Chronic kidney disease and prevalent atrial fibrillation: the Chronic Renal Insufficiency Cohort (CRIC)

Anemia and reduced kidney function as risk factors for new onset of atrial fibrillation (from the Ibaraki prefectural health study)

Chronic kidney disease (CKD) is a potential independent risk factor for atrial fibrillation (AF). It remains unclear whether anemia is synergistically associated with increased risk of AF onset in subjects with CKD. We evaluated the association of kidney function, hemoglobin (Hb), and their combination with new-onset AF in a population-based cohort study. We conducted a 15-year prospective cohort study of 132,250 Japanese subjects aged 40 to 79 years who participated in annual health checkups from 1993. Kaplan-Meier survival analysis was used to compare freedom from new-onset AF between groups classified by estimated glomerular filtration rate grade, Hb grade, and their combination. Cox proportional hazard model analysis was used to estimate hazard ratios (HRs) for new-onset AF. During a 13.8-year mean follow-up period, 1,232 (0.93%) subjects with new-onset AF were identified. Lower estimated glomerular filtration rate and lower Hb grades were significantly associated with a higher incidence of new-onset AF. Multivariate HRs and 95% confidence intervals (CIs) of new-onset AF were 1.38 (1.21 to 1.56) for mild CKD group, 2.56 (2.09 to 3.13) for CKD group, and 1.50 (1.24 to 1.83) for anemia group. Borderline Hb level was not significantly associated with increased risk for new-onset AF (HR 1.07, CI 0.91 to 1.25, p = 0.4284). In the model with interaction term between CKD and anemia, the risk was significantly higher (p = 0.0343 for the interaction) than that predicted by each factor independently. In conclusion, decreased kidney function and lower Hb level are associated with increased risk for new-onset AF, especially when both are present.

Intersection of cardiovascular disease and kidney disease: atrial fibrillation

PURPOSE OF REVIEW

Atrial fibrillation is the most common sustained arrhythmia in patients with kidney disease. The purpose of this review is to describe the burden of atrial fibrillation in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD), postulate possible mechanisms to explain this burden of disease, understand the clinical consequences of atrial fibrillation and review the treatment options for atrial fibrillation specific to patients with kidney disease.

RECENT FINDINGS

Recent literature has revealed that the clinical multiorgan impact of atrial fibrillation in patients with CKD and ESRD is substantial. Although novel oral anticoagulants to treat atrial fibrillation and prevent associated complications have been tested in large trials in the general population, there is a paucity of data on the efficacy and safety of these agents in patients with advanced CKD and ESRD.

SUMMARY

Atrial fibrillation is a significant comorbidity in patients with CKD and ESRD with important prognostic implications. More research is needed to understand the mechanisms that contribute to the disproportionate burden of this arrhythmia in patients with kidney disease and in to treatment options specific to this population of high-risk patients.

Balancing ischaemia and bleeding risks with novel oral anticoagulants

Vitamin K antagonists (VKAs) have long been the standard of care for treatment of venous thromboembolism (VTE), and thromboprophylaxis in atrial fibrillation (AF). Despite their efficacy, their use requires frequent monitoring and is complicated by drug-drug interactions and the need to maintain a narrow therapeutic window. Since 2009, novel oral anticoagulants (NOACs), including the direct thrombin inhibitor dabigatran and the direct factor Xa inhibitors apixaban, edoxaban, and rivaroxaban, have become alternative options to VKAs owing to their predictable and safe pharmacological profiles. The overall clinical effect of these drugs, which is a balance between ischaemic benefit and bleeding harm, varies according to the clinical scenario. As adjunctive therapy to dual antiplatelet therapy in patients with acute coronary syndrome, NOACs are associated with incremental bleeding risks and modest benefits. For treatment of VTE, NOACs have a safer profile than VKAs and a similar efficacy. In thromboprophylaxis in AF, NOACs are associated with the greatest benefits by reducing both ischaemic events and haemorrhagic complications and might reduce mortality compared with VKAs. The role of NOACs continues to evolve as these drugs are evaluated in different patient populations, including those with renal impairment or with AF and undergoing percutaneous coronary intervention.

Chronic kidney disease and stroke

Chronic kidney disease (CKD) is associated with an increased risk of both ischemic and hemorrhagic stroke. In addition to shared risk factors, this higher cerebrovascular risk is mediated by several CKD-associated mechanisms including platelet dysfunction, coagulation disorders, endothelial dysfunction, inflammation, and increased risk of atrial fibrillation. CKD can also modify the effect of treatments used in acute stroke and in secondary stroke prevention. We review the epidemiology and pathophysiology that link CKD and stroke and the impact of CKD on stroke outcomes. Interdisciplinary collaboration between nephrologists, pharmacists, hematologists, nutrition therapists, primary care physicians, and neurologists in providing care to these subjects may potentially improve outcomes.

Clinical significance of chronic kidney disease and atrial fibrillation on morbidity and mortality in patients with acute myocardial infarction

BACKGROUND/AIMS

Atrial fibrillation (AF) often coexists with acute myocardial infarction (AMI), and chronic kidney disease (CKD) is a major risk for AMI. However, the combined impact of CKD and AF on the mortality and morbidity in AMI population has not been determined.

METHODS

Between January 2004 and December 2009, a total of 4,738 AMI patients were enrolled prospectively. Patients were divided into four groups according to the combined status of CKD and AF. The primary endpoint was a combination of 5-year major adverse cardiac and cerebrovascular events (MACCE).

RESULTS

The prevalence of AF was significantly higher in CKD patients than in non-CKD patients (6.76 vs. 3.31%, p < 0.001). The highest cumulative event rate of MACCE and death was observed in patients with both CKD and AF (68.5 and 64.0%), respectively. In multivariable analyses, compared with patients with neither AF nor CKD, hazard ratios (HR) for composite of MACCE were 1.66 (95% CI, 1.14-2.41), 1.24 (95% CI, 1.06-1.46), and 2.10 (95% CI, 1.42-3.13) for patients with AF only, those with CKD only, and those with both CKD and AF, respectively (p for interaction = 0.935). Patients with both CKD and AF had a greatest risk for all-cause mortality (HR 2.54; 95% CI, 1.60-4.53), and the significant synergistic interaction was observed between CKD and AF (p for interaction = 0.015).

CONCLUSION

The combined effect of AF and CKD on the risk of MACCE after an AMI is stronger than any separate condition, and it confers a synergistic effect on the all-cause mortality risk.

Polygenic overlap between kidney function and large artery atherosclerotic stroke

BACKGROUND AND PURPOSE

Epidemiological studies show strong associations between kidney dysfunction and risk of ischemic stroke (IS), the mechanisms of which are incompletely understood. We investigated whether these associations may reflect shared heritability because of a common polygenic basis and whether this differed for IS subtypes.

METHODS

Polygenic models were derived using genome-wide association studies meta-analysis results for 3 kidney traits: estimated glomerular filtration rate using serum creatinine (eGFRcrea: n=73 998), eGFR using cystatin C (eGFRcys: n=22 937), and urinary albumin to creatinine ratio (n=31 580). For each, single nucleotide polymorphisms passing 10 P value thresholds were used to form profile scores in 4561 IS cases and 7094 controls from the United Kingdom, Germany, and Australia. Scores were tested for association with IS and its 3 aetiological subtypes: large artery atherosclerosis, cardioembolism, and small vessel disease.

RESULTS

Polygenic scores correlating with higher eGFRcrea were associated with reduced risk of large artery atherosclerosis, with 5 scores reaching P<0.05 (peak P=0.004) and all showing the epidemiologically expected direction of effect. A similar pattern was observed for polygenic scores reflecting higher urinary albumin to creatinine ratio, of which 3 associated with large artery atherosclerosis (peak P=0.01) and all showed the expected directional association. One urinary albumin to creatinine ratio-based score also associated with small vessel disease (P=0.03). The global pattern of results was unlikely to have occurred by chance (P=0.02).

CONCLUSIONS

This study suggests possible polygenic correlation between renal dysfunction and IS. The shared genetic components may be specific to stroke subtypes, particularly large artery atherosclerotic stroke. Further study of the genetic relationships between these disorders seems merited.

Incident atrial fibrillation and risk of death in adults with chronic kidney disease

Background

Atrial fibrillation (AF) frequently occurs in patients with chronic kidney disease (CKD); however, the long‐term impact of development of AF on the risk of death among patients with CKD is unknown.

Methods and Results

We studied adults with CKD (glomerular filtration rate <60 mL/min per 1.73 m² by the Chronic Kidney Disease Epidemiology Collaboration equation) identified between 2002 and 2010 who were enrolled in Kaiser Permanente Northern California and had no previously documented AF. Incident AF was identified using primary hospital discharge diagnoses or ≥2 outpatient visits for AF. Death was comprehensively ascertained from health plan administrative databases, Social Security Administration vital status files, and the California death certificate registry. Covariates included demographics, comorbidity, ambulatory blood pressure, laboratory values (hemoglobin, proteinuria), and longitudinal medication use. Among 81 088 adults with CKD, 6269 (7.7%) developed clinically recognized incident AF during a mean follow‐up of 4.8±2.7 years. There were 2388 cases of death that occurred after incident AF (145 per 1000 person‐years) compared with 18 865 cases of death during periods without AF (51 per 1000 person‐years, P<0.001). After adjustment for potential confounders, incident AF was associated with a 66% increase in relative rate of death (adjusted hazard ratio 1.66, 95% CI 1.57 to 1.77).

Conclusion

Incident AF is independently associated with an increased risk of death in adults with CKD. Further study is needed to understand the mechanisms by which CKD is associated with AF and to identify potentially modifiable risk factors to decrease the burden of AF and subsequent risk of death in this high‐risk population.

Vitamin K antagonists: beyond bleeding

Warfarin is the most widely used oral anticoagulant in clinical use today. Indications range from prosthetic valve replacement to recurrent thromboembolic events due to antiphospholipid syndrome. In hemodialysis (HD) patients, warfarin use is even more frequent than in the nonrenal population due to increased cardiovascular comorbidities. The use of warfarin in dialysis patients with atrial fibrillation requires particular caution because side effects may outweigh the assumed benefit of reduced stroke rates. Besides increased bleeding risk, coumarins exert side effects which are not in the focus of clinical routine, yet they deserve special consideration in dialysis patients and should influence the decision of whether or not to prescribe vitamin K antagonists in cases lacking clear guidelines. Issues to be taken into consideration in HD patients are the induction or acceleration of cardiovascular calcifications, a 10-fold increased risk of calciphylaxis and problems related to maintaining a target INR range. New anticoagulants like direct thrombin inhibitors are promising but have not yet been approved for ESRD patients. Here, we summarize the nontraditional side effects of coumarins and give recommendations about the use of vitamin K antagonists in ESRD patients.

Establishment of a model of renal impairment with mild renal insufficiency associated with atrial fibrillation in canines

Background

Chronic kidney disease and occurrence of atrial fibrillation (AF) are closely related. No studies have examined whether renal impairment (RI) without severe renal dysfunction is associated with the occurrence of AF.

Methods

Unilateral RI with mild renal insufficiency was induced in beagles by embolization of small branches of the renal artery in the left kidney for 2 weeks using gelatin sponge granules in the model group (n = 5). The sham group (n = 5) underwent the same procedure, except for embolization. Parameters associated with RI and renal function were tested, cardiac electrophysiological parameters, blood pressure, left ventricular pressure, and AF vulnerability were investigated. The activity of the sympathetic nervous system, renin-angiotensin-aldosterone system, inflammation, and oxidative stress were measured. Histological studies associated with atrial interstitial fibrosis were performed.

Results

Embolization of small branches of the renal artery in the left kidney led to ischemic RI with mild renal insufficiency. The following changes occurred after embolization. Heart rate and P wave duration were increased. Blood pressure and left ventricular systolic pressure were elevated. The atrial effective refractory period and antegrade Wenckebach point were shortened. Episodes and duration of AF, as well as atrial and ventricular rate during AF were increased in the model group. Plasma levels of norepinephrine, renin, and aldosterone were increased, angiotensin II and aldosterone levels in atrial tissue were elevated, and atrial interstitial fibrosis was enhanced after 2 weeks of embolization in the model group.

Conclusions

We successfully established a model of RI with mild renal insufficiency in a large animal. We found that RI with mild renal insufficiency was associated with AF in this model.

Implications of Kidney Disease in the Cardiac Patient

Traditional cardiovascular risk factors, particularly hypertension and diabetes, are common in the disease processes of both renal and cardiac pathology. Unfortunately the coexistence of renal impairment is not an innocent bystander in cardiovascular disease; it disorder not only increases the prevalence and severity of cardiovascular disease, but also negatively affects prognostic outcomes and the safety and efficacy of cardiac interventions. This article discusses the role and impact of kidney disease in the cardiac patient in 3 key common cardiovascular processes: coronary artery disease, arrhythmia, and heart failure.

An evaluation of oral dabigatran etexilate pharmacokinetics and pharmacodynamics in hemodialysis

Dabigatran etexilate represents a possible improved alternative to warfarin for anticoagulation in hemodialysis patients with atrial fibrillation (AF). The objective was to determine dabigatran plasma concentrations and anticoagulant effects following administration of a single 110 mg oral dose of dabigatran etexilate to 10 adult patients immediately prior to starting hemodialysis. Mass spectrometry and the Hemoclot® assay were used, respectively, to determine free (unconjugated) dabigatran concentrations and thrombin time (TT) in plasma samples collected intermittently over 48 hours. The median time (tmax ) to reach the maximum plasma-free dabigatran concentration (Cmax ) was 2 hours (range 1-3 hours). The mean free dabigatran Cmax was 95.5 ± 33.4 ng/mL. The mean elimination half-lives on and off hemodialysis were, respectively, 2.6 ± 1.3 and 30.2 ± 7.8 hours. Hemodialysis effectively removed dabigatran with an extraction ratio of 0.63 ± 0.07. The maximal TT ratio was 2.1 and the TT ratio demonstrated a strong linear dependence on free dabigatran concentration (r(2)  = 0.741). A 110 mg oral dabigatran dose prior to hemodialysis was rapidly absorbed and achieved therapeutic concentrations. Hemodialysis effectively removed dabigatran from the plasma and may be an effective means of accelerating the elimination of dabigatran in circumstances of excessive anticoagulation.

Management of Atrial Fibrillation

Atrial fibrillation remains the most prevalent cardiac arrhythmia, and its incidence is increasing as the population ages. Common conditions associated with an increased incidence include advanced age, hypertension, heart failure, and valvular heart disease. Patients with atrial fibrillation may complain of palpitations, fatigue, and decreased exercise tolerance or may be completely asymptomatic. Options for treating patients who experience atrial fibrillation include rate-controlling drugs such as digoxin, β-blockers, and calcium channel blockers or a rhythm-controlling strategy with agents such as sodium channel blockers and potassium channel blockers. Atrial fibrillation increases the risk of stroke due to atrial thrombus formation and embolization. Anticoagulation with the vitamin K antagonist, warfarin, remains the most widely prescribed treatment option to decrease stroke risk. Several other antithrombotic agents have recently become available and offer excellent alternatives to warfarin. Catheter ablation can be undertaken as a nonpharmacologic rhythm control option with varying degrees of success depending on duration of atrial fibrillation and follow-up time from the procedure. This review article further describes the management options for patients presenting with atrial fibrillation.

Management of Atrial Fibrillation in Patients With Kidney Disease

The increasing burden of Chronic Kidney Disease (CKD) is highly relevant to cardiologists, as cardiovascular mortality is 10-30 times higher amongst people with End-stage Renal Disease (ESRD), comparing with general population. One of the commonest associations is the increased frequency of atrial fibrillation (AF) amongst those experiencing CKD. Overall, we know that AF is the most common cardiac arrhythmia. AF leads to a substantial risk of mortality and morbidity, from stroke and thromboembolism, heart failure, reduced cognitive function and impaired quality of life. However, most clinical trials in AF (for example, for stroke prevention in AF with anticoagulation therapy) have largely excluded patients with significant renal impairment. In this review article, we will focus on stroke prevention in AF, and the clinical impact of CKD and its implications for management.

Biomarkers in atrial fibrillation: an overview

Atrial fibrillation (AF) confers a raised risk of stroke and death, and this risk of adverse events is increased by the coexistence of other cardiovascular risk factors. The pathophysiology of AF is complex, involving the role of inflammation, structural remodelling with apoptosis, inflammation or fibrosis. These changes confer a prothrombotic or hypercoagulable state in this arrhythmia. Despite being easy to use for decision-making concerning oral anticoagulant therapy in AF, clinical risk scores used for stratification have shown modest capability in predicting thromboembolic events, and biomarkers may improve our identification of 'high risk' patients. Biomarkers, whether measured in the peripheral blood, urine or imaging-based may improve our knowledge of the pathophysiology of AF. Importantly these biomarkers could help in the assessment of AF prognosis. The aim of this review was to summarise the published data about biomarkers studied in AF, with focus on data from randomised prospective clinical trials and large community-based cohorts. We will also review the application of these biomarkers to prognosis on the main schemes used to help stratify risk in AF.

Different types of atrial fibrillation, renal function, and mortality in elderly Chinese patients with coronary artery disease

Background

Atrial fibrillation (AF) is the most common arrhythmia in patients with chronic kidney disease (CKD), and the combined prevalence of these two disorders increases as the population ages. Both AF and CKD have risk factors for development of each other and eventual mortality. However, the relationship between different types of AF, CKD, and mortality remains unclear, especially in elderly Chinese patients with coronary artery disease.

Methods

This study comprised 1,050 patients of median age 86 (60–104) years with coronary artery disease. The end point was all-cause death during a mean follow-up of 417 days.

Results

Of 219 patients identified to have AF, 128 had paroxysmal type, 44 had persistent type, and 47 had permanent type. After adjusting for confounders, the estimated glomerular filtration rate was lower and the prevalence of CKD was higher in patients with permanent AF but not in those with paroxysmal or persistent AF. During follow-up, 106 non-CKD patients and 112 CKD patients died; mortality was significantly higher in CKD patients with AF than in those without AF (36 [40.9%] versus 76 [26.8%]), but not in patients without CKD (17 [13.0%] versus 89 [16.3%]). In patients with CKD, paroxysmal AF was independently associated with higher mortality after adjustment but not persistent or permanent AF. No type of AF had an independent association with mortality in patients without CKD.

Conclusion

All types of AF had a high prevalence. Permanent AF was independently associated with an increased prevalence of CKD and a decreased estimated glomerular filtration rate. Paroxysmal AF was an independent risk factor for survival in patients with CKD but not in those without CKD.

Safety of new oral anticoagulant drugs: a perspective

The recent development of new oral anticoagulants (NOACs) offers the possibility of efficacy, relative safety and convenience compared with warfarin. This could lead to greater patient compliance, with easier management and improved provision of thromboprophylaxis. Safety whilst using NOACs should be focused on bleeding cases, surgery or on the management of patients receiving anticoagulant therapy with concomitant impairment of renal function, especially since many NOACs are dependent on renal excretion. Thus, if the clearance creatinine indicates severe renal impairment, NOACS will be contraindicated or their dose needs to be changed. In patients who need surgery, there are published protocols of management, depending on the severity of the intervention and renal function. In the case of severe hemorrhage, requiring rapid reversal of the anticoagulant effect and in the absence of specific antidotes, alternatives such as one of the nonspecific haemostatic agents must be considered. Clinical evaluation in bleeding situations and a meticulous risk-benefit appraisal for NOACs is needed, and these procoagulant agents and patients must be monitored closely. This article provides an overview of the pharmacology and potential risks, as well as the efficacy and safety of NOACs.

Performance of the Cockcroft-Gault, MDRD and CKD-EPI Formulae in Non-Valvular Atrial Fibrillation: Which one Should be Used for Risk Stratification?

Background: Renal dysfunction is a strong predictor of adverse events in patients with atrial fibrillation (AF). The Cokcroft-Gault, Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equations are available for estimating the glomerular filtration rate (GFR). No comparisons between these equations have yet been performed in patients with non-valvular AF concerning their mid-term prognostic performance. Methods: Cross-sectional study of 555 consecutive patients with non-valvular AF undergoing transesophageal echocardiogram. We tested the prognostic performance of the aforementioned GFR estimation formulae, namely their ability to predict all-cause mortality (primary endpoint) and major cardiac adverse or ischemic cerebrovascular events (secondary endpoints) during an average follow-up of 24 months. Results: Regarding the primary endpoint, Cockcroft-Gault (AUC=0.749±0.028) was superior to both MDRD (AUC=0.624±0.039) and CKD-EPI (AUC=0.641±0.034) [p<0.001 both comparisons] while CKD-EPI was superior to MDRD (p=0.011). Cockcroft-Gault was marginally superior to both MDRD (AUC=0.673±0.049 vs. AUC=0.586±0.054, p=0.041) and CKD-EPI (AUC=0.673±0.049 vs. AUC=0.604±0.054, p=0.063) in the prediction of ischemic cerebrovascular events, while no difference was found between CKD-EPI and MDRD. Concerning AUC for prediction of MACE, Cockcroft-Gault was superior to MDRD (p=0.009) and CKD-EPI (p=0.012), while CKD-EPI was similar to MDRD (p=0.215). Multivariate predictive models consistently included Cockcroft-Gault formula along with CHADS₂, excluding the other two equations. Measures of reclassification revealed a significant improvement in risk stratification for all studied endpoints with Cockcroft-Gault instead of CKD-EPI. Conclusions: In patients with non-valvular AF, the Cockcroft-Gault more appropriately classified individuals with respect to risk of all-cause mortality, ischaemic cerebrovascular event and major adverse cardiac event.

Incident atrial fibrillation among Asians, Hispanics, blacks, and whites

BACKGROUND

Because the association between atrial fibrillation (AF) and race has only been rigorously compared in population-based studies that dichotomized participants as white or black, it is unclear whether white race confers elevated AF risk or black race affords AF protection.

METHODS AND RESULTS

The Healthcare Cost and Utilization Project was used to identify patients receiving hospital-based care in California between January 1, 2005 and December 31, 2009. The association between race and incident AF was examined using Cox proportional hazards models. Interaction analyses were performed to elucidate the mechanism underlying the race-AF association. Among 13 967 949 patients, 375 318 incident AF episodes were observed over a median 3.2 (interquartile range 1.8-4.3) years. In multivariable Cox models adjusting for patient demographics and established AF risk factors, blacks (hazard ratio, 0.84; 95% confidence interval, 0.82-0.85; P<0.001), Hispanics (hazard ratio, 0.78; 95% confidence interval, 0.77-0.79; P<0.001), and Asians (hazard ratio, 0.78; 95% confidence interval, 0.77-0.79; P<0.001) each exhibited a lower AF risk compared with whites. AF risk among whites was disproportionately higher in the absence of acquired cardiovascular risk factors and diminished or reversed in the presence of comorbid diseases. Although Hispanics and Asians also had a lower adjusted risk of incident atrial flutter compared with whites, the risk of flutter was significantly higher among blacks.

CONCLUSIONS

In a large hospital-based cohort, whites have an increased risk of AF whether compared with blacks, Asians, or Hispanics. The heightened AF risk among whites is most pronounced in the absence of cardiovascular comorbidities.

Renal Dysfunction, Stroke Risk Scores (CHADS 2 , CHA 2 DS 2 -VASc, and R 2 CHADS 2 ), and the Risk of Thromboembolic Events After Catheter Ablation of Atrial Fibrillation

Background—

There are limited data on the predictive value of stroke risk scores for thromboembolic events (TEs) after catheter ablation of atrial fibrillation (AF). Our objectives were to report the incidence of TEs after AF ablation in a large contemporary AF ablation cohort and to investigate the impact of renal dysfunction and the value of stroke risk stratification scores (CHADS 2 , CHA 2 DS 2 -VASc, and R 2 CHADS 2 ) for predicting TE after AF ablation.

Methods and Results—

Using the Leipzig Heart Center AF Ablation Registry, we documented TEs in patients undergoing radiofrequency AF catheter ablation. TE was defined as stroke, transient ischemic attack, or systemic embolism. Study population (N=2069; 66% men; 60±10 years; 62% paroxysmal AF; mean CHADS 2 , 1.2±0.9; CHA 2 DS 2 -VASc, 2.1±1.4; and R 2 CHADS 2 , 1.3±1.1) were followed up for a median 18 (Q1–Q3, 12–29) months (ie, 3078 patient-years). Overall, 31 TEs occurred, with 16 events within 30 days of ablation and 15 TEs (0.72%) during the follow-up period. On multivariate analysis, CHADS 2 ( P <0.001), R 2 CHADS 2 ( P <0.001), and CHA 2 DS 2 -VASc ( P =0.003) scores were independent predictors of TEs during follow-up, and AF recurrence conferred a nonsignificant trend for increased TE risk ( P =0.071–0.094). The CHA 2 DS 2 -VASc score further differentiated TE risk in patients with CHADS 2 and R 2 CHADS 2 0 to 1 (0.13% if CHA 2 DS 2 -VASc was 0–1 and 0.71% if CHA 2 DS 2 -VASc was >2) and had the best predictive value in patients with AF recurrences (c-index 0.894, P =0.022 versus CHADS 2 , P =0.031 versus R 2 CHADS 2 ).

Conclusions—

CHADS 2 , CHA 2 DS 2 -VASc, and R 2 CHADS 2 scores were associated with TE risk. The CHA 2 DS 2 -VASc score differentiated TE risk in the low-risk strata based on CHADS 2 and R 2 CHADS 2 scores and may be superior in the subgroup with AF recurrences.

A review of apixaban for stroke prevention in atrial fibrillation: insights from ARISTOTLE

Atrial fibrillation (AF) is associated with significant mortality and morbidity, and stroke represents the most-feared complication. Consequently, AF treatment has focused on thromboprophylaxis, with warfarin as the mainstay of therapy. However, concerns over ease of use and safety have limited its use. Three novel oral anticoagulants have been approved for use in stroke prevention in AF based on randomized data: 1) dabigatran, studied in Randomized Evaluation of Long-term Anticoagulation Therapy (RE-LY); 2) rivaroxaban, studied in Rivaroxaban Once-daily, Oral, Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF); and 3) apixaban, studied in Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE). In this review, we focus on apixaban and discuss subgroup analyses that have been performed in the three trials comparing novel oral anticoagulants with warfarin. We conclude with recommendations regarding further investigations.

Renal function and outcomes in anticoagulated patients with non-valvular atrial fibrillation: the AMADEUS trial

AIMS

Limited data are available on the impact of renal function on the outcome of patients with atrial fibrillation (AF).

METHODS AND RESULTS

AMADEUS was a multicentre, randomized, open-label non-inferiority study that compared fixed-dose idraparinux with conventional anticoagulation by dose-adjusted vitamin K antagonists. We performed a post hoc analysis to assess the impact of renal function on the outcomes of anticoagulated AF patients. The primary efficacy outcome was the composite of stroke/systemic embolism (SE). The principal safety outcome of this analysis was major bleeding. We calculated c-indexes, reflecting the ability for discriminating diseased vs. non-diseased patients, and the net reclassification improvement (NRI, an index of inferior/superior performance of risk estimation scores). Of 4576 patients, 45 strokes and 103 major bleeding events occurred following an average follow-up of 325 ± 164 days. Patients with CrCl >90 mL/min had an annual stroke/SE rate of 0.6% compared with 0.8% for those with CrCl 60-90 mL/min and 2.2% for those with CrCl <60 mL/min (P < 0.001 for linear association). After adjusting for stroke risk factors, patients with CrCl <60 mL/min had more than two-fold higher risk of stroke/SE and almost 60% higher risk of major bleeding compared with those with CrCl ≥60. In patients with the CHA2DS2VASc score 1-2, CrCl <60 mL/min was associated with eight-fold higher stroke risk. When added to the CHA2DS2VASc or CHADS2 scores, CrCl <60 mL/min did not improve the c-indexes for CHADS2 (P = 0.054) or CHA2DS2VASc (P = 0.63) but resulted in significant NRI (0.26, P = 0.02) in this anticoagulated trial cohort.

CONCLUSION

Renal impairment (CrCl <60 mL/min) doubles the risk of stroke and increased the risk of major bleeding by almost 60% in anticoagulated patients with AF. Renal impairment was additive to stroke risk prediction scores based on a significant NRI, but no significant improvement in discrimination ability (based on c-indexes) for CHA2DS2VASc or CHADS2 was observed.

Management of atrial fibrillation in chronic kidney disease: double trouble

Chronic kidney disease (CKD) has a very well-established link with cardiovascular disease. Below stage 3 CKD (glomerular filtration rate <60 mL/min), there is a progressive increase in both total mortality and cardiovascular-specific mortality as kidney function declines; indeed, it is more likely for a patient with CKD stage 3 to die of cardiovascular disease than to progress to CKD stage 4 and beyond. Arrhythmia is particularly common in patients with CKD. Depending on the study and measurement used, the prevalence of patients with CKD with chronic atrial fibrillation (AF) is quoted at 7% to 18%, rising to 12% to 25% for those older than 70 years. These rates are up to 2 to 3 times higher than in the general population. Of all patients with AF, 10% to 15% will have CKD. However, not all standard rate and rhythm methods are suitable for this population and those that are tend to be less effective. Meanwhile, anticoagulation has long been a thorny subject, with much conflicting evidence around the balance between bleeding and stroke risk. To help clarify this, we first highlight the challenges of performing evidence-based medicine in the patient with renal disease, and then review recent and emerging research to suggest an approach to the management of patients with renal disease who have AF. We also review the potential role of the different new oral anticoagulant drugs in CKD.

Transitions of care in anticoagulation management for patients with atrial fibrillation

Thromboprophylaxis with oral anticoagulants (OACs) is an important but underused element of atrial fibrillation (AF) treatment. Reduction of stroke risk with anticoagulants comes at the price of increased bleeding risk. Patients with AF receiving anticoagulants require heightened attention with transition from one care setting to another. Patients presenting for emergency care of anticoagulant-related bleeding should be triaged for the severity and source of the bleeding using appropriate measures, such as discontinuing the OAC, administering vitamin K, when appropriate, to reverse warfarin-induced bleeding, or administering clotting factors for emergent bleeding. Reversal of OACs in patients admitted to the hospital for surgery can be managed similarly to patients with bleeding, depending on the urgency of the surgical procedure. Patients with AF who are admitted for conditions unrelated to AF should be assessed for adequacy of stroke risk prophylaxis and bleeding risk. Newly diagnosed AF should be treated in nearly all patients with either warfarin or a newer anticoagulant. Patient education is critically important with all anticoagulants. Close adherence to the prescribed regimen, regular international normalized ratio testing for warfarin, and understanding the stroke risk conferred by both AF and aging are goals for all patients receiving OACs. Detailed handoff from the hospitalist to the patient's primary care physician is required for good continuity of care. Monitoring by an anticoagulation clinic is the best arrangement for most patients. The elderly, or particularly frail or debilitated patients who are transferring to long-term care, need a detailed transfer of information between settings, education for the patient and family, and medication reconciliation. Communication and coordination of care among outpatient, emergency, inpatient, and long-term care settings are vital for patients with AF who are receiving anticoagulants to balance stroke prevention and bleeding risk.

An update on neurocritical care for the patient with kidney disease

Patients with kidney disease have increased rates of neurologic illness such as intracerebral hemorrhage and ischemic stroke. The acute care of patients with critical neurologic illness and concomitant kidney disease requires unique management considerations including attention to hyponatremia, renal replacement modalities in the setting of high intracranial pressure, reversal of coagulopathy, and seizure management to achieve good neurologic outcomes.

Care transitions in anticoagulation management for patients with atrial fibrillation: an emphasis on safety

BACKGROUND

Thromboprophylaxis with oral anticoagulants is an important but underused element of atrial fibrillation (AF) treatment. Reduction of stroke risk by anticoagulants comes at the price of bleeding risk. Patients with AF receiving anticoagulants require heightened attention with transition from one care setting to another.

METHODS

This review of the literature focuses on issues specific to the anticoagulation treatment of patients with AF.

RESULTS

Patients presenting for emergency care of anticoagulant-related bleeding should be triaged for the severity and source of the bleeding using appropriate measures, such as discontinuing the oral anticoagulant, administering vitamin K when appropriate to reverse warfarin-induced bleeding, or administering clotting factors for emergent bleeding. Reversal of oral anticoagulants in patients admitted to the hospital for surgery can be managed similarly to patients with bleeding, depending on the urgency of the surgical procedure. Patients with AF who are admitted for conditions unrelated to AF should be assessed for adequacy of stroke risk prophylaxis and bleeding risk. Newly diagnosed AF should be treated in nearly all patients with either warfarin or a newer anticoagulant.

CONCLUSIONS

Patient education is critically important with all anticoagulants. Close adherence to the prescribed regimen, regular international normalized ratio testing for warfarin, and understanding the stroke risk conferred by AF and aging are goals for all patients receiving oral anticoagulants. Detailed handoff from the hospitalist to the patient's primary care physician is required for good continuity of care. Monitoring by an anticoagulation clinic is the best arrangement for most patients. The elderly, particularly frail or debilitated patients who are transferring to long-term care, need a detailed transfer of information between settings, education for the patient and family, and medication reconciliation. Communication and coordination of care among outpatient, emergency, inpatient, subacute, and long-term care settings are vital in patients with AF who are receiving anticoagulants to balance stroke prevention and bleeding risk.