Early anti-coagulation therapy in new-onset atrial fibrillation after coronary artery bypass grafting: a randomized trial pilot study.

BACKGROUND: New-onset postoperative atrial fibrillation (POAF) is a common complication after coronary artery bypass grafting (CABG) surgery, increasing the risk of embolism and stroke. There is a lack of information on the use of anticoagulants in this context. The choice between Warfarin and Direct oral anticoagulants (DOACs) also is not well-established. This randomized study aimed to compare the feasibility and safety of Warfarin and Rivaroxaban in preventing thrombotic events in POAF patients after isolated CABG. METHODS: A total of 66 patients were randomized parallelly with 1:1 allocation to receive either Rivaroxaban (n = 34) or Warfarin (n = 32). Major bleeding events within 30 days after discharge were the primary outcome. Secondary outcomes included minor bleeding events and thrombotic episodes. Clinical characteristics, medication regimens, and left atrial diameter were assessed. Statistical analyses were performed using appropriate tests. RESULTS: No thrombotic episodes were observed in either treatment arm. No major bleeding events occurred in either group. Four minor bleeding events were reported, with no significant difference between the treatment groups (P = 0.6). Patients with atrial fibrillation had significantly larger left atrial diameters compared to those with normal sinus rhythm (40.5 vs. 37.8 mm, P = 0.01). CONCLUSIONS: This pilot study suggests that Warfarin and Rivaroxaban are both safe and effective for preventing thrombotic episodes in POAF patients after isolated CABG. No significant differences in major bleeding events were observed between the two anticoagulants. These findings may support the preference for DOACs like Rivaroxaban due to their convenience and easier maintenance. TRIAL REGISTRATION: Number IRCT20200304046696N1, Date 18/03/2020 https//irct.behdasht.gov.ir/ .

Assessing Safety of Anticoagulation for Atrial Fibrillation in Patients with Cirrhosis: A Real-World Outcomes Study.

AIMS: In patients with atrial fibrillation (AF) and stroke risk factors, randomized trials have demonstrated that anticoagulation decreases the risk of ischemic stroke. However, all trials to date have excluded patients with significant liver disease, leaving guidelines to extrapolate recommendations. We aim to evaluate the impact of anticoagulation on safety events in patients with AF and cirrhosis. METHODS AND RESULTS: In this retrospective cohort study, we obtained de-identified health record data to extract anticoagulation strategy, comorbidities, prescriptions, lab values, and procedures for a cohort of patients with cirrhosis who develop AF. After selecting a propensity matched population to match patients with various anticoagulation strategies, we tracked data on outcomes for death, transfusion requirements, hospital and ICU admissions. After propensity score weighting and multivariable adjustment, anticoagulation strategy was associated with increased hospital admission count (OR = 1.74 per admission, P < .001), binary risk of hospital admission (OR = 1.54, P = .010) and risk of ICU admission (OR = 1.41, P = .047). We detected no significant differences in mortality, transfusion of blood products, or average length of stay. Direct oral anticoagulant (DOAC) prescriptions were associated with increased binary risk of hospital admission compared to warfarin prescriptions. In a third comparison, DOAC strategy alone was associated with increased hospital admission count (OR = 1.41 per admission, P < .001) and binary risk of hospital admission (OR = 1.52, P = .038) compared to no anticoagulation strategy. CONCLUSION: Anticoagulation strategy in patients with cirrhosis and AF was associated with increased rate of hospital admission and ICU admission but not associated with increased risk of mortality or transfusion requirement.

Antithrombotic Therapy for Heart Failure in Sinus Rhythm - A Concise Review.

Heart failure (HF) is a common disorder associated with significant morbidity and mortality. It can increase the risk of thromboembolic events, which subsequently lead to increased risk of stroke, ischemic heart disease, thromboembolism, and death. Antithrombotic therapy has been investigated as a potential management strategy for HF patients in sinus rhythm, but its efficacy remains uncertain. Current guidelines do not recommend the routine use of antithrombotics in patients with HF in sinus rhythm without any other indication for their use. Several randomized controlled trials have investigated the efficacy of antithrombotics in HF patients in sinus rhythm. This article provides a concise review of the existing literature to assess the evidence supporting the use of antithrombotics in HF patients in sinus rhythm. The use of warfarin or other anticoagulants has demonstrated a lower risk of stroke but an increased risk of bleeding. The studies demonstrate that anticoagulant therapy in HF patients in sinus rhythm does not provide significant benefits in terms of overall ischemic events or death.

Comparison of warfarin, rivaroxaban, and dabigatran for effectiveness and safety in atrial fibrillation patients with different CHA2DS2-VASc scores: a retrospective cohort study.

BACKGROUND: This retrospective cohort study aims to compare the effectiveness and safety of warfarin, rivaroxaban, and dabigatran in atrial fibrillation (AF) patients with different CHA2DS2-VASc scores in northern China. METHODS: A retrospective cohort study was performed to evaluate anticoagulation in AF patients at the second affiliated hospital of Harbin Medical University from September 2018 to August 2019. Patients included in this study (n = 806) received warfarin (n = 300), or rivaroxaban (n = 203), or dabigatran (n = 303). Baseline characteristics and follow-up data including adherence, bleeding events and ischemic stroke (IS) events were collected. RESULTS: Patients receiving rivaroxaban (73.9%) or dabigatran (73.6%) showed better adherence than those receiving warfarin (56.7%). Compared with warfarin-treated patients, dabigatran-treated patients had lower incidence of bleeding events (10.9% vs 19.3%, χ2 = 8.385, P = 0.004) and rivaroxaban-treated patients had lower incidence of major adverse cardiovascular events (7.4% vs 13.7%, χ2 = 4.822, P = 0.028). We classified patients into three groups based on CHA2DS2-VASc score (0-1, 2-3, ≥ 4). In dabigatran intervention, incidence of bleeding events was higher in patients with score 0-1 (20.0%) than those with score 2-3 (7.9%, χ2 = 5.772, P = 0.016) or score ≥ 4 (8.6%, χ2 = 4.682, P = 0.030). Patients with score 0-1 in warfarin or rivaroxaban therapy had a similar but not significant increase of bleeding compared with patients with score 2-3 or score ≥ 4, respectively. During the follow-up, 33 of 806 patients experienced IS and more than half (19, 57.6%) were patients with score ≥ 4. Comparing patients with score 0-1 and 2-3, the latter had an significant reduction of IS in patients prescribed warfarin and non-significant reduction in rivaroxaban and dabigatran therapy. CONCLUSION: Compared with warfarin therapy, patients with different CHA2DS2-VASc scores receiving either rivaroxaban or dabigatran were associated with higher persistence. AF patients with score ≥ 4 were more likely to experience IS events while hemorrhagic tendency preferred patients with low score 0-1.

Warfarin-related nephropathy: unveiling the hidden dangers of anticoagulation.

Warfarin-related nephropathy (WRN) is defined as acute kidney injury subsequent to excessive anticoagulation with warfarin. Patients with mechanical prosthetic valves require long-term anticoagulant therapy. Nonetheless, warfarin remains the sole available option for anticoagulant therapy. Consequently, patients with mechanical prosthetic valves constitute a special group among the entire anticoagulant population. The present study recorded two cases of patients who had undergone mechanical prosthetic valve surgery and were receiving warfarin therapy. They presented to the hospital with gross hematuria and progressive creatinine levels. Notably, their international normalized ratio (INR) did not exceed three. Subsequent renal biopsies confirmed WRN with IgA nephropathy. The two patients continued to receive warfarin as anticoagulation therapy and were prescribed oral corticosteroids and cyclophosphamide, which resulted in improved renal function during the follow-up. Based on a review of all relevant literature and the present study, we proposed a new challenge: must elevated INR levels be one of the criteria for clinical diagnosis of WRN? Perhaps some inspiration can be drawn from the present article.

Dedicated anticoagulation management protocols in fragility femoral fracture care - a source of significant variance and limited effectiveness in improving time to surgery: The hip and femoral fracture anticoagulation surgical timing evaluation (HASTE) study.

INTRODUCTION: Approximately 20 % of femoral fragility fracture patients take anticoagulants, typically warfarin or Direct Oral AntiCoagulant (DOAC). These can impact timing of surgery affecting patient survival. Due to several possible approaches and numerous factors to consider in the preoperative workup of anticoagulated patients, potential for variations in clinical practice exist. Some hospitals employ dedicated anticoagulation management protocols to address this issue, and to improve time to surgery. This study aimed to determine the proportion of hospitals with such protocols, compare protocol guidance between hospitals, and evaluate the effectiveness of protocols in facilitating prompt surgery. METHODS: Data was prospectively collected through a collaborative, multicentre approach involving hospitals across the UK. Femoral fragility fracture patients aged ≥60 years and admitted to hospital between 1st May to 31st July 2023 were included. Information from dedicated anticoagulation management protocols were collated on several domains relating to perioperative care including administration of reversal agents and instructions on timing of surgery as well as others. Logistic regression was used to evaluate effects of dedicated protocols on time to surgery. RESULTS: Dedicated protocols for management of patients taking warfarin and DOACs were present at 41 (52.6 %) and 43 (55.1 %) hospitals respectively. For patients taking warfarin, 39/41 (95.1 %) protocols specified the dose of vitamin k and the most common was 5 milligrams intravenously (n=21). INR threshold values for proceeding to surgery varied between protocols; 1.5 (n=28), 1.8 (n=6), and 2 (n=6). For patients taking DOACs, 35/43 (81.4 %) and 8/43 (18.6 %) protocols advised timing of surgery based on renal function and absolute time from last dose respectively. Analysis of 10,197 patients from 78 hospitals showed fewer patients taking DOACs received surgery within 36 h of admission at hospitals with a dedicated protocol compared to those without (adjusted OR 0.73, 95% CI 0.54-0.99, p=0.040), while there were no differences among patients taking warfarin (adjusted OR 1.64, 95% CI 0.75-3.57, p=0.219). CONCLUSIONS: Around half of hospitals employed a dedicated anticoagulation management protocol for femoral fragility fracture patients, and substantial variation was observed in guidance between protocols. Dedicated protocols currently being used at hospitals were ineffective at improving the defined targets for time to surgery.

Web-Based Warfarin Management (Alfalfa App) Versus Traditional Warfarin Management: Multicenter Prospective Cohort Study.

BACKGROUND: Poor anticoagulation management of warfarin may lead to patient admission, prolonged hospital stays, and even death due to anticoagulation-related adverse events. Traditional non-web-based outpatient clinics struggle to provide ideal anticoagulation management services for patients, and there is a need to explore a safer, more effective, and more convenient mode of warfarin management. OBJECTIVE: This study aimed to compare differences in the quality of anticoagulation management and clinical adverse events between a web-based management model (via a smartphone app) and the conventional non-web-based outpatient management model. METHODS: This study is a prospective cohort research that includes multiple national centers. Patients meeting the nadir criteria were split into a web-based management group using the Alfalfa app or a non-web-based management group with traditional outpatient management, and they were then monitored for a 6-month follow-up period to collect coagulation test results and clinical events. The effectiveness and safety of the 2 management models were assessed by the following indicators: time in therapeutic range (TTR), bleeding events, thromboembolic events, all-cause mortality events, cumulative event rates, and the distribution of the international normalized ratio (INR). RESULTS: This national multicenter cohort study enrolled 522 patients between June 2019 and May 2021, with 519 (99%) patients reaching the follow-up end point, including 260 (50%) in the non-web-based management group and 259 (50%) in the web-based management group. There were no observable differences in baseline characteristics between the 2 patient groups. The web-based management group had a significantly higher TTR than the non-web-based management group (82.4% vs 71.6%, P<.001), and a higher proportion of patients received effective anticoagulation management (81.2% vs 63.5%, P<.001). The incidence of minor bleeding events in the non-web-based management group was significantly higher than that in the web-based management group (12.1% vs 6.6%, P=.048). Between the 2 groups, there was no statistically significant difference in the incidence of severe bleeding and thromboembolic and all-cause death events. In addition, compared with the non-web-based management group, the web-based management group had a lower proportion of INR in the extreme subtreatment range (17.6% vs 21.3%) and severe supertreatment range (0% vs 0.8%) and a higher proportion in the treatment range (50.4% vs 43.1%), with statistical significance. CONCLUSIONS: Compared with traditional non-web-based outpatient management, web-based management via the Alfalfa app may be more beneficial because it can enhance patient anticoagulation management quality, lower the frequency of small bleeding events, and improve INR distribution.

Negative Results, Positive Outcome: A Case of Primary Livedoid Vasculopathy With an Elusive Laboratory Workup.

Livedoid vasculopathy (LV) is a chronic, recurrent thrombotic vasculopathy characterized by painful ulcerations on the lower extremities, which heal slowly and leave atrophic white scars known as "atrophie blanche." This report presents the case of a 31-year-old woman with a 4-year history of recurrent painful ulcerations on her legs and feet. A skin biopsy revealed findings consistent with LV, and an exhaustive laboratory workup ruled out secondary causes such as thrombophilia, malignancies, autoimmune diseases, and peripheral arterial disease. The patient showed remarkable improvement with a treatment regimen of pentoxifylline, nifedipine, and warfarin, resulting in complete ulcer resolution and sustained remission over 5 months. Our case highlights the importance of a comprehensive diagnostic approach and a multidisciplinary treatment strategy in managing primary LV to achieve remission and prevent recurrence of skin ulcerations.

Pleiotropic Effects of Direct Oral Anticoagulants in Chronic Heart Failure and Atrial Fibrillation: Machine Learning Analysis.

Oral anticoagulant therapy (OAT) for managing atrial fibrillation (AF) encompasses vitamin K antagonists (VKAs, such as warfarin), which was the mainstay of anticoagulation therapy before 2010, and direct-acting oral anticoagulants (DOACs, namely dabigatran etexilate, rivaroxaban, apixaban, edoxaban), approved for the prevention of AF stroke over the last thirteen years. Due to the lower risk of major bleeding associated with DOACs, anticoagulant switching is a common practice in AF patients. Nevertheless, there are issues related to OAT switching that still need to be fully understood, especially for patients in whom AF and heart failure (HF) coexist. Herein, the effective impact of the therapeutic switching from warfarin to DOACs in HF patients with AF, in terms of cardiac remodeling, clinical status, endothelial function and inflammatory biomarkers, was assessed by a machine learning (ML) analysis of a clinical database, which ultimately shed light on the real positive and pleiotropic effects mediated by DOACs in addition to their anticoagulant activity.

Long-term discontinuation of warfarin in a patient with HeartMate 3 left ventricular assist device without thromboembolic events.

The gold standard therapy for end-stage heart failure is cardiac transplantation. However, in the face of a donor shortage, a mechanical assist device such as the left ventricular assist device HeartMate 3 (Abbott Laboratories, Abbott Park, IL, USA) serves as bridging therapy to transplantation and/or destination therapy. Current guidelines recommend anticoagulation with a vitamin K antagonist in combination with low-dose aspirin. We herein report a challenging anticoagulation regimen in a patient with a HeartMate 3 in whom systemic anticoagulation with warfarin was not feasible for 4 years because of low compatibility and a rare X-factor deficiency. This is a rare hematological disorder, estimated to affect approximately 1 in every 500,000 to 1,000,000 people in the general population. The patient finally received a modified anticoagulation regimen involving the combination of rivaroxaban and clopidogrel without warfarin. Under this regimen, the patient remained free of thromboembolic complications for 4 years with in situ placement of the left ventricular assist device. This case illustrates that under specific circumstances, long-term absence of warfarin therapy is feasible in patients with a HeartMate 3.

Direct oral anticoagulants for oral anticoagulants-naïve Asian patients with atrial fibrillation and end-stage renal disease undergoing dialysis.

In Asian patients with atrial fibrillation (AF) and end-stage renal disease (ESRD) undergoing dialysis, the use of direct oral anticoagulants (DOACs) remains debatable. From the national health insurance claims data in South Korea, we included 425 new users of OAC among patients with non-valvular AF and ESRD undergoing dialysis between 2013 and 2020. Patients were categorized into DOAC (n = 106) and warfarin group (n = 319). Clinical outcomes, including ischemic stroke, myocardial infarction (MI), intracranial hemorrhage (ICH), and gastrointestinal (GI) bleeding, were compared between the two groups using inverse probability of treatment weighting (IPTW) analysis. During the median follow-up of 3.2 years, the incidence of ischemic stroke was significantly reduced in the DOAC compared to the warfarin group [Hazard ratio (HR) 0.07; P = 0.001]. However, the incidence of MI (HR 1.32; P = 0.41) and GI bleeding (HR 1.78; P = 0.06) were not significantly different between the two groups. No ICH events occurred in the DOAC group, although the incidence rate did not differ significantly between the two groups (P = 0.17). In Asian patients with AF and ESRD undergoing dialysis, DOACs may be associated with a reduced risk of ischemic stroke compared with warfarin. The MI, ICH, and GI bleeding rates may be comparable between DOACs and warfarin.

Cost-Effectiveness and Budget Impact Analysis of Apixaban and Rivaroxaban Versus Warfarin in the Prevention of Stroke in Patients With Non-Valvular Atrial Fibrillation (NVAF) in Iran.

INTRODUCTION: This study evaluates the cost-effectiveness of Apixaban and Rivaroxaban, compared to Warfarin, for stroke prevention in patients with non-valvular atrial fibrillation in Iran. METHOD: A Markov model with a 30-year time horizon was employed to simulate and assess different treatment strategies' cost-effectiveness. The study population comprised Iranian adults with NVAF, identified through specialist consultations, hospital visits, and archival record reviews. Direct medical costs, direct nonmedical, and indirect costs were included. Quality-adjusted life years (QALY) were assessed using an EQ-5D questionnaire. This study utilized a cost-effectiveness threshold of $11 134 per QALY. RESULTS: Apixaban demonstrated superior cost-effectiveness compared to Rivaroxaban and Warfarin. Over 30 years, total costs were lower in the Apixaban and Rivaroxaban groups compared to the Warfarin group ($126.18 and $109.99 vs. $150.49). However, Apixaban showed higher total QALYs gained compared to others (0.134 vs. 0.133 and 0.116). The incremental cost-effectiveness ratio for comparing Apixaban to Warfarin was calculated at -1332.83 cost per QALY, below the threshold of $11 134, indicating Apixaban's cost-effectiveness. Sensitivity analyses confirmed the robustness of the findings, with ICER consistently remaining below the threshold. Over 5 years (2024-2028) of Apixaban usage, the incremental cost starts at USD 70 250 296 in the first year and gradually rises to USD 71 770 662 in the fifth year. DSA and PSA were assessed to prove the robustness of the results. CONCLUSION: This study shows that Apixaban is a cost-effective option for stroke prevention in non-valvular atrial fibrillation patients in Iran compared to Warfarin.

Knowledge, Adherence, and Satisfaction With Warfarin Therapy and Associated Factors Among Outpatients at University Teaching Hospital in Ethiopia.

Anticoagulation management using warfarin is challenging in clinical practice. This study aimed to evaluate the knowledge, adherence, and satisfaction with warfarin therapy and associated factors among outpatients at the Tikur Anbessa Specialized Hospital (TASH) in Addis Ababa, Ethiopia. An interview-based cross-sectional study was conducted among 350 patients receiving warfarin therapy at cardiac and hematology clinics of TASH. Anticoagulation knowledge assessment (AKA) questionnaires assessed the patients' warfarin knowledge. Adherence to warfarin was evaluated using the Morisky Green Levine Scale (MGLS), and patient satisfaction with warfarin therapy was assessed using the 17-item anticlot treatment scale (ACTS). Binary logistic regression was used to determine factors associated with the outcome variables, and p < .05 was used as the cut-off point to declare a significant association. The mean AKA score was 59.35 ± 13.04% (10.68 ± 2.34 correct answers), and 82 (23.4%) of participants achieved a passing score. Based on the MGLS, 192 (54.9%) study participants adhered well to warfarin. The mean level of satisfaction was 53.67 ± 8.56, with mean scores of 41.93 ± 7.80 and 11.74 ± 2.43 in the ACTS burden and benefit subscales, respectively. One hundred eighty-four (52.6%) patients were satisfied with warfarin therapy. The absence of hyperthyroidism was significantly associated with poor knowledge of warfarin therapy (adjusted odds ratio [AOR] = 4.28, 95% confidence interval [CI]: 1.01-18.22). Those living with family had a 56% lower chance of poor warfarin adherence (AOR: 0.44; 95% CI: 0.21-0.93) than those living alone. This study shows room for improvement in patient knowledge, adherence, and satisfaction with warfarin therapy.

Time-in-therapeutic-range defined warfarin and direct oral anticoagulants in atrial fibrillation: a Nationwide Cohort Study.

BACKGROUND: Little is known how individual time-in-therapeutic-range (TTR) impacts the effectiveness and safety of warfarin therapy compared to direct oral anticoagulants (DOACs) in patients with atrial fibrillation (AF). OBJECTIVE: To compare the effectiveness and safety of standard dose DOACs to warfarin in patients with AF, while categorizing warfarin treated patients into quartiles based on their individual TTR. MATERIALS AND METHODS: We conducted a nationwide study including all patients with new-onset AF between 2011 and 2018 in Finland. Hazard ratios (HR) were calculated using Cox regression analysis with the inverse probability of treatment weighted method to assess the risks of ischaemic stroke (IS), intracranial haemorrhage (ICH) and mortality for users of apixaban (n = 12,426), dabigatran (n = 4545), rivaroxaban (n = 12,950) and warfarin (n = 43,548). RESULTS: The median TTR for warfarin users was 72%. Compared to the second best TTR quartile (reference), the risk of IS was higher in the two poorest TTR quartiles, and lower in the best TTR quartile and on rivaroxaban [2.35 (95% confidence interval, 1.85-2.85), 1.44 (1.18-1.75), 0.60 (0.47-0.77) and 0.72 (0.56-0.92)]. These differences were non-significant for apixaban and dabigatran. HR of ICH was 6.38 (4.88-8.35) and 1.87 (1.41-2.49) in the two poorest TTR groups, 1.44 (1.02-1.93) on rivaroxaban, and 0.58 (0.40-0.85) in the best TTR group compared to the reference group. Mortality was higher in the two poorest TTR groups and lowest in the best TTR group. CONCLUSIONS: The outcome was unsatisfactory in the two lowest TTR quartiles - in half of the patients treated with warfarin. The differences between the high TTR groups and standard dose DOACs were absent or modest.

Thromboembolic and bleeding complications after elective cardioversion of atrial fibrillation: a nationwide cohort study.

AIMS: Elective cardioversion (ECV) is routinely used in atrial fibrillation (AF) to restore sinus rhythm. However, it includes a risk of thromboembolism even during adequate oral anticoagulation treatment. The aim of this study was to evaluate the risk of thromboembolic and bleeding complications after ECV in a real-life setting utilizing data from a large AF population. METHODS AND RESULTS: This nationwide register-based study included all (n = 9625) Finnish AF patients undergoing their first-ever ECV between 2012 and 2018. The thromboembolic and bleeding complications within 30 days after ECV were analysed. The mean age of the patients was 67.7 ± 9.9 years, 61.2% were men, and the mean CHA2DS2-VASc score was 2.6 ± 1.6. Warfarin was used in 6245 (64.9%) and non-vitamin K oral anticoagulants (NOACs) in 3380 (35.1%) cardioversions. Fifty-two (0.5%) thromboembolic complications occurred, of which 62% were ischaemic strokes, 25% transient ischaemic attacks, and 13% other systemic embolisms. Thromboembolic events occurred in 14 (0.4%) NOAC-treated patients and in 38 (0.6%) warfarin-treated patients (odds ratio 0.77; confidence interval: 0.42-1.39). The median time from ECV to the thromboembolic event was 2 days, and 78% of the events occurred within 10 days. Age and alcohol abuse were significant predictors of thromboembolic events. Among warfarin users, thromboembolic complications were more common with international normalized ratio (INR) <2.5 than INR ≥2.5 (0.9% vs. 0.4%, P = 0.026). Overall, 27 (0.3%) bleeding events occurred. CONCLUSION: The rate of thromboembolic and bleeding complications related to ECV was low without significant difference between NOAC- and warfarin-treated patients. With warfarin, INR ≥2.5 at the time of cardioversion reduced the risk of thromboembolic complications.

Construction of warfarin population pharmacokinetics and pharmacodynamics model in Han population based on Bayesian method.

The purpose of this paper is to study the genetic polymorphisms of related gene loci (CYP2C9*3, VKORC1-1639G > A) based on demographic and clinical factors, and use the maximum a posterior Bayesian method to construct a warfarin individualized dose prediction model in line with the Chinese Han population. Finally, the built model is compared and analyzed with the widely used models at home and abroad. In this study, a total of 5467 INR measurements are collected from 646 eligible subjects in our hospital, and the maximum a posterior Bayesian method is used to construct a warfarin dose prediction that conforms to the Chinese Han population on the basis of the Hamberg model. The model is verified and compared with foreign models. This study finds that body weight and concomitant use of amiodarone have a significant effect on the anticoagulant effect of warfarin. The model can provide an effective basis for individualized and rational dosing of warfarin in Han population more accurately. In the performance of comparison with different warfarin dose prediction models, the new model has the highest prediction accuracy, and the prediction percentage is as high as 72.56%. The dose predicted by the Huang model is the closest to the actual dose of warfarin. The population pharmacokinetics and pharmacodynamics model established in this study can better reflect the distribution characteristics of INR values after warfarin administration in the Han population, and performs better than the models reported in the literature.

Apixaban Versus Vitamin K Antagonists in Patients With Antiphospholipid Syndrome: A Cohort Study.

ABSTRACT: Current guidelines recommend that direct anticoagulants should not be used in prevention of recurrent thrombosis in patients with antiphospholipid syndrome (APS). However, except for triple-positive APS and rivaroxaban use, little evidence supports such recommendation. In a real-life cohort study, we evaluated the risk of thromboembolism and bleeding in patients with APS on apixaban versus vitamin K antagonists (VKA). We enrolled 152 patients with APS (aged 44 years [interquartile range 36-56], 83% women), including 66 patients treated with apixaban 5 mg bid and 86 with warfarin (target international normalized ratio [INR] 2-3). During a median follow-up of 53 months, we recorded venous thromboembolism, ischemic stroke, or myocardial infarction, along with major bleeding. We observed 4 thrombotic events (6.1%, 3 venous thromboembolism and 1 ischemic stroke) in patients on apixaban and 12 events (14%, 9 venous thromboembolism, 2 ischemic strokes and 1 myocardial infarction) in VKA patients. Patients with APS on apixaban had similar risk of recurrent thromboembolism compared with those on warfarin (hazard ratio [HR] = 0.327, 95% confidence interval [CI]: 0.104-1.035). Thromboembolic events occurred less commonly in statin users (8% vs. 50%, P = 0.01) and more frequently in triple-positive APS (50% vs. 22.1%, P = 0.028) and in patients with higher D-dimer at baseline ( P = 0.023); the latter difference was present in the apixaban group ( P = 0.02). Patients on apixaban had similar risk of major bleeding compared with warfarin (HR = 0.54, 95% CI: 0.201-1.448). In real-life patients with APS, apixaban appears to be similar to VKA for the prevention of thromboembolism and risk of bleeding, which might suggest that some patients with APS could be treated with apixaban.