Pharmacological and Non-pharmacological Treatments for Stroke Prevention in Patients with Atrial Fibrillation

Atrial fibrillation (AF) is associated with significant risk of stroke and other thromboembolic events, which can be effectively prevented using oral anticoagulation (OAC) with either vitamin K antagonists (VKAs) or non-VKA oral anticoagulants (NOACs) dabigatran, rivaroxaban, apixaban, or edoxaban. Until recently, VKAs were the only available means for OAC treatment. NOACs had similar efficacy and were safer than or as safe as warfarin with respect to reduced rates of hemorrhagic stroke or other intracranial bleeding in the respective pivotal randomized clinical trials (RCTs) of stroke prevention in non-valvular AF patients. Increasing “real-world” evidence on NOACs broadly confirms the results of the RCTs. However, individual patient characteristics including renal function, age, or prior bleeding should be taken into account when choosing the OAC with best risk–benefit profile. In patients ineligible for OACs, surgical or interventional stroke prevention strategies should be considered. In patients undergoing cardiac surgery for other reasons, the left atrial appendage excision, ligation, or amputation may be the best option. Importantly, residual stumps or insufficient ligation may result in even higher stroke risk than without intervention. Percutaneous left atrial appendage occlusion, although requiring minimally invasive access, failed to demonstrate reduced ischemic stroke events compared to warfarin. In this review article, we summarize current treatment options and discuss the strengths and major limitations of the therapies for stroke risk reduction in patients with AF.     

Clinical outcomes with unfractionated heparin or low-molecular-weight heparin as bridging therapy in patients on long-term oral anticoagulants: the REGIMEN registry.

BACKGROUND: Patients who receive long-term oral anticoagulant (OAC) therapy often require interruption of OAC for an elective surgical or an invasive procedure. Heparin bridging therapy has been used in these situations, although the optimal method has not been established. No large prospective studies have compared unfractionated heparin (UFH) with low-molecular-weight heparin (LMWH) for the perioperative management of patients at risk of thromboembolism requiring temporary interruption of long-term OAC therapy. PATIENTS/METHODS: This multicenter, observational, prospective registry conducted in North America enrolled 901 eligible patients on long-term OAC who required heparin bridging therapy for an elective surgical or invasive procedure. Practice patterns and clinical outcomes were compared between patients who received either UFH alone (n = 180) or LMWH alone (n = 721). RESULTS: Overall, the majority of patients (74.5%) requiring heparin bridging therapy had arterial indications for OAC. LMWH, in mostly twice-daily treatment doses, represented approximately 80% of the study population. LMWH-bridged patients had significantly fewer arterial indications for OAC, a lower mean Charlson comorbidity score, and were less likely to undergo major or cardiothoracic surgery, receive intraprocedural anticoagulants or thrombolytics, or receive general anesthesia than UFH-bridged patients (all P < 0.05). The LMWH group had significantly more bridging therapy completed in an outpatient setting or with a < 24-h hospital stay vs. the UFH group (63.6% vs. 6.1%, P < 0.001). In the LMWH and UFH groups, similar rates of overall adverse events (16.2% vs. 17.1%, respectively, P = 0.81), major composite adverse events (arterial/venous thromboembolism, major bleed, and death; 4.2% vs. 7.9%, respectively, P = 0.07) and major bleeds (3.3% vs. 5.5%, respectively, P = 0.25) were observed. The thromboembolic event rates were 2.4% for UFH and 0.9% for LMWH. Logistic regression analysis revealed that for postoperative heparin use a Charlson comorbidity score > 1 was an independent predictor of a major bleed and that vascular, general, and major surgery were associated with non-significant trends towards an increased risk of major bleed. CONCLUSIONS: Treatment-dose LMWH, mostly in the outpatient setting, is used substantially more often than UFH as bridging therapy in patients with predominately arterial indications for OAC. Overall adverse events, including thromboembolism and bleeding, are similar for patients treated with LMWH or UFH. Postoperative heparin bridging should be used with caution in patients with multiple comorbidities and those undergoing vascular, general, and major surgery. These findings need to be confirmed using large randomized trials for specific patient groups undergoing specific procedures.     

Oral Anticoagulation Therapy for Venous Thromboembolism in Norway: Time Trends and Treatment Patterns

PurposeData describing treatment patterns of patients with venous thromboembolism (VTE) patients in Scandinavia are scarce. This study sought to address this scarcity by describing demographic and clinical characteristics, trends in the use of oral anticoagulants (OACs), and treatment patterns in patients treated for VTE in Norway between 2013 and 2017.MethodsUsing data from Norway's nationwide registries, a cohort study included patients newly (after 2008) treated OACs who were diagnosed with VTE between January 2013 and December 2017 and were dispensed an OAC (warfarin, apixaban, rivaroxaban, dabigatran, or edoxaban) within 30 days. Patient characteristics and the percentage of patients with VTE who initiated treatment with each OAC for each calendar year were reported. Initial therapy persistence was assessed using Kaplan-Meier curves and compared between the OAC groups using the log-rank test.FindingsThe comorbidity burden was similar between patients taking warfarin and those taking apixaban but lower among patients taking rivaroxaban. Direct oral anticoagulant (DOAC) use increased from 33.2% to 93.6% during the study period, whereas warfarin use decreased. Persistence was higher in the apixaban cohort compared with the warfarin cohort, with the difference mostly apparent after 6 months, whereas persistence was similar between the patients taking rivaroxaban and those taking warfarin.ImplicationsBetween 2013 and 2017, DOAC use among patients with VTEs increased markedly in Norway, whereas the use of warfarin decreased. Patients taking apixaban had higher persistence compared with those taking warfarin, whereas patients taking warfarin and those taking rivaroxaban had similar persistence. Further studies with longer follow-up are required to examine the use of extended OAC treatment for VTE.     

Use of direct oral anticoagulants in antiphospholipid syndrome

Summary

The direct oral anticoagulants (DOACs) are therapeutic alternatives to warfarin and other vitamin K antagonists (VKAs), and constitute the standard of care for many indications. VKAs constitute the conventional therapy for the treatment and secondary thromboprophylaxis of thrombotic antiphospholipid syndrome (APS), but are often problematic, owing to the variable sensitivity of thromboplastins to lupus anticoagulant. Thus, the International Normalized Ratio may not accurately reflect anticoagulation intensity, or be clinically effective. Definition of the current role of DOACs in the treatment of APS is based on limited clinical trial data and information from other sources, including manufacturers’ data, case series or cohort studies, and expert consensus. The Rivaroxaban in Antiphospholipid Syndrome (RAPS) randomized controlled trial (RCT), which had a laboratory surrogate primary outcome measure, suggests that rivaroxaban has the potential to be an effective and convenient alternative to warfarin in thrombotic APS patients with a single venous thromboembolism event requiring standard‐intensity anticoagulation. However, further studies, in particular to provide better long‐term efficacy and safety data, are needed before it can be widely recommended. APS patients are clinically heterogeneous, with the risk of recurrent thrombosis and the intensity of anticoagulation being influenced by their clinical phenotype and risk profile. DOAC trials involving homogeneous thrombotic APS populations, with the antiphospholipid antibody status well defined, will help to optimize the appropriate treatment in APS patient subgroups. Ongoing and emerging DOAC RCTs should provide further information to guide the use of DOACs in APS patients. Optimal identification of APS patients is a key step in working towards improved therapeutic strategies in these individuals.

     

Perioperative management of patients on direct oral anticoagulants

Direct oral anticoagulants (DOACs) have been licensed worldwide for several years for various indications. Each year, 10–15% of patients on oral anticoagulants will undergo an invasive procedure and expert groups have issued several guidelines on perioperative management in such situations. The perioperative guidelines have undergone numerous updates as clinical experience of emergency management has increased and perioperative studies including measurement of residual anticoagulant levels have been published. The high inter-patient variability of DOAC plasma levels has challenged the traditional recommendation that perioperative DOAC interruption should be based only on the elimination half-life of DOACs, especially before invasive procedures carrying a high risk of bleeding. Furthermore, recent publications have highlighted the potential danger of heparin bridging use when DOACs are stopped before an invasive procedure.As antidotes are progressively becoming available to manage severe bleeding or urgent procedures in patients on DOACs, accurate laboratory tests have become the standard to guide their administration and their actions need to be well understood by clinicians.This review aims to provide a systematic approach to managing patients on DOACs, based on recent updates of various perioperative guidance, and highlighting the advantages and limits of recommendations based on pharmacokinetic properties and laboratory tests.     

Clinical Benefit of Direct Oral Anticoagulants Versus Vitamin K Antagonists in Patients with Atrial Fibrillation and Bioprosthetic Heart Valves

PurposeThe use of direct oral anticoagulants (DOACs) in patients with atrial fibrillation (AF) and bioprosthetic heart valve is still controversial. The aim of this study was to compare the tolerability and effectiveness of treatment with DOACs versus vitamin K antagonists (VKAs) in patients with AF and a bioprosthetic heart valve in clinical practice.MethodsData for this study were sourced from the multicenter, prospectively maintained AF Research Database (NCT03760874), which includes all patients with AF undergoing follow-up at participating centers through outpatient visits every 3–6 months. The rates of occurrence of thromboembolic events (ischemic stroke, transient ischemic attack, systemic embolism), major bleed, and intracranial hemorrhage (ICH) were assessed. These data were used for quantifying the net clinical benefit (NCB) of DOACs versus VKAs, in accordance with the following formula: (Thromboembolic events incidence rate with VKAs – Thromboembolic events incidence rate with DOACs) – Weighting factor × (ICH rate with DOACs – ICH incidence rate with VKAs). The database was retrospectively queried for patients with AF who were prescribed a DOAC or VKA and had a history of bioprosthetic heart valve replacement.FindingsA total of 434 patients with AF (DOACs, n = 211; VKAs, n = 223) were identified. Propensity score matching identified 130 patients prescribed DOACs (apixaban, 55.4%; rivaroxaban, 30.0%; dabigatran, 13.1%; edoxaban, 1.4%) and the same number of VKA recipients (warfarin, 89.2%; acenocoumarol, 10.8%). The mean (SD) duration of follow-up was 26.8 (2.3) months. The incidence rates of thromboembolic events were 1.3 per 100 person-years in the DOAC group versus 2.0 per 100 person-years in the VKA group (P = 0.14). The incidence rates of major bleed events were 2.6 per 100 person-years in the DOAC group versus 4.9 per 100 person-years in the VKA group (P = 0.47). The incidence rates of ICH were 0.38 per 100 person-years in the DOAC group versus 1.16 in the VKA group (hazard ratio = 0.33; 95% CI, 0.05–2.34; P = 0.3). A positive NCB of DOACs over VKAs of +1.87 was found.ImplicationsAccording to these data from clinical practice, DOACs seem to be associated with a greater NCB versus VKAs in patients with AF with a bioprosthetic heart valve, primarily due to lower rates of both major bleeds and thromboembolic events.     

Pharmacokinetics of Direct Oral Anticoagulants in Patients With Atrial Fibrillation and Extreme Obesity

PurposeDirect oral anticoagulants (DOACs) are recommended in preference to vitamin K antagonists (VKAs) for stroke prevention in patients with atrial fibrillation (AF) eligible for oral anticoagulation therapy; however, data and clinical experiences supporting the use of DOACs in patients with a body mass index ≥40 kg/m² or weight >120 kg remain limited. The aim of this study was to evaluate the pharmacokinetic properties of DOACs in patients with AF and extreme obesity.MethodsWe enrolled all consecutive patients with AF and extreme obesity undergoing treatment with DOACs followed up at Monaldi Hospital, Naples, Italy. To determine peak plasma and trough levels of DOACs, plasma samples were collected at 2nd, 4th, 6th, and 12th hours from the last dose intake in patients receiving apixaban and dabigatran and at the 2nd, 4th, 6th, and 24th hours in those receiving edoxaban and rivaroxaban. The DOACs’ peak and trough plasma levels obtained from our study population were compared with those sourced from pharmacokinetic studies among patients without obesity, defined as a normal reference range in the literature. If at least 1 peak or trough plasma level was found ​​below or above the normal reference ranges, the patients were classified as having out-of-range DOAC plasma levels. Study population was then divided into in-range and out-of-range groups. Baseline characteristics, including DOAC treatment, were compared between the 2 groups. Univariate and multivariate logistic regression analysis were performed to identify baseline variables associated with DOACs’ plasma concentration out of the expected range.FindingsA total of 58 patients (mean [SD] age, 70.93 [8.73] years; 40% female) with extreme obesity (mean [SD] body mass index. 44.43 [3.54] kg/m²) and AF while undergoing DOAC treatment were included in the present study. In 9 patients (15.5 %), the DOAC plasma concentrations were out of the expected ranges (out-of-range group);, indicating a greater likelihood of edoxaban 30 mg treatment (33% vs 2%; P < 0.01) and inappropriate DOAC underdosing (56% vs 4%; P < 0.005) compared with the in-range group. According to the multivariate logistic analysis (P = 0.0011), the inappropriate DOAC underdosing (hazard ratio = 29.37; P = 0.0002) was an independent predictor of DOAC plasma levels out of the expected ranges.ImplicationsPatients with extreme obesity and AF who were receiving DOAC therapy had DOAC plasma concentrations in the expected range. The inappropriate DOAC underdosing seems to be the only independent clinical factor associated with a plasma concentration of the drug out of the expected range.     

No increased bleeding events with continuation of oral anticoagulation therapy for patients undergoing cardiac device procedure

Background: Switching warfarin for heparin has been a practice for managing periprocedural anticoagulation in high‐risk patients undergoing device‐related procedures. We sought to investigate whether continuation of warfarin sodium therapy without heparin bridging is safe and, when it is continued, the optimal international normalized ratio (INR) without increased bleeding risk at time of device‐related procedure. Methods and Results: We retrospectively studied 766 consecutive patients taking warfarin long term who underwent device‐related procedures. Patients were grouped by treatment: discontinued warfarin (?warfarin, n = 243), no interruption of warfarin (+warfarin, n = 324), and discontinued warfarin with heparin bridging (+heparin, n = 199). The study primary endpoint was systemic bleeding or formation of moderate or severe pocket hematoma within 30 days of the procedure. Thirty‐one (4%) patients had bleeding events, including pocket hematoma in 29 patients. The bleeding events occurred more often for +heparin (7.0%) than ?warfarin (2.1%) or +warfarin (3.7%, P = 0.029). For +warfarin group, INR of 2.0–2.5 at time of procedure did not increase bleeding risk compared with INR less than 1.5 (3.7% vs 3.4%; P = 0.72), but INR greater than 2.5 increased the bleeding risk (10.0% vs 3.4%; P = 0.029). Concomitant aspirin use with warfarin significantly increased bleeding risk than warfarin alone (5.6% vs 1.4%, P = 0.02). Median length of hospitalization was significantly shorter for +warfarin than +heparin (1 vs 6 days; P < 0.001). Conclusion: Continuation of oral anticoagulation therapy with an INR level of <2.5 does not impose increased risk of bleeding for device‐related procedures, although precaution is necessary to avoid supratherapeutic anticoagulation levels. (PACE 2011; 34:868–874)     

Hemorrhagic risk and intracranial complications in patients with minor head injury (MHI) taking different oral anticoagulants

The correlation between direct oral anticoagulants (DOACs) or Vitamin K Antagonist (VKAs) intake and the incidence of intracranial complications after minor head injury (MHI) is still object of debate: preliminary observation seems to demonstrate lower incidence in intracranial bleeding complications (ICH) in patients taking DOACs than VKA. METHODS. This prospective and observational study was performed to clarify the incidence of ICH in patients in DOACs compared to VKAs. Between January 2016 and April 2018 we have recorded in our ED patients with MHI taking oral anticoagulants. Their hemorragic risk score was calculated and recorded for each patient (Has Bled, Atria and Orbit). RESULTS A total of 402 patients with MHI taking anticoagulant were collected: 226 were receiving one of the four DOACs (dabigatran, rivaroxaban, apixaban or edoxaban) while 176 patients were in therapy with VKA. The rate of intracranial complications was significantly lower in patients receiving DOACs than in patients treated with VKA (p < 0.01). In the VKA group two patients died because of intracranial bleeding. No deaths were recorded in the DOACs group. DISCUSSION patients with MHI who take DOACs have a significant lower incidence of intracranial bleeding complications than those treated with vitamin k antagonists. This statement is supported by the observation that the hemorrhagic risk, measured according to the chosen scores, was similar between the two groups.     

Mortality on DOACs Versus on Vitamin K Antagonists in Atrial Fibrillation: Analysis of the Hungarian Health Insurance Fund Database

PurposeLimited real-world data are available on the survival of patients treated with vitamin K antagonists (VKAs) versus with direct oral anticoagulants (DOACs) for nonvalvular atrial fibrillation (AF). In this nationwide registry, we analyzed the mortality risk of patients with nonvalvular AF taking DOACs versus VKAs, with a special attention to the early treatment period.MethodsThe Hungarian National Health Insurance Fund (NHIF) database was searched to identify patients treated with VKA or DOAC as a thromboembolic prophylaxis for nonvalvular AF between 2011 and 2016. The overall and the early (0–3, 4–6, and 7–12 months) mortality risks with the 2 types of anticoagulation were compared. A total of 144,394 patients with AF treated with either a VKA (n = 129,925) or a DOAC (n = 14,469) were enrolled.FindingsA 28% improvement in 3-year survival with DOAC treatment compared with VKA treatment was shown. Mortality reduction with DOACs was consistent across different subgroups. However, younger patients (30–59 years old) initiated on DOAC therapy had the greatest RRR (53%) in mortality. Furthermore, DOAC treatment also yielded a benefit of greater magnitude (HR = 0.55; 95% CI, 0.40–0.77, P = 0.001) in the lower (0-1) CHA₂DS₂-VASc score segment and in those with fewer (0–1) bleeding risk factors (HR = 0.50, CI 0.34–0.73, P = 0.001). The RRR in mortality with DOACs was 33% within the first 3 months, and 6% in the second year.ImplicationsThromboembolic prophylaxis with DOACs in this study yielded significantly lower mortality compared with VKA treatment in patients with nonvalvular AF. The largest benefit was shown in the early period after treatment initiation, as well as in younger patients, those with a lower CHA₂DS₂-VASc score, and those with fewer bleeding risk factors.     

Anticoagulation management in the ambulatory surgical setting

Many people receiving maintenance anticoagulation therapy require surgery each year in ambulatory surgery centers. National safety organizations focus attention toward improving anticoagulation management, and the American College of Chest Physicians has established guidelines for appropriate anticoagulation management to balance the risk of thromboembolism when warfarin is discontinued with the risk of bleeding when anticoagulation therapy is maintained. The guidelines recommend that patients at high or moderate risk for thromboembolism should be bridged with subcutaneous low-molecular-weight heparin or IV unfractionated heparin with the interruption of warfarin, and low-risk patients may require subcutaneous low-molecular-weight heparin or no bridging with the interruption of warfarin. The guidelines recommend the continuation of warfarin for patients who are undergoing minor dermatologic or dental procedures or cataract removal. The literature reveals, however, that there is not adequate adherence to these recommendations and guidelines. Management of anticoagulation therapy by a nurse practitioner may improve compliance and safety in ambulatory surgery centers.     

Predictors of major bleeding in peri‐procedural anticoagulation management

Summary. Background: Appropriate periprocedural management for chronically anticoagulated patients requires assessment of patient‐specific thrombosis and bleeding risks. However, predictors of post‐procedure bleeding are unknown. Objectives: To determine the 3‐month cumulative incidence and independent predictors of peri‐procedural bleeding in chronically anticoagulated patients requiring temporary warfarin interruption for an invasive procedure. Methods: In a protocol driven, cohort study design, all patients referred to the Mayo Clinic Thrombophilia Center for peri‐procedural anticoagulation management (1997–2007; n = 2182), were followed forward in time to determine the 3‐month cumulative incidence of peri‐procedural bleeding (Kaplan–Meier product limit) and potential predictors of bleeding (Cox proportional hazards). Decisions to ‘bridge’ with low‐molecular‐weight heparin were based on estimated thromboembolism and bleeding risk. Results: Indications for chronic anticoagulation included venous thromboembolism (38%), atrial fibrillation (30%) and mechanical heart valves (27%). Of these, 1496 (69%) patients received bridging therapy. The 3‐month cumulative incidence rates of major and overall bleeding were 2.1% and 5.1%, respectively. Major bleeding occurred more frequently in patients receiving bridging therapy (3% vs. 1%; P = 0.017). Independent predictors (hazard ratio; 95% confidence interval) of major bleeding included mitral mechanical heart valve (2.2; 1.1–4.3), active cancer (1.8; 1.0–3.1), prior bleeding history (2.6; 1.5–4.5) and re‐initiation of heparin therapy within 24 h after the procedure (1.9; 1.1–3.4). Conclusion: Factors predisposing to peri‐procedural bleeding are primarily patient‐specific. Premature heparin re‐initiation is an avoidable provider‐specific variable to consider.     

Laboratory testing in patients treated with direct oral anticoagulants: a practical guide for clinicians

Click to hear Dr Baglin's perspective on the role of the laboratory in treatment with new oral anticoagulants

Summary

One of the key benefits of the direct oral anticoagulants (DOACs) is that they do not require routine laboratory monitoring. Nevertheless, assessment of DOAC exposure and anticoagulant effects may become useful in various clinical scenarios. The five approved DOACs (apixaban, betrixaban, dabigatran etexilate, edoxaban and rivaroxaban) have different characteristics impacting assay selection and the interpretation of results. This article provides an updated overview on (i) which test to use (and their advantages and limitations), (ii) when to assay DOAC levels, (iii) how to interpret the results relating to bleeding risk, emergency situations and perioperative management, and (iv) what is the impact of DOACs on routine and specialized coagulation assays. Assays for anti‐Xa or anti‐IIa activity are the preferred methods when quantitative information is useful, although the situations in which to test for DOAC levels are still debated. Different reagent sensitivities and variabilities in laboratory calibrations impact assay results. International calibration standards for all specific tests for each DOAC are needed to reduce the inter‐laboratory variability and allow inter‐study comparisons. The impact of the DOACs on hemostasis testing may cause false‐positive or false‐negative results; however, these can be minimized by using specific assays and collecting blood samples at trough concentrations. Finally, prospective clinical trials are needed to validate the safety and efficacy of proposed laboratory thresholds in relation to clinical decisions. We offer recommendations on the tests to use for measuring DOACs and practical guidance on laboratory testing to help patient management and avoid diagnostic errors.     

左心室血栓治疗的系统回顾及meta分析

目的 左心室血栓(left ventricular thrombus, LVT)是多种心脏疾病的并发症,血栓脱落可导致后果严重的体循环栓塞,因此及早治疗LVT极为重要。方法 本文分别从抗凝治疗、溶栓治疗、抗血小板治疗、手术治疗4方面对LVT的治疗进行文献检索。在web of science, Ovid,EMBASE,Pubmed和Cochrane数据库应用“左心室血栓”“新型口服抗凝药”“Xa因子抑制剂”,“NOAC”,“DOAC”,“达比加群”,“利伐沙班”,“依度沙班”,“阿哌沙班”“维生素K拮抗剂”和“华法林”作为主题词进行检索。共25篇文章可用于meta分析以比较新型口服抗凝剂(direct oral anticoagulant,DOAC)与维生素K拮抗剂(vitamin K antagonist,VKA)的治疗效果及不良事件的发生率,对目前可检索到的应用肝素、抗血小板药物、溶栓、手术治疗LVT的文章进行系统回顾。结果 DOAC治疗LVT的出血及卒中事件的发生率、全因死亡率低于VKA,而LVT的消失率、严重出血事件的发生率、出现全身栓塞事件的发生率两种治疗方法差异无统计学意义。...     

Decision-Making in Clinical Practice: Oral Anticoagulant Therapy in Patients with Non-valvular Atrial Fibrillation and a Single Additional Stroke Risk Factor

Approximately 1 in 3–4 patients presenting with an ischemic stroke will also have atrial fibrillation (AF), and AF-related strokes can be effectively prevented using oral anticoagulant therapy (OAC), either with well-controlled vitamin K antagonists (VKAs) or non-vitamin K antagonist oral anticoagulants (NOACs). In addition, OAC use (both VKAs and NOACs) is associated with a 26% reduction in all-cause mortality (VKAs) or an additional 10% mortality reduction with NOACs relative to VKAs. The decision to use OAC in individual AF patient is based on the estimated balance of the benefit from ischemic stroke reduction against the risk of major OAC-related bleeding [essentially intracranial hemorrhage (ICH)]. Better appreciation of the importance of VKAs’ anticoagulation quality [a target time in therapeutic range (TTR) of ≥70%] and the availability of NOACs (which offer better safety compared to VKAs) have decreased the estimated threshold for OAC treatment in AF patients towards lower stroke risk levels. Still, contemporary registry-based data show that OAC is often underused in AF patients at increased risk of stroke. The uncertainty whether to use OAC may be particularly pronounced in AF patients with a single additional stroke risk factor, who are often (mis)perceived as having a “borderline” or insufficient stroke risk to trigger the use of OAC. However, observational data from real-world AF cohorts show that the annual stroke rates in such patients are higher than in patients with no additional stroke risk factors, and OAC use has been associated with reduction in stroke, systemic embolism, or death in comparison to no therapy or aspirin, with no increase in the risk of bleeding relative to aspirin. In this review article, we summarize the basic principles of stroke risk stratification in AF patients and discuss contemporary real-world evidence on OAC use and outcomes of OAC treatment in AF patients with a single additional stroke risk factor in various real-world AF cohorts.     

Bridging therapy in patients on long-term oral anticoagulants who require surgery: the Prospective Peri-operative Enoxaparin Cohort Trial (PROSPECT)

BACKGROUND: The peri-operative management of patients on oral anticoagulants (OACs) is a common clinical problem. Our aim was to determine the incidence of major bleeding during peri-operative administration of treatment-dose enoxaparin and the impact of the extensiveness of the procedure on the risk of bleeding. METHODS: We performed a prospective cohort study of 260 patients at 24 North American sites on OACs for atrial fibrillation or a history of deep vein thrombosis (DVT) requiring invasive or surgical procedures whose treating physician felt that bridging therapy was required. Warfarin was withheld, and once-daily s.c. enoxaparin (1.5 mg kg(-1)) was given peri-operatively. Patients were followed for 28 days after OAC was therapeutic. RESULTS: Major bleeding was observed in nine of 260 patients (3.5%, 95% CI: 1.6-6.5). The bleeding risk varied markedly by extensiveness of procedure: the incidence of major bleeding for invasive procedures, minor surgery and major surgery was 0.7% (95% CI: 0.02-3.7), 0% (95% CI: 0-5.0), and 20.0% (95% CI: 9.1-35.7), respectively. There were five thromboembolic events in total (1.9%, 95% CI: 0.6-4.4). There were four arterial events (2.3%, 95% CI: 0.6-5.7) in 176 patients with atrial fibrillation, and one venous event (1.0%, 95% ci: 0.03-5.7) in 96 patients with prior DVT/ CONCLUSIONS: Bridging therapy with once-daily therapeutic-dose enoxaparin administered primarily in an outpatient setting has a low incidence of major bleeding for patients undergoing invasive procedures and minor surgery. Further studies are needed to optimize the bridging strategy for patients undergoing major surgery.     

Impact of clinical characteristics of colonic diverticular bleeding in extremely elderly patients treated with direct oral anti-coagulant drugs: a retrospective multi-center study

Since there were no available data about colonic diverticular bleeding in extremely elderly patients (>80 years old) treated with direct oral anticoagulants (DOACs), we tried to determine clinical characteristics in those with colonic diverticular bleeding taking DOACs and to compare clinical outcomes of those in DOAC-treated to those in warfarin-treated . We enrolled DOAC-treated (n = 20) and warfarin-treated (n = 23) extremely elderly patients with diverticular bleeding diagnosed by colonoscopy. We performed a retrospective review of patients’ medical charts and endoscopic findings. We classified colonic diverticular bleeding based on endoscopic features due to modified previous study following three groups, type A (active bleeding), type B (non-active bleeding) and type C (bleeding suspected). Clinical outcomes such as number of recurrent bleeding, thrombotic events and mortality were estimated. There were no differences in endoscopical features and clinical characteristics between patients treated with DOAC and warfarin therapy. However, the number of recurrent bleeding, frequency of required blood transfusions and units of blood transfusion in warfarin-treated patients were significantly higher (p<0.05) compared to those in DOAC-treated groups. In addition, mortality and thrombotic events did not differ between DOAC- and warfarin-treated patients. Clinical outcomes suggest that DOACs can be recommended for extremely elderly patients with colonic diverticular disease.     

Comparative Effectiveness and Safety of Direct-acting Oral Anticoagulants and Warfarin in Patients with Venous Thromboembolism and Active Cancer: An Observational Analysis

PurposeThere is limited evidence to support the use of direct-acting oral anticoagulants (DOACs) in patients with venous thromboembolism (VTE) and active cancer. This study aimed to assess the effectiveness of DOACs versus warfarin for the prevention of recurrent VTE and major bleeding events in patients with VTE and active cancer.MethodsWe identified patients with incident VTE and active cancer who newly initiated treatment with DOACs or warfarin from Truven Health MarketScan Commercial Claims and Medicare supplemental databases. Patients were followed up from treatment initiation (index date) until the occurrence of >7-day gap in treatment, the start of the study comparator, an outcome of interest (recurrent VTE or major bleeding), inpatient death, disenrollment, or end of the study period, whichever occurred first. We controlled for confounders via propensity score matching and estimated the hazard ratios (HRs) using Cox proportional hazards regression models.FindingsA total of 9952 patients were included in the matched cohort (4976 DOACs users and 4976 warfarin users). Patient characteristics were well balanced after matching. We observed a lower incidence of recurrent VTE (3 vs 5 per 100 person-years) and major bleeding events (2 vs 3 per 100 person-years) in the DOAC group compared to warfarin group, respectively. In Cox regression models, use of DOACs (vs warfarin) was associated with a lower risk of recurrent VTE (hazard ratio (HR), 0.59; 95% CI, 0.42–0.82) and major bleeding events (HR, 0.64; 95% CI, 0.44–0.94).ImplicationsOn the basis of our findings, among patients with VTE and active cancer, DOACs offer superior effectiveness with a lower risk of bleeding when compared with warfarin for the secondary prevention of VTE.     

Analysis of risk factors involved in oral-anticoagulant-related intracranial haemorrhages

We examined risk factors for intracranial bleeding while on oral anticoagulants (OACs) in 68 patients admitted to hospital over a 6-year period, and 204 out-patient controls followed-up in an OAC clinic. Under multivariate analysis, significant risk factors for OAC-related intracranial bleeds were hypertension (OR (95%CI) 2.69 (1.04-6.97), duration of OAC therapy < or =12 months (OR 3.74 (1.21-11.56)), duration > or =96 months (OR 0.25 (0.07-0.88)), and International Normalized Ratio on admission >4.5 (OR 10.92 (2.46-48.43)). A logistic regression model including the above variables along with a history of 'cerebrovascular disease' (OR 2.32 (0.98-5.46)) correctly predicted intracranial bleeding (or its absence) during OAC therapy in 85% of all patients. The risk associated with advanced age and concomitant aspirin use was not significantly increased in this analysis. It is important to achieve tight control of INR, particularly in the early months of treatment. Patients with previous cerebrovascular disease are at increased risk of intracranial bleeding on warfarin, and hypertensive patients should have especially close monitoring and optimal control of their blood pressure.     

Rivaroxaban and Apixaban for Initial Treatment of Acute Venous Thromboembolism of Atypical Location

Objectives

To assess the outcome of direct oral anticoagulants (DOACs), specifically Xa inhibitors: rivaroxaban and apixaban, for the treatment of venous thromboembolism (VTE) of atypical location (VTE-AL), portal, mesenteric, hepatic, splenic, gonadal, renal, and cerebral veins, prospectively collected data of Mayo Thrombophilia Clinic Registry were used.