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Objectives: A history of gastrointestinal bleeding (GIB) in patients with atrial fibrillation (AF) may impact decisions about anticoagulation treatment. We sought to determine whether prior GIB in patients with AF taking anticoagulants was associated with an increased risk of stroke or major hemorrhage., Methods: We analyzed key efficacy and safety outcomes in patients with prior GIB in ARISTOTLE. Centrally adjudicated outcomes according to GIB history were analyzed using Cox proportional hazards models adjusted for randomized treatment and established risk factors., Results: A total of 784 (4.3%) patients had prior GIB events (321 [41%] lower, 463 [59%] upper); 215 (27%) occurred <1 year before study enrollment. Patients with prior GIB were older, had more comorbidities, and higher CHADS 2 and HAS-BLED scores than those with no GIB. Major GIB occurred more frequently in those with prior GIB (lower: aHR 1.72, 95% CI 0.86-3.42; upper: aHR 3.13, 95% CI 1.97-4.96). This association with major GIB was more pronounced in patients with GIB <1 year before randomization versus no recent GIB (recent lower: aHR 2.58, 95% CI 0.95-7.01; recent upper: aHR 5.16, 95% CI 2.66-10.0). There was no association between prior GIB and risk of stroke/systemic embolism or all-cause death. In those with prior GIB, the apixaban versus warfarin relative risks for stroke/systemic embolism, hemorrhagic stroke, death, or major bleeding were consistent with the results of the overall trial., Conclusions: In patients with AF on oral anticoagulants, prior GIB was associated with an increased risk of subsequent major GIB but not stroke, intracranial bleeding, or all-cause mortality. For the key outcomes of stroke, hemorrhagic stroke, death, and major bleeding, we found no evidence that the treatment effect (apixaban vs. warfarin) was modified by a history of GIB., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: The use of nonsteroidal anti-inflammatory drugs (NSAIDs) with oral anticoagulants has been associated with an increased risk of bleeding. We investigated the risk of bleeding and major cardiovascular outcomes in patients with atrial fibrillation taking NSAIDs and apixaban or warfarin., Methods: The ARISTOTLE trial (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation; n=18 201) compared apixaban with warfarin in patients with atrial fibrillation at an increased risk of stroke. Patients in ARISTOTLE without severe renal (creatine clearance ≤30 mL/min) or liver disease were included in this analysis (n=17 423). NSAID use at baseline, NSAID use during the trial (incident NSAID use), and never users were described. The primary outcome was major bleeding. Secondary outcomes included clinically relevant nonmajor bleeding, gastrointestinal bleeding, heart failure hospitalization, stroke or systemic embolism, and all-cause mortality. NSAID use during the trial, and the interaction between randomized treatment, was analyzed using time-dependent Cox proportional hazards models., Results: Those with baseline NSAID use (n=832 [4.8%]), incident NSAID use (n=2185 [13.2%]), and never users were similar in median age (age [25th, 75th]; 70 [64, 77] versus 70 [63, 75] versus 70 [62, 76]). Those with NSAID use at baseline and incident NSAID use were more likely to have a history of bleeding than never users (24.5% versus 21.0% versus 15.6%, respectively). During a median follow-up (25th, 75th) of 1.8 (1.4, 2.3) years and when excluding those taking NSAID at baseline, we found that incident NSAID use was associated with an increased risk of major bleeding (hazard ratio [HR], 1.61 [95% CI, 1.11-2.33]) and clinically relevant nonmajor bleeding (HR, 1.70 [95% CI, 1.16-2.48]), but not gastrointestinal bleeding. No significant interaction was observed between NSAID use and randomized treatment for any outcome., Conclusions: A substantial number of patients in the ARISTOTLE trial took NSAIDs. Incident NSAID use was associated with major and clinically relevant nonmajor bleeding, but not with gastrointestinal bleeding. The safety and efficacy of apixaban versus warfarin appeared not significantly to be altered by NSAID use. This study warrants more investigation of the effect of NSAIDs on the outcomes of patients treated with apixaban., Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00412984.

Background: The purpose of the study was to examine the association between the type of preceding oral anticoagulant use (warfarin or direct oral anticoagulants [DOACs]) and in-hospital mortality among patients admitted with gastrointestinal bleeding., Methods: In this observational cohort study, all patients admitted with a first-time gastrointestinal bleeding from January 2011 to March 2017 while receiving any oral anticoagulant therapy prior to admission were identified using data from Danish nationwide registries. The risk of in-hospital mortality according to type of oral anticoagulation therapy was examined by multivariable logistic regression models., Results: Among 5,774 patients admitted with gastrointestinal bleeding (median age, 78 years [25th-75th percentile, 71-85 years]; 56.8% men), 2,038 (35.3%) were receiving DOACs and 3,736 (64.7%) were receiving warfarin prior to admission. The unadjusted in-hospital mortality rates were 7.5% for DOAC (7.2% for dabigatran, 6.4% for rivaroxaban, and 10.1% for apixaban) and 6.5% for warfarin. After adjustment for baseline demographic and clinical characteristics, there was no statistically significant difference in in-hospital mortality between prior use of any DOAC and warfarin (unadjusted odds ratio [OR] 1.18 [95% CI 0.95-1.45], adjusted OR 0.97 [95% CI 0.77-1.24]). Similar results were found for each individual DOAC as compared with warfarin (dabigatran: unadjusted OR 1.12 [95% CI 0.84-1.49], adjusted OR 0.96 [95% CI 0.71-1.30]); rivaroxaban: unadjusted OR 0.98 [95% CI 0.71-1.37], adjusted OR 0.84 [95% CI 0.59-1.21]; and apixaban: unadjusted OR 1.62 [95% CI 0.84-1.49], adjusted OR 1.22 [95% CI 0.83-1.79])., Conclusions: Among patients admitted with gastrointestinal bleeding, there was no statistically significant difference in in-hospital mortality between prior use of DOAC and warfarin., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Direct oral anticoagulants (DOACs) are surpassing warfarin as the anticoagulant of choice for stroke prevention in nonvalvular atrial fibrillation. DOAC outcomes in elective periprocedural settings have not been well elucidated and remain a source of concern for clinicians. The aim of this meta-analysis was to evaluate the periprocedural safety and efficacy of DOACs versus warfarin in patients with nonvalvular atrial fibrillation., Methods: We reviewed the literature for data from phase III randomized controlled trials comparing DOACs with warfarin in the periprocedural period among patients with nonvalvular atrial fibrillation. Substudies from 4 trials (RE-LY [Randomized Evaluation of Long-Term Anticoagulation Therapy], ROCKET AF [Rivaroxaban Once Daily Oral Direct Factor Xa Inhibitor Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation], ARISTOTLE [Apixaban for the Prevention of Stroke in Subjects With Atrial Fibrillation], and ENGAGE-AF [Effective Anticoagulation With Factor xA Next Generation in Atrial Fibrillation]) were included in the meta-analysis. DOACs as a group and warfarin were compared in terms of the 30-day pooled risk for stroke/systemic embolism, major bleeding, and death, according to whether the study drug was interrupted or not periprocedurally. The overall relative risk (RR) was estimated with a random-effects model. The I 2 test was used to assess heterogeneity in RR among the studies., Results: In the uninterrupted anticoagulant strategy, there were no differences in the rates of stroke/systemic embolism (pooled risk, 0.6% [29 events/4519 procedures] versus 1.1% [31/2971]; RR, 0.70; 95% confidence interval [CI], 0.41-1.18) and death (1.4% versus 1.8%; RR, 0.77; 95% CI, 0.53-1.12) between DOACs and warfarin and significantly fewer major bleeding events (2.0% versus 3.3%; RR, 0.62; 95% CI, 0.47-0.82) with DOACs compared to warfarin. Under an interrupted strategy, there was no significant difference between DOACs versus warfarin for stroke/systemic embolism (0.4% [41/9260] versus 0.5% [31/7168]; RR, 0.95; 95% CI, 0.59-1.55), major bleeding (2.1% versus 2.0%; RR, 1.05; 95% CI, 0.85-1.30), and death (0.7% versus 0.6%; RR, 1.24; 95% CI, 0.76-2.04). The studies were homogeneous ( I 2 =0.0%) for all calculated pooled associations except for the RR of death in the interrupted strategy ( I 2 =26.3%)., Conclusions: The short-term safety and efficacy of DOACs and warfarin are not different in patients with nonvalvular atrial fibrillation periprocedurally. Under an uninterrupted anticoagulation strategy, DOACs are associated with a 38% lower risk of major bleeding compared with warfarin.

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., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Tecarfarin is a novel vitamin K antagonist that is metabolised by carboxyl estererase, thereby eliminating the variability associated with cytochrome-mediated metabolism. EmbraceAC was designed to compare the quality of anticoagulation with tecarfarin and warfarin as determined by time in therapeutic range (TTR). In this phase 2/3 randomised and blinded trial, 607 patients with indications for chronic anticoagulation were assigned to warfarin (n=304) or tecarfarin (n=303). Dosing of study drugs was managed by a centralised dose control centre, which had access to genotyping. The primary analysis tested superiority of tecarfarin over warfarin for TTR. Patients were recruited between May 12, 2008 and May 12, 2009. TTR with tecarfarin and warfarin were similar (72.3 % and 71.5 %, respectively; p=0.51). In those taking CYP2C9 interacting drugs, the TTR on tecarfarin (n=92) was similar to that on warfarin (n=87, 72.2 % and 69.9 %, respectively; p=0.15). In patients with mechanical heart valves, the TTR of tecarfarin (n=42) was similar to that of warfarin (n=42, 68.4 % and 66.3 %, respectively; p=0.51). The same was true for the TTR in patients with any CYP2C9 variant allele and on CYP2C9-interacting drugs (tecarfarin, n=24, 76.5 % vs warfarin, n=31, 69.5 %; p=0.09). There was no difference in thromboembolic or bleeding events. In conclusion, superiority of tecarfarin over warfarin for TTR was not demonstrated. The TTR with tecarfarin was similar to that with well-controlled warfarin and tecarfarin appeared to be safe and well tolerated with few major bleeding and no thrombotic events. Favourable trends in certain subpopulations make tecarfarin a promising oral anticoagulant that deserves further study.

Background: Whether and when to resume oral anticoagulant therapy for patients who survive warfarin-related intracranial hemorrhage (ICH) remains a dilemma lacking consensus recommendations and high-quality evidence to guide clinical decision making., Objective: To determine the incidences of recurrent ICH, thrombosis, and death in relation to resumption or non-resumption of warfarin therapy during the 365 days after incident ICH., Methods: We conducted a retrospective cohort study of adult patients in an integrated healthcare delivery system who were receiving warfarin therapy at the time of incident (index) ICH between 1/1/2000 and 12/31/2007 and survived to hospital discharge. The primary outcomes were recurrent ICH, thrombosis (stroke, systemic embolism, and venous thromboembolism), and all-cause mortality during the 365 days following index ICH. Patients were assigned to one of two groups defined by warfarin therapy resumption after the index ICH., Results: There were 160 patients discharged from the hospital following warfarin-related index ICH; of these 54 (33.8%) resumed warfarin therapy and 106 (66.2%) did not. Recurrent ICH occurred in a numerically greater, but statistically non-significant, proportion of patients who did not resume warfarin therapy (7.6% vs. 3.7%, p=0.497). Similarly, patients who did not resume warfarin had a three-fold higher (12.3% vs. 3.7%, p=0.092) and approximately two-fold higher (31.1% vs. 18.5%, p=0.089) rates of thrombosis and all-cause mortality, respectively, during follow up., Conclusion: Resumption of warfarin therapy following warfarin-associated ICH appeared not to be associated with increased risk of recurrent ICH but trended toward reduced thrombosis and all-cause mortality., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Using data from ARISTOTLE, we describe the periprocedural management of anticoagulation and rates of subsequent clinical outcomes among patients chronically anticoagulated with warfarin or apixaban. We recorded whether (and for how long) anticoagulant therapy was interrupted preprocedure, whether bridging therapy was used, and the proportion of patients who experienced important clinical outcomes during the 30 days postprocedure. Of 10 674 procedures performed during follow-up in 5924 patients, 9260 were included in this analysis. Anticoagulant treatment was not interrupted preprocedure 37.5% of the time. During the 30 days postprocedure, stroke or systemic embolism occurred after 16/4624 (0.35%) procedures among apixaban-treated patients and 26/4530 (0.57%) procedures among warfarin-treated patients (odds ratio [OR] 0.601; 95% confidence interval [CI] 0.322-1.120). Major bleeding occurred in 74/4560 (1.62%) procedures in the apixaban arm and 86/4454 (1.93%) in the warfarin arm (OR 0.846; 95% CI 0.614-1.166). The risk of death was similar with apixaban (54/4624 [1.17%]) and warfarin (49/4530 [1.08%]) (OR 1.082; 95% CI 0.733-1.598). Among patients in ARISTOTLE, the 30-day postprocedure stroke, death, and major bleeding rates were low and similar in apixaban- and warfarin-treated patients, regardless of whether anticoagulation was stopped beforehand. Our findings suggest that many patients on chronic anticoagulation can safely undergo procedures; some will not require a preprocedure interruption of anticoagulation. ARISTOTLE was registered at www.clinicaltrials.gov as #NCT00412984., (© 2014 by The American Society of Hematology.)

Aims: The risk of stroke in patients with atrial fibrillation (AF) increases with age. In the ARISTOTLE trial, apixaban when compared with warfarin reduced the rate of stroke, death, and bleeding. We evaluated these outcomes in relation to patient age., Methods and Results: A total of 18 201 patients with AF and a raised risk of stroke were randomized to warfarin or apixaban 5 mg b.d. with dose reduction to 2.5 mg b.d. or placebo in 831 patients with ≥2 of the following criteria: age ≥80 years, body weight ≤60 kg, or creatinine ≥133 μmol/L. We used Cox models to compare outcomes in relation to patient age during 1.8 years median follow-up. Of the trial population, 30% were <65 years, 39% were 65 to <75, and 31% were ≥75 years. The rates of stroke, all-cause death, and major bleeding were higher in the older age groups (P < 0.001 for all). Apixaban was more effective than warfarin in preventing stroke and reducing mortality across all age groups, and associated with less major bleeding, less total bleeding, and less intracranial haemorrhage regardless of age (P interaction >0.11 for all). Results were also consistent for the 13% of patients ≥80 years. No significant interaction with apixaban dose was found with respect to treatment effect on major outcomes., Conclusion: The benefits of apixaban vs. warfarin were consistent in patients with AF regardless of age. Owing to the higher risk at older age, the absolute benefits of apixaban were greater in the elderly., (© The Author 2014. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Objectives: The aim of this study was to determine the risk of major clinical and thromboembolic events after cardioversion for atrial fibrillation in subjects treated with apixaban, an oral factor Xa inhibitor, compared with warfarin., Background: In patients with atrial fibrillation, thromboembolic events may occur after cardioversion. This risk is lowered with vitamin K antagonists and dabigatran., Methods: Using data from the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial, we conducted a post-hoc analysis of patients undergoing cardioversion., Results: A total of 743 cardioversions were performed in 540 patients: 265 first cardioversions in patients assigned to apixaban and 275 in those assigned to warfarin. The mean time to the first cardioversion for patients assigned to warfarin and apixaban was 243 ± 231 days and 251 ± 248 days, respectively; 75% of the cardioversions occurred by 1 year. Baseline characteristics were similar between groups. In patients undergoing cardioversion, no stroke or systemic emboli occurred in the 30-day follow-up period. Myocardial infarction occurred in 1 patient (0.2%) receiving warfarin and 1 patient receiving apixaban (0.3%). Major bleeding occurred in 1 patient (0.2%) receiving warfarin and 1 patient receiving apixaban (0.3%). Death occurred in 2 patients (0.5%) receiving warfarin and 2 patients receiving apixaban (0.6%)., Conclusions: Major cardiovascular events after cardioversion of atrial fibrillation are rare and comparable between warfarin and apixaban. (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation [ARISTOTLE]; NCT00412984)., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Importance: The effect of antibiotic coadministration on the international normalized ratio (INR) in a relatively stable, real-world warfarin population has not been adequately described. Case reports and studies of healthy volunteers do not account for the potential contribution of acute illness to INR variability., Objective: To compare the risk of excessive anticoagulation among patients with stable warfarin therapy purchasing an antibiotic (antibiotic group) with the risk in patients purchasing a warfarin refill (stable controls) and patients with upper respiratory tract infection but not receiving an antibiotic (sick controls)., Design, Setting, and Participants: A retrospective, longitudinal cohort study evaluated patients receiving warfarin between January 1, 2005, and March 31, 2011, at Kaiser Permanente Colorado, an integrated health care delivery system. Continuous data were expressed as mean (SD) or median (interquartile range). Multivariable logistic regression analysis was used to identify factors independently associated with a follow-up INR of 5.0 or more. A total of 5857 (48.8%), 5579 (46.5%), and 570 (4.7%) patients were included in the antibiotic, stable control, and sick control groups, respectively. Mean age was 68.3 years, and atrial fibrillation was the most common (44.4%) indication for anticoagulation., Exposures: Warfarin therapy with a medical visit for upper respiratory tract infection or coadministration of antibiotics., Main Outcomes and Measures: Primary outcomes were the proportion of patients experiencing a follow-up INR of 5.0 or more and change between the last INR measured before the index date and the follow-up INR., Results: The proportion of patients experiencing an INR of 5.0 or more was 3.2%, 2.6%, and 1.2% for the antibiotic, sick, and stable groups, respectively (P < .001, antibiotic vs stable control group; P < .017, sick vs stable control group; P = .44, antibiotic vs sick control group). Cancer diagnosis, elevated baseline INR, and female sex predicted a follow-up INR of 5.0 or more. Among antibiotics, those interfering with warfarin metabolism posed the greatest risk for an INR of 5.0 or more., Conclusions and Relevance: Acute upper respiratory tract infection increases the risk of excessive anticoagulation independent of antibiotic use. Antibiotics also increase the risk; however, most patients with previously stable warfarin therapy will not experience clinically relevant increases in INR following antibiotic exposure or acute upper respiratory tract infection.

Background: Patients with atrial fibrillation who are vitamin K antagonist (VKA)-naive may have a higher risk of thrombosis and/or bleeding than VKA-experienced patients., Methods and Results: Using data from ARISTOTLE, we assessed baseline characteristics and the treatment effect of apixaban versus warfarin in the VKA-naive and VKA-experienced cohorts. We compared rates of study drug discontinuation and time-in-therapeutic range. Overall, 7,800 (43%) were VKA naive, and 10,401 were VKA experienced. At baseline, both groups were similar with respect to age and congestive heart failure, hypertension, age, diabetes, stroke score (CHADS2). Fewer VKA-naive patients had a history of prior stroke (18% vs 21%) or prior bleeding (10% vs 22%) and were more often female (39% vs 33%). The effect of apixaban on the primary efficacy and safety outcomes was similar in VKA-naive (stroke/systemic embolism: hazard ratio [HR] 0.86, 95% CI 0.67-1.11 and major bleeding: HR 0.73, 95% CI 0.59-0.91) and VKA-experienced populations (stroke/systemic embolism: HR 0.73, 95% CI 0.57-0.95, P value for interaction = 0.39 and major bleeding: HR 0.66, 95% CI 0.55-0.80, P value for interaction = 0.50). Permanent study drug discontinuation was numerically less likely in patients receiving apixaban whether they were VKA naive (HR for discontinuation: 0.87, 95% CI 0.79-0.95) or VKA experienced (HR for discontinuation: 0.93, 95% CI 0.85-1.02). Among patients receiving warfarin, the mean/median times in therapeutic range were lower in the VKA-naive group (VKA-naive: 57.5/61.4, VKA-experienced: 66.0/69.1, P < .001)., Conclusion: The treatment effects of apixaban (vs warfarin) were not modified by VKA naivety. The rates of stroke/systemic embolism and major bleeding were numerically lower among the patients assigned to apixaban, irrespective of prior VKA use., (Copyright © 2013 Mosby, Inc. All rights reserved.)

Aims: It is uncertain whether the benefit from apixaban varies by type and duration of atrial fibrillation (AF)., Methods and Results: A total of 18 201 patients with AF [2786 (15.3%) with paroxysmal and 15 412 (84.7%) with persistent or permanent] were randomized to apixaban or warfarin. In this pre-specified secondary analysis, we compared outcomes and treatment effect of apixaban vs. warfarin by AF type and duration. The primary efficacy endpoint was a composite of ischaemic or haemorrhagic stroke or systemic embolism. The secondary efficacy endpoint was all-cause mortality. There was a consistent reduction in stroke or systemic embolism (P for interaction = 0.71), all-cause mortality (P for interaction = 0.75), and major bleeding (P for interaction = 0.50) with apixaban compared with warfarin for both AF types. Apixaban was superior to warfarin in all studied endpoints, regardless of AF duration at study entry (P for all interactions >0.13). The rate of stroke or systemic embolism was significantly higher in patients with persistent or permanent AF than patients with paroxysmal AF (1.52 vs. 0.98%; P = 0.003, adjusted P = 0.015). There was also a trend towards higher mortality in patients with persistent or permanent AF (3.90 vs. 2.81%; P = 0.0002, adjusted P = 0.066)., Conclusion: The risks of stroke, mortality, and major bleeding were lower with apixaban than warfarin regardless of AF type and duration. Although the risk of stroke or systemic embolism was lower in paroxysmal than persistent or permanent AF, apixaban is an attractive alternative to warfarin in patients with AF and at least one other risk factor for stroke, regardless of the type or duration of AF.

Introduction: This study tests the hypothesis that nonadherence with INR monitoring is associated with an increased risk for warfarin-related bleeding and thrombosis and describes patient characteristics associated with INR monitoring nonadherence., Materials and Methods: This was a retrospective, longitudinal, matched cohort study wherein patients were categorized into adherent and nonadherent cohorts; adherent patients were matched 2:1 to nonadherent patients. The primary study endpoint was the first occurrence of bleeding or thromboembolism. Multivariate logistic regression modeling identified patient characteristics associated with INR monitoring adherence or nonadherence., Results: A total of 4995 and 2544 patients contributed 10729 and 5385 patient-years of warfarin therapy in the adherent and nonadherent groups, respectively. The rate of thromboembolic events during follow up was higher in the nonadherent group than in the adherent group (0.95% vs. 0.62% per patient-year, respectively; p=0.019) and nonadherence to INR monitoring was associated with a moderately higher risk of thromboembolism (adjusted Hazard Ratio=1.51; 95% confidence interval=1.04 - 2.20). The difference in bleeding between the two groups was not statistically significant., Conclusions: Repeatedly missing INR tests is an easily identified clinical parameter that is associated with moderately increased risk for thromboembolism in patients taking chronic warfarin therapy. Clinicians should carefully consider the underlying thromboembolic risk and extent of nonadherence when weighing the benefits of continued warfarin therapy for a given patient., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The second decade of the 21st century will be remembered as a significant milestone in the treatment and prevention of thromboembolic diseases. The approval of target-specific oral anticoagulants (TSOACs) means that patients with atrial fibrillation (AF) have, for the first time ever, multiple treatment options for the prevention of embolic stroke. Evidence from the landmark registration trials convincingly shows that the TSOACs are at least as safe and effective as warfarin in this setting. Because the new agents do not require routine coagulation monitoring and have very few drug or dietary interactions, they offer both convenience and, possibly, a public health benefit if they are used by patients who otherwise would have declined to take warfarin. However, patients on a highly stable, therapeutic dose of warfarin should not expect better health outcomes if switching to a TSOAC.

Introduction: Avoiding intracranial hemorrhage (ICH) during warfarin therapy is critical but little is known about factors that affect warfarin-related ICH outcomes. We aimed to define the impact of warfarin on ICH incidence rates and to identify baseline clinical characteristics of patients who experienced ICH and factors associated with fatal ICH., Materials and Methods: The primary outcome of this retrospective cohort study was the incident ICH rate per 10,000 person-years for patients receiving and not receiving warfarin therapy. Cox proportional hazards modeling was used to adjust for potential confounding factors in assessment of the association of warfarin with fatal ICH., Results: A total of 1348 patients with incident ICH, 259 (19%) who were receiving warfarin therapy, were included. The incident ICH rates were 74/10,000 (warfarin) and 5/10,000 (non-warfarin) person-years (p<0.001). Warfarin patients were older and carried a higher burden of chronic disease. The unadjusted hazard ratio (HR) for fatal ICH was 1.64 (95% confidence interval [CI] 1.31-2.05) for warfarin patients compared to non-warfarin patients. However, the HR was no longer significant after adjustment for confounding variables (1.10; 95% CI 0.84-1.42). An INR greater than 3.5 at presentation doubled the adjusted risk for fatal ICH with warfarin therapy. Subarachnoid and subdural ICHs were less likely to be fatal than other ICH types, and each year increase in age was associated with 4% increased risk of fatal ICH., Conclusions: Although warfarin use increases the rate of incident ICH, other factors impact the risk of fatal ICH, even among anticoagulated patients., (© 2013.)

Background: Patients who not only survive a warfarin-associated gastrointestinal tract bleeding (GIB) event but also have an ongoing risk for thromboembolism present 2 clinical dilemmas: whether and when to resume anticoagulation. The objective of this study was to determine the incidence of thrombosis, recurrent GIB, and death, as well as the time to resumption of anticoagulant therapy, during the 90 days following a GIB event., Methods: In this retrospective, cohort study using administrative and clinical databases, patients experiencing GIB during warfarin therapy were categorized according to whether they resumed warfarin therapy after GIB and followed up for 90 days. Variables describing the management and severity of the index GIB were also collected. Kaplan-Meier curves were constructed to estimate the survival function of thrombosis, recurrent GIB, and death between the "resumed warfarin therapy" and "did not resume warfarin therapy" groups, with Cox proportional hazards modeling to adjust for potentially confounding factors., Results: There were 442 patients with warfarin-associated index GIB included in the analyses. Following the index GIB, 260 patients (58.8%) resumed warfarin therapy. Warfarin therapy resumption after the index GIB was associated with a lower adjusted risk for thrombosis (hazard ratio [HR], 0.05; 95% CI, 0.01-0.58) and death (HR, 0.31; 95% CI, 0.15-0.62), without significantly increasing the risk for recurrent GIB (HR, 1.32; 95% CI, 0.50-3.57)., Conclusions: The decision to not resume warfarin therapy in the 90 days following a GIB event is associated with increased risk for thrombosis and death. For many patients who have experienced warfarin-associated GIB, the benefits of resuming anticoagulant therapy will outweigh the risks.

Ms TS is a 66-year-old woman who receives warfarin for prevention of systemic embolization in the setting of hypertension, diabetes, and atrial fibrillation. She had a transient ischemic attack about 4 years ago when she was receiving aspirin. Her INR control was excellent; however, over the past few months it has become erratic, and her average dose required to maintain an INR of 2.0 to 3.0 appears to have decreased. She has had back pain over this same period and has been taking acetaminophen at doses at large as 650 mg four times daily, with her dose varying based on her symptoms. You recall a potential interaction and wonder if (1) her acetaminophen use is contributing to her loss of INR control, and (2) does this interaction place her at increased risk of warfarin-related complications?

Background: Vitamin K antagonists are highly effective in preventing stroke in patients with atrial fibrillation but have several limitations. Apixaban is a novel oral direct factor Xa inhibitor that has been shown to reduce the risk of stroke in a similar population in comparison with aspirin., Methods: In this randomized, double-blind trial, we compared apixaban (at a dose of 5 mg twice daily) with warfarin (target international normalized ratio, 2.0 to 3.0) in 18,201 patients with atrial fibrillation and at least one additional risk factor for stroke. The primary outcome was ischemic or hemorrhagic stroke or systemic embolism. The trial was designed to test for noninferiority, with key secondary objectives of testing for superiority with respect to the primary outcome and to the rates of major bleeding and death from any cause., Results: The median duration of follow-up was 1.8 years. The rate of the primary outcome was 1.27% per year in the apixaban group, as compared with 1.60% per year in the warfarin group (hazard ratio with apixaban, 0.79; 95% confidence interval [CI], 0.66 to 0.95; P<0.001 for noninferiority; P=0.01 for superiority). The rate of major bleeding was 2.13% per year in the apixaban group, as compared with 3.09% per year in the warfarin group (hazard ratio, 0.69; 95% CI, 0.60 to 0.80; P<0.001), and the rates of death from any cause were 3.52% and 3.94%, respectively (hazard ratio, 0.89; 95% CI, 0.80 to 0.99; P=0.047). The rate of hemorrhagic stroke was 0.24% per year in the apixaban group, as compared with 0.47% per year in the warfarin group (hazard ratio, 0.51; 95% CI, 0.35 to 0.75; P<0.001), and the rate of ischemic or uncertain type of stroke was 0.97% per year in the apixaban group and 1.05% per year in the warfarin group (hazard ratio, 0.92; 95% CI, 0.74 to 1.13; P=0.42)., Conclusions: In patients with atrial fibrillation, apixaban was superior to warfarin in preventing stroke or systemic embolism, caused less bleeding, and resulted in lower mortality. (Funded by Bristol-Myers Squibb and Pfizer; ARISTOTLE ClinicalTrials.gov number, NCT00412984.).

Vitamin K antagtonists (VKAs) have, for decades, been the corner-stone of anticoagulation in the outpatient setting. While the long half life makes once daily administration practical, close monitoring of VKA effect is necessary because these medicines have a narrow therapeutic index. Despite inter-individual variations in response to VKA doses, the increasing availability of specialized anticoagulation monitoring systems, along with a better understanding of potential drug and dietary interactions, has made the use of VKAs safer and less burdensome. In the future, newer classes of oral anticoagulants and genomic-based dosing strategies may further expand or improve the management options for many patients at risk for thromboembolism., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The use of generic drugs has become increasingly common in clinical practice. However, for drugs with a narrow therapeutic index, such as warfarin, there may be some concern regarding the definition of bioequivalence. Clinical studies that compared brand name and generic warfarin products provided conflicting results. Therefore, we performed a systematic review of the literature to better assess the characteristics of each generic warfarin product. Several sources were searched, including MEDLINE and EMBASE, electronic records of meetings' abstracts, and reference lists of included articles. Articles were considered relevant if they were original studies, enrolled patients receiving oral anticoagulant treatment, and compared any approved generic warfarin with brand name warfarin in at least one clinical, laboratory, or management outcome. Eleven studies, with a total of more than 40,000 patients, were included; five were randomized controlled trials, and six were observational studies. In three crossover trials evaluating the mean difference of the international normalized ratio (INR) after switching to the alternate formulation of warfarin, no statistically significant difference was found between patients randomly assigned to receive brand name or generic warfarin. The two other randomized trials found no significant differences in the magnitude or number of dosage changes between patients switched to brand name or generic warfarin. The results of the observational studies are more conflicting, suggesting different features for different generic warfarin products. In these observational studies, the time in the therapeutic range and the number of thromboembolic and hemorrhagic complications were similar in studies that compared the anticoagulation control before and after the switch to a generic warfarin product. In one observational study, however, a change in therapeutic INR control after the switch to generic warfarin was reported at the individual patient level. The results of our systematic review suggest that generic warfarin products may be as safe and effective as brand name products and that patients may be safely treated with these products. However, closer monitoring may be reasonable when switching brands, as variations in individual INR response may be seen.

Atrial fibrillation is a common condition that increases the risk of stroke in many patients. Although warfarin has been shown to reduce the risk of stroke, many patients who might benefit from anticoagulation do not receive this therapy. Fear of bleeding is the most often cited reason. Several new anticoagulant medications are being studied to determine their efficacy and safety relative to warfarin. Unlike earlier trials that established the superiority of warfarin over placebo, recent trials in atrial fibrillation have enrolled a disproportionate number of patients already taking warfarin. This review suggests that the risk of both haemorrhage and stroke are highest when atrial fibrillation is newly diagnosed and during the initiation of anticoagulant medication. Randomised controlled trials designed to evaluate the safety and efficacy of new anti-thrombotic agents should include substantial numbers of patients without prior exposure to anticoagulation since these individuals are at the highest risk for bleeding and thromboembolism.

Unanticipated elevation of the INR is common in patients receiving warfarin. We performed a prospective cohort study of 107 warfarin-treated patients with INR values of more than 10 who received a single 2.5 mg dose of oral vitamin K. During the first week, one patient experienced major bleeding, and one died. In the first 90 days after enrolment four patients had major bleeding (3.7%, 1.0% to 9.3%), eight patients (7.5%, 3.3% to 14.2%) died and two had objectively confirmed thromboembolism. Based on our low rate of observed major bleeding we conclude that 2.5 mg of oral vitamin K is a reasonable treatment for patients with INR values of more than 10 who are not actively bleeding.

For patients on warfarin therapy, an international normalized ratio (INR) recall interval not exceeding 4 weeks has traditionally been recommended. Less frequent INR monitoring may be feasible in stable patients. We sought to identify patients with stable INRs (defined as having INR values exclusively within the INR range) and comparator patients (defined as at least one INR outside the INR range) in a retrospective, longitudinal cohort study. Occurrences of thromboembolism, bleeding, and death were compared between groups. Multivariate logistic regression models were used to identify independent predictors of stable INR control. There were 2504 stable and 3569 comparator patients. The combined rates of bleeding and thromboembolism were significantly lower in stable patients. Independent predictors of stable INR control were age older than 70 years and the absence of comorbid heart failure and diabetes. Stable patients were significantly less likely to have target INR of 3.0 or higher or chronic diseases. We hypothesize that many patients demonstrating stable INR control could be safely treated with INR recall intervals greater than the traditional 4 weeks.

Background: Genotype-guided initial warfarin dosing may reduce over-anticoagulation and serious bleeding compared to a one-dose-fits-all dosing method., Objective: The objective of this review was to investigate the safety and efficacy of genotype-guided dosing of warfarin in reducing the occurrence of serious bleeding events and over-anticoagulation., Data Sources: The authors searched PubMed, EMBASE and International Pharmaceutical Abstracts through January 23, 2009, without language restrictions. Selected articles were randomized trials comparing pharmacogenetic dosing of warfarin versus a "standard" dose control algorithm in adult patients taking warfarin for the first time., Review Methods: Two reviewers independently extracted data and assessed study quality using a validated instrument. The primary outcomes were major bleeding and time spent within the therapeutic range International Normalized Ratio (INR). Secondary outcomes included minor bleeding, thrombotic events and other measures of anticoagulation quality., Results: Three of 2,014 studies (423 patients) met the inclusion and exclusion criteria. Differences in study quality, dosing algorithms, length of follow-up and outcome measures limited meta-analysis. Summary estimates revealed no statistically significant difference in bleeding rates or time within the therapeutic range INR. The highest quality study found no significant difference in primary or secondary outcomes, although there was a trend towards more rapid achievement of a stable dose (14.1 vs. 19.6 days, p = 0.07) in the pharmocogenetic arm., Conclusions: We did not find sufficient evidence to support the use of pharmacogenetics to guide warfarin therapy. Additional clinical trials are needed to define the optimal approach to use warfarin pharmacogenetics in clinical practice.

Background: Low-dose oral vitamin K decreases the international normalized ratio (INR) in overanticoagulated patients who receive warfarin therapy. Its effects on bleeding events are uncertain., Objective: To see whether low-dose oral vitamin K reduces bleeding events over 90 days in patients with warfarin-associated coagulopathy., Design: Multicenter, randomized, placebo-controlled trial. Randomization was computer-generated, and participants were allocated to trial groups by using sequentially numbered study drug containers. Patients, caregivers, and those who assessed outcomes were blinded to treatment assignment., Setting: 14 anticoagulant therapy clinics in Canada, the United States, and Italy., Patients: Nonbleeding patients with INR values of 4.5 to 10.0., Intervention: Oral vitamin K, 1.25 mg (355 patients randomly assigned; 347 analyzed), or matching placebo (369 patients randomly assigned; 365 analyzed)., Measurements: Bleeding events (primary outcome), thromboembolism, and death (secondary outcomes)., Results: 56 patients (15.8%) in the vitamin K group and 60 patients (16.3%) in the placebo group had at least 1 bleeding complication (absolute difference, -0.5 percentage point [95% CI, -6.1 to 5.1 percentage points]); major bleeding events occurred in 9 patients (2.5%) in the vitamin K group and 4 patients (1.1%) in the placebo group (absolute difference, 1.5 percentage points [CI, -0.8 to 3.7 percentage points]). Thromboembolism occurred in 4 patients (1.1%) in the vitamin K group and 3 patients (0.8%) in the placebo group (absolute difference, 0.3 percentage point [CI, -1.4 to 2.0 percentage points]). Other adverse effects were not assessed. The day after treatment, the INR had decreased by a mean of 1.4 in the placebo group and 2.8 in the vitamin K group (P < 0.001)., Limitation: Patients who were actively bleeding were not included, and warfarin dosing after enrollment was not mandated or followed., Conclusion: Low-dose oral vitamin K did not reduce bleeding in warfarin recipients with INRs of 4.5 to 10.0., Funding: Canadian Institutes of Health Research and Italian Ministry of Universities and Research.

Study Objective: To quantify the absolute risk of thromboembolism associated with a significant subtherapeutic international normalized ratio (INR) in patients with previously stable anticoagulation while receiving warfarin., Design: Retrospective, matched cohort analysis., Setting: Centralized anticoagulation service in an integrated health care delivery system., Patients: A total of 2597 adult patients receiving warfarin from January 1998-December 2005; 1080 patients were in the low INR cohort and were matched to 1517 patients in the therapeutic INR cohort based on index INR date, indication for warfarin, and age., Measurements and Main Results: Stable, therapeutic anticoagulation was defined as two INR values, measured at least 2 weeks apart, within or above the therapeutic range. The low INR cohort included patients with a third INR value of 0.5 or more units below their therapeutic range. The therapeutic INR cohort included patients with a third therapeutic INR value and no INR value 0.2 or more units below their target INR range in the ensuing 90 days. The primary outcome was anticoagulation-related thromboembolism during the 90 days after the index INR. Secondary outcomes were times to the first occurrence of anticoagulation-related complications (bleeding, thromboembolism, or death) in the 90 days after the index INR. Four thromboembolic events (0.4%) occurred in the low INR cohort and one event (0.1%) in the therapeutic INR cohort (p=0.214). The differences in the proportions of thromboembolism, bleeding, or death were not significant between the cohorts (p>0.05). No significant differences were noted in the hazard of thromboembolism, bleeding, or death between the cohorts (p>0.05)., Conclusion: Patients with stable INRs while receiving warfarin who experience a significant subtherapeutic INR value have a low risk of thromboembolism in the ensuing 90 days. The risk was similar to that observed in a matched control population in whom therapeutic anticoagulation was maintained. These findings do not support the practice of anticoagulant bridge therapy for patients stabilized on warfarin therapy to reduce their risk for thromboembolism during isolated periods of subtherapeutic anticoagulation.

Objective: To provide recommendations, policies, and procedures pertaining to the provision of optimized anticoagulation therapy designed to achieve desired clinical endpoints while minimizing the risk of anticoagulant-related adverse outcomes (principally bleeding and thrombosis)., Study Selection and Data Extraction: Due to this document's scope, the medical literature was searched using a variety of strategies. When possible, recommendations are supported by available evidence; however, because this paper deals with processes and systems of care, high-quality evidence (eg, controlled trials) is unavailable. In these cases, recommendations represent the consensus opinion of all authors who constitute the Board of Directors of The Anticoagulation Forum, an organization dedicated to optimizing anticoagulation care. The Board is composed of physicians, pharmacists, and nurses with demonstrated expertise and significant collective experience in the management of patients receiving anticoagulation therapy., Data Synthesis: Recommendations for delivering optimized anticoagulation therapy were developed collaboratively by the authors and are summarized in 9 key areas: (I) Qualifications of Personnel, (II) Supervision, (III) Care Management and Coordination, (IV) Documentation, (V) Patient Education, (VI) Patient Selection and Assessment, (VII) Laboratory Monitoring, (VIII) Initiation and Stabilization of Warfarin Therapy, and (IX) Maintenance of Therapy. Recommendations are intended to inform the development of care systems containing elements with demonstrated benefit in improvement of anticoagulation therapy outcomes. Recommendations for delivering optimized anticoagulation therapy are intended to apply to all clinicians involved in the care of outpatients receiving anticoagulation therapy, regardless of the structure and setting in which that care is delivered., Conclusions: Anticoagulation therapy, although potentially life-saving, has inherent risks. Whether a patient is managed in a solo practice or a specialized anticoagulation management service, a systematic approach to the key elements outlined herein will reduce the likelihood of adverse events. The need for continued research to validate optimal practices for managing anticoagulation therapy is acknowledged.

Warfarin is highly effective at reducing the risk of stroke in AF. The benefit of oral anticoagulant therapy strongly outweighs the risk in most patients who have AF. More data are needed to define the overall risk-to-benefit ratio better for patients aged 80 years and older. Because a significant proportion of elderly individuals may not be optimal candidates for anticoagulant therapy, we must continue to evaluate alternative stroke prevention strategies while redoubling our efforts to understand the mechanisms underlying AF and thrombogenesis.

Background: Significant uncertainty surrounds the treatment of patients who must discontinue warfarin sodium therapy before an invasive procedure. In part, the uncertainty results from the lack of published information about the risk of thromboembolism associated with short-term warfarin therapy interruption. We aimed to assess the frequency of thromboembolism and bleeding within a large cohort of patients whose warfarin therapy was temporarily withheld for an outpatient invasive procedure., Methods: This prospective, observational cohort study was performed at 101 sites (primarily community-based physician office practices) in the United States. Enrollment was conducted from April 4, 2000, to March 6, 2002. The main outcome measures were thromboembolism or clinically significant hemorrhage within 30 days of warfarin therapy interruption., Results: A total of 1293 episodes of warfarin therapy interruption in 1024 individuals were included. The mean (SD) patient age was 71.9 (10.6) years; 438 (42.8%) were female. The most common indications for anticoagulant therapy were atrial fibrillation (n=550), venous thromboembolism (n=144), and mechanical heart valve (n=132). The most common procedures were colonoscopy and oral and ophthalmic surgery. Perioperative heparin or low-molecular-weight heparin was used in only 8.3% of cases overall. Seven patients (0.7%; 95% confidence interval [CI], 0.3%-1.4%) experienced postprocedure thromboembolism within 30 days. None of the 7 patients who experienced thromboembolism received periprocedural bridging therapy. Six patients (0.6%; 95% CI, 0.2%-1.3%) experienced major bleeding, whereas an additional 17 patients (1.7%; 95% CI, 1.0%-2.6%) experienced a clinically significant, nonmajor bleeding episode. Of these 23 patients who had bleeding episodes, 14 received periprocedural heparin or low-molecular-weight heparin. The duration of warfarin therapy interruption was variable; however, more than 80% of patients had warfarin therapy withheld for 5 days or fewer., Conclusions: For many patients receiving long-term anticoagulation who need to undergo a minor outpatient intervention, a brief (< or =5 days) periprocedural interruption of warfarin therapy is associated with a low risk of thromboembolism. The risk of clinically significant bleeding, even among outpatients undergoing minor procedures, should be weighed against the thromboembolic risk of an individual patient before the administration of bridging anticoagulant therapy.

Objectives: Among warfarin-treated patients with international normalized ratio (INR) >5, we sought to determine the risk of major bleeding within 30 days., Background: For warfarin-treated patients, the risk of bleeding increases as the INR rises, particularly if the INR exceeds 4. The 30-day risk of hemorrhage among outpatients with excessively prolonged INR values is unknown., Methods: To assess anticoagulation care in the U.S., a cohort of 6,761 patients taking warfarin was prospectively assembled from 101 participating sites (43% were community-based cardiology practices). From this cohort, 1,104 patients were identified with a first episode of INR >5., Results: A total of 979 met eligibility criteria; complete follow-up information was available for 976 (99.7%). Ninety-six percent (n = 937) of patients had an INR value between 5 and 9; 80% of INR values were <7. Thirteen patients (1.3%) experienced major hemorrhage during the 30-day follow-up period; among patients whose INR was >5 and <9, 0.96% experienced major hemorrhage. None of the bleeding events was fatal. Intervention with vitamin K was uncommon (8.7%). Warfarin doses were withheld for the majority of patients. Fifty percent of patients who were managed conservatively and retested on day 4 or 5 had an INR of 2.0 or less., Conclusions: For warfarin-treated outpatients presenting with an INR >5 and <9, the 30-day risk of major bleeding is low (0.96%). Intervention with vitamin K among asymptomatic patients presenting with an INR <9 is not routine practice in the U.S.

Background: The use of anticoagulant therapy is expanding among the elderly population, in part because of the increasing prevalence of atrial fibrillation. Published data describing the warfarin maintenance dose requirements for this age group are limited. Because warfarin therapy is often initiated in the outpatient setting where significant barriers to daily monitoring exist for this patient population, a better understanding of the factors that predict lower dose requirements may reduce the risk of unanticipated over-anticoagulation and hemorrhage., Objective: To define the effects of age and gender on the warfarin maintenance dose among ambulatory adult patients with an international normalized ratio target between 2.0 and 3.0., Design: Prospective cohort study and retrospective cohort secondary data source., Setting: One hundred one community-based physician practices with dedicated warfarin management systems and an academic medical center anticoagulation clinic., Patients: A total of 4,616 patients comprised the prospective cohort, and 7,586 patients comprised the retrospective cohort. Of the 12,202 patients, 2,359 were > or = 80 years of age., Measurements: Median weekly and daily maintenance warfarin dose., Results: The warfarin dose was inversely related to age and was strongly associated with gender. The median weekly dose ranged from 45 mg (6.4 mg/d) for men who were < 50 years of age to 22 mg (3.1 mg/d) for women > or = 80 years of age. The weekly dose declined by 0.4 mg/yr (95% confidence interval [CI], 0.37 to 0.44; p < 0.001) and women required 4.5 mg less per week than men (95% CI, 3.8 to 5.3; p < 0.001). Among patients who were > 70 years of age, the often-suggested initiation dose of 5 mg/d will be excessive for 82% of women and 65% of men., Conclusions: Warfarin dose requirements decrease greatly with age. Older women require the lowest warfarin doses. These observations suggest that, when warfarin is being initiated, the commonly employed empiric starting dose of 5 mg/d will lead to over-anticoagulation for the majority of patients in the geriatric age group; lower initiation and maintenance doses should be considered for the elderly.

The optimal perioperative anticoagulation management in patients on warfarin therapy is poorly defined due to the lack of randomized trials. Because guidelines are heterogeneous, it was hypothesized that "treatment strategies are not uniform in clinical practice". Between February 2003 and May 2003, a questionnaire with 4 different clinical scenarios was distributed to physicians by e-mail, or direct contact was made by a survey monitor. Two scenarios described the cases of patients with a mechanical heart valve (MHV) in the mitral position, with additional risk factors for a systemic embolism; one undergoing major (scenario 1) and the other minor surgery (scenario 3). Two scenarios described patients with an aortic MHV; one undergoing major (scenario 2) and the other minor (scenario 4) surgery. Different preoperative and postoperative management options were offered. The treatment options for all scenarios were the same. Of the 90 questionnaires distributed, 52 (57.8%) were returned. Hospitalization for full-dose intravenous unfractionated heparin (IV UH) was the most commonly selected strategy in the preoperative phase for scenarios 1 (59%), 2 (42%) and 3 (44%). In scenario 4, 34% chose IV UH. Outpatient, full- dose, subcutaneous UH or low-molecular-weight heparin (LMWH) was the most selected option in the postoperative phase for all scenarios, with the exception of number 4 (52.9% in scenario 1, 34% in scenario 2, 32%, in scenario 3 and 28% in scenario 4). Even among expert clinicians, the management of perioperative anticoagulation is heterogeneous. In particular, the definition of risk categories and the optimal intensity of antithrombotic drugs need to be defined by well-designed prospective studies.

Background: Despite published reports of its safety and efficacy, oral vitamin K (phytonadione) may not be widely used for patients with warfarin-associated coagulopathy. We tested the hypothesis that recommendations for phytonadione use from the American College of Chest Physicians (ACCP) Fifth Consensus Conference on Antithrombotic Therapy are not routinely incorporated into the clinical practice of many anticoagulation clinics., Methods: Surveys were mailed to 100 separate clinics in the southwestern region of the United States that are members of the Anticoagulation Forum, an association of anticoagulation clinic personnel and medical directors in the United States and Canada. Respondents were presented with 4 scenarios involving asymptomatic patients taking warfarin whose international normalized ratio is supratherapeutic. In each scenario, the respondents were told the patient's international normalized ratio and whether the patient was at "high" risk for bleeding., Results: Of 53 respondents, 13 (25%) indicated that their clinics never use oral phytonadione. Eighteen (34%) indicated that their clinics use subcutaneous phytonadione, despite the absence of a recommendation for this in the ACCP guidelines published in 1998. For each scenario, we made a judgment as to whether the respondent's management was consistent with guidelines found in the ACCP Fifth Consensus Conference on Antithrombotic Therapy. Overall, only 17 respondents (32%) provided all 4 answers consistent with the ACCP recommendations., Conclusion: For patients with supratherapeutic international normalized ratio values, our survey suggests that a substantial number of anticoagulation clinics underutilize oral phytonadione.

Background: Anticoagulation requires urgent reversal in cases of life-threatening bleeding or invasive procedures.Study Design and Methods: Network meta-analysis for comparing the safety and efficacy of warfarin reversal strategies including plasma and prothrombin complex concentrates (PCCs).Results: Seven studies including 594 subjects using reversal agents plasma, 3-factor-PCC (Uman Complex and Konyne), and 4-factor-PCC (Beriplex/KCentra, Octaplex, and Cofact) met inclusion criteria. Compared with plasma, patients receiving Cofact probably have a higher rate of international normalized ratio (INR) correction (risk difference [RD] 499 more per 1000 patients, 95% confidence interval [CI], 176-761, low certainty[LC]); higher reversal of bleeding (323 more per 1000 patients, 11-344 more, LC); and fewer transfusion requirements (0.96 fewer units, 1.65-0.27 fewer, LC). Patients receiving Beriplex/KCentra probably have a higher rate of INR correction (476 more per 1000 patients, 332-609 more, LC); higher reversal of bleeding (127 more per 1000 patients, 43 fewer to 236 more); and similar transfusion requirements (0.01 fewer units, 0.31 fewer to 0.28 more, high/moderate certainty). Patients receiving Octaplex probably have a higher rate of INR correction (RD 579 more per 1000 patients, 189-825 more, LC).Conclusions: PCCs probably provide an advantage in INR reversal compared to plasma. There was no added risk of adverse events with PCCs. [ABSTRACT FROM AUTHOR]

After the introduction of warfarin, long-term oral anticoagulation treatment remained unchanged for more than 50 years. Most recently, with the development and approval of new oral anticoagulants, the treatment of medical conditions that require thrombosis prophylaxis and long-term anticoagulation has become more complex. In the case of venous thromboembolism (VTE) prevention after orthopedic surgery, the new oral agents will be less costly than the parenteral alternative. In other settings (such as atrial fibrillation or treatment of acute VTE), the new agents will offer additional convenience at higher cost, but the degree to which they will reduce clinically important events such as thrombosis or bleeding will be limited, especially for patients on optimally controlled warfarin. As the use of the new oral anticoagulants becomes more widespread, it will be important for all clinicians to have a basic understanding of their pharmacology, advantages, and limitations. Although the need to measure or reverse the effect of these drugs will arise infrequently, clinicians--especially hematologists--will desire evidence-based recommendations about how to manage such scenarios, which will require research studies. [ABSTRACT FROM AUTHOR]