[Interference of oral anti-Xa anticoagulants during monitoring of unfractionated heparin treatments: practical and future attitudes]. / Interférence des anticoagulants oraux directs anti-Xa lors de la surveillance des traitements par héparine non-fractionnée : attitudes pratiques et à venir.

Contrary to direct oral anticoagulants (DOAC), unfractionated heparin (UFH) requires daily monitoring when administered at therapeutic dose. At present, UFH monitoring is preferably carried out by measuring plasma anti-Xa activity, however, in patients previously treated with an anti-Xa DOAC and switched to UFH, there is a high risk of DOAC interfering with the measurement of UFH anti-Xa activity. Residual anti-Xa DOAC in the sample can lead to an overestimation of the anticoagulant activity attributed to heparin and thus to incorrect anticoagulation. This risk of interference should not be overlooked because interference may occur even at concentration of DOAC below the hemostatic safety threshold and can last several days. To overcome this issue, several alternatives are being studied. This note provides an update on anti-Xa DOAC interference and different strategies available in current practice. It also underlines the importance of communication between biologists and clinicians on anticoagulant treatments received by patients.

Early unfractionated heparin treatment in patients with STEMI - trial design and rationale.

The early unfractionated heparin (UFH) treatment in patients with ST-elevation myocardial infarction (STEMI) is a single-center, open-label, randomized controlled trial. The study population are patients with STEMI that undergo primary percutaneous coronary intervention (PPCI). The trial was designed to investigate whether early administration of unfractionated heparin immediately after diagnosis of STEMI is beneficial in terms of patency of infarct-related coronary artery (IRA) when compared to established UFH administration at the time of coronary intervention. The patients will be randomized in 1:1 fashion in one of the two groups. The primary efficacy endpoint of the study is Thrombolysis in myocardial infarction (TIMI) flow grades 2 and 3 on diagnostic coronary angiography. Secondary outcome measures are: TIMI flow after PPCI, progression to cardiogenic shock, 30-day mortality, ST-segment resolution, highest Troponin I and Troponin I values at 24 hours. The safety outcome is bleeding complications. The study of early heparin administration in patients with STEMI will address whether pretreatment with UFH can increase the rate of spontaneous reperfusion of infarct-related coronary artery.

Improving Compliance with a Nurse-Driven Protocol for Unfractionated Heparin Infusions in Patients with Venous Thromboembolism.

BACKGROUND: Unfractionated heparin (UFH) is a high-risk medication that can cause bleeding and/or thrombotic complications if not managed appropriately. Between January and July 2019, our institution experienced a high number of patient safety events related to UFH infusion for the treatment of venous thromboembolism (VTE). PURPOSE: The aim of this quality improvement (QI) initiative was to prevent these safety events by improving compliance with our institution's nurse-driven VTE UFH infusion protocol. METHODS: Baseline data for patients on the VTE UFH protocol were collected to identify improvement opportunities. Compliance with eight standards of care related to the VTE UFH infusion protocol was measured. Time to first therapeutic activated partial thromboplastin time (aPTT) was recorded to assess the benefit of improved compliance. INTERVENTIONS: Institutional policy updates were made to clarify the management of UFH infusions and documentation in the electronic health record. A multidisciplinary workgroup implemented order set changes, nursing communication orders, UFH infusion reports, and a nursing education module to promote compliance with the protocol. RESULTS: The overall rate of compliance with the VTE UFH infusion protocol increased from 79.4% at baseline to 85.2% following implementation of the QI initiative, and the median time to first therapeutic aPTT decreased from 831.5 minutes to 808 minutes over the same period. CONCLUSIONS: A multidisciplinary initiative to address improvement opportunities in a nurse-driven UFH protocol for VTE treatment increased compliance with the protocol and decreased the time to first therapeutic aPTT.

Agreement between the thromboelastography reaction time parameter using fresh and citrated whole blood during extracorporeal membrane oxygenation with Teg®5000 and Teg®6s.

PURPOSE: We aimed at assessing the correlation between TEG reaction time (TEG-R) in citrated and fresh blood samples with TEG5000 and TEG 6S during heparin administration in patients with and without ECMO support. MATERIALS AND METHODS: Paired TEG5000 (fresh and citrated whole blood, kaolin and kaolin-heparinase) and TEG6S (citrated whole blood) samples were obtained, together with standard coagulation laboratory tests. Bland-Altman analysis and Lin's concordance correlation coefficient were used to assess agreement. RESULTS: Thirteen consecutive ECMO patients and eight consecutive non-ECMO patients were enrolled and TEG was performed for a total of 84 paired samples. ECMO patients received 19.2 (12.6-25.8) U/kg/h of heparin. Five of the non-ECMO patients did not receive heparin, two of them received a very low prophylactic dose (1.6 and 2.9 IU/kg/h, respectively), and one of them 13.1 U/kg/h of heparin. Using TEG®5000, TEG-R was 21.0 (-23.4; 65.5) min longer on fresh compared to citrated blood in patients receiving heparin while only 1.58 (-5.5; 8.7) min longer in patients not-receiving heparin. These differences were reverted by heparinase. CONCLUSIONS: Using citrated-recalcified blood to perform TEG might lead to underestimation of the effect of heparin.

Differential Use of Glycoprotein IIb/IIIa Inhibitors with Bivalirudin in Patients with STEMI Undergoing PCI: A Systematic Review and Meta-Analysis.

AIM: The efficacy and safety of bivalirudin when used concurrently with glycoprotein IIb/IIIa inhibitors (GPI) is uncertain. In this systematic review and meta-analysis, we aimed to evaluate the efficacy and safety of bivalirudin versus heparin in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) and to explore the impact of differential use (greater and balanced) of GPI. METHODS: Online databases were queried from inception to March 2023 to identify eight randomized controlled trials (n = 22,483) for inclusion. The primary outcomes included all-cause mortality, major bleeding, major adverse cardiovascular events (MACE), and net adverse clinical events (NACE). Secondary efficacy endpoints included cardiac death, reinfarction, stent thrombosis (ST), and stroke. Data were pooled using a random-effects model to derive risk ratios (RRs) and 95% confidence intervals (CIs). RESULTS: When compared to heparin, bivalirudin was associated with a significant reduction in all-cause mortality (RR 0.83; 95% CI 0.72-0.97; P = 0.02), major bleeding (RR 0.73; 95% CI 0.57-0.93; P = 0.01), cardiac death (RR 0.79; 95% CI 0.66-0.94; P = 0.01), and NACE (RR 0.80; 95% CI 0.72-0.89; P < 0.0001). However, while the bivalirudin arm showed an increased likelihood of ST in the greater GPI subgroup (RR 1.70; 95% CI 1.13-2.56; P = 0.01), it was associated with a decreased likelihood of ST in the balanced GPI subgroup (RR 0.40; 95% CI 0.24-0.65; P = 0.0003). CONCLUSION: Overall, our findings suggest that bivalirudin may be a more efficacious intervention than heparin for reducing certain adverse events in patients with STEMI undergoing primary PCI.

Acute coronary syndrome in patients treated by vitamin K antagonists or non-vitamin K antagonist oral anticoagulants: Proposed management algorithm for the first 48hours.

Around 10% of patients with acute coronary syndrome are treated by vitamin K antagonists or non-vitamin K antagonist oral anticoagulants for various indications. The initial management of these patients is highly complex, and new guidelines specify that, only during percutaneous coronary intervention, a bolus of unfractionated heparin is recommended in one of the following circumstances: (1) if the patient is receiving a non-vitamin K antagonist oral anticoagulant; or (2) if the international normalized ratio is<2.5 in a patient being treated with a vitamin K antagonist. In this review, we report on five key messages essential for the management of these patients. There are no randomized studies to date, and we propose two diagnostic and/or therapeutic decision algorithms. However, randomized studies are needed to validate these strategies.

Don't Fear the Bleed: Assessing Postoperative Bleeding Incidence After Instituting a Standardized Prophylactic Heparin Protocol in Bariatric Patients.

Background: Bariatric surgery is a frequently performed procedure in the United States, accounting for ∼40,000 procedures annually. Patients undergoing bariatric surgery are at high risk for postoperative thrombosis, with a venous thromboembolism (VTE) rate of up to 6.4%. Despite this risk, there is a lack of guidelines recommending postoperative VTE prophylaxis and it is not routine practice at most hospitals. The postoperative bleeding rate after bariatric surgery is only 1.5%; however, the risk of bleeding may lead to hesitancy for more liberal VTE prophylaxis. Methods: This is a retrospective analysis of bariatric surgeries at a single institution in 2019 and 2021. Data were obtained from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) and electronic medical record review for all patients undergoing sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), or conversion to RYGB. The primary outcomes were composite bleeding events, which included postoperative transfusion, postoperative endoscopy or return to operating room (OR) (for bleeding), intra-abdominal hematoma, gastrointestinal (GI) bleeding, or incisional hematoma. Results: There were a total of 2067 patients in the cohort, with 1043 surgeries in 2019 and 1024 surgeries in 2021. There was no difference between bleeding events after instituting a deep venous thrombosis (DVT) prophylaxis protocol in 2021 (27 versus 28 events, P = .76). There was no difference in individual bleeding events between 2019 and 2021. Additionally, there was no significant difference in the rate of VTE between 2019 and 2021 (2 versus 5 events, P = .28). Conclusions: After instituting a standard protocol of prophylactic heparin postdischarge, we did not find an increased rate of bleeding events in patients undergoing bariatric surgery. Thus, surgeons can consider prescribing postdischarge chemical VTE prophylaxis without concern for bleeding.

Comparison of Outcomes in Patients Requiring Mechanical Circulatory Support Who Received Cangrelor in Addition to Anticoagulation Versus Anticoagulation Alone.

OBJECTIVES: To evaluate the safety of cangrelor administered concurrently with heparin or bivalirudin in patients on mechanical circulatory support. DESIGN: A single-center, retrospective cohort study of adult patients consecutively admitted between January 2016 and October 2020. SETTING: A tertiary medical center. PARTICIPANTS: Adult patients admitted to the cardiovascular intensive care unit put on mechanical circulatory support for acute myocardial infarction (AMI) or non-AMI indications. Patients who received cangrelor underwent percutaneous coronary intervention with stenting during the index event or within the last year. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the incidence of major bleeding, defined by the Extracorporeal Life Support Organization criteria, in patients with mechanical circulatory support receiving cangrelor plus anticoagulation with heparin or bivalirudin with or without aspirin versus patients who did not receive cangrelor. Sixty-eight patients were included in the study. Twenty-nine patients received cangrelor, and 39 did not. Cangrelor was not associated with an increase in major bleeding; however, the CI was wide (adjusted hazard ratio 1.93, 95% CI 0.61-6.11; p = 0.262). CONCLUSIONS: Patients receiving cangrelor did not appear to be at higher risk of major bleeding compared to patients not receiving cangrelor. Larger trials should be conducted to better evaluate the safety of cangrelor in patients with mechanical circulatory support.

Strategy to optimize PeriproCeduraL AnticOagulation in structural transseptal interventions: Design and rationale of the STOP CLOT trial.

BACKGROUND: Both transcatheter edge-to-edge repair (TEER) of mitral regurgitation or left atrial appendage closure (LAAC) require periprocedural anticoagulation with unfractionated heparin (UFH) that is administered either before or immediately after transseptal puncture (TSP). The optimal timing of UFH administration (before or after TSP) is unknown. The Strategy To Optimize PeriproCeduraL AnticOagulation in Structural Transseptal Interventions trial (STOP CLOT Trial) was designed to determine if early anticoagulation is effective in reducing ischemic complications without increasing the risk of periprocedural bleeding. METHODS: The STOP CLOT trial is a multicenter, prospective, double-blind, placebo-controlled, randomized trial. A total of 410 patients scheduled for TEER or LAAC will be randomized 1:1 either early UFH administration (iv. bolus of 100 units/kg UFH or placebo, given after obtaining femoral vein access and at least 5 minutes prior to the start of the TSP) or late UFH administration (iv. bolus of 100 units/kg UFH or placebo given immediately after TSP). Prespecified preliminary statistical analysis will be performed after complete follow-up of the first 196 randomized subjects. To ensure blinding, a study nurse responsible for randomization and UFH/placebo preparation is not involved in the care of the patients enrolled into the study. The primary study endpoint is a composite of (1) major adverse cardiac and cerebrovascular events (death, stroke, TIA, myocardial infarction, or peripheral embolization) within 30 days post-procedure, (2) intraprocedural fresh thrombus formation in the right or left atrium as assessed with periprocedural transesophageal echocardiography, or (3) occurrence of new ischemic lesions (diameter ≥4 mm) on brain magnetic resonance imaging performed 2 to 5 days after the procedure. The safety endpoint is the occurrence of moderate or severe bleeding complications during the index hospitalization. CONCLUSIONS: Protocols of periprocedural anticoagulation administration during structural interventions have never been tested in a randomized clinical trial. The Stop Clot trial may help reach consensus on the optimal timing of initiation of periprocedural anticoagulation. CLINICAL TRIALS REGISTRATION NUMBER: The study protocol is registered at ClinicalTrials.gov, identifier NCT05305612.

Impact of anticoagulation intensity on blood transfusion for venoarterial extracorporeal membrane oxygenation during lung transplantation.

Venoarterial extracorporeal membrane oxygenation is increasingly used for mechanical circulatory support during lung transplant. Optimal intensity of intraoperative anticoagulation would be expected to mitigate thromboembolism without increasing bleeding and blood product transfusions. Yet, the optimal intensity of intraoperative anticoagulation is unknown. We performed a retrospective cohort study of 163 patients who received a bilateral lung transplant at a single center. We categorized the intensity of anticoagulation into 4 groups (very low to high) based on the bolus dose of unfractionated heparin given during lung transplant and compared the rates of intraoperative blood transfusions and the occurrence of thromboembolism between groups. When compared to the very low-intensity group, each higher intensity group was associated with higher red blood cell, fresh frozen plasma, and platelet transfusions. The occurrence of thromboembolism was similar across groups. These preliminary data suggest that lower intensity anticoagulation may reduce the rate of intraoperative blood transfusions, although further study is needed.

Comparison of the safety and efficacy for different regimens of pharmaco-prophylaxis among severely burned patients: a randomized controlled trial.

PURPOSE: Venous thromboembolism (VTE) is a common complication in critically ill patients, including severe burn cases. Burn patients respond differently to medications due to pharmacokinetic changes. This study aims to assess the feasibility and safety of different VTE pharmaco-prophylaxis in patients admitted to the ICU with severe burns. METHODS: A pilot, open-label randomized controlled trial was conducted on ICU patients with severe burns (BSA ≥ 20%). By using block randomization, patients were allocated to receive high-dose enoxaparin 30 mg q12hours (E30q12), standard-dose enoxaparin 40 mg q24hours (E40q24), or unfractionated heparin (UFH) 5000 Units q8hours. In this study, the primary outcomes assessed were the recruitment and consent rates, as well as bleeding or hematoma at both the donor and graft site. Additionally, secondary measures were evaluated to provide further insights. RESULTS: Twenty adult patients out of 114 screened were enrolled and received E30q12 (40%), E40q24 (30%), and UFH (30%). The recruitment rate was one patient per month with a 100% consent rate. Donor site bleeding occurred in one patient (16.7%) in the UFH group. On the other hand, graft site bleeding was only reported in one patient (12.5%) who received E30q12. Major bleeding happened in two patients, one in E30q12 and one in the UFH group. Five patients (25.0%) had minor bleeding; two patients (25.0%) received E30q12, two patients E40q24, and one patient UFH. RBC transfusion was needed in four patients, two on E30q12 and two on UFH. Only one patient had VTE, while four patients died in the hospital. CONCLUSION: The study observed a low recruitment rate but a high consent rate. Furthermore, there were no major safety concerns identified with any of the three pharmacologic prophylaxis regimens that were evaluated. TRIAL REGISTRATION NUMBER: NCT05237726.

Antithrombin Levels and Heparin Responsiveness during Venoarterial Extracorporeal Membrane Oxygenation: A Prospective Single-center Cohort Study.

BACKGROUND: Unfractionated heparin, administered during venoarterial extracorporeal membrane oxygenation to prevent thromboembolic events, largely depends on plasma antithrombin for its antithrombotic effects. Decreased heparin responsiveness seems frequent on extracorporeal membrane oxygenation; however, its association with acquired antithrombin deficiency is poorly understood. The objective of this study was to describe longitudinal changes in plasma antithrombin levels during extracorporeal membrane oxygenation support and evaluate the association between antithrombin levels and heparin responsiveness. The hypothesis was that extracorporeal membrane oxygenation support would be associated with acquired antithrombin deficiency and related decreased heparin responsiveness. METHODS: Adults receiving venoarterial extracorporeal membrane oxygenation were prospectively included. All patients received continuous intravenous unfractionated heparin using a standardized protocol (target anti-Xa 0.3 to 0.5 IU/ml). For each patient, arterial blood was withdrawn into citrate-containing tubes at 11 time points (from hour 0 up to day 7). Anti-Xa (without dextran or antithrombin added) and antithrombin levels were measured. The primary outcome was the antithrombin plasma level. In the absence of consensus, antithrombin deficiency was defined as a time-weighted average of antithrombin less than or equal to 70%. Data regarding clinical management and heparin dosage were collected. RESULTS: Fifty patients, including 42% postcardiotomy, were included between April 2020 and May 2021, with a total of 447 samples. Median extracorporeal membrane oxygenation duration was 7 (interquartile range, 4 to 12) days. Median antithrombin level was 48% (37 to 60%) at baseline. Antithrombin levels significantly increased throughout the follow-up. Time-weighted average of antithrombin levels was 63% (57 to 73%) and was less than or equal to 70% in 32 (64%) of patients. Overall, 45 (90%) patients had at least one antithrombin value less than 70%, and 35 (70%) had at least one antithrombin value less than 50%. Antithrombin levels were not significantly associated with heparin responsiveness evaluated by anti-Xa assay or heparin dosage. CONCLUSIONS: Venoarterial extracorporeal membrane oxygenation support was associated with a moderate acquired antithrombin deficiency, mainly during the first 72 h, that did not correlate with heparin responsiveness.