Ezekowitz, Michael D.

AbstractBackgroundAn unmet need exists to reliably predict the risk of intracranial hemorrhage (ICH) in patients with atrial fibrillation (AF) treated with oral anticoagulants (OACs).HypothesisAn externally validated model improves ICH risk stratification.MethodsIndependent factors associated with ICH were identified by Cox proportional hazard modeling, using pooled data from the GARFIELD‐AF (Global Anticoagulant Registry in the FIELD‐Atrial Fibrillation) and ORBIT‐AF (Outcomes Registry for Better Informed Treatment of Atrial Fibrillation) registries. A predictive model was developed and validated by bootstrap sampling and by independent data from the Danish National Patient Register.ResultsIn the combined training data set, 284 of 53 878 anticoagulated patients had ICH over a 2‐year period (0.31 per 100 person‐years; 95% confidence interval [CI]: 0.28–0.35). Independent predictors of ICH included: older age, prior stroke or transient ischemic attack, concomitant antiplatelet (AP) use, and moderate‐to‐severe chronic kidney disease (CKD). Vitamin K antagonists (VKAs) were associated with a significantly higher risk of ICH compared with non‐VKA oral anticoagulants (NOACs) (adjusted hazard ratio: 1.61; 95% CI: 1.25–2.08; p = .0002). The ability of the model to discriminate individuals in the training set with and without ICH was fair (optimism‐corrected C‐statistic: 0.68; 95% CI: 0.65–0.71) and outperformed three previously published methods. Calibration between predicted and observed ICH probabilities was good in both training and validation data sets.ConclusionsAge, prior ischemic events, concomitant AP therapy, and CKD were important risk factors for ICH in anticoagulated AF patients. Moreover, ICH was more frequent in patients receiving VKA compared to NOAC. The new validated model is a step toward mitigating this potentially lethal complication.

Oral anticoagulants (OACs) are medications commonly used in patients with atrial fibrillation and other cardiovascular conditions. Both warfarin and direct oral anticoagulants are susceptible to drug-drug interactions (DDIs). DDIs are an important cause of adverse drug reactions and exact a large toll on the health care system. DDI for warfarin mainly involve moderate to strong inhibitors/inducers of cytochrome P450 (CYP) 2C9, which is responsible for the elimination of the more potent S-isomer of warfarin. However, inhibitor/inducers of CYP3A4 and CYP1A2 may also cause DDI with warfarin. Recognition of these precipitating agents along with increased frequency of monitoring when these agents are initiated or discontinued will minimize the impact of warfarin DDI. Direct oral anticoagulants are mainly affected by medications strongly affecting the permeability glycoprotein (P-gp), and to a lesser extent, strong CYP3A4 inhibitors/inducers. Dabigatran and edoxaban are affected by P-gp modulation. Strong inducers of CYP3A4 or P-gp should be avoided in all patients taking direct oral anticoagulant unless previously proven to be otherwise safe. Simultaneous strong CYP3A4 and P-gp inhibitors should be avoided in patients taking apixaban and rivaroxaban. Concomitant antiplatelet/anticoagulant use confers additive risk for bleeding, but their combination is unavoidable in many cases. Minimizing duration of concomitant anticoagulant/antiplatelet therapy as indicated by evidence-based clinical guidelines is the best way to reduce the risk of bleeding.

Antiarrhythmic drugs (AAD) play an important role in the management of arrhythmias. Drug interactions involving AAD are common in clinical practice. As AADs have a narrow therapeutic window, both pharmacokinetic as well as pharmacodynamic interactions involving AAD can result in serious adverse drug reactions ranging from arrhythmia recurrence, failure of device-based therapy, and heart failure, to death. Pharmacokinetic drug interactions frequently involve the inhibition of key metabolic pathways, resulting in accumulation of a substrate drug. Additionally, over the past 2 decades, the P-gp (permeability glycoprotein) has been increasingly cited as a significant source of drug interactions. Pharmacodynamic drug interactions involving AADs commonly involve additive QT prolongation. Amiodarone, quinidine, and dofetilide are AADs with numerous and clinically significant drug interactions. Recent studies have also demonstrated increased morbidity and mortality with the use of digoxin and other AAD which interact with P-gp. QT prolongation is an important pharmacodynamic interaction involving mainly Vaughan-Williams class III AAD as many commonly used drug classes, such as macrolide antibiotics, fluoroquinolone antibiotics, antipsychotics, and antiemetics prolong the QT interval. Whenever possible, serious drug-drug interactions involving AAD should be avoided. If unavoidable, patients will require closer monitoring and the concomitant use of interacting agents should be minimized. Increasing awareness of drug interactions among clinicians will significantly improve patient safety for patients with arrhythmias.

Background. Oral anticoagulation therapy (OAC) reduces the risk of thromboembolic events associated with atrial fibrillation (AF), yet a substantial proportion of patients with AF are not prescribed OAC. The frequencies of and factors associated with contraindications to OAC therapy in clinical practice are not well-described. Methods. We used data from the ORBIT-AF study, a national, prospective, outpatient registry of incident and prevalent AF. OAC contraindications were uniformly collected at study enrollment by site personnel. Patient and provider characteristics were compared between participants with documented OAC contraindications at baseline and those without OAC contraindications. Results. From June 2010 to August 2011, 10124 patients ≥18 years old with electrocardiographically documented AF were enrolled at 176 practices. Of these, 1409 (13.9%) had OAC contraindications documented at the baseline visit: prior bleed (26.2%), patient refusal/preference (26.0%), high bleeding risk (22.6%), frequent falls/frailty (16.6%), other (11.9%), need for dual antiplatelet therapy (9.8%), unable to adhere/monitor warfarin (5.7%), comorbid illness (5.0%), prior intracranial hemorrhage (4.7%), allergy (2.3%), occupational risk (0.8%), and pregnancy (0.2%). Compared to patients without contraindications, those with contraindications had higher stroke risk (CHADS2>2) and were older, more likely to be female, more likely to be seen by a cardiologist and less likely to be seen by an electrophysiologist (Table 1). Among those patients with reported contraindications, 28.4% were taking warfarin. Conclusions. Contraindications to OAC therapy among AF patients are common and often due to high bleeding risk. Furthermore, many patients with reported contraindications are taking warfarin, suggesting that many contraindications to warfarin therapy are minor, relative, or temporary.

Introduction: Patient understanding of available therapies for atrial fibrillation (AF) is foundational to shared medical decision making and long term medication adherence. Yet, there is a paucity of data regarding the extent to which patients newly diagnosed with AF in routine community practice understand their options. Hypotheses: 1) Understanding of warfarin, novel oral anticoagulants (NOAC), rhythm control therapy, cardioversion and radio frequency ablation changes little from baseline to 6 months and 2) treatment rates at 6 months are associated with patient understanding of therapies at baseline. Methods: We analyzed survey data from SATELLITE, a substudy of new-onset AF patients enrolled at 56 US sites participating in the ORBIT-AF registry. Patients were surveyed at the baseline and 6 month follow up clinic visit using Likert scales. Agreement between time points was assessed with the McNemar test, and the relationship between understanding and treatment was assessed only for the subset not on treatment at baseline. Results: Of 1000 patients enrolled in SATELLITE, 506 had 6-month survey data (data collection is continuing). Among these, the median age was 69.0 years (IQR 63.0 - 76.0) and 93.7% (474 of 506) were white. There was evidence of improvement in the self-reported understanding of warfarin and NOACs from baseline to 6 months, but not for rhythm control, ablation or cardioversion. The proportion reporting high understanding improved significantly for warfarin (p<.0001) and NOACs (p<.0001) from 47% (223 of 474) and 51% (245 of 481) at baseline to 60% (284 of 474) and 69% (332 of 481) at 6 months respectively (Figure 1). Patients with high understanding of the benefits of ablation (p=0.0005) and options for ablation (p=0.0093) at baseline were more likely to have this therapy at the 6 month follow up (N=590), but improved understanding was not associated with increased use of warfarin/NOACs (N=83) or rhythm control (N=444). Conclusions: Patients with new-onset AF had improved self-reported understanding of some treatment options over the first 6-months from diagnosis; however, factors other than patient understanding may influence AF treatments received at 6 months. Patient understanding of AF treatments remains suboptimal at 6 months, and our results suggest a need for ongoing patient education.

Objectives Growth differentiation factor 15 (GDF-15) is a biomarker independently associated with bleeding and death in anticoagulated patients with atrial fibrillation (AF). GDF-15 is also used as one component in the more precise biomarker-based ABC (age, biomarkers, clinical history)-AF-bleeding and ABC-AF-death risk scores. Data from large trials indicate a geographic variability in regard to overall outcomes, including bleeding and mortality risk. Our aim was to assess the consistency of the association between GDF-15, ABC-AF-bleeding score and ABC-AF-death score, with major bleeding and death, across world geographic regions. Methods Data were available from 14 767 patients with AF from the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial and 8651 patients with AF from the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial in this cohort study. GDF-15 was analysed from plasma samples obtained at randomisation. The geographical consistency of the associations between outcomes and GDF-15, ABC-AF-bleeding score and ABC-AF-death scores were assessed by Cox-regression models including interactions with predefined geographical region. Results GDF-15 and the ABC-AF-bleeding score were associated with major bleeding in both trials across regions (p<0.0001). Similarly, GDF-15 and the ABC-AF-death score were associated with all-cause mortality in both trials across regions (p<0.0001). Overall, the association between GDF-15, the ABC-AF-bleeding score and ABC-AF-death risk score with major bleeding and death was consistent across regions in both ARISTOTLE and the RE-LY trial cohorts. The ABC-AF-bleeding and ABC-AF-death risk scores were consistent regarding discriminative ability when comparing geographic regions in both trial cohorts. The C-indices ranged from 0.649 to 0.760 for the ABC-AF-bleeding and from 0.677 to 0.806 for the ABC-AF-death score by different geographic regions. Conclusions In patients with AF on anticoagulation, GDF-15 and the biomarker-based ABC-AF-bleeding and ABC-AF-death risk scores are consistently associated with respectively increased risk of major bleeding and death and have similar prognostic value across world geographic regions. Trial registration number ClinicalTrials.gov Registry NCT00412984 and NCT00262600.

Background Cardioversion is common among patients with atrial fibrillation (AF). We hypothesised that novel oral anticoagulants (NOAC) used in clinical practice resulted in similar rates of stroke compared with vitamin K antagonists (VKA) for cardioversion. Methods Using the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation II, patients with AF who had a cardioversion, follow-up data and an AF diagnosis within 6 months of enrolment were identified retrospectively. Clinical outcomes were compared for patients receiving a NOAC or VKA for 1 year following cardioversion. Results Among 13 004 patients with AF, 2260 (17%) underwent cardioversion. 1613 met the inclusion criteria for this analysis. At the time of cardioversion, 283 (17.5%) were receiving a VKA and 1330 (82.5%) a NOAC. A transoesophageal echocardiogram (TOE) was performed in 403 (25%) cardioversions. The incidence of stroke/transient ischaemic attack (TIA) at 30 days was the same for patients having (3.04 per 100 patient-years) or not having (3.04 per 100 patient-years) a TOE (p=0.99). There were no differences in the incidence of death (HR 1.19, 95% CI 0.62 to 2.28, p=0.61), cardiovascular hospitalisation (HR 1.02, 95% CI 0.76 to 1.35, p=0.91), stroke/TIA (HR 1.18, 95% CI 0.30 to 4.74, p=0.81) or bleeding-related hospitalisation (HR 1.29, 95% CI 0.66 to 2.52, p=0.45) at 1 year for patients treated with either a NOAC or VKA. Conclusions Cardioversion was a low-risk procedure for patients treated with NOAC, and there were statistically similar rates of stroke/TIA 30 days after cardioversion as for patients treated with VKA. There were no statically significant differences in death, stroke/TIA or major bleeding at 1 year among patients treated with NOAC compared with VKA after cardioversion.

Abstract Aims To determine the extent of shared decision-making (SDM), during selection of oral anticoagulant (OAC) and rhythm control treatments, in patients with newly diagnosed atrial fibrillation (AF). Methods and results We evaluated survey data from 1006 patients with new-onset AF enrolled at 56 US sites participating in the SATELLITE substudy of the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT II). Patients completed surveys at enrolment and at 6-month follow-up. Patients were asked about who made their AF treatment decisions. Shared decision-making was classified as one that the patient felt was an autonomous decision or a shared decision with their healthcare provider (HCP). Approximately half of patients reported that their OAC treatment decisions were made entirely by their HCP. Compared with those reporting no SDM, patients reporting SDM for OAC were more often female (47.2% vs. 38.4%), while patients reporting SDM for rhythm control were more often male (62.2% vs. 57.6%). The most important factors cited by patients during decision-making for OAC were reducing stroke and bleeding risk, and their HCP’s recommendations. After adjustment, patients with self-reported understanding of OAC, and rhythm control options, had higher odds of having participated in SDM [odds ratio (OR) 2.54, confidence interval (CI): 1.75–3.68 and OR 2.36, CI: 1.50–3.71, both P ≤ 0.001, respectively]. Conclusion Shared decision-making is not widely implemented in contemporary AF practice. Patient understanding about available therapeutic options is associated with a more than a two-fold higher likelihood of SDM, and may be a potential target for future interventions.

Background: Atrial fibrillation (AF) adversely impacts health-related quality of life (hrQoL). While some patients demonstrate improvements in hrQoL, the factors associated with large improvements in hrQoL are not well described. Methods: We assessed factors associated with a 1-year increase in the Atrial Fibrillation Effect on Quality-of-Life score of 1 SD (≥18 points; 3× clinically important difference), among outpatients in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation I registry. Results: Overall, 28% (181/636) of patients had such a hrQoL improvement. Compared with patients not showing large hrQoL improvement, they were of similar age (median 73 versus 74, P =0.3), equally likely to be female (44% versus 48%, P =0.3), but more likely to have newly diagnosed AF at baseline (18% versus 8%; P =0.0004), prior antiarrhythmic drug use (52% versus 40%, P =0.005), baseline antiarrhythmic drug use (34.8% versus 26.8%, P =0.045), and more likely to undergo AF-related procedures during follow-up (AF ablation: 6.6% versus 2.0%, P =0.003; cardioversion: 12.2% versus 5.9%, P =0.008). In multivariable analysis, a history of alcohol abuse (adjusted OR, 2.41; P =0.01) and increased baseline diastolic blood pressure (adjusted OR, 1.23 per 10-point increase and >65 mm Hg; P =0.04) were associated with large improvements in hrQoL at 1 year, whereas patients with prior stroke/transient ischemic attack, chronic obstructive pulmonary disease, and peripheral arterial disease were less likely to improve ( P <0.05 for each). Conclusions: In this national registry of patients with AF, potentially treatable AF risk factors are associated with large hrQoL improvement, whereas less reversible conditions appeared negatively associated with hrQoL improvement. Understanding which patients are most likely to have large hrQoL improvement may facilitate targeting interventions for high-value care that optimizes patient-reported outcomes in AF. Registration: URL: http://www.clinicaltrials.gov . Unique identifier: NCT01165710.

Objective Non-vitamin K oral anticoagulants (NOACs) require dose adjustment for renal function. We sought to investigate change in renal function over time in patients with atrial fibrillation (AF) and whether those on NOACs have appropriate dose adjustments according to its decline. Methods We included patients with AF enrolled in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation II registry treated with oral anticoagulation. Worsening renal function (WRF) was defined as a decrease of >20% in creatinine clearance (CrCl) from baseline. The US Food and Drug Administration (FDA)-approved package inserts were used to define the reduction criteria of NOACs dosing. Results Among 6682 patients with AF from 220 sites (median age (25th, 75th): 72.0 years (65.0, 79.0); 57.1% male; median CrCl at baseline: 80.1 mL/min (57.4, 108.5)), 1543 patients (23.1%) experienced WRF with mean decline in CrCl during 2 year follow-up of −6.63 mL/min for NOACs and −6.16 mL/min for warfarin. Among 4120 patients on NOACs, 154 (3.7%) patients had a CrCl decline sufficient to warrant FDA-recommended dose reductions. Of these, NOACs dosing was appropriately reduced in only 31 (20.1%) patients. Compared with patients with appropriately reduced NOACs, those without were more likely to experience bleeding complications (major bleeding: 1.7% vs 0%; bleeding hospitalisation: 2.6% vs 0%) at 1 year. Conclusions In the US practice, about one-fourth of patients with AF had >20% decline in CrCl over time during 2 year follow-up. As a result, about 3.7% of those treated with NOACs met guideline criteria for dose reduction, but of these, only 20.1% actually had a reduction.