Cardiovascular and Bleeding Outcomes with Anticoagulants across Kidney Disease Stages: Analysis of a National US Cohort

Risk and Management of Bleeding Complications with Direct Oral Anticoagulants in Patients with Atrial Fibrillation and Venous Thromboembolism: a Narrative Review

Atrial fibrillation (AF) and venous thromboembolism (VTE) are highly prevalent conditions with a significant healthcare burden, and represent the main indications for anticoagulation. Direct oral anticoagulants (DOACs) are the first choice treatment of AF/VTE, and have become the most prescribed class of anticoagulants globally, overtaking vitamin K antagonists (VKAs). Compared to VKAs, DOACs have a similar or better efficacy/safety profile, with reduced risk of intracerebral hemorrhage (ICH), while the risk of major bleeding and other bleeding harms may vary depending on the type of DOAC. We have critically reviewed available evidence from randomized controlled trials and observational studies regarding the risk of bleeding complications of DOACs compared to VKAs in patients with AF and VTE. Special patient populations (e.g., elderly, extreme body weights, chronic kidney disease) have specifically been addressed. Management of bleeding complications and possible resumption of anticoagulation, in particular after ICH and gastrointestinal bleeding, are also discussed. Finally, some suggestions are provided to choose the optimal DOAC to minimize adverse events according to individual patient characteristics and bleeding risk.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Apixaban versus Warfarin for Treatment of Venous Thromboembolism in Patients Receiving Long-Term Dialysis

BACKGROUND AND OBJECTIVES

The association of apixaban compared with warfarin for the treatment of venous thromboembolism in patients receiving maintenance dialysis is not well studied.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a retrospective cohort study of Medicare fee-for-service beneficiaries receiving dialysis using United States Renal Data System data from 2013 to 2018. The study included patients who received a new prescription for apixaban or warfarin following a venous thromboembolism diagnosis. The outcomes were recurrent venous thromboembolism, major bleeding, and death. Outcomes were analyzed using Cox proportional hazards regression for intention-to-treat and censored-at-drug-switch-or-discontinuation analyses. Models incorporated inverse probability of treatment and censoring weights to minimize confounding and informative censoring.

RESULTS

In 12,206 individuals, apixaban, compared with warfarin, was associated with lower risks of both recurrent venous thromboembolism (hazard ratio [HR], 0.58; 95% confidence interval [95% CI], 0.43 to 0.77) and major bleeding (HR, 0.78; 95% CI, 0.62 to 0.98) in the intention-to-treat analysis over 6 months of follow-up. However, there was no difference between apixaban and warfarin in terms of risk of all-cause death (HR, 1.04; 95% CI, 0.94 to 1.16). Corresponding hazard ratios for the 6-month censored-at-drug-switch-or-discontinuation analysis and for corresponding analyses limited to a shorter (3-month) follow-up were all highly similar to the primary analysis.

CONCLUSIONS

In a large group of US patients on dialysis with recent venous thromboembolism, we observed that apixaban was associated with lower risk of recurrent venous thromboembolism and of major bleeding than warfarin. There was no observed difference in mortality.

[Features of anticoagulant therapy of atrial fibrillation in combination with impaired renal function]

This review focuses on issues of anticoagulant therapy in patients with atrial fibrillation (AF) associated with chronic kidney disease (CKD). Such patients are at high risk of stroke whereas the choice of an anticoagulant is difficult. A wealth of information about a negative effect of warfarin on the kidney function has accumulated. A need for an alternative therapy to warfarin for patients with stage 3-4 CKD has become imminent. In this regard, rivaroxaban seems to be an appropriate replacement for warfarin in such patients. In randomized, controlled studies that evaluated the efficacy of direct oral anticoagulants in comparison with warfarin, the efficacy and safety profile of a "kidney" dose in moderate disorders of kidney function has been studied only for rivaroxaban. Moreover, both randomized, controlled studies and studies performed in the conditions of clinical practice, have demonstrated a more favorable effect of rivaroxaban on kidney function compared to warfarin. Patients with AF associated with CKD require a comprehensive protection, which, according to results of clinical studies, may be provided by rivaroxaban.

Non-valvular Atrial Fibrillation in CKD: Role of Vitamin K Antagonists and Direct Oral Anticoagulants. A Narrative Review

Atrial fibrillation (AF) is the most common arrhythmia in chronic kidney disease (CKD), with a close bidirectional relationship between the two entities. The presence of CKD in AF increases the risk of thromboembolic events, mortality and bleeding. Vitamin K antagonists (VKA) have been the mainstay of treatment for the prevention of thromboembolic events in AF until recently, with confirmed benefits in AF patients with stage 3 CKD. However, the risk-benefit profile of VKA in patients with AF and stages 4-5 CKD is controversial due to the lack of evidence from randomized controlled trials. Treatment with VKA in CKD patients has been associated with conditions such as poorer anticoagulation quality, increased risk of bleeding, faster progression of vascular/valvular calcification and higher risk of calciphylaxis. Direct oral anticoagulants (DOACs) have shown equal or greater efficacy in stroke/systemic embolism prevention, and a better safety profile than VKA in post-hoc analysis of the pivotal randomized controlled trials in patients with non-valvular AF and stage 3 CKD, yet evidence of its risk-benefit profile in more advanced stages of CKD is scarce. Observational studies associate DOACs with a good safety/effectiveness profile compared to VKA in non-dialysis CKD patients. Further, DOACs have been associated with a lower risk of acute kidney injury and CKD development/progression than VKA. This narrative review summarizes the evidence of the efficacy and safety of warfarin and DOACs in patients with AF at different CKD stages, as well as their effects on renal function, vascular/valvular calcification and bone health.