Oral anticoagulants and risk of nephropathy

Dabigatran-related Nephropathy Complicated by Tubulointerstitial Nephritis in a Patient with a Normal Renal Function and Undiagnosed IgA Nephropathy

A 69-year-old woman was referred to our hospital because of an acute kidney injury with macroscopic hematuria. She had been taking dabigatran for atrial flutter for six years. Based on the typical histological findings of her kidney biopsy and her history of dabigatran use with prolonged activated partial thromboplastin time, she was diagnosed with dabigatran-related nephropathy complicated by tubulointerstitial nephritis with IgA nephropathy. After prednisolone therapy, the renal function improved. Direct-acting oral anticoagulants, including dabigatran, may cause anticoagulant-related nephropathy similar to warfarin, even in patients with a normal renal function. Tubulointerstitial nephritis may coexist with dabigatran-related nephropathy, and prednisolone therapy should be considered in such cases. IgA nephropathy has been reported as a background disease, and caution should be exercised when encountering it.

Left atrial appendage occlusion in patients suffering from advanced chronic kidney disease (stage 4 and 5). Long-term follow-up

INTRODUCTION AND OBJECTIVES

Advanced chronic kidney disease (A-CKD) combined with atrial fibrillation increases the risk of both thrombogenic and bleeding events. Left atrial appendage occlusion (LAAO) may be an alternative to oral anticoagulation to prevent thromboembolic events. We aimed to evaluate the outcomes of LAAO in patients with A-CKD.

METHODS

Comparison at long-term follow-up of patients diagnosed with and without A-CKD (eGFR<30 mL/min/1.73 m2 ) who underwent LAAO between 2009 and May 2022.

RESULTS

Five hundred seventy-three patients were included. Eighty-one (14%) were diagnosed with A-CKD. There were no differences in sex, age, and cardiovascular risk factors, except for diabetes which was more frequent in patients with A-CKD. The control group had higher rates of stroke, both ischemic and hemorrhagic. There were no differences in the CHA2 DS2 -VASc score, although A-CKD patients had a higher bleeding risk according to the HASBLED scale. Global procedural success was 99.1%. At follow-up, there were no differences in stroke rate: at 1-year (HR: 1.22, IC-95%: 0.14-10.42, p = 0.861); at 5-years (HR: 0.60, IC-95%: 0.08-4.58, p = 0.594). Although bleeding events were higher in the A-CKD group, no differences were found in major bleeding (defined BARC ≥ 3) at 1-year (HR: 1.34, IC-95%: 0.63-2.88, p = 0.464) or at 5-years follow-up (HR: 1.30, IC-95%: 0.69-2.48, p = 0.434). Mortality rate at 5 years was higher in the A-CKD patients (HR: 1.84, IC-95%: 1.18-2.87, p = 0.012).

CONCLUSIONS

LAAO is an effective and safe treatment in A-CKD patients to prevent ischemic events and bleeding. This strategy could be an alternative to oral anticoagulation in this high-risk group of patients.

Use of non-vitamin K antagonists oral anticoagulants in atrial fibrillation patients on dialysis

Background

Non-vitamin K antagonist oral anticoagulants (NOACs) showed a benefit-risk profile superior to that of warfarin in atrial fibrillation (AF) patients with mild to moderate chronic kidney disease. However, the effectiveness and safety of NOACs in AF patients with end-stage renal disease (ESRD) on dialysis remain unclear. Therefore, we performed a meta-analysis regarding the effect of NOACs vs. warfarin in AF patients undergoing dialysis.

Methods

A search of the Pubmed and EMBASE databases until November 2021 was performed. Adjusted risk ratios (RRs) and 95%confidence intervals (CIs) were pooled by a random-effects model with an inverse variance method.

Results

Six studies involving 3,744 NOAC- and 26,973 warfarin- users were deemed to meet the criteria. In the pooled analysis, the use of mixed NOACs had similar incidences of effectiveness and safety outcomes compared with warfarin use. And factor Xa inhibitors (rivaroxaban or apixaban) did not have significantly better effectiveness than warfarin. For the safety outcomes, the use of factor Xa inhibitors was associated with a reduced risk of gastrointestinal bleeding (RR = 0.81, 95% CI 0.70–0.95), but not major bleeding and intracranial bleeding.

Conclusion

Compared with warfarin, the use of NOACs, especially factor Xa inhibitors (rivaroxaban or apixaban), showed at least similar effectiveness and safety outcomes in AF patients on dialysis.

The change of renal functions after nonvitamin K oral anticoagulants in patients with atrial fibrillation

Oral anticoagulants decreased stroke and mortality in atrial fibrillation patients. There have been cumulative data suggesting that some oral anticoagulants may exert favorable renal outcomes.The aim of this study is to evaluate the renal outcomes in patients with atrial fibrillation who took oral anticoagulant.

METHODS

A Retrospective cohort study using hospital electronic database. Serum creatinine and GFR were collected at baseline and at 1 and 2 years.

RESULTS

Authors identified 734 patients with non-valvular AF who took oral anticoagulants. At the end of 2-year, the cumulative risk of significant GFR decline (eGFR drop > 30%) was 10.94% in warfarin group and 9.69% in NOACs group.The incidence rate of significant eGFR decline were comparable between NOACs and warfarin group which were 4.82 and 5.34 per 100-patient year respectively(HR 1.01 CI 0.62-1.66 , p- value 0.964).However, the adjusted mean eGFR change per year was significantly lower in NOAC group, especially rivaroxaban (coefficient 7.83 ,CI 4.44 11.22 , p-value < 0.001) and dabigatran (coefficient 6.22 ,CI 2.67-9.77 , p-value = 0.001) at 2 years.

CONCLUSIONS

Significant GFR decline was not uncommon in non-valvular AF patients who received anticoagulant. Among these, the proportion of patients who had significant eGFR decline(>30%) were comparable between NOACs and warfarin at 2 years. However, there is a significantly less mean eGFR decline per year in patients who receive NOACs, notably with dabigatran and rivaroxaban, than those who receive warfarin.The findings of this study should be interpreted in the context of patients included in this study.

Anticoagulation in special patient populations with atrial fibrillation

Anticoagulation in patients with atrial fibrillation (AF) should be guided by considerations of the risk of thromboembolism, stroke, and bleeding as well as the patient's preference. Well-recognized scores have been developed to help the clinician in daily risk assessment, but there are several special patient populations for whom scores are not developed or validated. Furthermore, these patients were not adequately represented in the pivotal randomized trials for non-vitamin K antagonist oral anticoagulants (NOACs). In patients with cancer, the intrinsic hypercoagulable state has to be balanced against an increased risk of bleeding, and a dynamic concept should be applied, taking into account the cancer type, current disease state, therapeutic strategy, and patient-related factors, with NOACs playing an increasingly larger role. In women with planned pregnancy or already pregnant, NOACs should be avoided. However, accidental exposure during pregnancy should not lead to recommendations for pregnancy termination in view of current observational data. Whether patients on dialysis with AF benefit from anticoagulation at all is questionable. But if the decision for anticoagulation is made, NOACs may contribute to a more favorable risk-benefit profile than vitamin- K antagonists. Finally, patients on the ward deserve special considerations regarding periprocedural management of anticoagulation. Although for the majority of procedures a short discontinuation of oral anticoagulation seems appropriate, there are some low-bleeding-risk procedures that do not require cessation. The aim of the present review is to discuss the major particularities of these four patient subgroups and thus to facilitate the clinical decision-making.

Dabigatran-Induced Nephropathy and Gastrointestinal Bleeding and Its Successful Treatment with Idarucizumab: A Case Report

Recently, the atrial fibrillation treatment guidelines have been updated to now recommend Non-vitamin K antagonist oral anticoagulants (NOACs) as the preferred alternative to warfarin for systemic embolism and stroke prevention in patients with non-valvular atrial fibrillation. NOACs have major pharmacologic advantages over warfarin, although the most common complications are gastrointestinal bleeding and NOAC-induced nephropathy within 6 weeks after starting therapy, as several recent case-reports stated. We are reporting for the first time a chronic delayed adverse reaction (regularly reported to Authorities) observed in an 82-year-old woman 27 months after starting dabigatran (110 mg twice a day), characterized by concomitant gastrointestinal bleeding and nephropathy. Idarucizumab administration immediately improved both bleeding and renal parameters. Moreover, we are going to highlight the importance of the compliance, the adherence to the therapeutic plan and the supervision of the Hospital Pharmacy on drug prescriptions. In fact in our case, dabigatran was firstly prescribed by the neurologist and delivered by the hospital pharmacy, but the patient continued the treatment for 27 months, prescribed by general practitioner without any laboratory control. This lack of supervision certainly contributed to the onset of the adverse reaction reported.

CKD Progression in Medicare Beneficiaries With Nonvalvular Atrial Fibrillation Treated With Apixaban Versus Warfarin

RATIONALE & OBJECTIVE

Comparing kidney disease progression among patients treated with direct oral anticoagulants (DOACs) versus warfarin has not been well studied. We hypothesized that apixaban would be associated with lower risks of progression of chronic kidney disease (CKD) and progression to incident kidney failure than warfarin in patients with atrial fibrillation (AF).

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Medicare recipients with stage 3, 4, or 5 CKD and incident AF who received a new prescription for apixaban or warfarin from 2013 through 2017.

EXPOSURE

Apixaban or warfarin.

OUTCOMES

Progression to incident kidney failure or, separately, to a more advanced stage of CKD.

ANALYTICAL APPROACH

Marginal structural cause-specific proportional hazards models with inverse probability weighting to estimate marginal hazard ratios (HRs) for each outcome. HRs compared apixaban to warfarin in intention-to-treat and censored-at-drug-switch analyses.

RESULTS

12,816 individuals met inclusion criteria (50.3% received apixaban; 49.7% received warfarin). After weighting, the mean age of the cohort was 80 ± 7 years, 51% were women, and 88% were White. Approximately 84% had stage 3, 15% had stage 4, and 1% had stage 5 CKD. In the intention-to-treat analysis, apixaban, relative to warfarin, was associated with an HR of developing incident kidney failure of 0.98 (95% confidence interval [CI], 0.79-1.22) and of CKD stage progression of 0.90 (95% CI, 0.82-0.99). Corresponding HRs for censored-at-drug-switch analyses were 0.81 (95% CI, 0.56-1.17) and 0.81 (95% CI, 0.70-0.92). Results were similar for a series of subgroup and sensitivity analyses.

LIMITATIONS

CKD was defined based on diagnosis codes from claims; findings may not be generalizable to non-Medicare CKD populations.

CONCLUSIONS

Apixaban, compared with warfarin, was associated with lower risk of CKD stage progression, but not with incident kidney failure.

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.

Dabigatran-induced anticoagulant-related nephropathy with undiagnosed IgA nephropathy in a patient with normal baseline renal function

Occasionally, over-anticoagulation with warfarin induces acute kidney injury (AKI) characterized by glomerular hemorrhage with tubular obstruction by red blood cell casts, which is widely acknowledged as warfarin-related nephropathy. Owing to extensive use of direct oral anticoagulants, similar AKI cases have been reported among patients treated with dabigatran. Dabigatran is primarily excreted by the kidneys; thus, renal impairment is one of the risk factors for dabigatran-induced bleeding complications. Nevertheless, risk factors for dabigatran-induced anticoagulant-related nephropathy (ARN) remain partially clarified. Here, we report a histologically established case of dabigatran-induced ARN with undiagnosed IgA nephropathy in a patient with normal baseline renal function. In addition, we summarize previously published cases of biopsy-proven, dabigatran-related ARN. A 67-year-old female with normal preexisting renal function developed macrohematuria and AKI. She had been treated with dabigatran for deep vein thrombosis. A renal biopsy diagnosed ARN with inactive IgA nephropathy. After dabigatran withdrawal, her macrohematuria and renal function improved. This report demonstrates that ARN could occur in patients with normal baseline renal function. Our case and prior reports suggest that IgA nephropathy could be a risk factor for dabigatran-induced ARN.

Exposure to vitamin k antagonists and kidney function decline in patients with atrial fibrillation and chronic kidney disease

BACKGROUND

Exposure to vitamin K antagonists (VKA) has been suggested to accelerate progression of chronic kidney disease (CKD) but robust clinical data are currently lacking.

METHODS

We retrospectively evaluated the impact of VKA exposure on kidney function in patients with atrial fibrillation (AF) and CKD stage 3/4. Patients were prospectively followed within a primary care electronic database (median follow-up of 1.45 years). The kidney function trajectory over time, defined as the annualized change in estimated glomerular filtration rate (eGFR), was analyzed with linear mixed-effects regression including propensity score adjustment.

RESULTS

14 432 patients (median age 78 years, median CHA 2 DS 2-VASc score 4 points) contributed 97 792 eGFR measurements (mean 6.8 measurements/patient; range: 1-197). Mean baseline eGFR was 50.3 mL/min/1.73 m2; and declined by 1.10 mL/min/1.73 m2/year (95% CI: 0.91-1.28, P < 0.0001). In 7409 patients with VKA exposure, CKD progression was significantly faster compared to patients without VKA exposure (5-year absolute eGFR loss from baseline: 6.0 mL/min/1.73 m2 vs 4.5 mL/min/1.73 m2, for an absolute 5-year excess eGFR decline with VKA exposure of 1.5 mL/min/1.73 m2 (95% CI: 0.4-2.7, P = 0.002). These results prevailed upon adjusting for CHA 2 DS 2-VASc score and other potential imbalances in prognostic variables, and in several sensitivity analyses. In the group without documented VKA exposure, 1775 VKA patients (24%) and 1012 patients (14%) developed a 30% decline in eGFR during follow-up (P < 0.0001).

CONCLUSIONS

In patients with AF and CKD, VKA use is associated with accelerated eGFR decline. Within the limitations of a retrospective analysis, this finding supports the "VKA-renal-calcification hypothesis." However, although statistically significant, the excess loss in eGFR over 5 years with VKA was modest.

The risk of acute kidney injury in Asians treated with apixaban, rivaroxaban, dabigatran, or warfarin for non-valvular atrial fibrillation: A nationwide cohort study in Taiwan

BACKGROUND

Whether or not non-vitamin K antagonist oral anticoagulants (NOACs) are associated with a lower risk of acute kidney injury (AKI) in patients with non-valvular atrial fibrillation (NVAF) remains unknown in real world practice.

METHODS

In this nationwide retrospective cohort study, 1507, 3200, 5765 and 4227 NVAF patients with chronic kidney disease (CKD) and 4368, 16,945, 22,301, and 16,908 NVAF patients without CKD taking apixaban, dabigatran, rivaroxaban, and warfarin, respectively, from June 1, 2012 to December 31, 2016 were enrolled from the Taiwan National Health Insurance Program. Propensity-score weighted method was used to balance covariates across study groups. Patients were followed until occurrence of AKI or end date of study.

RESULTS

Three NOACs were all associated with a significantly lower risk of AKI compared with warfarin for both CKD-free (hazard ratio, [95% confidential interval]; 0.65, [0.60-0.72] for apixaban; 0.68, [0.64-0.74] for dabigatran; 0.73, [0.68-0.79] for rivaroxaban) and CKD cohorts (0.50, [0.45-0.56] for apixaban; 0.54, [0.49-0.59] for dabigatran; 0.53, [0.49-0.58] for rivaroxaban). The annual incidence of AKI for all NOACs and warfarin increased gradually as the increment of CHA₂DS₂-VASc for both CKD-free and CKD cohorts after propensity score weighting. The reduced risk of AKI for three NOACs persisted in most subgroups in either CKD-free or CKD cohort. Multivariate analysis indicated that all three NOACs were all associated with lower risk of AKI than warfarin in either CKD-free or CKD cohort.

CONCLUSIONS

All three NOACs are associated with a lower risk of AKI than warfarin among Asians with NVAF in real-world practice.

Anticoagulant-related nephropathy: systematic review and meta-analysis

Background

The aim of this study was to report the prevalence and mortality associated with anticoagulant-related nephropathy (ARN) through a systematic review of the literature.

Methods

Electronic searches were conducted in the Medline and EMBASE databases, and manual searches were performed in the reference lists of the identified studies. The studies were selected by two independent researchers, first by evaluating the titles and abstracts and then by reading the complete texts of the identified studies. Case series, cross-sectional studies, cohort studies and case–control studies reporting the prevalence and factors associated with ARN were selected. The methodological quality was assessed using the Newcastle–Ottawa scale. Meta-analyses of the prevalence of ARN and 5-year mortality using the random effects model were performed when possible. Heterogeneity was assessed using the I² statistic.

Results

Five studies were included. Prevalence of ARN ranged from 19% to 63% among the four included cohort studies. Meta-analysis of these resulted in high heterogeneity [I² 96%, summary effect 31%; 95% confidence interval (CI) 22–42%]. Subgroup meta-analysis yielded an ARN prevalence of 20% among studies that included patients with fewer comorbidities (I² 12%; 95% CI 19–22%). In a direct comparison, meta-analysis of the 5-year mortality rate between anticoagulated patients who had experienced ARN and anticoagulated patients without ARN, patients with ARN were 91% more likely to die (risk ratio = 1.91; 95% CI 1.22–3; I² 87%). Risk factors for ARN that were reported in the literature included initial excessive anticoagulation, chronic kidney disease, age, diabetes, hypertension, cardiovascular disease and heart failure.

Conclusions

ARN studies are scarce and heterogeneous, and present significant methodological limitations. The high prevalence of ARN reported herein suggests that this entity is underdiagnosed in clinical practice. Mortality in patients with ARN seems to be high compared with patients without this condition in observational studies.

Anticoagulant Related Nephropathy Induced by Dabigatran

We describe a case of biopsy-proven dabigatran related nephropathy in a patient without underlying IgA nephropathy. To date, dabigatran related nephropathy was only reported in patients with concurrent or undiagnosed IgA nephropathy, suggesting that it may predispose patients to dabigatran associated injury. The patient is an 81-year-old woman with multiple medical comorbidities, including nonvalvular atrial fibrillation, who was anticoagulated with dabigatran. She presented to hospital with acute kidney injury in the setting of volume overload. Her estimated glomerular filtration rate decreased from a baseline of 57 mL/min/1.73 m² to 4 mL/min/1.73 m², necessitating hemodialysis. Renal ultrasound findings, fractional excretion of sodium, and urinalysis suggested acute kidney injury. Renal biopsy showed acute tubular injury, tubular red blood cell casts, and an absence of active glomerulonephritis, similar to the pathological findings of warfarin related nephropathy. A diagnosis of anticoagulant related nephropathy secondary to dabigatran was therefore established. This case demonstrates that dabigatran, like warfarin, may increase tubular bleeding risk in patients, irrespective of underlying kidney or glomerular disease.

Decreased risk of renal impairment in atrial fibrillation patients receiving non-vitamin K antagonist oral anticoagulants: A pooled analysis of randomized controlled trials and real-world studies

BACKGROUND

Patients with warfarin have a potential risk of warfarin-related nephropathy, which could result in the discontinuation of anticoagulation therapy. The question of whether non-vitamin K antagonist oral anticoagulants (NOACs) use is associated with increased risk of renal impairment in atrial fibrillation (AF) patients remains unanswered.

METHODS

Studies were systematically searched through Medline, Embase, Cochrane Library databases, and ClinicalTrials.gov Website. Randomized controlled trials (RCTs) reporting renal impairment events and observational nationwide database studies presenting adjusted hazard ratio (HR) in AF patients with NOACs were identified. The Primacy outcome was renal impairment, defined as a composite of any renal disorder. The secondary outcomes were narrow definition of renal failure (including renal failure, acute renal failure, chronic renal failure, acute prerenal failure and postrenal failure) and individual renal impairment reported in involved studies. HR and 95% confidence intervals (95%CI) were calculated using fixed- or random-effects models according to the extent of heterogeneity. Subgroup analyses were conducted according to individual NOACs, study types and different controls.

RESULTS

Totally, 189,483 patients from 11 RCTs and 3 observational database studies were included in the analysis (119,188 patients with NOACs and 70,295 patients with vitamin K Antagonists or acetylsalicylic acid). Overall results indicated a significantly lower risk of renal impairment in AF patients with NOACs versus VKAs/acetylsalicylic acid (HR: 0.67, 95%CI: 0.62-0.73). Results of narrow definition of renal impairment were accordant with the primacy outcome (HR: 0.65, 95%CI: 0.60-0.71). Compared with VKAs or acetylsalicylic acid, dabigatran (HR: 0.64, 95%CI: 0.56-0.72), rivaroxaban (HR: 0.66, 95%CI: 0.55-0.77) and apixaban (HR: 0.73, 95%CI: 0.59-0.87) were all associated with a significantly lower risk of renal impairment, with the exception of edoxaban (HR: 0.79, 95%CI: 0.30-1.27).

CONCLUSIONS

Patients with NOACs might bring about a lower risk of renal impairment compared to VKA or acetylsalicylic acid. Further specialized designs of RCTs and real-world studies on evaluation of renal function are warranted to obtain a robust result on this issue.

Anticoagulant-Related Nephropathy

Anticoagulant-related nephropathy (ARN) is a newly recognized form of AKI in which overanticoagulation causes profuse glomerular hemorrhage, which manifests on renal biopsy as numerous renal tubules filled with red cells and red cell casts. The glomeruli show changes, but they are not sufficient to account for the glomerular hemorrhage. We were the first to study ARN, and since then, our work has been confirmed by numerous other investigators. Oral anticoagulants have been in widespread use since the 1950s; today, >2 million patients with atrial fibrillation take an oral anticoagulant. Despite this history of widespread and prolonged exposure to oral anticoagulants, ARN was discovered only recently, suggesting that the condition may be a rare occurrence. This review chronicles the discovery of ARN, its confirmation by others, and our animal model of ARN. We also provide new data on analysis of "renal events" described in the post hoc analyses of three pivotal anticoagulation trials and three retrospective analyses of large clinical databases. Taken together, these analyses suggest that ARN is not a rare occurrence in the anticoagulated patient with atrial fibrillation. However, much work needs to be done to understand the condition, particularly prospective studies, to avoid the biases inherent in post hoc and retrospective analyses. Finally, we provide recommendations regarding the diagnosis and management of ARN on the basis of the best information available.

Bioptically Proven "Anticoagulation-Related Nephropathy" Induced by Dual Antiplatelet Therapy

Anticoagulation-related nephropathy (ARN) is a significant and underdiagnosed complication in patients who receive anticoagulation therapy. It is characterized by acute kidney injury in the setting of excessive anticoagulation defined as an international normalized ratio > 3.0 in patients treated with warfarin. A definitive diagnosis is made by renal biopsy showing acute tubular necrosis with obstruction of the tubuli by red blood cell casts. However, the evidence shows that ARN can occur during treatment with novel oral anticoagulants as well. Although it has been suggested that antiplatelet therapy, such as aspirin, might contribute to coagulopathy (and therefore the hypothetical risk of ARN), there are no reports of ARN induced by antiplatelet therapy according to our knowledge. It is also reported that glomerular lesions (i.e., kidney disease) represent a risk factor for ARN. We present a case of an 82-year-old man who developed biopsy-proven ARN after the administration of dual antiplatelet therapy with no previous anticoagulation treatment and normal coagulation tests.

Dabigatran-induced nephropathy and its successful treatment with Idarucizumab - case report and literature review

BACKGROUND

Anticoagulant induced renal injury has been previously described with Warfarin treatment. In the last decade direct oral anticoagulants (DOAC) were introduced. They include direct inhibitors of factor Xa (Rivaroxaban, Apixaban, Edoxaban) and a thrombin inhibitor (Dabigatran). There are isolated reports describing acute kidney injury (AKI) due to the use of DOACs.

CASE REPORT

We report a clinical case of an 80-year-old patient recently started on Dabigatran for new onset atrial fibrillation. She presented with AKI and hematuria, urine specimen showed RBC casts, and a working diagnosis of anticoagulant nephropathy due to Dabigatran was made. During hospitalization she was treated with Idarucizumab with a full recovery of renal function. To the best of our knowledge, there are 4 published case reports describing kidney injury produced by Dabigatran.

CONCLUSION

The use of DOACs is increasing rapidly, with increasing concern about its safety profile and, in particular, its potential harmful effect on renal function. As described in our case, treatment with Praxbind for Dabigatran induced kidney injury may be an acceptable management strategy that may obviate the need for urgent dialysis in selected cases by complete reversal of the AKI.

Renal function in patients with mechanical prosthetic valves : Long-term effects of anticoagulation and over-anticoagulation with warfarin

BACKGROUND

Warfarin-related nephropathy (WRN) is a complication of warfarin over-anticoagulation that is associated with acute and/or chronic renal dysfunction and increased mortality. The long-term effects of warfarin on renal function has not been adequately studied in patients with a mechanical prosthetic valve (MPV).

AIM

To study the time-dependent effects of over-anticoagulation on renal function in patients with a MPV.

METHODS

A total of 193 patients who underwent MPV implantation and were followed up in this study were eligible for inclusion. Time above therapeutic international normalized ratio (INR) range (TATR) was calculated by dividing the number of INR measurements above target in a year by the total number of INR measurements within a year. Patients were divided into quartiles according to average TATR at 60 months.

RESULTS

At 60 months more patients within the 4th quartile had a ≥20% reduction in the estimated glomerular filtration rate (eGFR, 25.0%, p = 0.04) and chronic kidney disease (CKD, 33.0%, p = 0.07) compared to patients within the 1st quartile. High TATR remained a significant determinant for reduction in eGFR (odds ratio OR: 7.50, 95% confidence interval CI:1.55-36.32) and CKD (OR:5.15, 95% CI: 1.26-20.62) after adjusting for other variables. Longitudinal analysis revealed that the change in eGFR was related to the duration of warfarin use (p < 0.001) and the interaction between the duration of warfarin use and TATR (p = 0.03). Similar findings were observed in patients without CKD at baseline, but not in those with CKD before the index operation.

CONCLUSION

Anticoagulation over targeted INR values is associated with a steeper decline in eGFR and an increased frequency of CKD in patients with a MPV.

Warfarin-related nephropathy in a patient with renal pelvic cancer

An 83-year-old Japanese man had a history of chronic heart failure due to bradycardia-tachycardia syndrome. He was admitted to our hospital because of macrohematuria and acute kidney injury (AKI), which were detected by an urologist at an outpatient visit. He had a history of recurrent macrohematuria and transurethral resection of bladder tumors twice in the preceding 2 years. He had been on warfarin for 12 years, with a stable international normalized ratio (INR) that was usually less than 2.1. Urinalysis revealed numerous red blood cells (RBCs) and mild proteinuria without RBC casts. His serum creatinine level was elevated to 2.41 mg/dL from 0.96 mg/dL at 3 weeks before admission. INR was 1.44. Hydronephrosis was not observed. Ureteroscopy detected invasive urothelial carcinoma of the renal pelvis, and right laparoscopic nephroureterectomy was performed at 41 days after diagnosis of AKI. The background renal parenchyma displayed tubular obstruction by red blood cell casts and acute tubular injury, which were changes compatible with warfarin-related nephropathy (WRN). Warfarin was discontinued, and the serum creatinine level recovered to 1.66 mg/dL after 3 months. In the present patient with nephrosclerosis, WRN occurred at a therapeutic INR level after 12 years of uneventful warfarin therapy, and the coexisting urothelial malignancy was a unique feature.

Acute Kidney Injury in Asians With Atrial Fibrillation Treated With Dabigatran or Warfarin

BACKGROUND

Whether dabigatran is associated with a lower risk of acute kidney injury (AKI) in patients with nonvalvular atrial fibrillation (NVAF) remains unknown.

OBJECTIVES

The authors compared the risk of AKI in Asians with NVAF who were prescribed dabigatran versus warfarin.

METHODS

The authors analyzed patients enrolled in the Taiwan nationwide retrospective cohort study from June 1, 2012, to December 31, 2013. Dabigatran and warfarin were taken by 7,702 and 7,885 NVAF patients without a history of chronic kidney disease (CKD) and 2,256 and 2,089 NVAF patients with a history of CKD, respectively. A propensity-score weighted method was used to balance covariates across study groups.

RESULTS

A total of 6,762 (88%) and 940 (12%) CKD-free patients and 2,025 (90%) and 231 (10%) CKD patients took dabigatran 110 mg and 150 mg twice daily, respectively. Dabigatran was associated with a lower risk of AKI than warfarin for either the CKD-free (hazard ratio [HR]: 0.62; 95% confidence interval [CI]: 0.49 to 0.77; p < 0.001) or CKD (HR: 0.56; 95% CI: 0.46 to 0.69; p < 0.001) cohort. As the increment in CHA₂DS₂-VASc score (a risk score based on congestive heart failure, hypertension, age 75 years or older, diabetes mellitus, previous stroke/transient ischemic attack, vascular disease, aged 65 to 74 years, and female sex) increased from 0/1 to 6+ points, the incidence of AKI for the dabigatran group was relatively stable (1.87% to 2.91% per year for the CKD-free cohort; 7.31% to 13.15% per year for the CKD cohort) but increased obviously for patients taking warfarin for either CKD-free (2.00% to 6.16% per year) or CKD cohorts (6.82 to 26.03% per year). The warfarin group had a significantly higher annual risk of AKI than the dabigatran group for those with a high CHA₂DS₂-VASc score (≥4 for the CKD-free cohort and ≥3 for the CKD cohort). Subgroup analysis revealed that among dabigatran users, those taking either low-dose or standard-dose dabigatran, those with a warfarin-naïve or warfarin-experienced history, those with or without diabetes, and those with CHA₂DS₂-VASc ≥4 or HAS-BLED ≥3 (risk score based on hypertension, abnormal renal and liver function, stroke, prior major bleeding, labile international normalized ratios, age 65 years or older, drugs or alcohol usage history) all had a lower risk of AKI than those taking warfarin.

CONCLUSIONS

Among Asians with NVAF, dabigatran is associated with a lower risk of AKI than warfarin.

Emerging therapeutic uses of direct-acting oral anticoagulants: An evidence-based perspective

Direct-acting oral anticoagulants (DOACs) were claimed to cause a potential paradigm shift in the therapeutic scenario of patients requiring short- and long-term anticoagulation, by virtue of their pharmacological properties, perceived as innovative. The evidence gathered so far (from pre-approval pivotal trials to real-world post-marketing observational data) consistently confirmed that DOACs are overall comparable to vitamin-K antagonists (VKAs) in terms of safety, efficacy and effectiveness and unequivocally documented a consistent and clinically relevant reduced risk of intracranial bleeding in the settings of non-valvular atrial fibrillation (NVAF) and venous thromboembolism (VTE). Interestingly, two parallel paths can be identified in the current research scenario: A) in the aforementioned consolidated therapeutic indications, an innovative approach is directed towards tailored treatment strategies, to identify patients most likely to benefit from one of the different anticoagulant drugs, in particular subpopulations at increased risk of adverse events (e.g., bleeding); B) in unconventional settings, DOACs are gaining interest for potential use in emerging diseases characterized by arterial and venous thromboembolic risk. In these scenarios, the risk-benefit profile of DOACs, as compared to VKAs or heparins, is less defined. The aim of this review is to critically assess the body of evidence underlying emerging therapeutic uses of DOACs (e.g., heparin-induced thrombocytopenia, anti-phospholipid antibody syndrome), including evolving issues in special populations (e.g., patients with VTE and cancer or cirrhosis). This will be achieved by analyzing the strength (i.e., systematic reviews, randomized clinical trials, observational studies, case report/series) and consistency (i.e., concordance) of both published and unpublished evidence registered in major public repositories.

Management of Patients on Non-Vitamin K Antagonist Oral Anticoagulants in the Acute Care and Periprocedural Setting: A Scientific Statement From the American Heart Association

Non-vitamin K oral anticoagulants (NOACs) are now widely used as alternatives to warfarin for stroke prevention in atrial fibrillation and management of venous thromboembolism. In clinical practice, there is still widespread uncertainty on how to manage patients on NOACs who bleed or who are at risk for bleeding. Clinical trial data related to NOAC reversal for bleeding and perioperative management are sparse, and recommendations are largely derived from expert opinion. Knowledge of time of last ingestion of the NOAC and renal function is critical to managing these patients given that laboratory measurement is challenging because of the lack of commercially available assays in the United States. Idarucizumab is available as an antidote to rapidly reverse the effects of dabigatran. At present, there is no specific antidote available in the United States for the oral factor Xa inhibitors. Prothrombin concentrate may be considered in life-threatening bleeding. Healthcare institutions should adopt a NOAC reversal and perioperative management protocol developed with multidisciplinary input.