Assessment of Temporary Warfarin Reversal in Patients With Left Ventricular Assist Devices: the KVAD Study.

BACKGROUND: Patients with left ventricular assist devices (LVADs) require interruption of warfarin for invasive procedures, but parenteral bridging is associated with many complications. Four-factor prothrombin complex concentrate (4F-PCC) can temporarily restore hemostasis in patients undergoing anticoagulation with warfarin. OBJECTIVES: This pilot study evaluated the strategy of using variable-dose 4F-PCC to immediately and temporarily reverse warfarin before invasive procedures without holding warfarin in patients with LVADs. The duration of effect of 4F-PCC on factor levels and time to reestablish therapeutic anticoagulation post procedure were assessed. METHODS: Adult patients with LVADs and planned invasive procedures were enrolled from a single center. Warfarin was continued uninterrupted. The 4F-PCC dose administered immediately pre-procedure was based on study protocol. International normalized ratio (INR)- and vitamin K-dependent factor levels were collected before and during the 48 hours after 4F-PCC administration. The use of parenteral bridging, International Society for Thrombosis and Haemostasis major and clinically relevant nonmajor bleeding (CRNMB) and thromboembolic events at 7 and 30 days were collected. RESULTS: In 21 episodes of 4F-PCC reversal, median baseline INR was 2.7 (IQR 2.2-3.2). The median dosage of 4F-PCC administered was 1794 units (IQR 1536-2130). At 24 and 48 hours post 4F-PCC administration, median INRs were 1.8 (IQR 1.7-2.0) and 2.0 (IQR 1.9-2.4). Two patients required postoperative bridging. One patient experienced major bleeding within 72 hours, and 2 experienced CRNMB within 30 days. There were no thromboembolic events. Baseline and post 4F-PCC vitamin K-dependent factor levels corresponded with changes in INR values. The median time to achieve therapeutic INR post-procedure was 2.5 days (IQR, 1-4). CONCLUSION: Administration of 4F-PCC for temporary reversal of warfarin for invasive procedures in patients with LVADs allowed for continued warfarin dosing with minimal use of post-intervention bridging, limited bleeding and no thromboembolic events.

Perioperative risks associated with administration of andexanet alfa during emergency cardiac surgery with circulatory arrest.

This case report describes the perioperative course of a patient undergoing emergency repair of acute type A thoracic aortic dissection. Andexanet alfa was administered intraoperatively to obtain a dry operative field for right axillary artery exposure and cannulation. Andexanet alfa-induced heparin resistance resulted in cardiopulmonary bypass circuit and pericardial thrombosis requiring more than 400,000 units of unfractionated heparin and antithrombin III to overcome. Postoperatively, excessive chest tube output was observed secondary to protracted heparin rebound requiring continuous dosing of protamine. This case demonstrates the significant challenging perioperative, not just intraoperative, hazards associated with intraoperative andexanet alfa use during emergency cardiac surgery with cardiopulmonary bypass.

Hyperfibrinolysis during the treatment of rhabdomyosarcoma.

Background: Coagulopathies are frequently observed in alveolar rhabdomyosarcoma (ARMS), with disseminated intravascular coagulation (DIC) being the most common presentation. However, hyperfibrinolysis represents a distinct but often overlapping and potentially life-threatening subset of coagulation disorders that requires specific diagnostic and management approaches. Key Clinical Question: How can clinicians identify hyperfibrinolysis and what are the implications for management? Clinical Approach: This case report describes a 25-year-old man with metastatic ARMS arising from the prostate who developed persistent gross hematuria one week after initiating chemotherapy. A comprehensive coagulation workup was performed, including assessment of platelet count, prothrombin time, activated partial thromboplastin time, fibrinogen, D-dimer, and fibrin degradation products. Management included repletion of fibrinogen and the use of anti-fibrinolytic agents. Conclusion: Recognizing hyperfibrinolysis in ARMS patients is crucial for appropriate management. Clinicians should maintain a high index of suspicion for hyperfibrinolysis in ARMS patients presenting with severe coagulation abnormalities, particularly those with prostatic involvement or undergoing chemotherapy. In cases of primary hyperfibrinolysis, antifibrinolytic agents may be considered, whereas they are generally contraindicated in DIC.

Impact of as Needed Heparin Boluses on Supratherapeutic Activated Partial Thromboplastin Time in Patients Managed With Extracorporeal Membrane Oxygenation.

INTRODUCTION: Brigham and Women's Hospital historically used titratable weight-based heparin nomograms with as needed boluses managed by extracorporeal membrane oxygenation specialists to achieve a predetermined goal-activated partial thromboplastin time (aPTT). Due to concern amongst providers that as needed boluses may lead to supratherapeutic aPTT's and subsequent bleeding, new nomograms without as needed boluses were implemented. The purpose of this retrospective observational analysis is to provide a comparison in safety and efficacy between the heparin nomograms with as needed boluses and the new nomograms without boluses. METHODS: Adult patients who were cannulated on extracorporeal membrane oxygenation and initiated on an approved heparin bolus nomogram (January 1, 2018-December 31, 2019) or an approved heparin no-bolus nomogram (October 20, 2020-March 31, 2021) were screened for inclusion. The major endpoint evaluated was the percentage of supratherapeutic aPTTs, defined as an aPTT above the upper limit of the specified nomogram goal, within the first 72 hours. RESULTS: A total of 23 patients were included in the bolus nomogram cohort and 9 patients in the no-bolus nomogram cohort. Within the first 72 hours of initiation, there were 11.5% supratherapeutic aPTTs in the bolus group and 5.1% in the no-bolus group ( P = 0.101). Overall there was 1 bleeding event in the no-bolus group (11.1%) and 7 in the bolus group (30.4%) ( P = 0.26). There were no thromboembolic events in either group. CONCLUSIONS: Overall, there was no difference found in the percentage of supratherapeutic aPTTs within the first 72 hours of heparin initiation between the bolus and no-bolus nomograms.

Four years into the pandemic, managing COVID-19 patients with acute coagulopathy: what have we learned?

Coagulopathy alongside micro- and macrovascular thrombotic events were frequent characteristics of patients presenting with acute COVID-19 during the initial stages of the pandemic. However, over the past 4 years, the incidence and manifestations of COVID-19-associated coagulopathy have changed due to immunity from natural infection and vaccination and the appearance of new SARS-CoV-2 variants. Diagnostic criteria and management strategies based on early experience and studies for COVID-19-associated coagulopathy thus require reevaluation. As many other infectious disease states are also associated with hemostatic dysfunction, the coagulopathy associated with COVID-19 may be compounded, especially throughout the winter months, in patients with diverse etiologies of COVID-19 and other infections. This commentary examines what we have learned about COVID-19-associated coagulopathy throughout the pandemic and how we might best prepare to mitigate the hemostatic consequences of emerging infection agents.

Acquired von Willebrand syndrome during extracorporeal membrane oxygenation support: a comprehensive review of current evidence: communication from the ISTH SSC on perioperative and critical care thrombosis and hemostasis.

During extracorporeal membrane oxygenation (ECMO) support, the high shear stress in the ECMO circuit results in increased proteolysis of von Willebrand factor (VWF), loss of VWF high-molecular-weight multimers, and impaired ability to bind to platelets and collagen. These structural changes in VWF are consistent with acquired von Willebrand syndrome (AVWS) type 2A and may contribute to the bleeding diathesis frequently observed in ECMO patients. We performed a systematic review of all clinical studies evaluating the prevalence and associated outcomes of AVWS in ECMO patients. Our findings suggest that almost all ECMO patients develop partial or complete loss of VWF high-molecular-weight multimers within a few hours of device implantation. The AVWS persists as long as the patient is supported by ECMO. Weaning from ECMO rapidly and completely resolves the AVWS. Nevertheless, few studies have reported bleeding outcomes in ECMO patients with AVWS, and the extent to which AVWS contributes to the bleeding diathesis during ECMO support cannot be determined by current evidence. Data supporting the use of VWF concentrates to prevent bleeding complications in ECMO patients remain limited.

Electronic alerts to improve management of heparin-induced thrombocytopenia.

Background: Heparin-induced thrombocytopenia (HIT) is a difficult clinicopathologic diagnosis to make and to treat. Delays in identification and appropriate treatment can lead to increased morbidity and mortality. Objectives: To use electronic health alert interventions to improve provider diagnosis and management of heparin-induced thrombocytopenia through guideline-based, accurate care delivery. Methods: This quality improvement initiative developed 3 electronic health record-based interventions at our 750-bed academic medical center to improve the initial management of suspected HIT between 2018 and 2021: 1. an interruptive alert to recommend discontinuation of active heparin products when signing a heparin-platelet factor 4 test (PF4) order, 2. integrated 4T score calculation in the heparin-PF4 test order, and 3. interruptive alert suggesting not to order heparin-PF4 tests when the 4T score is <4. Changes in practice were assessed over defined time periods pre and post each intervention. Results: Intervention 1 resulted in heparin discontinuation in more patients, with 65% (191 heparin orders/293 heparin-PF4 enzyme-linked immunosorbent assay tests) of cases continuing heparin prealert and only 54% (127 heparin orders/235 heparin-PF4 enzyme-linked immunosorbent assay tests) postinterruptive alert (95% CI 2.3-19.9; P = .015). Intervention 2 increased appropriate heparin-PF4 test ordering from 40.4% (110/272) preintervention to 79.1% (246/311) (95% CI 30.9-46.4; P < .00001) postintervention, with inappropriate PF4 ordering defined as testing when 4T score was <4. Intervention 3 did not lead to reduction in heparin-PF4 testing in the control group (96 inappropriate orders/402 total orders, 24%) compared to the randomized alert group (56 inappropriate orders/298 total orders; 19%) (95% CI -1.2 to 11.5; P = .13). Conclusion: Implementation of unique electronic health record interventions, including both diagnostic and management interventions, led to improved guideline-based, accurate care delivery with 4T score calculation and cessation of heparin for patients with suspected HIT.

Finding a common definition of heparin resistance in adult cardiac surgery: communication from the ISTH SSC subcommittee on perioperative and critical care thrombosis and hemostasis.

Ensuring adequate anticoagulation for patients requiring cardiac surgery and cardiopulmonary bypass (CPB) is important due to the adverse consequences of inadequate anticoagulation with respect to bleeding and thrombosis. When target anticoagulation is not achieved with typical doses, the term heparin resistance is routinely used despite the lack of uniform diagnostic criteria. Prior reports and guidance documents that define heparin resistance in patients requiring CPB and guidance documents remain variable based on the lack of standardized criteria. As a result, we conducted a review of clinical trials and reports to evaluate the various heparin resistance definitions employed in this clinical setting and to identify potential standards for future clinical trials and clinical management. In addition, we also aimed to characterize the differences in the reported incidence of heparin resistance in the adult cardiac surgical literature based on the variability of both target-activated clotting (ACT) values and unfractionated heparin doses. Our findings suggest that the most extensively reported ACT target for CPB is 480 seconds or higher. Although most publications define heparin resistance as a failure to achieve this target after a weight-based dose of either 400 U/kg or 500 U/kg of heparin, a standardized definition would be useful to guide future clinical trials and help improve clinical management. We propose the inability to obtain an ACT target for CPB of 480 seconds or more after 500 U/kg as a standardized definition for heparin resistance in this setting.

Current Gaps in the Provision of Safe and Effective Anticoagulation in Atrial Fibrillation and the Potential for Factor XI-Directed Therapeutics.

The global prevalence of atrial fibrillation is rapidly increasing, in large part due to the aging of the population. Atrial fibrillation is known to increase the risk of thromboembolic stroke by 5 times, but it has been evident for decades that well-managed anticoagulation therapy can greatly attenuate this risk. Despite advances in pharmacology (such as the shift from vitamin K antagonists to direct oral anticoagulants) that have increased the safety and convenience of chronic oral anticoagulation in atrial fibrillation, a preponderance of recent observational data indicates that protection from stroke is poorly achieved on a population basis. This outcomes deficit is multifactorial in origin, stemming from a combination of underprescribing of anticoagulants (often as a result of bleeding concerns by prescribers), limitations of the drugs themselves (drug-drug interactions, bioaccumulation in renal insufficiency, short half-lives that result in lapses in therapeutic effect, etc), and suboptimal patient adherence that results from lack of understanding/education, polypharmacy, fear of bleeding, forgetfulness, and socioeconomic barriers, among other obstacles. Often this adherence is not reported to treating clinicians, further subverting efforts to optimize care. A multidisciplinary, interprofessional panel of clinicians met during the 2023 International Society of Thrombosis and Haemostasis Congress to discuss these gaps in therapy, how they can be more readily recognized, and the potential for factor XI-directed anticoagulants to improve the safety and efficacy of stroke prevention. A full appreciation of this potential requires a reevaluation of traditional teaching about the "coagulation cascade" and decoupling the processes that result in (physiologic) hemostasis and (pathologic) thrombosis. The panel discussion is summarized and presented here.

Early Time Courses of Recurrent Venous Thromboembolism and Bleeding during Apixaban or Dalteparin Therapy for Patients with Cancer.

BACKGROUND: In patients with acute venous thromboembolism (VTE), the rates of recurrence and major bleeding are highest during the first weeks of anticoagulation. The CARAVAGGIO trial demonstrated noninferiority of apixaban to dalteparin for treatment of cancer-associated VTE without an increased risk of major bleeding. We compared the early time course of VTE recurrence and major bleeding events of apixaban compared with dalteparin at 7, 30, and 90 days of treatment in patients with cancer-associated VTE. METHODS: The study design of the CARAVAGGIO trial has been described. Eligible patients were randomly assigned to receive monotherapy with either apixaban or dalteparin for 6 months. The primary efficacy outcome was the incidence of objectively confirmed recurrent VTE. The primary safety outcome was major bleeding. RESULTS: In 1,155 patients, recurrent VTE after 7, 30, and 90 days occurred in 6 (1%), 15 (2.6%), and 27 (4.7%) patients in the apixaban arm versus 5 (0.9%), 20 (3.5%), and 36 (6.2%) patients respectively in the dalteparin arm. By day 7, 30, and 90, major bleeding events had occurred in 3 (0.5%), 9 (1.6%), and 16 (2.8%) patients in the apixaban group versus 5 (0.9%), 11 (1.9%), and 17 (2.9%) patients in the dalteparin group. CONCLUSION: The frequencies of recurrent VTE and major bleeding events at 7, 30, and 90 days of apixaban compared with dalteparin were similar in patients with cancer-associated VTE. This supports the use of apixaban for the initiation and early phase of anticoagulant therapy in cancer-associated VTE.

Reversal of direct oral anticoagulants: guidance from the SSC of the ISTH.

The currently approved direct oral anticoagulants (DOACs) are increasingly used in clinical practice. Although serious bleeding risks are lower with DOACs than with vitamin K antagonists, bleeding remains the most frequent side effect. Andexanet alfa and idarucizumab are the currently approved specific reversal agents for oral factor (F)Xa inhibitors and dabigatran, respectively. Our prior guidance document was published in 2016, but with more information available on the utility and increased use of these reversal agents and other bleeding management strategies, we have updated this International Society on Thrombosis and Haemostasis guidance document on DOAC reversal. In this narrative review, we compare the mechanism of action of specific and nonspecific reversal agents, review the clinical data supporting their use, and provide guidance on when reversal is indicated. In addition, we briefly discuss the reversal of oral FXIa inhibitors, a new class of DOACs currently under clinical development.

When Direct Oral Anticoagulants Should Not Be Standard Treatment: JACC State-of-the-Art Review.

For most patients, direct oral anticoagulants (DOACs) are preferred over vitamin K antagonists for stroke prevention in atrial fibrillation and for venous thromboembolism treatment. However, randomized controlled trials suggest that DOACs may not be as efficacious or as safe as the current standard of care in conditions such as mechanical heart valves, thrombotic antiphospholipid syndrome, and atrial fibrillation associated with rheumatic heart disease. DOACs do not provide a net benefit in conditions such as embolic stroke of undetermined source. Their efficacy is uncertain for conditions such as left ventricular thrombus, catheter-associated deep vein thrombosis, cerebral venous sinus thrombosis, and for patients with atrial fibrillation or venous thrombosis who have end-stage renal disease. This paper provides an evidence-based review of randomized controlled trials on DOACs, detailing when they have demonstrated efficacy and safety, when DOACs should not be the standard of care, where their safety and efficacy are uncertain, and areas requiring further research.

Optimizing antithrombotic therapy in patients with coexisting cardiovascular and gastrointestinal disease.

Balancing the safety and efficacy of antithrombotic agents in patients with gastrointestinal disorders is challenging because of the potential for interference with the absorption of antithrombotic drugs and for an increased risk of bleeding. In this Review, we address considerations for enteral antithrombotic therapy in patients with cardiovascular disease and gastrointestinal comorbidities. For those with gastrointestinal bleeding (GIB), we summarize a general scheme for risk stratification and clinical evidence on risk reduction approaches, such as limiting the use of concomitant medications that increase the risk of GIB and the potential utility of gastrointestinal protection strategies (such as proton pump inhibitors or histamine type 2 receptor antagonists). Furthermore, we summarize the best available evidence and potential gaps in our knowledge on tailoring antithrombotic therapy in patients with active or recent GIB and in those at high risk of GIB but without active or recent GIB. Finally, we review the recommendations provided by major medical societies, highlighting the crucial role of teamwork and multidisciplinary discussions to customize the antithrombotic regimen in patients with coexisting cardiovascular and gastrointestinal diseases.

Outpatient Randomized Controlled Trials in the Covid-19 Era and Beyond.

Outpatient Trials in the Covid-19 Era and BeyondA group of investigators had a meeting at the National Heart, Lung, and Blood Institute in May 2020 to discuss ways to decrease thrombotic complications among symptomatic outpatients with Covid-19. The investigators discuss their approach to three specific challenges: conducting a trial remotely, working through regulatory hurdles, and recruiting a diverse population of participants.