Haemorragic and thromboembolic risk in CKD patients with non valvular atrial fibrillation: Do we need a novel risk score calculator?

Oral anticoagulants, time in therapeutic range and renal function over time in real-life patients with atrial fibrillation and chronic kidney disease

Aims

To describe the use of warfarin and direct oral anticoagulants (DOACs) in patients with atrial fibrillation (AF) and chronic kidney disease (CKD), to evaluate changes in renal function over time and predictors of rapid decline, and to describe time in therapeutic range (TTR) and predictors of poor TTR among patients on warfarin.

Methods and results

Using data from AuriculA, the Swedish oral anticoagulation registry, patients with AF on warfarin or DOAC were identified between 2013 and 2018 (N=6567). Estimated glomerular filtration rate (eGFR) was calculated and categorised into normal (≥90 mL/min/1.73 m²), mild CKD (60–89 mL/min/1.73 m²), moderate CKD (30–59 mL/min/1.73 m²), severe CKD (15–29 mL/min/1.73 m²) and end-stage CKD (<15 mL/min/1.73 m²)/dialysis. TTR was estimated using international normalised ratio (INR) measurements. Predictors of eGFR decline over time and of poor TTR were estimated using regression analysis. Between 2013 and 2018, use of DOAC increased from 9.2% to 89.3%, with a corresponding decline in warfarin. A similar trend was observed in patients with mild to moderate CKD, while DOAC over warfarin increased slower among patients with severe to end-stage CKD/dialysis. In patients treated with warfarin, the median TTR was 77.1%. Worse TTR was observed among patients with severe CKD (70.0%) and end-stage CKD/dialysis (67.5%). A gradual annual decline in eGFR was observed (−1.1 mL/min/1.73 m²), with a more rapid decline among patients with older age, female sex, diabetes mellitus and/or heart failure.

Conclusion

In patients with AF, use of DOAC has steadily increased across different CKD stages, but not in patients with severe to end-stage CKD/dialysis despite these patients having poor INR control. Patients with AF have a gradual decline in renal function, with a more rapid decline among a subgroup of patients.

Thromboembolic and Hemorrhagic Outcomes in the Direct Oral Anticoagulant Trials Across the Spectrum of Kidney Function

Chronic kidney disease is a common comorbidity among patients taking direct-acting oral anticoagulants (DOACs). Herein, we evaluate the influence of kidney function on stroke or systemic embolism (SEE), hemorrhage, and composite end points (stroke/SEE/hemorrhage/death and stroke/SEE/death) among patients on DOACs and warfarin. Baseline kidney function was categorized as glomerular filtration rate (GFR) ≥ 60 (reference), 45-59, and < 45mL/min/1.73 m2 for participants in the Randomized Evaluation of Long-Term Anticoagulant Therapy (RE-LY) (n = 18,049), Apixaban for Reduction in Stroke and Other Thromboembolic Events (ARISTOTLE) (n = 18,187), and The Effective Anticoagulation with Factor Xa Next Generation in AF (ENGAGE AF) (n = 20,798) trials. Incidence of events was compared across GFR categories. Hazard ratios for events were estimated using Cox regression using intention-to-treat analysis adjusting for known predictors. A large proportion of participants had GFR < 60 (25-29% had 45 ≤ GFR < 60 and 9.5-12.6% with GFR < 45). Compared with patients with GFR ≥ 60, warfarin users across the trials with GFR ≥ 45-59 and GFR < 45 had a higher incidence of hemorrhage (P values < 0.0001) and warfarin users in the ARISTOTLE and ENGAGE trials had higher incidence of stroke/SEE (P values ≤ 0.05). Compared with patients with GFR ≥ 60, dabigatran users with GFR ≥ 45-59 and GFR < 45 had a higher incidence of stroke/SEE (P ≤ 0.02), hemorrhage (P < 0.001), and both composite end points (P < 0.0001). Compared with patients with GFR ≥ 60, apixaban and edoxaban users with GFR ≥ 45-59 and GFR < 45 had a higher incidence of hemorrhage (P values ≤ 0.05) and composite end points (P values ≤ 0.05). After adjustment, compared with patients with GFR ≥ 60, warfarin users with GFR < 60 in the ARISTOTLE and RE-LY trials had a higher risk of hemorrhage (P < 0.05), as did dabigatran (P < 0.001) and edoxaban (P ≤ 0.005) users, while apixaban users did not exhibit an increased risk (P = 0.08 GFR ≥ 45-59; P = 0.71 GFR < 45). Kidney function significantly influences the safety and efficacy of oral anticoagulants.

Thromboembolic and Bleeding Risk in Atrial Fibrillation Patients with Chronic Kidney Disease: Role of Anticoagulation Therapy

Atrial fibrillation (AF) and chronic kidney disease (CKD) are strictly related; several independent risk factors of AF are often frequent in CKD patients. AF prevalence is very common among these patients, ranging between 15% and 20% in advanced stages of CKD. Moreover, the results of several studies showed that AF patients with end stage renal disease (ESRD) have a higher mortality rate than patients with preserved renal function due to an increased incidence of stroke and an unpredicted elevated hemorrhagic risk. Direct oral anticoagulants (DOACs) are currently contraindicated in patients with ESRD and vitamin K antagonists (VKAs), remaining the only drugs allowed, although they show numerous critical issues such as a narrow therapeutic window, increased tissue calcification and an unfavorable risk/benefit ratio with low stroke prevention effect and augmented risk of major bleeding. The purpose of this review is to shed light on the applications of DOAC therapy in CKD patients, especially in ESRD patients.

Uremic Toxic Blood-Brain Barrier Disruption Mediated by AhR Activation Leads to Cognitive Impairment during Experimental Renal Dysfunction

BACKGROUND

Uremic toxicity may play a role in the elevated risk of developing cognitive impairment found among patients with CKD. Some uremic toxins, like indoxyl sulfate, are agonists of the transcription factor aryl hydrocarbon receptor (AhR), which is widely expressed in the central nervous system and which we previously identified as the receptor of indoxyl sulfate in endothelial cells.

METHODS

To characterize involvement of uremic toxins in cerebral and neurobehavioral abnormalities in three rat models of CKD, we induced CKD in rats by an adenine-rich diet or by 5/6 nephrectomy; we also used AhR^-/- knockout mice overloaded with indoxyl sulfate in drinking water. We assessed neurologic deficits by neurobehavioral tests and blood-brain barrier disruption by SPECT/CT imaging after injection of ^99mTc-DTPA, an imaging marker of blood-brain barrier permeability.

RESULTS

In CKD rats, we found cognitive impairment in the novel object recognition test, the object location task, and social memory tests and an increase of blood-brain barrier permeability associated with renal dysfunction. We found a significant correlation between ^99mTc-DTPA content in brain and both the discrimination index in the novel object recognition test and indoxyl sulfate concentrations in serum. When we added indoxyl sulfate to the drinking water of rats fed an adenine-rich diet, we found an increase in indoxyl sulfate concentrations in serum associated with a stronger impairment in cognition and a higher permeability of the blood-brain barrier. In addition, non-CKD AhR^-/- knockout mice were protected against indoxyl sulfate-induced blood-brain barrier disruption and cognitive impairment.

CONCLUSIONS

AhR activation by indoxyl sulfate, a uremic toxin, leads to blood-brain barrier disruption associated with cognitive impairment in animal models of CKD.

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.

Factors associated with renal impairment in Chinese patients with non-valvular AF and without an established renal disease: a cross-sectional study

BACKGROUND

Renal impairment and atrial fibrillation (AF) often coexist. However, risk factors associated with renal impairment in AF patients have not been studied in a large population. Accordingly, this study investigated clinical factors associated with renal impairment in AF patients.

METHODS

From January 2012 to December 2016, 2,298 inpatients with non-valvular AF (NVAF) mainly for catheter ablation were enrolled in this cross-sectional study. Data collection included past medical history, echocardiography measurements, current medicine use and biochemical results. The estimated glomerular filtration rate (eGFR) was calculated using the abbreviated Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Renal impairment was defined as a history of chronic kidney disease or an eGFR ≤90 ml/min/1.73 m². Multivariate logistic regression was conducted to evaluate the relationship between the factors screened and eGFR.

RESULTS

The mean eGFR was 88.6 ± 17.1 ml/min/1.73 m². The overall prevalence of renal impairment was 47.4%. Multivariate logistic regression showed that factors associated with renal impairment were age (OR: 1.12; 95% CI: 1.11-1.14), non-paroxysmal AF (OR: 1.28; 95% CI: 1.04-1.58), use of angiotensin-converting enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB) (OR: 1.58; 95% CI: 1.28-1.95), congestive heart failure (OR: 1.80; 95% CI: 1.05-3.07), left ventricular ejection fraction (LVEF) <50% (OR: 2.39; 95% CI: 1.34-4.28), and prior transient ischemic attack (TIA)/stroke/systematic embolism (SE) (OR: 2.69; 95% CI: 1.68-4.29).

CONCLUSIONS

Renal dysfunction is highly prevalent in Chinese NVAF patients and is significantly associated with older age, non-paroxysmal AF, use of ACEI/ARB, congestive heart failure, LVEF <50% and prior TIA/stroke/SE. Further studies on the mechanisms by which these risk factors affect renal function in NVAF patients need to be conducted.

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.