Serial measurement of interleukin-6 and risk of mortality in anticoagulated patients with atrial fibrillation: Insights from ARISTOTLE and RE-LY trials.

BACKGROUND: The inflammatory biomarker interleukin-6 (IL-6) is associated with mortality in atrial fibrillation (AF). OBJECTIVE: To investigate if repeated IL-6 measurements improve the prognostication for stroke or systemic embolism, major bleeding, and mortality in anticoagulated patients with AF. METHODS: IL-6 levels by ELISA were measured at study entry and at 2 months in 4830 patients in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial with 1.8 years median follow-up. In the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial, IL-6 was measured at study entry, 3, 6, and 12 months in 2559 patients with 2.0 years median follow-up. Associations between a second IL-6 measurement and outcomes, adjusted for baseline IL-6, clinical variables, and other cardiovascular biomarkers, were analyzed by Cox regression. RESULTS: Median IL-6 levels were 2.0 ng/L (interquartile range [IQR] 1.30-3.20) and 2.10 ng/L (IQR 1.40-3.40) at the two time-points in ARISTOTLE, and, in RE-LY, 2.5 ng/L (IQR 1.6-4.3), 2.5 ng/L (IQR 1.6-4.2), 2.4 ng/L (IQR 1.6, 3.9), and 2.4 ng/L (IQR 1.5, 3.9), respectively. IL-6 was associated with mortality; hazard ratios per 50% higher IL-6 at 2 or 3 months, respectively, were 1.32 (95% confidence interval, 1.23-1.41; P < .0001) in ARISTOTLE, and 1.11 (1.01-1.22, P = .0290) in RE-LY; with improved C index from 0.74 to 0.76 in ARISTOTLE, but not in the smaller RE-LY cohort. There were no consistent associations with second IL-6 and stroke or systemic embolism, or major bleeding. CONCLUSIONS: Persistent systemic inflammatory activity, assessed by repeated IL-6 measurements, is associated with mortality independent of established clinical risk factors and other strong cardiovascular biomarkers in anticoagulated patients with AF.

Temporal trends in pharmacologic prophylaxis for venous thromboembolism after hip and knee replacement in older adults.

Trends in prescription for venous thromboembolism (VTE) prophylaxis following total hip (THR) and knee replacement (TKR) since the approval of direct oral anticoagulants (DOACs) and the 2012 guideline endorsement of aspirin are unknown, as are the risks of adverse events. We examined practice patterns in the prescription of prophylaxis agents and the risk of adverse events during the in-hospital period (the 'in-hospital sample') and 90 days following discharge (the 'discharge sample') among adults aged ⩾ 65 undergoing THR and TKR in community hospitals in the Institute for Health Metrics database over a 30-month period during 2011 to 2013. Eligible medications included fondaparinux, DOACs, low molecular weight heparin (LMWH), other heparin products, warfarin, and aspirin. Outcomes were validated by physician review of source documents: VTE, major hemorrhage, cardiovascular events, and death. The in-hospital and the discharge samples included 10,503 and 5722 adults from 65 hospitals nationwide, respectively (mean age 73, 74 years; 61%, 63% women). Pharmacologic prophylaxis was near universal during the in-hospital period (93%) and at discharge (99%). DOAC use increased substantially and was the prophylaxis of choice for nearly a quarter (in-hospital) and a third (discharge) of the patients. Aspirin was the sole discharge prophylactic agent for 17% and 19% of patients undergoing THR and TKR, respectively. Warfarin remained the prophylaxis agent of choice for patients aged 80 years and older. The overall risk of adverse events was low, at less than 1% for both the in-hospital and discharge outcomes. The low number of adverse events precluded statistical comparison of prophylaxis regimens.

Dabigatran Reversal With Idarucizumab in Patients With Renal Impairment.

BACKGROUND: Dabigatran and idarucizumab, its reversal agent, are renally cleared. OBJECTIVES: The purpose of this study was to determine the extent of reversal and outcomes according to baseline renal function in dabigatran-treated nondialysis patients receiving idarucizumab. METHODS: In 503 patients in RE-VERSE AD (Reversal of Effects of Idarucizumab in Patients on Active Dabigatran), the extent of dabigatran reversal and clinical outcomes were compared according to baseline renal function (creatinine clearance: normal ≥80, mild 50 to <80, moderate 30 to <50, and severe <30 ml/min). RESULTS: Compared with patients with normal renal function, those with impaired renal function were older, were more often women, and had lower body mass indexes, more comorbidities, higher CHADS2 scores, and higher dabigatran plasma levels despite more frequent use of lower-dose dabigatran regimens. Regardless of renal function, median reversal measured by dilute thrombin time was 100% within 4 h of idarucizumab administration, and over 98% of patients achieved this with corresponding undetectable levels of unbound dabigatran. By 12 or 24 h, 56% of patients with severe, 29.1% with moderate, and 9.2% with mild renal impairment had dabigatran levels >20 ng/ml compared with 8.3% of patients with normal renal function at baseline. Time to cessation of bleeding and the proportion with normal hemostasis with procedures were similar regardless of renal function, but patients with severe renal impairment had higher 30- and 90-day mortality rates. CONCLUSIONS: Idarucizumab completely reverses dabigatran in >98% of patients regardless of renal function. Although re-elevation of dabigatran levels within 12 to 24 h is more common with renal impairment, the time to bleeding cessation and the extent of hemostasis during procedures are similar. (Reversal of Dabigatran Anticoagulant Effect With Idarucizumab; NCT02104947).

Outcomes of apixaban versus warfarin in patients with atrial fibrillation and multi-morbidity: Insights from the ARISTOTLE trial.

BACKGROUND: Patients with atrial fibrillation (AF) often have multi-morbidity, defined as ≥3 comorbid conditions. Multi-morbidity is associated with polypharmacy, adverse events, and frailty potentially altering response to anticoagulation. We sought to describe the prevalence of multi-morbidity among older patients with AF and determine the association between multi-morbidity, clinical outcomes, and the efficacy and safety of apixaban compared with warfarin. METHODS: In this post-hoc subgroup analysis of the ARISTOTLE trial, we studied enrolled patients age ≥ 55 years (n = 16,800). Patients were categorized by the number of comorbid conditions at baseline: no multi-morbidity (0-2 comorbid conditions), moderate multi-morbidity (3-5 comorbid conditions), and high multi-morbidity (≥6 comorbid conditions). Association between multi-morbidity and clinical outcomes were analyzed by treatment with a median follow-up of 1.8 (1.3-2.3) years. RESULTS: Multi-morbidity was present in 64% (n = 10,713) of patients; 51% (n = 8491) had moderate multi-morbidity, 13% (n = 2222) had high multi-morbidity, and 36% (n = 6087) had no multi-morbidity. Compared with the no multi-morbidity group, the high multi-morbidity group was older (74 vs 69 years), took twice as many medications (10 vs 5), and had higher CHA2DS2-VASc scores (4.9 vs 2.7) (all P < .001). Adjusted rates per 100 patient-years for stroke/systemic embolism, death, and major bleeding increased with multi-morbidity (Reference no multi-morbidity; moderate multi-morbidity 1.42 [1.24-1.64] and high multi-morbidity 1.92 [1.59-2.31]), with no interaction in relation to efficacy or safety of apixaban. CONCLUSIONS: Multi-morbidity is prevalent among the population with AF; efficacy and safety of apixaban is preserved in this subgroup supporting extension of trial results to the most complex AF patients.

Use of Biomarkers to Predict Specific Causes of Death in Patients With Atrial Fibrillation.

BACKGROUND: Atrial fibrillation is associated with an increased risk of death. High-sensitivity troponin T, growth differentiation factor-15, NT-proBNP (N-terminal pro-B-type natriuretic peptide), and interleukin-6 levels are predictive of cardiovascular events and total cardiovascular death in anticoagulated patients with atrial fibrillation. The prognostic utility of these biomarkers for cause-specific death is unknown. METHODS: The ARISTOTLE trial (Apixaban for the Prevention of Stroke in Subjects With Atrial Fibrillation) randomized 18 201 patients with atrial fibrillation to apixaban or warfarin. Biomarkers were measured at randomization in 14 798 patients (1.9 years median follow-up). Cox models were used to identify clinical variables and biomarkers independently associated with each specific cause of death. RESULTS: In total, 1272 patients died: 652 (51%) cardiovascular, 32 (3%) bleeding, and 588 (46%) noncardiovascular/nonbleeding deaths. Among cardiovascular deaths, 255 (39%) were sudden cardiac deaths, 168 (26%) heart failure deaths, and 106 (16%) stroke/systemic embolism deaths. Biomarkers were the strongest predictors of cause-specific death: a doubling of troponin T was most strongly associated with sudden death (hazard ratio [HR], 1.48; P<0.001), NT-proBNP with heart failure death (HR, 1.62; P<0.001), and growth differentiation factor-15 with bleeding death (HR, 1.72; P=0.028). Prior stroke/systemic embolism (HR, 2.58; P>0.001) followed by troponin T (HR, 1.45; P<0.0029) were the most predictive for stroke/ systemic embolism death. Adding all biomarkers to clinical variables improved discrimination for each cause-specific death. CONCLUSIONS: Biomarkers were some of the strongest predictors of cause-specific death and may improve the ability to discriminate among patients' risks for different causes of death. These data suggest a potential role of biomarkers for the identification of patients at risk for different causes of death in patients anticoagulated for atrial fibrillation. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT00412984.

Characteristics and outcomes of adults with chronic obstructive pulmonary disease and atrial fibrillation.

OBJECTIVE: Chronic obstructive pulmonary disease (COPD) is associated with the development of atrial fibrillation (AF), and may complicate treatment of AF. We examined the association between COPD and symptoms, quality of life (QoL), treatment and outcomes among patients with AF. METHODS: We compared patients with and without a diagnosis of COPD in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation, a prospective registry that enrolled outpatients with AF not secondary to reversible causes, from both academic and community settings. RESULTS: Among 9749 patients with AF, 1605 (16%) had COPD. Relative to patients without COPD, those with COPD were more likely to be older, current/former smokers (73% vs 43%), have heart failure (54% vs 29%) and coronary artery disease (49% vs 34%). Oral anticoagulant and beta blocker use were similar, whereas digoxin use was more common among patients with COPD. Symptom burden was generally higher, and QoL worse, among patients with COPD (median Atrial Fibrillation Effect on QualiTy-of-Life score 76 vs 83). Patients with COPD had higher risk of all-cause mortality (adjusted HR 1.52 (95% CI 1.32 to 1.74)), cardiovascular mortality (adjusted HR 1.51 (95% CI 1.24 to 1.84)) and cardiovascular hospitalisation (adjusted HR 1.15 (95% CI 1.05 to 1.26)). Patients with COPD also had higher risk of major bleeding events (adjusted HR 1.25 (95% CI 1.05 to 1.50)). There did not appear to be associations between COPD and AF progression, ischaemic events or new-onset heart failure. CONCLUSIONS: Among patients with AF, COPD is associated with higher symptom burden, worse QoL, and worse cardiovascular and bleeding outcomes. These associations were not fully explained by cardiovascular risk factors, AF treatment or smoking history. CLINICAL REGISTRATION NUMBER: NCT01165710.

Management and outcomes of patients with atrial fibrillation and a history of cancer: the ORBIT-AF registry.

Aims: The presence of cancer can complicate treatment choices for patients with atrial fibrillation (AF) increasing both the risk of thrombotic and bleeding events. Methods and results: Using data from Outcomes Registry for Better Informed Treatment of Atrial Fibrillation, we aimed to characterize AF patients with cancer, to describe their management and to assess the association between cancer and cardiovascular (CV) outcomes. Among 9749 patients, 23.8% had history of cancer (57% solid malignancy, 1.3% leukaemia, 3.3% lymphoma, 40% other type, and 2.2% metastatic cancer). Patients with history of cancer were older, more likely to have CV disease, CV risk factors, and prior gastrointestinal bleeding. No difference in antiarrhythmic and antithrombotic therapy was observed between those with and without cancer. Patients with history of cancer had a significantly higher risk of death (7.8 vs. 4.9 deaths per 100 patient-years follow-up, P = 0.0003) mainly driven by non-CV death (4.2 vs. 2.4 per 100 patient-years follow-up; P = 0.0004) and higher risk of major bleeding (5.1 vs. 3.5 per 100 patient-years follow-up; P = 0.02) compared with non-cancer patients; no differences were observed in risks of strokes/non-central nervous system embolism (1.96 vs. 1.48, P = 0.74) and CV death (2.89 vs. 2.07, P = 0.35) between the two groups. Conclusion: A history of cancer is common among AF patients with up to one in four patients having both. Antithrombotic therapy, rates of cerebrovascular accident, other thrombotic events and cardiac death were similar in AF patients with or without a history of cancer. Patients with cancer, however, were at higher risk of major bleeding and non-CV death.

Efficacy and Safety of Apixaban Versus Warfarin in Patients with Atrial Fibrillation and a History of Cancer: Insights from the ARISTOTLE Trial.

BACKGROUND: Cancer is associated with a prothrombotic state and increases the risk of thrombotic events in patients with atrial fibrillation. We described the clinical characteristics and outcomes and assessed the safety and efficacy of apixaban versus warfarin in patients with atrial fibrillation and cancer in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial. METHODS: The association between cancer and clinical outcomes was assessed using Cox regression models. At baseline, 1236 patients (6.8%) had a history of cancer; 12.7% had active cancer, and 87.3% had remote cancer. RESULTS: There were no significant associations between history of cancer and stroke/systemic embolism, major bleeding, or death. The effect of apixaban versus warfarin for the prevention of stroke/systemic embolism was consistent among patients with a history of cancer (event/100 patient-years = 1.4 vs 1.2; hazard ratio [HR], 1.09; 95% confidence interval [CI], 0.53-2.26) and no cancer (1.3 vs 1.6; HR, 0.77; 95% CI, 0.64-0.93) (P interaction = .37). The safety and efficacy of apixaban versus warfarin were preserved among patients with and without active cancer. Apixaban was associated with a greater benefit for the composite of stroke/systemic embolism, myocardial infarction, and death in active cancer (HR, 0.30; 95% CI, 0.11-0.83) versus without cancer (HR, 0.86; 95% CI, 0.78-0.95), but not in remote cancer (HR, 1.46; 95% CI, 1.01-2.10) (interaction P = .0028). CONCLUSIONS: Cancer was not associated with a higher risk of stroke. The superior efficacy and safety of apixaban versus warfarin were consistent in patients with and without cancer. Our positive findings regarding apixaban use in patients with atrial fibrillation and cancer are exploratory and promising, but warrant further evaluation.

Gender and tachycardia: independent modulation of platelet reactivity in patients with atrial fibrillation.

BACKGROUND: Female patients with atrial fibrillation (AF) experience increased risk of thromboembolism compared to males, an observation that is reflected by its inclusion in the CHA2DS2VASc score. New onset AF (often associated with tachycardia) also confers upon patients increased thromboembolic risk. The mechanisms underlying this risk are uncertain, but new onset AF is associated with profound impairment of platelet nitric oxide (NO) signalling. Given that cardiovascular responses to catecholamines are gender-dependent, and that the presence of tachycardia in new onset AF may represent a response to catecholaminergic stimulation, we explored the potential impact of gender and tachycardia on platelet aggregation and NO signalling. METHODS: Interactions were sought in 87 AF patients between the extent of adenosine diphosphate (ADP)-induced platelet aggregation, the anti-aggregatory effects of the NO donor, sodium nitroprusside, gender, and admission heart rate. The potential impact of platelet expression of thioredoxin-interacting protein (Txnip) was also evaluated. RESULTS: Analysis of covariance confirmed the presence of physiological antagonism between platelet ADP and NO responses [F (1, 74) = 12.212, P < 0.01], while female sex correlated with impaired NO responses independent of platelet aggregability [F (2, 74) = 8.313, P < 0.01]. Admission heart rate correlated directly with platelet aggregation (r = 0.235, P < 0.05), and inversely with NO response (r = -0.331, P < 0.01). Txnip expression varied neither with gender nor with heart rate. CONCLUSIONS: These results indicate that gender and heart rate are independent determinants of platelet function. Prospective studies of the putative benefit of reversal of tachycardia on restoration of normal platelet function are therefore a priority.

The novel biomarker-based ABC (age, biomarkers, clinical history)-bleeding risk score for patients with atrial fibrillation: a derivation and validation study.

BACKGROUND: The benefit of oral anticoagulation in atrial fibrillation is based on a balance between reduction in ischaemic stroke and increase in major bleeding. We aimed to develop and validate a new biomarker-based risk score to improve the prognostication of major bleeding in patients with atrial fibrillation. METHODS: We developed and internally validated a new biomarker-based risk score for major bleeding in 14,537 patients with atrial fibrillation randomised to apixaban versus warfarin in the ARISTOTLE trial and externally validated it in 8468 patients with atrial fibrillation randomised to dabigatran versus warfarin in the RE-LY trial. Plasma samples for determination of candidate biomarker concentrations were obtained at randomisation. Major bleeding events were centrally adjudicated. The predictive values of biomarkers and clinical variables were assessed with Cox regression models. The most important variables were included in the score with weights proportional to the model coefficients. The ARISTOTLE and RE-LY trials are registered with ClinicalTrials.gov, numbers NCT00412984 and NCT00262600, respectively. FINDINGS: The most important predictors for major bleeding were the concentrations of the biomarkers growth differentiation factor-15 (GDF-15), high-sensitivity cardiac troponin T (cTnT-hs) and haemoglobin, age, and previous bleeding. The ABC-bleeding score (age, biomarkers [GDF-15, cTnT-hs, and haemoglobin], and clinical history [previous bleeding]) score yielded a higher c-index than the conventional HAS-BLED and the newer ORBIT scores for major bleeding in both the derivation cohort (0·68 [95% CI 0·66-0·70] vs 0·61 [0·59-0·63] vs 0·65 [0·62-0·67], respectively; ABC-bleeding vs HAS-BLED p<0·0001 and ABC-bleeding vs ORBIT p=0·0008). ABC-bleeding score also yielded a higher c-index score in the the external validation cohort (0·71 [95% CI 0·68-0·73] vs 0·62 [0·59-0·64] for HAS-BLED vs 0·68 [0·65-0·70] for ORBIT; ABC-bleeding vs HAS-BLED p<0·0001 and ABC-bleeding vs ORBIT p=0·0016). A modified ABC-bleeding score using alternative biomarkers (haematocrit, cTnI-hs, cystatin C, or creatinine clearance) also outperformed the HAS-BLED and ORBIT scores. INTERPRETATION: The ABC-bleeding score, using age, history of bleeding, and three biomarkers (haemoglobin, cTn-hs, and GDF-15 or cystatin C/CKD-EPI) was internally and externally validated and calibrated in large cohorts of patients with atrial fibrillation receiving anticoagulation therapy. The ABC-bleeding score performed better than HAS-BLED and ORBIT scores and should be useful as decision support on anticoagulation treatment in patients with atrial fibrillation. FUNDING: BMS, Pfizer, Boehringer Ingelheim, Roche Diagnostics.

Biomarkers of inflammation and risk of cardiovascular events in anticoagulated patients with atrial fibrillation.

OBJECTIVE: Atrial fibrillation (AF) is a risk factor for stroke and mortality and the prothrombotic state has been linked to inflammation. In this study we evaluated the relationship between inflammatory biomarkers at baseline and future risk of cardiovascular events in the Apixaban for Reduction In Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial. METHODS: The ARISTOTLE trial randomised 18,201 patients with AF to apixaban or warfarin. Interleukin 6 (IL-6) and C reactive protein (CRP) were analysed in plasma obtained at randomisation from 14,954 participants, and median follow-up was 1.9 years. Association between quartile groups of IL-6 and CRP and outcomes were analysed by Cox regression adjusted for clinical risk factors and other cardiovascular biomarkers (NT-proBNP, troponin, GDF-15, cystatin C). RESULTS: The IL-6 median level was 2.3 ng/L (IQR 1.5-3.9), median CRP level was 2.2 mg/L (1.0-4.8). IL-6 and CRP were significantly associated with all-cause mortality independent of clinical risk factors and other biomarkers (HR (95% CI) 1.93 (1.57 to 2.37) and 1.49 (1.24 to 1.79), respectively, Q4 vs Q1). IL-6 was associated with myocardial infarction, cardiovascular mortality, and major bleeding beyond clinical risk factors but not in the presence of cardiovascular biomarkers (NT-proBNP, troponin, GDF-15, cystatin C). Neither inflammatory biomarker was associated with stroke/systemic embolism. Risk prediction for stroke, death and major bleeding was not improved by IL-6 or CRP when added to clinical risk factors and the other cardiovascular biomarkers (NT-proBNP, troponin, GDF-15, cystatin C). CONCLUSIONS: In patients with AF on anticoagulation, after accounting for clinical risk factors and other biomarkers, biomarkers of inflammation were significantly associated with an increased risk of mortality. However, there were no associations with the risk of stroke or major bleeding. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier: NCT00412984 post-results.

Who, when, and how to reverse non-vitamin K oral anticoagulants.

Non-vitamin K oral anticoagulants (NOACs) have been a major addition to our therapeutic armamentarium. They are at least as effective as warfarin in the thromboprophylaxis of non-valvular atrial fibrillation and management of thromboembolic disease, with a more favorable safety profile. Their predictable pharmacokinetics and pharmacodynamics allow for a fixed oral dosing without the need for anticoagulation monitoring. A major concern regarding NOACs is the lack of a readily available antidote to reverse their anticoagulation effect in case of life-threatening bleeding or need for emergent surgery. In this review, we summarize preclinical and clinical data on (a) hemostatic agents used to reverse NOACs, and (b) novel, target-specific NOACs reversal agents under development. The prothrombin complex concentrates, activated prothrombin complex concentrates and recombinant activated factor VII are hemostatic agents that have been assessed in reversing NOACs. Preclinical studies with hemostatic agents report variable results and there is only limited clinical data available to date. Idarucizumab and andexanet alfa are NOAC-specific reversal agents designed to reverse dabigatran and factor Xa inhibitors accordingly. Aripazine is a universal anticoagulation reversal agent. Preclinical studies show promising results and these agents are already in different stages of clinical development. Phase I and II clinical trials demonstrate efficacy in reversing NOACs without major side effects. Until these agents become commercially available, management of patients receiving NOACs who present with major bleeding or require emergent surgery should focus on (a) immediate discontinuation of NOACs, (b) supportive measures or postponing surgery for 12-24 h after the last NOAC dose, and/or

Platelet hyperaggregability in patients with atrial fibrillation. Evidence of a background proinflammatory milieu.

OBJECTIVE: Atrial fibrillation (AF) is a condition where platelet hyperaggregability is commonly present. We examined potential physiological bases for platelet hyperaggregability in a cohort of patients with acute and chronic AF. In particular, we sought to identify the impact of inflammation [myeloperoxidase (MPO) and C-reactive protein (CRP)] and impaired nitric oxide (NO) signaling. METHODS: Clinical and biochemical determinants of adenosine diphosphate (ADP)-induced platelet aggregation were sought in patients (n = 106) hospitalized with AF via univariate and multivariate analysis. RESULTS: Hyper-responsiveness of platelets to ADP was directly (r = 0.254, p < 0.01) correlated with plasma concentrations of thrombospondin-1 (TSP-1), a matricellular protein that impairs NO responses and contributes to development of oxidative stress. In turn, plasma TSP-1 concentrations were directly correlated with MPO concentrations (r = 0.221, p < 0.05), while MPO concentrations correlated with those of asymmetric dimethylarginine (ADMA, r = 0.220, p < 0.05), and its structural isomer symmetric dimethylarginine (SDMA, r = 0.192, p = 0.05). Multivariate analysis identified TSP-1 (ß = 0.276, p < 0.05) concentrations, as well as female sex (ß = 0.199, p < 0.05), as direct correlates of platelet aggregability, and SDMA concentrations (ß = - 0.292, p < 0.05) as an inverse correlate. CONCLUSION: We conclude that platelet hyperaggregability, where present in the context of AF, may be engendered by impaired availability of NO, as well as via MPO-related inflammatory activation.

Patients' time in therapeutic range on warfarin among US patients with atrial fibrillation: Results from ORBIT-AF registry.

BACKGROUND: Time in therapeutic range (TTR) of international normalized ratio (INR) of 2.0 to 3.0 is important for the safety and effectiveness of warfarin anticoagulation. There are few data on TTR among patients with atrial fibrillation (AF) in community-based clinical practice. METHODS: Using the US Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF), we examined TTR (using a modified Rosendaal method) among 5,210 patients with AF on warfarin and treated at 155 sites. Patients were grouped into quartiles based on TTR data. Multivariable logistic regression modeling with generalized estimating equations was used to determine patient and provider factors associated with the lowest (worst) TTR. RESULTS: Overall, 59% of the measured INR values were between 2.0 and 3.0, with an overall mean and median TTR of 65% ± 20% and 68% (interquartile range [IQR] 53%-79%). The median times below and above the therapeutic range were 17% (IQR 8%-29%) and 10% (IQR 3%-19%), respectively. Patients with renal dysfunction, advanced heart failure, frailty, prior valve surgery, and higher risk for bleeding (ATRIA score) or stroke (CHA2DS2-VASc score) had significantly lower TTR (P < .0001 for all). Patients treated at anticoagulation clinics had only slightly higher median TTR (69%) than those not (66%) (P < .0001). CONCLUSIONS: Among patients with AF in US clinical practices, TTR on warfarin is suboptimal, and those at highest predicted risks for stroke and bleeding were least likely to be in therapeutic range.

Design and rationale for RE-VERSE AD: A phase 3 study of idarucizumab, a specific reversal agent for dabigatran.

Idarucizumab, a Fab fragment directed against dabigatran, produced rapid and complete reversal of the anticoagulation effect of dabigatran in animals and in healthy volunteers. The Study of the REVERSal Effects of Idarucizumab in Patients on Active Dabigatran (RE-VERSE AD™) is a global phase 3 prospective cohort study aimed at investigating idarucizumab in dabigatran-treated patients who present with uncontrollable or life-threatening bleeding, and in those requiring urgent surgery or intervention. We describe the rationale for, and design of the trial (clinicaltrials.gov NCT02104947).

Biomarkers in lone atrial fibrillation - an additional 'fine tuning' of risk?

Lone atrial fibrillation (LAF) is generally regarded as a benign disorder that does not significantly increase the risk of thromboembolism and mortality. However, there is growing evidence that "lone" atrial fibrillation (AF) is a "heterogeneous" disorder with varying risk for thromboembolism based on the patient's underlying cardiovascular risk factors. Blood biomarkers, including markers of myocardial strain, inflammation, endothelial injury, platelet activation, and hypercoagulability, have potential to improve our risk stratification and management of LAF. Currently, there is a paucity of data on biomarkers in strictly defined LAF. The majority of studies that aimed to study lone atrial fibrillation excluded patients with structural heart disease, but did not exclude patients with co-existing cardiovascular risk factors such as hypertension or diabetes mellitus. Moreover, many of the studies did not exclude patients based on age, thereby increasing the likelihood of including patients with cardiovascular co-morbidities. There are currently a limited number of studies aimed to investigate the role of biomarkers in true LAF. The results are conflicting as to whether these biomarkers are associated with LAF or stroke risk. Future studies enrolling patients with true LAF using strict definition are needed. Herein, we review our current knowledge of biomarkers in association with atrial fibrillation and LAF and discuss their potential clinical utility.

Explaining racial disparities in anticoagulation control: results from a study of patients at the Veterans Administration.

Higher rates of stroke, major hemorrhage, and death among black patients receiving warfarin, compared with white patients, is likely related to poorer anticoagulation control. The research team investigated patient-level and site-level factors that might account for this group difference. A summary measure of anticoagulation control (percent time in therapeutic range [TTR]), patient characteristics, and site-level process of care measures were obtained for 9572 black and 88 481 white patients at the Veterans Health Administration. The research team studied disparity in TTR adjusting for patient and site characteristics. Mean unadjusted TTR for black patients was 6.5% lower than for white patients (P<.001). After accounting for the younger age of blacks, greater degrees of medication use, hospitalization, poverty, living in the South, and 11 other patient characteristics, only 2.0% of this racial disparity persisted. Process of care measures had minimal additional effect. These findings may inform efforts to reduce this racial disparity in achieving good anticoagulation control.