Warfarin Woes: A Rare Case of Hemoperitoneum with Intramural Small Bowel Hematoma.

BACKGROUND Small bowel hematoma is a rare yet clinically significant condition characterized by the accumulation of blood within the mucosa and submucosa layers of the small intestine wall. It can lead to complications such as bowel obstruction, ischemia, perforation, and even hemorrhagic shock. The etiology of intramural small bowel hematoma is diverse, encompassing factors such as anticoagulant therapy, coagulopathies, vascular disorders, trauma, and underlying systemic conditions. CASE REPORT We present the case of a 67-year-old man with a history of aortic valve replacement who presented with intense abdominal pain. Physical examination revealed generalized abdominal tenderness and black stools upon rectal examination. Laboratory tests indicated coagulopathy with a prolonged thrombin time. A computed tomography scan confirmed the presence of an intramural small bowel hematoma and hemoperitoneum. The patient's condition significantly improved within 48 h under conservative management, including nasogastric tube insertion, continuous monitoring of gastric aspirate, nil per os status, intravenous fluids, and analgesics. Warfarin was temporarily stopped, and fresh frozen plasma was administered for anticoagulation reversal. Heparin infusion was initiated once the INR became within the therapeutic level. CONCLUSIONS The occurrence of spontaneous intramural small bowel hematoma, although rare, demands rapid diagnosis and prompt, well-coordinated management. This case underscores the pivotal role of multidisciplinary collaboration in providing a comprehensive assessment and a tailored approach to treatment. While conservative measures, including careful monitoring and supportive care, have demonstrated favorable outcomes, the consideration of surgical intervention remains crucial, particularly in severe cases.

Repeated Measurement of the Novel Atrial Biomarker BMP10 (Bone Morphogenetic Protein 10) Refines Risk Stratification in Anticoagulated Patients With Atrial Fibrillation: Insights From the ARISTOTLE Trial.

BACKGROUND: BMP10 (bone morphogenic protein 10) has emerged as a novel biomarker associated with the risk of ischemic stroke and other outcomes in patients with atrial fibrillation (AF). The study aimed to determine if repeated BMP10 measurements improve prognostication of cardiovascular events in patients with AF. METHODS AND RESULTS: BMP10 was measured using a prototype Elecsys immunoassay in plasma samples collected at randomization and after 2 months in patients with AF randomized to apixaban or warfarin in the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial (n=2878). Adjusted Cox-regression models were used to evaluate the association between 2-month BMP10 levels and outcomes. BMP10 levels increased by 7.8% (P<0.001) over 2 months. The baseline variables most strongly associated with BMP10 levels at 2 months were baseline BMP10 levels, body mass index, sex, age, creatinine, diabetes, warfarin treatment, and AF-rhythm. During median 1.8 years follow-up, 34 ischemic strokes/systemic embolism, 155 deaths, and 99 heart failure hospitalizations occurred. Comparing the third with the first sample quartile, higher BMP10 levels at 2 months were associated with higher risk of ischemic stroke (hazard ratio [HR], 1.33 [95% CI, 0.67-2.63], P=0.037), heart failure (HR, 1.91 [95% CI, 1.17-3.12], P=0.012) and all-cause death (HR, 1.61 [95% CI, 1.17-2.21], P<0.001). Adding BMP10 levels at 2 months on top of established risk factors and baseline BMP10 levels improved the C-indices for ischemic stroke/systemic embolism (from 0.73 to 0.75), heart failure hospitalization (0.76-0.77), and all-cause mortality (0.70-0.72), all P<0.05. CONCLUSIONS: Elevated levels of BMP10 at 2 months strengthened the associations with the risk of ischemic stroke, hospitalization for heart failure, and all-cause mortality. Repeated measurements of BMP10 may further refine risk stratification in patients with AF.

Warfarin induced spontaneous gastric intramural haematoma presenting with palpitations.

Spontaneous gastric intramural haematoma is an uncommon complication associated with anticoagulant therapy. A patient receiving chronic warfarin for paroxysmal atrial fibrillation was admitted due to atrial fibrillation with rapid ventricular response (RVR). An incidental intra-abdominal mass was detected on a CT scan. Following the initiation of the amiodarone infusion, the patient experienced bleeding attributed to warfarin-amiodarone-induced coagulopathy, with no identifiable bleeding source. Subsequent CT scans revealed an enlargement of the intra-abdominal mass, suggesting gastric intramural haematoma. After coagulopathy reversal, the haematoma is managed conservatively. Our case underscores the potential for incidental bleeding even when the international normalised ratio is within the normal range in patients on chronic warfarin therapy. When managing such patients with atrial fibrillation with RVR, physicians should maintain a high index of suspicion for bleeding, emphasising the importance of prompt coagulopathy reversal.

Spinal subdural haemorrhage secondary to strenuous exercise and warfarin, complicated by acute ischaemic stroke.

Spinal subdural haemorrhage or haematoma (SSDH) is a rare condition that is often overlooked and missed on initial presentation due to its non-specific features that may mimic other more common pathologies. It is associated with high morbidity and mortality rates, with few evidence-based management principles, particularly during the subacute stages of recovery. In this report, we detail a case of SSDH associated with exercise and anticoagulation therapy, which was complicated by acute ischaemic stroke. SSDH should be suspected in cases of acute back pain without a clear alternative cause, particularly in coagulopathic individuals. Following treatment, early recommencement of anticoagulation therapy may be justified in certain cases where indicated, after careful consideration of the affected individual's risk profile.

Being precise with anticoagulation to reduce adverse drug reactions: are we there yet?

Anticoagulants are potent therapeutics widely used in medical and surgical settings, and the amount spent on anticoagulation is rising. Although warfarin remains a widely prescribed oral anticoagulant, prescriptions of direct oral anticoagulants (DOACs) have increased rapidly. Heparin-based parenteral anticoagulants include both unfractionated and low molecular weight heparins (LMWHs). In clinical practice, anticoagulants are generally well tolerated, although interindividual variability in response is apparent. This variability in anticoagulant response can lead to serious incident thrombosis, haemorrhage and off-target adverse reactions such as heparin-induced thrombocytopaenia (HIT). This review seeks to highlight the genetic, environmental and clinical factors associated with variability in anticoagulant response, and review the current evidence base for tailoring the drug, dose, and/or monitoring decisions to identified patient subgroups to improve anticoagulant safety. Areas that would benefit from further research are also identified. Validated variants in VKORC1, CYP2C9 and CYP4F2 constitute biomarkers for differential warfarin response and genotype-informed warfarin dosing has been shown to reduce adverse clinical events. Polymorphisms in CES1 appear relevant to dabigatran exposure but the genetic studies focusing on clinical outcomes such as bleeding are sparse. The influence of body weight on LMWH response merits further attention, as does the relationship between anti-Xa levels and clinical outcomes. Ultimately, safe and effective anticoagulation requires both a deeper parsing of factors contributing to variable response, and further prospective studies to determine optimal therapeutic strategies in identified higher risk subgroups.

Major bleeding in patients with atrial fibrillation treated with apixaban versus warfarin in combination with amiodarone: nationwide cohort study.

BACKGROUND: Amiodarone is an established treatment for atrial fibrillation (AF) but might interfere with the metabolism of apixaban or warfarin. Therefore, the aim was to investigate the occurrence of major bleeding among patients with AF treated with amiodarone in combination with apixaban or warfarin. METHODS: Retrospective observational study using Swedish health registers. All patients with AF in the National Patient Register and the National Dispensed Drug Register with concomitant use of amiodarone and warfarin or apixaban between 1 June 2013 and 31 December 2018 were included. Propensity score matching was performed, and matched cohorts were compared using Cox proportional HRs. The primary outcome was major bleeding resulting in hospitalisation based on International Classification of Diseases (ICD)-10 codes. Secondary outcomes included intracranial bleeding, gastrointestinal bleeding and other bleeding. Exploratory outcomes included ischaemic stroke/systemic embolism and all-cause/cardiovascular (CV) mortality. RESULTS: A total of 12 103 patients met the inclusion criteria and 8686 patients were included after propensity score matching. Rates of major bleeding were similar in the apixaban (4.3/100 patient-years) and warfarin cohort (4.5/100 patient-years) (HR: 1.03; 95% CI: 0.76 to 1.39) during median follow-up of 4.4 months. Similar findings were observed for secondary outcomes including gastrointestinal bleeding and other bleeding, and exploratory outcomes including ischaemic stroke/systemic embolism and all-cause/CV mortality. CONCLUSIONS: Among patients treated with amiodarone in combination with apixaban or warfarin, major bleeding and thromboembolic events were rare and with no significant difference between the treatment groups. EUPAS REGISTRY NUMBER: EUPAS43681.

Relationship of Warfarin and Apixaban with Vascular Function in Patients with Atrial Fibrillation.

INTRODUCTION: Atrial fibrillation (AF) is associated with endothelial damage/dysfunction. Herein, we tested the hypothesis that brachial artery flow-mediated dilation (FMD) is superior in AF patients taking apixaban compared to warfarin. METHODS: AF patients on apixaban (n = 46; 67 [7] years; mean [standard deviation]; 15 women) and warfarin (n = 27; 73 [9] years (p < 0.01); 11 women) were recruited. Duplex Doppler ultrasound imaging was undertaken during baseline (2 min), cuff inflation (5 min), and following cuff deflation (3 min). FMD was defined as peak increase in brachial artery diameter following cuff deflation and analysed as percentage change in diameter, as a ratio of FMD, shear rate area under the curve (SRAUC; FMD-to-SRAUC), and using SRAUC as a covariate (FMDSR). RESULTS: Baseline artery diameter (4.96 [1.14] vs. 4.89 [0.88] mm), peak diameter (5.12 [1.17] vs. 5.14 [0.93] mm), and FMDSR (3.89 [3.62] vs. 4.80 [3.60] %) were not different between warfarin and apixaban (p > 0.05; analysis of covariance with age, CHA2DS2-VASc, years since AF diagnosis, number of diabetics, alcohol drinkers, and units of alcohol consumed per week as covariates). Stepwise multiple regression identified independent association of fibrillation, hypertension, and increased age with FMD. CONCLUSION: AF patients on warfarin and apixaban exhibit similar endothelium-dependent vasodilation. Increased blood pressure negatively impacts vasodilator capacity in AF patients.

Hemorrhage induced by antithrombotic agents: new insights from a real-world pharmacovigilance study.

BACKGROUND: Hemorrhage represents the most common and serious side effect of antithrombotic agents. Many studies have compared the risk of bleeding between different antithrombotic agents, but analysis of time-to-onset for hemorrhage induced by these drugs is yet sparse. METHODS: We conducted a retrospective study based on the adverse drug reaction reports on antithrombotic agents collected by the Henan Adverse Drug Reaction Monitoring Center. We assessed the reporting odds ratio to determine the disproportionate reporting signals for bleeding and the Weibull shape parameter was used to evaluate the time-to-onset data. RESULTS: In the signal detection, crude low molecular weight heparin-hemorrhage was found as a positive signal. The hemorrhage for most antithrombotic agents was random failure profiles. In particular, the hazard of hemorrhage decreased over time for warfarin and clopidogrel and increased for alteplase, nadroparin, and dipyridamole. CONCLUSION: We found that the risk of bleeding in patients taking Crude low molecular weight heparins was significantly higher compared to other antithrombotic agents, but with a small magnificence, which may be attributed to the severely irrational use of this medication under improper management. Statistics in days, results showed that the risk of bleeding decreased over time for warfarin and clopidogrel and increased for alteplase, nadroparin, and dipyridamole.

Comparative Effectiveness and Safety of Direct Oral Anticoagulants Compared with Warfarin in Patients with Low Bodyweight who have Atrial Fibrillation: A Systematic Review and Meta-analysis.

INTRODUCTION: oral anticoagulant (DOAC) agents are becoming the anticoagulation strategy of choice for most clinical risks for which they are indicated. However, residual uncertainty remains regarding their use in preventing stroke in patients with low bodyweight [< 60 kg or body mass index (BMI) < 18 kg/m2]. We have carried out pooled systematic analyses of published studies to determine the efficacy and safety of these agents compared with warfarin in stroke prevention in patients with low bodyweight. METHODS: We carried out a comprehensive search of electronic databases from inception to June 2023 for eligible studies reporting on the efficacy and safety of direct oral anticoagulants versus warfarin in patients with atrial fibrillation who had low bodyweight. These include PubMed, EMBASE, the Cochrane Database of Systematic Reviews, the Science Citation Index, and the Database of Abstracts of Reviews of Effectiveness. Using the random effects model, derived pooled odd ratios (with their corresponding confidence intervals) of mortality outcomes in patient cohorts exposed to direct oral anticoagulants versus warfarin in patients with atrial fibrillation who had low bodyweight. RESULTS: Nine studies (n = 159,514 patients) were included in our meta-analysis. DOAC analogs were associated with lower stroke recurrence compared with warfarin [odds ratio (OR) 0.66, 95% confidence interval (CI) 0.49-0.9]; however, there was no significant difference in the composite outcome (OR 0.81, 95% CI 0.59-1.09) and mortality (OR 0.82, 95% CI 0.48-1.41). Additionally, DOAC analogs showed a significant reduction in major bleeding events by 30% compared with warfarin (OR 0.70, 95% CI 0.62-0.80). CONCLUSION: In this pooled meta-analytical synthesis of studies comprising both real-world and randomized controlled data, the use of DOAC analogs in patients with atrial fibrillation and low bodyweight (< 60 kg or BMI < 18 kg/m2) was associated with a significant reduction in risks of stroke and major bleeding compared with patient cohorts stabilized on warfarin-based therapy. There was uncertainty regarding the composite outcome and mortality point estimate between these two anticoagulation strategies. This finding helps to resolve the uncertainty associated with the use of DOACs in this cohort. Additionally, it suggests the need for confirmatory non-inferiority randomized controlled trials evaluating DOACs versus warfarin in this cohort of patients.

Trends in Anticoagulant Utilization and Clinical Outcomes for Cancer-Associated Thrombosis: A Multicenter Cohort Study in Thailand's Upper-Middle-Income Country Setting.

PURPOSE: To evaluate anticoagulant trends and clinical outcomes in the management of cancer-associated thrombosis (CAT) within Thailand, an upper-middle-income country (UMIC). METHODS: This multicenter retrospective cohort study included adult patients with cancer diagnosed with venous thromboembolism (VTE) hospitalized in Thailand from 2017 to 2021. Anticoagulants were classified as low-molecular-weight heparin (LMWH), direct oral anticoagulants (DOACs), and warfarin. Prescription trends were assessed, and patients were followed for 1 year, or until 2022 to evaluate outcomes. The primary effectiveness outcome was recurrent VTE, whereas the primary safety outcome was major bleeding. Secondary outcomes included net clinical benefit and all-cause mortality. Treatment effects were examined using inverse probability of treatment weighting (IPTW) Cox proportional hazards models. RESULTS: Among 1,611 patients (61.3% female; mean age, 58.8 years; standard deviation, 13.1 years), 86% received LMWH, 10% warfarin, and 4% DOACs. In the study cohort, LMWH prescriptions remained consistent, warfarin use declined, and DOAC prescriptions notably increased. In IPTW analysis, DOACs showed comparable rates of VTE recurrence (weighted hazard ratio [HR], 0.77 [95% CI, 0.22 to 2.70]; P = .679) and major bleeding (weighted HR, 0.62 [95% CI, 0.15 to 2.55]; P = .506) with LMWH. Warfarin had a higher risk of major bleeding (weighted HR, 2.74 [95% CI, 1.12 to 6.72]; P = .028) but a similar rate of VTE recurrence (weighted HR, 1.46 [95% CI, 0.75 to 2.84]; P = .271) compared with LMWH. Secondary outcomes were consistent across groups. CONCLUSION: LMWH remains the primary treatment for CAT, in line with current guidelines. The study highlights the challenges faced in these settings with the continuous use of warfarin. The comparable efficacy and safety of DOACs with LMWH suggest a potential shift in CAT management within UMICs.

Tramadol-warfarin interaction.

Overview of: Danbury G Susan Gladstone: Prevention of future deaths report [online], 2023. Available: https://www.judiciary. uk/​prevention-​of-​future-​death-​reports/​susan-​gladstone-​prevention-​offuture-​deaths-​report/ [Accessed 8 January 2024].

Evaluation of warfarin management in primary health care centers in Qatar: A retrospective cross-sectional analysis of the national dataset.

BACKGROUND: Warfarin management is associated with severe complications, highlighting the critical need to evaluate the quality of its administration. OBJECTIVES: To evaluate the quality of warfarin management for patients managed in primary healthcare centers by measuring the percentage of Time in Therapeutic Range (TTR) and the proportion of extreme out-of-range international normalized ratio (INR) values. METHODS: This is a cross-sectional study. Data was extracted from a national dataset retrieved from the largest primary healthcare provider in Qatar. TTR was calculated using the traditional method. Inferential and descriptive analyses were performed as appropriate. RESULTS: Four hundred ninety-four patients met the inclusion criteria. The mean (SD) TTR was 45.3 % (17.5). This was significantly lower than the recommended cutoff value (P<0.001). Extreme out-of-range INR accounted for 24.7 % of total INR readings. CONCLUSIONS: The management of patients taking warfarin in Qatar is inadequate. More effective strategies are warranted to ensure safe and effective therapy.

Non-vitamin K oral anticoagulants versus warfarin for the treatment of left ventricular thrombus.

INTRODUCTION: Left ventricular thrombus (LVT) is associated with significant morbidity and mortality. Conventional treatment comprises warfarin-mediated anticoagulation; it is unclear whether non-vitamin K oral anticoagulants (NOACs) exhibit comparable efficacy and safety. Limited data are available for Asian patients. This study compared NOACs with warfarin in terms of clinical efficacy and safety for managing LVT. METHODS: Clinical and echocardiographic records were retrieved for all adult patients with echocardiography-confirmed LVT at a major regional centre in Hong Kong from January 2011 to January 2020. Discontinuation of anticoagulation by 1 year was recorded. Outcomes were compared between patients receiving NOACs and those receiving warfarin. Primary outcomes were cumulative mortality and net adverse clinical events (NACEs). Secondary outcomes were complete LVT resolution and percentage reduction in LVT size at 3 months. RESULTS: Forty-three patients were included; 28 received warfarin and 15 received NOACs, with follow-up periods (mean ± standard deviation) of 20 ± 12 months and 22 ± 9 months, respectively (P=0.522). Use of NOACs was associated with significantly lower NACE risk (hazard ratio [HR]=0.111, 95% confidence interval [CI]=0.012-0.994; P=0.049) and a tendency towards lower cumulative mortality (HR=0.184, 95% CI=0.032-1.059; P=0.058). There were no significant differences in secondary outcomes. Considering LVT resolution, discontinuation of anticoagulation by 1 year was not significantly associated with different outcomes. CONCLUSION: Non-vitamin K oral anticoagulants may be an efficacious and safe alternative to warfarin for LVT management. Future studies should explore the safety and efficacy of anticoagulation discontinuation by 1 year as an overall strategy.

Initiation patterns of anticoagulants for atrial fibrillation among older UK adults with and without chronic kidney disease, 2010-2020.

BACKGROUND: There is a paucity of data on the initiation patterns of anticoagulants among older atrial fibrillation patients with and without chronic kidney disease (CKD). SETTING AND METHODS: We used the UK Clinical Practice Research Datalink (2010-2020) to conduct a retrospective cohort study to evaluate anticoagulant initiation patterns for older adults (≥65 years) with CKD (N=18 421) and without CKD (N=41 901), categorised by severity of CKD: stages 3a, 3b and 4, and initiation dose by respective direct oral anticoagulant (DOAC). RESULTS: Over the study period, warfarin initiations sharply declined and were replaced by DOACs regardless of CKD status or stage. By 2020, patients with CKD were modestly more likely (8.8% difference) to initiate apixaban compared with those without CKD (58.8% vs 50.0%; p<0.01). Among patients with CKD, those with stages 3a and 3b CKD had higher apixaban initiations compared with stage 4 CKD (56.9% and 64.6% vs 52.9%, respectively; p<0.01). Conversely, patients with stage 4 CKD were over three times more likely to initiate warfarin (14.7%) compared with those with stage 3a (2.6%) and 3b (4.0%) CKD (p<0.01). Throughout the study period, there was a rise in the proportion of patients initiating the higher 10 mg daily dose for apixaban, with an increase of 20.6% (from 64.3% in 2013 to 84.9% in 2020; p value for trend <0.01) among patients without CKD, and 21.8% (53.1% to 74.9%; p<0.01), 24.4% (18.8% to 43.2%; p<0.01) and 18.5% (0.0% to 18.2%; p<0.01) among patients with stages 3a, 3b and 4 CKD, respectively. CONCLUSIONS AND RELEVANCE: Initiation of DOACs increased regardless of CKD status and stage, although with a reduced magnitude in severe CKD. Apixaban emerged as the preferred agent, with a secular trend towards the higher initiation dose in all subgroups. These findings illuminate evolving trends and priorities in anticoagulant preferences among patients with and without CKD.

A Novel Nomogram for Predicting Warfarin-Related Bleeding: A Retrospective Cohort Study.

Warfarin is a widely used anticoagulant, and bleeding complications are the main reason why patients discontinue the drug. Currently, there is no nomogram model for warfarin-associated bleeding risk. The aim of this study was to develop a risk-prediction nomogram model for warfarin-related major and clinically relevant non-major (CRNM) bleeding. A total of 280 heart disease outpatients taking warfarin were enrolled, 42 of whom experienced major or CRNM bleeding at the one-year follow-up. The Least Absolute Shrinkage and Selection Operator regression model was employed to identify potential predictors. Backward stepwise selection with the Akaike information criterion was used to establish the optimal predictive nomogram model. The receiver operating characteristic (ROC) curve, calibration plot, Hosmer-Lemeshow goodness-of-fit test, and decision curve analysis (DCA) were used to evaluate the performance of the nomogram. The nomogram consisted of four predictors: female (OR = 1.85; 95% CI: 0.91-3.94), TIA (OR = 6.47; 95% CI: 1.85-22.7), TTR (OR = 0.99; 95% CI: 0.97-1.00), and anemia (OR = 2.30; 95% CI: 1.06-4.84). The model had acceptable discrimination (area under the ROC curve = 0.68, 95% CI: 0.59-0.78), and was significantly better than the existing nine warfarin-related bleeding prediction scoring systems. The calibration plot and Hosmer-Lemeshow test (χ² = 7.557; P = .478) indicated well-calibrated data in the model. The DCA demonstrated good clinical utility. In this study, we developed a nomogram to predict the risk of warfarin-related major or CRNM bleeding. The model has good performance, allows rapid risk stratification of warfarin users, and provides a basis for personalized treatment.

A retrospective analysis of anticoagulant safety among heart transplant recipients undergoing endomyocardial biopsy.

BACKGROUND: Transvenous endomyocardial biopsy is an invasive procedure which is used to diagnose rejection following an orthotopic heart transplant. Endomyocardial biopsy is widely regarded as low risk with all-cause complication rates below 5% in most safety studies. Following transplant, some patients require therapeutic anticoagulation. It is unknown whether anticoagulation increases endomyocardial biopsy bleeding risk. METHODS: Records from 2061 endomyocardial biopsies performed for post-transplant rejection surveillance at our institution between November 2016 and August 2022 were reviewed. Bleeding complications were defined as vascular access-related hematoma or bleeding, procedure-related red blood cell transfusion, and new pericardial effusion. Relative risk and small sample-adjusted 95% confidence interval was calculated to investigate the association between bleeding complications and anticoagulation. RESULTS AND CONCLUSIONS: The overall risk of bleeding was 1.2% (25/2061 cases). There was a statistically significant increase in bleeding among patients on intravenous (RR 4.46, CI 1.09-18.32) but not oral anticoagulants (RR .62, CI .15-2.63) compared to patients without anticoagulant exposure. There was a trend toward increased bleeding among patients taking warfarin with INR ≥ 1.8 (RR 3.74, CI .90-15.43). Importantly, no bleeding events occurred in patients taking direct oral anticoagulants such as apixaban. Based on these results, intravenous rather than oral anticoagulation was associated with a significantly higher risk of bleeding complications following endomyocardial biopsy.

Effectiveness and safety of anticoagulants among patients with venous thromboembolism and active cancer who also had prior bleed or prior renal disease.

OBJECTIVE: Patients with active cancer and venous thromboembolism (VTE) have elevated risk of recurrent VTE (rVTE) and major bleeding (MB). The risk is even higher within those with a prior bleeding event or renal disease. There is a need to understand the risk of rVTE and MB of commonly used anticoagulants among these high-risk patients. METHODS: VTE patients with active cancer and treated with apixaban, warfarin, or low molecular weight heparin (LMWH) within 30 days of VTE were identified from five claims databases in the United States. Inverse probability of treatment weighting (IPTW) was used to balance patient characteristics. The post-IPTW population was stratified by prior bleed or renal disease status. Cox proportional hazards models were used to evaluate interactions between treatment and prior bleed or renal disease on risk of rVTE and MB, with p value <.1 considered significant. RESULTS: Study criteria were met by 30,586 VTE cancer patients: 35.0% had prior bleed and 29.0% had renal disease. For apixaban, LMWH, and warfarin cohorts, the incidence (events per 100 person-years) of MB was higher in patients with prior bleed (17.48 vs 7.58, 25.61 vs 13.11, and 20.38 vs 8.97) or renal disease (15.79 vs 8.71, 22.11 vs 15.90, and 18.49 vs 10.39) vs those without the conditions. Generally, there were no significant interactions between anticoagulant use and prior bleed or renal disease on rVTE and MB (p for interaction >.1). CONCLUSION: The incidence of MB was higher among those with prior bleed or renal disease. Effects of apixaban, warfarin, or LMWH were generally consistent regardless of prior bleed or renal disease status.

Six-week low-molecular-weight heparin versus 12-week warfarin for calf deep vein thrombosis: A randomized, prospective, open-label study.

Current guidelines suggest a 3-month anticoagulant treatment course for isolated distal deep vein thrombosis (IDDVT), but shorter durations of treatment are frequently prescribed in clinical practice. We investigated whether a 6-week treatment with low-molecular-weight heparin (LMWH) at intermediate dosage can be an effective and safe alternative to vitamin K antagonists (VKA) in patients with IDDVT (non-inferiority trial). In a multicenter, open-label, randomized trial, 260 outpatients with symptomatic IDDVT were randomly assigned to receive either LMWH followed by VKA for 12 weeks or LMWH 1 mg/kg subcutaneously twice a day for 2 weeks followed by 1 mg/kg subcutaneously once a day for 4 weeks. The follow-up was 6 months and the primary endpoint was the composite measure of recurrent venous thromboembolism (VTE) defined as: recurrence or extension of IDDVT, proximal DVT, and pulmonary embolism (PE). The study was stopped prematurely due to slow recruiting rates. The primary efficacy outcome occurred in 14 patients receiving LMWH (10.8%) and in five patients receiving VKA (3.8%); risk difference was 0.069 (95% CI: 0.006-0.132), hazard ratio 2.8 (95% CI: 1.04-7.55). There was one PE in the VKA group and one proximal DVT in the LMWH group. IDDVT recurrence was 10.0% in the LMWH group versus 3.1% in the VKA group (p = .024). Two patients had clinically relevant bleedings (1.6%) in the LMWH group versus one (0.8%) in VKA group (p = .56). In conclusion, VKA for 12 weeks seems superior to LMWH for 6 weeks in reducing the risk of VTE recurrences in our cohort of outpatients with IDDVT.