The nephrologist’s anticoagulation treatment patterns/regimens in chronic hemodialysis patients with atrial fibrillation

Canadian Nephrologist Views Regarding Stroke and Systemic Embolism Prevention in Dialysis Patients With Nonvalvular Atrial Fibrillation: A Survey

Background:

Nonvalvular atrial fibrillation (NVAF) is an independent risk factor for ischemic stroke and is common in chronic kidney disease (CKD) and dialysis patients. The use of oral anticoagulation to prevent stroke and systemic embolism in the setting of kidney disease is controversial. Novel alternatives to vitamin K antagonists include left atrial appendage occlusion devices (LAAOD) and apixaban.

Objective:

We sought to elicit Canadian nephrologist views regarding stroke and systemic embolism prevention therapies in CKD and dialysis patients with NVAF.

Design:

Survey.

Setting:

Online via https://www.surveymonkey.com.

Participants:

Canadian Society of Nephrology members actively treating adult dialysis patients with NVAF.

Measurements:

Management questions were asked with response options consisting of a Likert scale ranging from 1 to 8 (with 1 being definitely would not and 8 being definitely would).

Methods:

We randomly allocated each respondent to 2 of 4 cases that varied by stroke and bleeding risks (using varying CHADS2 and HASBLED scores, respectively).

Results:

There were 91 responses (36.3% response rate) from mostly university (83.5%) and also community with university affiliation (12.1%) and community (4.4%) nephrologists. Warfarin was more likely to be recommended in individuals at high stroke risk and low bleeding risk (mean = 5.47, 95% confidence interval = 4.87-6.07) and less likely to be recommended in individuals at moderate stroke risk and high bleeding risk (mean = 2.89, 95% confidence interval = 2.37-3.41). The likelihood of recommending LAAOD did not vary by stroke or bleeding risks (means ranging from 3.92-4.90). Apixaban was not likely to be recommended in any case (means ranging from 2.60-3.50). However, nephrologists felt there was equipoise regarding anticoagulation strategies allowing participation in appropriate randomized controlled trials (RCTs).

Limitations:

The survey only involved nephrologists and only 4 cases with dichotomized risk categories were presented instead of complete range of stroke and bleeding risk combinations. As with any survey, there was the potential for responder bias and treatment decisions are not anchored directly to patient management.

Conclusions:

Nephrologists caring for patients with kidney disease appear willing to include patients in clinical trials examining alternatives to warfarin for stroke and systemic embolism prevention for NVAF in the setting of kidney disease.

Atrial fibrillation in dialysis patients: is there a place for non-vitamin K antagonist oral anticoagulants?

Atrial fibrillation (AF) occurs approximately in 3% of general population, with greater prevalence in elderly. Non-vitamin K-dependent oral anticoagulant agents (NOACs) according to the current European guidelines are recommended for patients with AF at high risk for stroke as a first-choice treatment. NOACs are not inferior to warfarin or some of them are better than warfarin in reducing the rate of ischemic stroke. Moreover, they significantly reduce the rate of intracranial hemorrhages, major bleedings, and mortality compared with warfarin. Nevertheless according to ESC guidelines, NOACs are not recommended in patients with creatinine clearance < 30 mL/min. Observational studies provide contradictive data. Only few new trials are ongoing. Therefore, it is not clear if NOACs should be in the future prescribed to patients with advanced CKD and those on dialysis. Moreover, the risk of stroke and bleeding is much higher in such population than in patients without end-stage renal disease (ESRD). The authors provide data on pros and cons of use of NOACs in ESRD patients with AF.

Treatment of atrial fibrillation with warfarin among older adults with end stage renal disease

BACKGROUND

There is increasing evidence questioning the use of warfarin for atrial fibrillation (AF) among older adults with end stage renal disease (ESRD). We assessed the patterns and determinants of warfarin utilization among these patients in the US.

METHODS

We assembled a cohort of older adults (age ≥65) undergoing dialysis with incident AF from July 2007 to November 2011 from the US Renal Data System (USRDS). We used descriptive statistics to characterize warfarin utilization within 30 days of AF discharge, and logistic regression to quantify patient characteristics associated with warfarin initiation.

RESULTS

Among 5730 older adults undergoing dialysis with incident AF, 15.5% initiated warfarin. Among 2906 patients with high risk of bleeding, 12.7% initiated warfarin; whereas 14.9% initiated warfarin among 4824 patients with high risk of stroke. After adjustment for patient characteristics, warfarin initiation was lower among patients who were older [odds ratio (OR) = 0.74 per 10-year increase, 95% confidence interval (CI) 0.66-0.83] and those with a history of diabetes (OR = 0.75, 95% CI 0.63-0.90), myocardial infarction (OR = 0.64, 95% CI 0.50-0.80), or bleeding (OR = 0.63, 95% CI 0.50-0.80). There was no association between sex, race, or dialysis modality and warfarin initiation. Among patients who initiated warfarin, 46.8% discontinued warfarin use after a median treatment length of 8.6 months.

CONCLUSION

Despite the unclear benefit and increased bleeding risk of warfarin treatment in patients with ESRD, 1 in 8 older adults undergoing dialysis with incident AF in the US who had high risk of bleeding used warfarin. Changes to warfarin therapy due to discontinuation were common after initiation.

Dabigatran etexilate: appropriate use in patients with chronic kidney disease and in the elderly patients

Dabigatran etexilate (DE) is a direct thrombin inhibitor, which has been approved for the treatment of non-valvular atrial fibrillation (AF), and for the prevention and treatment of venous thromboembolism (VTE). Despite large randomized clinical trials and independent observational studies providing robust data concerning DE safety and efficacy, some physicians still perceive mild-to-moderate renal impairment and old age as a relative contraindication to its use. In this article, we review the available scientific evidence supporting the use of DE in these clinical situations. Patients with AF and chronic kidney disease (CKD) are per se at high risk of stroke, bleeding and mortality. Although there is evidence of clinical benefit of anticoagulation in these patients, anticoagulant therapy requires caution and demands careful clinical monitoring, regardless of the drug used. In patients with no contraindication to its use, the clinical benefit of DE versus warfarin is independent of renal function. The elderly with AF are frequently undertreated because of the perception of high bleeding risk and limited clinical benefit. However, the clinical benefit of anticoagulation is independent of patient age, and age per se should not represent a contraindication to anticoagulation. DE has been extensively studied in the elderly, both in randomized clinical trials and in observational studies: DE 150 mg BID should not be used in patients 80 years of age or older, while DE 110 mg BID is as safe as warfarin. Intracranial haemorrhages reduction by DE compared with warfarin is preserved in the elderly. Therefore, mild and moderate CKD and being elderly should not deter physicians from prescribing DE. Furthermore, the availability of a specific antidote is expected to improve the safety of the use of DE in clinical practice.

Prediction of Mortality in Incident Hemodialysis Patients: A Validation and Comparison of CHADS2, CHA2DS2, and CCI Scores

Background

The CHADS2 and CHA2DS2 scores are usually applied for stroke prediction in atrial fibrillation patients, and the Charlson comorbidity index (CCI) is a commonly used scale for assessing morbidity. The role in assessing mortality with score system in hemodialysis is not clear and comparisons are lacking. We aimed at evaluating CHADS2, CHA2DS2, and CCI scores to predict mortality in incident hemodialysis patients.

Methods

Using data from the Nation Health Insurance system of Taiwan (NHIRD) from 1 January 2005 to 31 December 2009, individuals ≧20 y/o who began hemodialysis identified by procedure code and receiving dialysis for > 3 months were included for our study. Renal transplantation patients after dialysis or PD patients were excluded. We calculated the CHADS2, CHA2DS2, and CCI score according to the ICD-9 code and categorized the patients into three groups in each system: 0–1, 2–3, over 4. A total of 3046 incident hemodialysis patients enrolled from NHIRD were examined for an association between the separate scoring systems (CHADS2, CHA2DS2, and CCI score) and mortality.

Results

CHADS2 and CHA2DS2 scores revealed good predictive value for total mortality (CHADS2 AUC = 0.805; CHA2DS2 AUC = 0.790). However, the CCI score did not reveal a similarly satisfying result (AUC = 0.576).

Conclusions

Our results show that CHADS2 and CHA2DS2 scores can be applied for mortality prediction in incident hemodialysis patients.

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.

Warfarin use and the risks of stroke and bleeding in hemodialysis patients with atrial fibrillation: A systematic review and a meta-analysis

BACKGROUND AND AIM

The efficacy and safety of warfarin therapy in hemodialysis (HD) patients with atrial fibrillation (AF) remains controversial. Thus, we performed, up to date, the first meta-analysis on the risks of stroke and bleeding in warfarin treatment in these populations.

METHODS AND RESULTS

The relevant literature was searched using the following electronic databases without any language restrictions: the Cochrane Library Database, PubMed, ISI, Ovid, and Chinese Biomedical Database from the establishment of the database to October 2014. The studies were included if (a) studies described the risk of stroke or bleeding with or without warfarin in dialysis patients with AF, (b) studies provided information about hazard ratio (HR) and 95% confidence interval (CI) of stroke or bleeding, and (c) the study design was a clinical cohort. The inverse variance method was used to obtain overall HRs and 95% CIs. Sensitivity analyses and publication bias were also performed. We identified six eligible studies with a total of 9816 patients. Combined HRs showed that warfarin cannot prevent strokes in HD patients with AF (HR = 1.23, 95% CI 0.80-1.87; P = 0.347), but its use was associated with a higher risk of bleeding (HR = 1.20, 95% CI 1.03-1.39; P = 0.019).

CONCLUSION

This meta-analysis suggested that warfarin should not be recommended for the routine treatment of HD patients with AF.

Anticoagulation in Chronic Hemodialysis: Progress Toward an Optimal Approach

Appropriate anticoagulation for hemodialysis (HD) requires a subtle balance between under- and over-heparinization to prevent extracorporeal circuit (ECC) clotting and bleeding, respectively. We discuss five key issues relating to anticoagulation therapy for chronic HD in adults following a review of relevant literature published since 2002: (i) options for standardization of anticoagulation in HD settings. The major nephrology societies have issued low evidence level recommendations on this subject. Interventional studies have generally investigated novel low-molecular weight heparins and provided data on safety of dosing regimens that cannot readily be extrapolated to clinical practice; (ii) identification of clinical and biological parameters to aid individualization of anticoagulation treatment. We find that use of clinical and biological monitoring of anticoagulation during HD sessions is currently not clearly defined in routine clinical practice; (iii) role of ECC elements (dialysis membrane and blood lines), dialysis modalities, and blood flow in clotting development; (iv) options to reduce or suppress systemic heparinization during HD sessions. Alternative strategies have been investigated, especially when the routine mode of anticoagulation was not suitable in patients at high risk of bleeding or was contraindicated; (v) optimization of anticoagulation therapy for the individual patient. We conclude by proposing a standardized approach to deliver anticoagulation treatment for HD based on an individualized prescription prepared according to the patient's profile and needs.