Enoxaparin Dosage Adjustment in Patients with Severe Renal Failure: Antifactor Xa Concentrations and Safety

Antithrombotic and anticoagulation therapies in cardiogenic shock: a critical review of the published literature

Cardiogenic shock (CS) is a complex multifactorial clinical syndrome, developing as a continuum, and progressing from the initial insult (underlying cause) to the subsequent occurrence of organ failure and death. There is a large phenotypic variability in CS, as a result of the diverse aetiologies, pathogenetic mechanisms, haemodynamics, and stages of severity. Although early revascularization remains the most important intervention for CS in settings of acute myocardial infarction, the administration of timely and effective antithrombotic therapy is critical to improving outcomes in these patients. In addition, other clinical settings or non-acute myocardial infarction aetiologies, associated with high thrombotic risk, may require specific regimens of short-term or long-term antithrombotic therapy. In CS, altered tissue perfusion, inflammation, and multi-organ dysfunction induce unpredictable alterations to antithrombotic drugs' pharmacokinetics and pharmacodynamics. Other interventions used in the management of CS, such as mechanical circulatory support, renal replacement therapies, or targeted temperature management, influence both thrombotic and bleeding risks and may require specific antithrombotic strategies. In order to optimize safety and efficacy of these therapies in CS, antithrombotic management should be more adapted to CS clinical scenario or specific device, with individualized antithrombotic regimens in terms of type of treatment, dose, and duration. In addition, patients with CS require a close and appropriate monitoring of antithrombotic therapies to safely balance the increased risk of bleeding and thrombosis.

The Trilogy of SARS-CoV-2 in Pediatrics (Part 3): Thrombosis, Anticoagulant, and Antiplatelet Considerations

The hypercoagulable state induced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affects all patients regardless of age. The incidence of venous thromboembolism in pediatric patients with SARS-CoV-2-related illnesses is not well established. Although deep vein thrombosis is rare in children in the absence of risk factors, coagulopathy and the development of thromboses have been described in pediatric patients with acute COVID-19 and multisystem inflammatory syndrome. This comprehensive review provides a detailed overview of SARS-CoV-2-associated coagulopathy as well as strategies for optimizing the evaluation, management, and prevention of thrombosis in pediatric patients.

Life-Threatening Mediastinal Hematoma Formation After Removal of the Hemodialysis Catheter in a Boxer: A Case Report

A 4-year-old female Boxer was referred for renal replacement therapy 2 days after observed grape ingestion. An 11-French dual-lumen dialysis catheter was placed into the right jugular vein and continuous renal replacement therapy was initiated for 66 h. Afterwards the patient received enoxaparin subcutaneously as a thromboprophylaxis. Four hours after removal of the dialysis catheter the patient developed severe dyspnea with hypercapnia and signs of hemorrhagic shock. Bedside ultrasound and X-rays of the thorax revealed a soft tissue opacity dorsally of the trachea, located in the mediastinum. The findings were consistent with mediastinal bleeding and hematoma formation. Blood gas examination indicated hypoventilation. The dog was managed conservatively with multiple blood transfusions and mechanical ventilation. The patient survived to discharge, and the hematoma was fully absorbed in the radiographs after 17 days. Patients with impaired kidney function should receive individualized enoxaparin dosage adjusted to anti-Xa levels and should be strictly monitored for complications. Mediastinal hemorrhage and hematoma formation should be considered as a potential complication in patients receiving a jugular vein catheter.

Oral Factor Xa Inhibitors versus Warfarin for the Treatment of Venous Thromboembolism in Advanced Chronic Kidney Disease

Introduction

Warfarin remains the preferred oral anticoagulant for the treatment of venous thromboembolism (VTE) in patients with advanced chronic kidney disease (CKD). Although the direct oral anticoagulants (DOACs) have become preferred for treatment of VTE in the general population, patients with advanced CKD were excluded from the landmark trials. Postmarketing, safety data have demonstrated oral factor Xa inhibitors (OFXais) such as apixaban and rivaroxaban to be alternatives to warfarin for the prevention of stroke and systemic embolism in patients with atrial fibrillation. However, it remains unknown if these safety data can be extrapolated to the treatment of VTE and CKD.

Methods

A retrospective cohort study from January 2013 to October 2019 was performed at NYU Langone Health. All adult patients with CKD stage 4 or greater, treated with anticoagulation for VTE, were screened. The primary outcome was tolerability of anticoagulant therapy at 3 months, defined as a composite of bleeding, thromboembolic events, and/or discontinuation rates. The secondary outcomes included bleeding, discontinuations, and recurrent thromboembolism.

Results

There were 56 patients evaluated, of which 39 (70%) received warfarin and 17 (30%) received an OFXai (apixaban or rivaroxaban). Tolerability at 3 months was assessed in 48/56 patients (86%). A total of 34/48 (71%) patients tolerated anticoagulation at 3 months, 12 (80%) in the OFXai arm, and 22 (67%) in the warfarin arm (p=0.498). There were 10/48 (21%) patients that experienced any bleeding events within 3 months, 7 on warfarin, and 3 on apixaban. Recurrence of thromboembolism within 3 months occurred in 3 patients on warfarin, with no recurrence in the OFXai arm. Discussion. OFXais were better tolerated compared to warfarin for the treatment of VTE in CKD, with lower rates of bleeding, discontinuations, and recurrent thromboembolism in a small cohort. Future prospective studies are necessary to confirm these findings.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: optimal management of anticoagulation therapy

BACKGROUND

Clinicians confront numerous practical issues in optimizing the use of anticoagulants to treat venous thromboembolism (VTE).

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians and other health care professionals in their decisions about the use of anticoagulants in the management of VTE. These guidelines assume the choice of anticoagulant has already been made.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 25 recommendations and 2 good practice statements to optimize management of patients receiving anticoagulants.

CONCLUSIONS

Strong recommendations included using patient self-management of international normalized ratio (INR) with home point-of-care INR monitoring for vitamin K antagonist therapy and against using periprocedural low-molecular-weight heparin (LMWH) bridging therapy. Conditional recommendations included basing treatment dosing of LMWH on actual body weight, not using anti-factor Xa monitoring to guide LMWH dosing, using specialized anticoagulation management services, and resuming anticoagulation after episodes of life-threatening bleeding.

Guidance for the practical management of the heparin anticoagulants in the treatment of venous thromboembolism

Venous thromboembolism (VTE) is a serious and often fatal medical condition with an increasing incidence. Despite the changing landscape of VTE treatment with the introduction of the new direct oral anticoagulants many uncertainties remain regarding the optimal use of traditional parenteral agents. This manuscript, initiated by the Anticoagulation Forum, provides clinical guidance based on existing guidelines and consensus expert opinion where guidelines are lacking. This specific chapter addresses the practical management of heparins including low molecular weight heparins and fondaparinux. For each anticoagulant a list of the most common practice related questions were created. Each question was addressed using a brief focused literature review followed by a multidisciplinary consensus guidance recommendation. Issues addressed included initial anticoagulant dosing recommendations, recommended baseline laboratory monitoring, managing dose adjustments, evidence to support a relationship between laboratory tests and meaningful clinical outcomes, special patient populations including extremes of weight and renal impairment, duration of necessary parenteral therapy during the transition to oral therapy, candidates for outpatient treatment where appropriate and management of over-anticoagulation and adverse effects including bleeding and heparin induced thrombocytopenia. This article concludes with a concise table of clinical management questions and guidance recommendations to provide a quick reference for the practical management of heparin, low molecular weight heparin and fondaparinux.

Analysis of Enoxaparin Dose Titration at a Large, Tertiary Teaching Facility

Therapeutic drug monitoring of enoxaparin with antifactor Xa levels (AXALs) is recommended in some populations; however, the approach to dose titration is poorly described. Our study at a large, tertiary teaching facility examined the dose response to titration of enoxaparin based on AXAL. Patients from 2008 to 2012 receiving enoxaparin were included, provided 2 or more steady state AXAL were obtained within 30 days and that the enoxaparin was prescribed for treatment rather than prophylaxis. The primary outcome was the percentage of dose change required to obtain goal range AXAL following dose titration. Eighty-seven patients were available for analysis with the following key characteristics: renal dysfunction during treatment 72%, obesity 8%, and solid organ transplant 26%. Initial goal AXAL was attained in 27 (31%) patients, and ultimately 54 (62%) patients achieved goal AXAL. Of the 31 patients who had initial AXAL above goal, 13 (42%) patients reached goal with a median dose decrease of 24%. In the 29 patients who had an initial AXAL below goal, 11 (38%) achieved therapeutic AXAL with a median dose increase of 16%. The AXAL monitoring can guide enoxaparin titration with subtherapeutic or supratherapeutic AXAL and an increase or decrease of roughly 20% is suggested as an initial change.

Pancreas graft thrombosis: causes, prevention, diagnosis, and intervention

PURPOSE OF REVIEW

Pancreas graft thrombosis remains one of the most common reasons for pancreas transplant loss. Patients with a history of thrombotic events should be identified and evaluated for thrombophilia to identify transplant candidates at highest risk.

RECENT FINDINGS

Early after transplant, vascular thrombosis is multifactorial, but beyond 2 weeks, inflammation or acute rejection predominate as the cause of thrombosis. Most pancreas transplant centers utilize some form of anticoagulation following transplantation. Aspirin is highly recommended. Unfractionated or low-molecular-weight heparin is often administered, but some centers use heparin selectively and typically at low dose to avoid postoperative bleeding. Warfarin is less frequently given and its use should probably be limited to patients with thrombophilia.

SUMMARY

Thrombectomy, either surgical or percutaneous, may salvage the pancreas graft if performed early after the occurrence of thrombosis.

Anticoagulation: Low-Molecular-Weight Heparins in Renal Impairment and Obesity: Available Evidence and Clinical Practice Recommendations Across Medical and Surgical Settings

Objective

To develop practical recommendations for the use of low-molecular-weight heparins (LMWHs) as prophylaxis and treatment of venous thromboembolism and acute coronary syndromes in patients with impaired renal function or obesity.

Data Sources

Multiple MEDLINE searches were performed (November 2008) to identify studies for inclusion, using a comprehensive list of search terms including, but not limited to, LMWH, enoxaparin, dalteparin, tinzaparin, obesity, weight, renal, kidney, elderly, monitoring, and anti-Xa.

Study Selection And Data Extraction

Only articles published in English that were relevant for this review were included.

Data Synthesis

In the majority of patients, standardized prophylaxis or treatment doses of LMWHs can be used without the need for monitoring and adjusting regimens. For patients with severe renal impairment (estimated creatinine clearance [CrCl] <30 mL/min), doses of some LMWHs should be adjusted or unfractionated heparin should be used instead. CrCl should be estimated using the Cockcroft-Gault method. Differences are noted in the degree of accumulation of various LMWHs in patients with moderate-to-severe renal impairment, and thus, the degree of dose adjustment may differ among the various LMWHs. Increasing the prophylactic doses of LMWH may be appropriate in morbidly obese patients (body mass index ≥40 kg/m2). The use of total body weight is appropriate for therapeutic doses of LMWH in obese patients. Laboratory monitoring of the anticoagulation effect of LMWHs is generally not necessary, but should be considered in patients with morbid obesity (weight >190 kg), those with severe renal impairment, and those with moderate renal impairment with prolonged (>10 days) LMWH use. When anti-Xa activity is monitored, it should be determined using a chromogenic method and a calibration curve based on the LMWH used.

Conclusions

Additional data are needed for specific dose guiding in obese and renally impaired patients, who are often excluded from larger clinical trials. Practice recommendations are made based on available evidence and authors' clinical opinions.

Low-molecular-weight heparin in patients with chronic renal insufficiency

Low-molecular-weight heparin (LMWH) has largely replaced unfractionated heparin for the treatment of venous thromboembolism. The predictable anticoagulant effect of LMWH is seen across almost all patient populations, with few exceptions. However, because LMWH is primarily eliminated through the kidneys, patients with renal insufficiency are at risk of LMWH accumulation and bleeding complications. The risk of LMWH accumulation and bleeding is dependent on several factors including the degree of renal insufficiency, dose and type of LMWH. These risks are greatest when therapeutic doses of LMWH are used in patients with creatinine clearance less than 30 ml/min. Prophylactic dose LMWH does not appear to be associated with an increased bleeding risk, but has not been evaluated in large trials. LMWHs with a higher molecular weight may be less prone to accumulation and bleeding. LMWH must be used carefully in patients with renal insufficiency, particularly in those with severe renal impairment.