2) statistics. In 6 trials involving 40,145 patients, the risk of bleeding with apixaban in patients with mild renal impairment was significantly less (risk ratio 0.80, 95% confidence interval 0.66 to 0.96, I(2) = 13%) compared with conventional anticoagulants. In patients with moderate to severe renal impairment, the risk of bleeding with was found to be similar (risk ratio 1.01, 95% confidence interval 0.49 to 2.10, I(2) = 72%). In conclusion, compared with the conventional agents, bleeding risk with apixaban in patients with mild and moderate to severe renal insufficiency is lower and similar, respectively.

Meta-analysis of the influence of chronic kidney disease on the risk of thromboembolism among patients with nonvalvular atrial fibrillation

Chronic kidney disease (CKD) and atrial fibrillation (AF) frequently coexist. However, the extent to which CKD increases the risk of thromboembolism in patients with nonvalvular AF and the benefits of anticoagulation in this group remain unclear. We addressed the role of CKD in the prediction of thromboembolic events and the impact of anticoagulation using a meta-analysis method. Data sources included MEDLINE, EMBASE, and Cochrane (from inception to January 2014). Three independent reviewers selected studies. Descriptive and quantitative information was extracted from each selected study and a random-effects meta-analysis was performed. After screening 962 search results, 19 studies were considered eligible. Among patients with AF, the presence of CKD resulted in an increased risk of thromboembolism (hazard ratio [HR] 1.46, 95% confidence interval [CI] 1.20 to 1.76, p = 0.0001), particularly in case of end-stage CKD (HR 1.83, 95% CI 1.56 to 2.14, p <0.00001). Warfarin decreased the incidence of thromboembolic events in patients with non-end-stage CKD (HR 0.39, 95% CI 0.18 to 0.86, p <0.00001). Recent data on novel oral anticoagulants suggested a higher efficacy of these agents compared with warfarin (HR 0.80, 95% CI 0.66 to 0.96, p = 0.02) and aspirin (HR 0.32, 95% CI 0.19 to 0.55, p <0.0001) in treating non-end-stage CKD. In conclusion, the presence of CKD in patients with AF is associated with an almost 50% increased thromboembolic risk, which can be effectively decreased with appropriate antithrombotic therapy. Further prospective studies are needed to better evaluate the interest of anticoagulation in patients with severe CKD.

End-stage renal disease with atrial fibrillation: uncharted territory in the modern world of anticoagulants

INTRODUCTION

End-stage renal disease (ESRD) and atrial fibrillation are increasingly common concurrent findings among many patients. Coexisting ESRD and atrial fibrillation can further exacerbate each disease process; thus, evidence-based medicine protocols are needed for the treatment of patients with both ESRD and new-onset atrial fibrillation to clarify the appropriate anticoagulant management of such patients.

AREAS COVERED

The manuscript surveys the literature to look for a suitable answer to the pressing question that requires development of an evidence-based protocol: 'Which anticoagulant is best for the patient with ESRD and atrial fibrillation?'

EXPERT OPINION

Unlike many disease processes that have ample evidence available in order to better manage the patient, in the patient with end-stage kidney disease and new onset of atrial fibrillation, the situation becomes much more complicated. We believe randomized controlled trials for both the classical and the newer oral anticoagulants could provide evidence-based medicine protocols for the treatment of patients with ESRD and new-onset atrial fibrillation.

Quantifying a rare disease in administrative data: the example of calciphylaxis

BACKGROUND

Calciphylaxis, a rare disease seen in chronic dialysis patients, is associated with significant morbidity and mortality. As is the case with other rare diseases, the precise epidemiology of calciphylaxis remains unknown. Absence of a unique International Classification of Diseases (ICD) code impedes its identification in large administrative databases such as the United States Renal Data System (USRDS) and hinders patient-oriented research. This study was designed to develop an algorithm to accurately identify cases of calciphylaxis and to examine its incidence and mortality.

DESIGN, PARTICIPANTS, AND MAIN MEASURES

Along with many other diagnoses, calciphylaxis is included in ICD-9 code 275.49, Other Disorders of Calcium Metabolism. Since calciphylaxis is the only disorder listed under this code that requires a skin biopsy for diagnosis, we theorized that simultaneous application of code 275.49 and skin biopsy procedure codes would accurately identify calciphylaxis cases. This novel algorithm was developed using the Partners Research Patient Data Registry (RPDR) (n = 11,451 chronic hemodialysis patients over study period January 2002 to December 2011) using natural language processing and review of medical and pathology records (the gold-standard strategy). We then applied this algorithm to the USRDS to investigate calciphylaxis incidence and mortality.

KEY RESULTS

Comparison of our novel research strategy against the gold standard yielded: sensitivity 89.2%, specificity 99.9%, positive likelihood ratio 3,382.3, negative likelihood ratio 0.11, and area under the curve 0.96. Application of the algorithm to the USRDS identified 649 incident calciphylaxis cases over the study period. Although calciphylaxis is rare, its incidence has been increasing, with a major inflection point during 2006-2007, which corresponded with specific addition of calciphylaxis under code 275.49 in October 2006. Calciphylaxis incidence continued to rise even after limiting the study period to 2007 onwards (from 3.7 to 5.7 per 10,000 chronic hemodialysis patients; r = 0.91, p = 0.02). Mortality rates among calciphylaxis patients were noted to be 2.5-3 times higher than average mortality rates for chronic hemodialysis patients.

CONCLUSIONS

By developing and successfully applying a novel algorithm, we observed a significant increase in calciphylaxis incidence. Because calciphylaxis is associated with extremely high mortality, our study provides valuable information for future patient-oriented calciphylaxis research, and also serves as a template for investigating other rare diseases.

Clinical utility of rivaroxaban in stroke prevention associated with nonvalvular atrial fibrillation - patient considerations

The direct factor Xa inhibitor rivaroxaban was the first within the group of orally available direct factor Xa inhibitors to gain clinical approval for oral anticoagulation in patients with nonvalvular atrial fibrillation in 2011. The –xabans, as drugs from the group of oral direct factor Xa inhibitors are often referred to, comprise currently three drugs (apixaban, edoxaban, and rivaroxaban) with clinical approval for a variety of clinical indications that require oral anticoagulation therapy. The number of patients with nonvalvular atrial fibrillation requiring long-term oral anticoagulation therapy for the prevention of stroke and systemic embolism is predicted to increase up to five times by 2050. Many of these patients will be within the elderly and aging population that is at a higher risk of stroke and also at a higher risk for bleeding events. This requires novel options for efficient and safe oral anticoagulation, and rivaroxaban is one of the novel oral anticoagulants that have been shown to be at least as effective as vitamin K antagonists in patients with nonvalvular atrial fibrillation. Furthermore, like all of the novel oral anticoagulants, rivaroxaban provides a significant reduction in intracerebral hemorrhage compared with vitamin K antagonists such as warfarin. The clinical utility of oral anticoagulation with rivaroxaban in patients with nonvalvular atrial fibrillation is discussed here, along with special patient considerations, including impaired renal function, switching from a vitamin K antagonist, and patients with concomitant acute coronary syndrome.

New anticoagulant and antiplatelet agents: a primer for the gastroenterologist

A large number of patients worldwide receive anticoagulant and antiplatelet agents, collectively known as antithrombotic agents. Several new anticoagulants and antiplatelet agents recently were approved for use. Gastroenterologists may be unfamiliar with the mechanism of action, indications for use, and pharmacokinetics of these newer drugs. In patients undergoing elective and urgent endoscopic procedures, clinicians must be familiar with these medications to optimize outcomes. When the decision is made to continue the newer antithrombotic agents for elective procedures, the clinician must understand the risk that these agents may impart on procedural-induced bleeding. Finally, it is important to understand how to manage these agents in the presence of acute gastrointestinal bleeding. In this article the use of newer antithrombotic agents is reviewed.

Comparisons between novel oral anticoagulants and vitamin K antagonists in patients with CKD

Novel oral anticoagulants (NOACs) (rivaroxaban, dabigatran, apixaban) have been approved by international regulatory agencies to treat atrial fibrillation and venous thromboembolism in patients with kidney dysfunction. However, altered metabolism of these drugs in the setting of impaired kidney function may subject patients with CKD to alterations in their efficacy and a higher risk of bleeding. This article examined the efficacy and safety of the NOACs versus vitamin K antagonists (VKAs) for atrial fibrillation and venous thromboembolism in patients with CKD. A systematic review and meta-analyses of randomized controlled trials were conducted to estimate relative risk (RR) with 95% confidence interval (95% CIs) using a random-effects model. MEDLINE, Embase, and the Cochrane Library were searched to identify articles published up to March 2013. We selected published randomized controlled trials of NOACs compared with VKAs of at least 4 weeks' duration that enrolled patients with CKD (defined as creatinine clearance of 30-50 ml/min) and reported data on comparative efficacy and bleeding events. Eight randomized controlled trials were eligible. There was no significant difference in the primary efficacy outcomes of stroke and systemic thromboembolism (four trials, 9693 participants; RR, 0.64 [95% CI, 0.39 to 1.04]) and recurrent thromboembolism or thromboembolism-related death (four trials, 891 participants; RR, 0.97 [95% CI, 0.43 to 2.15]) with NOACs versus VKAs. The risk of major bleeding or the combined endpoint of major bleeding or clinically relevant nonmajor bleeding (primary safety outcome) (eight trials, 10,616 participants; RR 0.89 [95% CI, 0.68 to 1.16]) was similar between the groups. The use of NOACs in select patients with CKD demonstrates efficacy and safety similar to those with VKAs. Proactive postmarketing surveillance and further studies are pivotal to further define the rational use of these agents.

Consistency of safety profile of new oral anticoagulants in patients with renal failure

BACKGROUND

The use of new oral anticoagulants (NOACs) in patients with impaired renal function has raised major concerns, in particular the possibility of an increased risk of bleeding due to accumulation. The aims of this work were to assess the safety of NOACs in patients with renal failure and describe the relationship between clinical events and drug renal excretion magnitude.

METHODS

All phase III trials comparing NOACs with vitamin K antagonists (VKAs) in patients with estimated glomerular filtration (eGFR) rate < 50 mL min(-1) were eligible. The main safety and efficacy outcomes were major bleeding and thrombosis. A meta-regression was performed to estimate the correlation between the treatment effect estimate and the percentage of renal excretion.

RESULTS

Nine studies (12 272 patients) were included. A significantly greater relative reduction in major bleeding was seen for NOACs with renal excretion <50% (RR, 0.61; CI, 0.51-0.74) than for those with high renal excretion (RR, 0.96; CI, 0.85-1.07) (interaction test, P < 0.0001). A linear relationship between the relative risk of major bleeding and the magnitude of renal excretion was found by meta-regression (R(2)  = 0.66, P = 0.03). For thrombosis, a greater treatment effect of NOA vs. INR-adjusted VKA was observed in patients with eGFR < 50 mL min(-1) (RR 0.78, CI 0.67-0.92), but no correlation between treatment effect and renal excretion was found.

CONCLUSIONS

New oral anticoagulants were at least as effective as VKAs, with reduced risks of major bleeding and thrombosis in patients with eGFR < 50 mL min(-1) . The renal excretion of these new drugs seemed to modify the safety profile, contrary to the efficacy.

The current status of bridging anticoagulation

For patients prescribed chronic vitamin K antagonist therapy requiring a surgical or invasive procedure, the question of whether or not to bridge and how to bridge is commonly encountered in clinical practice. Bridging anticoagulation has evolved over the years and the evidence base for current practice is deficient in many areas. Clinical trials currently being completed with conventional anticoagulants should help strengthen the evidence base for future practice. The availability of novel oral anticoagulants is a welcome addition, though their optimal management peri-procedure is yet to be determined. Prospective multi-centre controlled studies that can provide the evidence base for novel oral anticoagulant peri-procedural management are required.

Anticoagulation in Patients Aged ≥75 years with Atrial Fibrillation: Role of Novel Oral Anticoagulants

Atrial fibrillation (AF) is an important cause of preventable, disabling stroke and is increasingly prevalent with advancing age. As life expectancies increase around the world, AF-related stroke is a growing global public health concern. Most AF patients are elderly (≥75 years old) and increasing age is a consistent independent risk factor for AF-associated stroke. Warfarin anticoagulation is highly effective for stroke prevention in AF patients, but is underutilized especially in the elderly. Although elderly patients are at increased risk of hemorrhage with oral anticoagulants, the benefit for ischemic stroke reduction exceeds the risk of hemorrhage for most elderly patients. Consequently, age alone should not be considered a contraindication for anticoagulation. Novel oral anticoagulants such as dabigatran, rivaroxaban and apixaban are at least as effective as warfarin in preventing strokes in patients with AF. Relative to warfarin, these novel agents reduce the risk of intracranial hemorrhage, the most devastating complication of anticoagulation therapy in elderly AF patients. The novel oral anticoagulants are especially appealing for stroke prevention in elderly patients with AF.