Anti-factor Xa Levels Research Articles

Retrospective study evaluating safety, clinical effect, and dosing of dalteparin for the treatment of venous thromboembolism in term neonates.

There is an increased risk of venous thromboembolism (VTE) among neonates due to their unique hemostatic system. However, there is lack of approved treatment options for VTE in neonatal population. Importantly, dalteparin, a low molecular weight heparin approved for pediatric VTE in children ≥1month of age, has also been used for the treatment of neonatal VTE. Based on the request from the Food and Drug Administration, this retrospective study aimed to characterize the safety, clinical effects, and dosing of dalteparin for treatment of VTE among neonates. Data from electronic medical records for neonates (born ≥35weeks of gestation) treated with dalteparin for VTE between January 2010 and December 2021 were collected. The data assessed included bleeding and deterioration in hematological biomarkers among other adverse events, changes in relevant factor antifactor Xa (anti-Xa) levels and VTE status, and dosing of dalteparin and corresponding anti-Xa assay levels. Sixteen neonates from five participating sites in the United Kingdom were included. There were no bleeding events or deaths. Only one serious adverse event of hypoglycemic brain injury (unrelated to dalteparin) was documented in a patient with a history of hyperinsulinism. Median (range) daily dose of dalteparin at initiation was 309 (297-314)IU/kg. Eight of 16 neonates achieved therapeutic anti-Xa level, including two patients who did so after the first dose. Dalteparin treatment in neonates raised no major safety concerns. Larger cohort studies may help provide further insights on clinical effects of dalteparin for neonatal VTE.

Evaluating chemical venous thromboembolism prophylaxis in trauma patients at a single Australian center.

Trauma patients are at an elevated risk of developing venous thromboembolism (VTE), with the subsequent mortality in patients requiring intensive care unit admission ranging from 25% to 38%. There remains significant variability in clinical practice related to VTE prophylaxis in trauma patients due to the frequent presence of contraindications impacting the timing and consistency of application. This study aimed to assess the effectiveness of the current practice of chemical VTE prophylaxis in trauma patients at a single Australian center. A prospective review was conducted on patients admitted to the ACT Trauma Service (Canberra, Australia) from July to November 2022. The included patients were 18 years or older, without a direct contraindication to anticoagulation, who received chemical VTE prophylaxis with low-molecular-weight heparin (enoxaparin) for at least three doses and underwent subsequent testing of anti-factor Xa (aFXa) levels. During the study period, 187 patients were admitted, of whom 63 were included in the study. Of these, 47 patients achieved therapeutic levels of anticoagulation as determined by their aFXa levels, while 16 were subtherapeutic. The only statistically significant difference between the two groups was in weight, with patients in the subtherapeutic group weighing an average of 91.9 kg compared to 79.1 kg in the therapeutic group (P<0.05). A fixed-dose enoxaparin regimen was utilized, with limited individualization based on patient factors, such as injuries, comorbidities, and other biological factors. Sixteen patients (25%) had subtherapeutic VTE prophylaxis, as measured by aFXa levels. Higher weight was significantly correlated with inadequate VTE prophylaxis dosing. While age, sex, and smoking status might play important roles in clinical decision-making, weight-based dosing of low-molecular-weight heparin may be more effective in achieving adequate VTE prophylaxis.

Finding individualised treatment in obese needing enoxaparin (FIT ONE): a multicentre study of therapeutic enoxaparin and the role of anti-factor Xa monitoring.

Enoxaparin is dosed according to actual body weight in treatment of arterial and venous thrombosis. Due to its hydrophilic nature, it distributes according to lean body mass which may be problematic when dosing obese patients as this may increase the risk of bleeding events in this population. The aimwasto evaluate current therapeutic enoxaparin dosing strategies, including Antifactor Xa (AFXa) level monitoring, in obese patients and to identify factors that contribute to treatment failure and excess anticoagulation. A retrospective cohort study was conducted reviewing patients administered therapeutic enoxaparin between May 2020 and April 2021. Data were collected on patient characteristics, enoxaparin therapy, AFXa monitoring, and outcomes. Regression models were constructed to assess variables of interest to estimate any association with AFXa levels. In total 762 patients were included in the analysis. The mean initial weight-based dose was 0.95mg/kg twice daily (SD: ± 0.12, IQR 0.92-1.01) and 1.04mg/kg once daily (SD: ± 0.26, IQR 0.93-1.12) and 14.4% of patients had AFXa monitoring. Treatment failure was experienced by 2.2%, 5% experienced bleeding. There was no association between the mean actual milligram per kilogram weight-based twice daily doses and subtherapeutic, therapeutic and supratherapeutic AFXa levels(P = 0.135). Obesity was not includedin the final regression models due to lack of significance. At a mean therapeutic enoxaparin dose of 0.95mg/kg twice daily and 1.04mg/kg once daily no excess in treatment failure or bleeding events were observed in obese patients compared to the product information. Obesity was not an independent variable that affected the achievement of target AFXa levels.

Therapeutic Enoxaparin Dosing in Obesity.

This review aims to systematically summarize the available data on efficacy and safety of therapeutic enoxaparin in obese patients and to identify gaps to guide future research. Medline and Embase were systematically searched for eligible studies (last searched December 20, 2023). Studies were included if they reported on therapeutic dosing regimens, adverse bleeding, thrombotic outcomes, or antifactor Xa (AFXa) monitoring in obese adult patients. The systematic review management tool Covidence was used to manage the study selection and data extraction process. The reference list from eligible studies was screened to determine any additional eligible studies. Sixteen studies were included in the analysis. Studies used a variety of doses, indications, and study designs making comparison difficult. Twelve studies reported the incidence of thrombotic events (median = 1.3% [interquartile range [IQR] = 0.3%-2.3%]) and all studies reported the incidence of bleeding events (median = 5.7% [IQR = 2.4%-14.5%]). Two of the 8 studies analyzing the influence of weight/body mass index (BMI) or dose per kg on AFXa levels reported statistically significant results. One study concluded that BMI did not affect achievement of target AFXa levels. However, the second study found that dosing using actual body weight was an independent predictor of supratherapeutic AFXa levels in the obese population. This is the first comprehensive review with a focus on therapeutic dosing of enoxaparin in obesity and has been conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement. Seven of the included studies were published since 2018 indicating that new evidence on this topic is emerging. There was inadequate evidence to support an optimal dosing strategy in obese patients due to the heterogeneity of the studies. The AFXa monitoring may be appropriate to guide dosing in this population. Further research is required to determine a suitable dosing regimen.

Enoxaparin treatment dosing for venous thromboembolism in pediatric patients with obesity.

The optimal enoxaparin dosing for treatment of venous thromboembolism (VTE) in pediatric patients with obesity remains uncertain. We described the mean enoxaparin dose required to attain anti-factor Xa (anti-Xa) levels of 0.5-1unit/mL in pediatric patients with obesity. Pediatric patients with obesity (body mass index [BMI]≥95th percentile) who received treatment dose of enoxaparin from 2013 to 2022 and had at least one appropriately timed anti-Xa level were retrospectively evaluated. Daily enoxaparin dose required to achieve an anti-Xa level of 0.5-1unit/mL was reviewed and compared by the severity of obesity. The correlation coefficients between enoxaparin dose requirement and BMI, BMI percentile, and weight were measured by Spearman's rank correlation coefficient. Pediatric patients with obesity (n=89) required a mean enoxaparin dose of 0.8±0.18mg/kg twice daily to attain a therapeutic anti-Xa level. Children with BMI 95th-99th percentile and weight ≤100kg achieved the target level on a significantly higher weight-based enoxaparin dose compared to BMI greater than 99th percentile (0.95±0.15 vs. 0.75±0.15mg/kg twice daily; p<.001) and weight greater than 100kg (0.95±0.14 vs. 0.7±0.12mg/kg twice daily; p<.001). BMI, BMI percentile, and weight showed a moderate to strong negative correlation with enoxaparin dose requirement. Pediatric patients with obesity required a lower weight-based dose of enoxaparin to achieve a therapeutic anti-Xa than the recommended starting dose of 1mg/kg twice daily for treatment of VTE. Among obesity indices, weight showed the strongest negative correlation with total daily enoxaparin requirement.

Anti factor Xa monitoring for venous thromboprophylaxis in severely burn-injured patients: A systematic review

IntroductionPatients with severe burn injuries are at risk of venous thromboembolism (VTE) and associated sequelae. Burn-injured patients may require larger doses of VTE prophylaxis so underdosing may occur with standard regimens. Monitoring anti-factor Xa (AFXa) levels may allow tailoring of dosage but is currently uncommon. The purpose of this systematic review was to methodically review the available literature with respect to AFXa in severe burn-injured patients, and thereby assess its efficacy. MethodsUsing PRISMA guidelines, “Xa” and “burns” were used to systematically review MEDLINE (1946 - present) and EMBASE (1974 - present) databases for publications regarding the monitoring of AFXa levels for thromboprophylaxis in burn-injured patients. ResultsEight studies (432 patients) met inclusion. Peak AFXa level at initial measurement was reported in all studies and was within the range for prophylaxis in 184 of 432 cases (42.6%), below range in 246 of 432 cases (56.9%) and above range for 2/432 (0.5%). Complications were reported in 7 studies (412 patients), with a total of 30 (7.3%) complications, comprising of 16 (53.3%) VTE events and 14 (46.7%) mortalities. Three studies comprising 270 patients compared complications between patients who were within the reference range with patients who were below the range. There were 164 patients from the ‘within the reference range’ groups that had a total of 6 (3.7%) complications, comprised of 4 (66.7%) VTE events and 2 (33.3%) mortalities. There were 106 patients from the ‘below reference range group’ that had a total of 11 (10.4%) complications, comprised of 9 (81.8%) VTE events and 2 (18.2%) mortalities. ConclusionOur findings suggest standard prophylactic anticoagulation dosing risks underdosing and therefore, an increased risk in the development of VTE. AFXa monitoring allows individually tailored dose adjustment to reach therapeutic levels, which may be efficacious in reducing VTE events and is therefore recommended where possible.

Is monitoring of anti-factor Xa levels required for low molecular weight heparin prophylaxis of venous thromboembolism in critically ill patients?

The incidence and mortality of venous thromboembolism (VTE) are high in critically ill patients, and there is still a risk of VTE and bleeding after the use of fixed-dose low molecular weight heparin (LMWH) for prophylaxis. The level of anti-factor Xa is not up to standard after LMWH prophylaxis in patients with surgery or trauma. The condition of critically ill patients is complicated, and the proportion of patients with low antithrombin III is high, which can affect the prophylactic efficacy of LMWH and contribute to VTE occurrence. There is currently no consensus on whether adjusting LMWH dose according to anti-factor Xa levels can reduce VTE occurrence in critically ill patients. High-quality multicenter randomized controlled studies are needed in the future to establish new approaches for precise prevention of VTE in critically ill patients.

Evaluation of Initial Enoxaparin Dosing and Antifactor Xa Levels in Infants Admitted to the Neonatal Intensive Care Unit

Introduction: Infants are at risk for thrombotic conditions due to multiple risk factors such as congenital heart defects and sepsis. According to the American College of Chest Physicians (ACCP) 2012 guidelines, enoxaparin may be given for thrombotic conditions at a dose of 1.5 mg/kg/dose every 12 h for patients less than 2 months of age and 1 mg/kg/dose every 12 h for those older than 2 months. Several studies have reported that infants typically require a higher initial dose of enoxaparin to reach therapeutic antifactor Xa levels than what is currently recommended. Methods: This is a single-center retrospective case-control study of hospitalized infants less than 12 months of age who received treatment with enoxaparin while admitted to the neonatal intensive care unit (NICU) at a freestanding children’s hospital. The primary objective was the difference between the initial enoxaparin dose (mg/kg) compared to the enoxaparin dose in which the patient first achieved a therapeutic antifactor Xa level of 0.5–1.0 units/mL. Results: A total of 56 infants were included in this study. The median enoxaparin dose at initiation was 1.5 mg/kg/dose, and the median enoxaparin dose at the first therapeutic antifactor Xa level was 1.9 mg/kg/dose (z = −12.7, p < 0.0001). There was no correlation between gestational age and weight with the enoxaparin dose required to reach a therapeutic antifactor Xa level. Conclusion: Infants admitted to the NICU, specifically those less than 4 months of age, require higher initial enoxaparin dosing to reach therapeutic antifactor Xa levels than what is currently recommended.

Anticoagulation with argatroban using hemoclot™ targets is safe and effective in CARDS patients receiving venovenous extracorporeal membrane oxygenation: An exploratory bi-centric cohort study

Direct thrombin inhibitors, including argatroban, are increasingly used for anticoagulation during venovenous extracorporeal membrane oxygenation (VV ECMO). In many centers activated partial thromboplastin time (aPTT) is used for monitoring, but it can be affected by several confounders. The aim of this study was to evaluate the safety and efficacy of anticoagulation with argatroban titrated according to diluted thrombin time targets (hemoclot™ assay) compared to anti-Xa guided anticoagulation with unfractionated heparin (UFH). MethodsThis cohort study included adults at two tertiary care centers who required VV ECMO for severe COVID-19-related acute respiratory distress syndrome (CARDS). Patients received center-dependent argatroban or UFH for anticoagulation during ECMO. Argatroban was guided following a hemoclot™ target range of 0.4–0.6 μg/ml. UFH was guided by anti-factor Xa (antiXa) levels (0.2–0.3 IU/ml). The primary outcome was safety of argatroban compared to UFH, assessed by time to first clinically relevant bleeding event or death during ECMO. Secondary outcomes included efficacy (time to thromboembolism) and feasibility (proportion of anticoagulation targets within range). ResultsFrom 2019 to 2021 57 patients were included in the study with 27 patients (47 %) receiving argatroban and 30 patients (53 %) receiving UFH. The time to the first clinically relevant bleeding or death during ECMO was similar between groups (HR (argatroban vs. UFH): 1.012, 95 % CI 0.44–2.35, p = 0.978). Argatroban was associated with a decreased risk for thromboembolism compared to UFH (HR 0.494 (95 % CI 0.26–0.95; p = 0.034)). The overall proportion of anticoagulation within target ranges was not different between groups (46 % (23–54 %) vs. 46 % (37 %–57 %), p = 0.45). ConclusionAnticoagulation with argatroban according to hemoclot™ targets (0.4–0.6 μg/ml) compared to antiXa guided UFH (0.2–0.3 IU/ml) is safe and may prolong thromboembolism-free time in patients with severe ARDS requiring VV ECMO.

Comparison of enoxaparin 40 mg versus 60 mg dosage for venous thromboprophylaxis in patients undergoing bariatric surgery: A randomized controlled trial

BackgroundVenous thromboembolism (VTE) is a common cause of morbidity and mortality after bariatric surgery. Morbid obesity is an independent risk factor for VTE, with goals of prophylactic anti-factor Xa levels within 0.2–0.5 IU/mL. The recommended dosing regimen of enoxaparin for VTE prophylaxis in patients with morbid obesity is lacking in available guidelines. ObjectivesTo evaluate the achieving prophylactic anti-factor Xa levels with different dosages of enoxaparin for morbid obesity patients. SettingWe conducted a study at Chulalongkorn Bariatric and Metabolic Institute, King Chulalongkorn Memorial Hospital. MethodsWe conducted a randomized controlled trial comparing anti-factor Xa levels 4 h after the administration of enoxaparin. All recruited patients randomly received 40 mg or 60 mg of enoxaparin 12 h before the operation. Blood specimens were collected 4 h after the administration of enoxaparin. ResultsIn total, 56 patients who presented between April 2019 and March 2020 at King Chulalongkorn Memorial Hospital were recruited. Of these patients, 28 received 40 mg and 28 received 60 mg of enoxaparin. In both groups, the rates of achieving target levels were 53.57% and 78.57%, respectively (p-value = 0.048). The mean anti-factor Xa levels were 0.19 IU/mL ± 0.06 IU/mL and 0.28 and 0.28 ± 0.10 IU/mL, respectively (p < 0.001). No significant difference was found in the estimated blood loss between the groups. No patient obtained anti-factor Xa levels exceeding 0.5 IU/mL. In both groups, no symptomatic VTE occurred. ConclusionsA 60 mg of enoxaparin regimen achieved more prophylactic anti-factor Xa levels than 40 mg in obese patients undergoing bariatric surgery without any adverse events.

Inadequate Anti–Factor Xa Levels With Daily 40-mg Enoxaparin After Cardiac Surgery

BackgroundCardiac surgery patients are at increased risk for venous thromboembolism (VTE). Prevention is the most critical strategy to reduce VTE-associated morbidity and death. However, there is a lack of data on the optimal approach to VTE prophylaxis in this population of high-risk patients. This study aimed to assess whether the standard dose of enoxaparin, the subcutaneous injection of 40 mg of enoxaparin daily, achieves adequate anti–factor Xa (aFXa) levels for VTE prophylaxis in patients after open heart surgery. MethodsAll patients with open heart surgery with cardiopulmonary bypass from August to December 2022 who received at least 3 consecutive doses of subcutaneously administered enoxaparin were included in the study. Patients receiving therapeutic anticoagulation, patients who underwent cardiac transplantation or placement of ventricular assist device, and patients with renal insufficiency were excluded. Serum aFXa was measured 0.5 to 1 hour before the fourth dose to attain the steady-state trough levels. ResultsData were completed for 44 patients. The target aFXa level was between 0.10 and 0.20 IU/mL for the avoidance of both underanticoagulation (≤0.10 IU/mL) and overanticoagulation (>0.20 IU/mL). The mean was 0.049 IU/mL with SD of 0.026 IU/mL, which was statistically significantly lower than the lower end of the target aFXa values (0.10 IU/mL; t43 = −13; P < .001; d = −1.9; 99% CI, −0.059 to −0.043). ConclusionsThe daily subcutaneous administration of 40 mg of enoxaparin leads to subprophylactic aFXa levels for most patients who undergo cardiac surgery. Further studies on the clinical relevance are warranted.

Large variation in anti-factor Xa levels with nadroparin as thromboprophylaxis in COVID-19 and non-COVID-19 critically ill patients

PurposeCritically ill COVID-19 and non-COVID-19 patients receive thromboprophylaxis with the LMWH nadroparin. Whether a standard dosage is adequate in attaining the target anti-FXa levels (0.20–0.50 IU/ml) in these groups is unknown.MethodsThis study was a prospective, observational study in the ICU of a large general teaching hospital in the Netherlands. COVID-19 and non-COVID-19 patients admitted to the ICU who received LMWH in a prophylactic dosage of 2850 IU, 5700 IU or 11400 IU subcutaneously were eligible for the study. Anti-FXa levels were determined 4 h after administration. Relevant laboratory parameters, prespecified co-variates and clinical data were extracted from the electronic health record system. The primary goal was to evaluate anti-FXa levels in critically ill patients on a prophylactic dosage of nadroparin. The second goal was to investigate whether covariates had an influence on anti-FXa levels.ResultsA total of 62 patients were included in the analysis. In the COVID-19 group and non-COVID-19 group, 29 (96%) and 12 patients (38%) reached anti-FXa levels above 0.20 IU/ml, respectively. In the non-COVID-19 group, 63% of the patients had anti-FXA levels below the target range. When adjusted for nadroparin dosage a significant relation was found between body weight and the anti-FXa level (p = 0.013).ConclusionA standard nadroparin dosage of 2850 IU sc in the critically ill patient is not sufficient to attain target anti-FXa levels in the majority of the studied patient group. We suggest a standard higher dosage in combination with body-weight dependent dosing as it leads to better exposure to nadroparin.Clinical trials registrationRetrospectively registered, ClinicalTrials.gov ID NTC 05926518 g, date of registration 06/01/23, unique ID 2020/1725.

Weight-based enoxaparin thromboprophylaxis in young trauma patients: analysis of the CLOTT-1 registry

IntroductionOptimal venous thromboembolism (VTE) enoxaparin prophylaxis dosing remains elusive. Weight-based (WB) dosing safely increases anti-factor Xa levels without the need for routine monitoring but it is unclear if it leads...

Pilot study examining anti-factor Xa levels for heparin monitoring and outcomes in patients with cerebral venous thrombosis.

There are no studies to date that examine the association between anti-factor-Xa (AFXa)-based heparin monitoring and clinical outcomes in the setting of cerebral venous thrombosis (CVT). This pilot study included adults aged ≥18 admitted with CVT between 1 January 2018 and 1 January 2021, who were treated with unfractionated heparin (UFH) and were monitored via AFXa-based nomogram within 24 h of arrival. Comparisons were made between patients with AFXa levels within the target therapeutic range (0.25-0.5 IU/mL) and patients whose levels were not within the therapeutic range within 24 h of arrival; the time (hours) from arrival to reach the therapeutic range was also examined. Outcomes were length of stay (LOS) in the hospital, major (actionable) bleeding events, and discharge home (vs. higher acuity location). Continuous data are reported in the form of the median (interquartile range). Among 45 patients, treatment with UFH was initiated 2 (1-11) h after arrival, and the majority (84%) of UFH infusions did not need dose adjustment. AFXa assays were conducted every 6 (5.5-7) h. Thirty patients (67%) fell within the therapeutic range. Outcomes were similar for patients with levels within the therapeutic range vs. not: major bleeding events, 10% vs. 0% (p = 0.54); discharge home, 77% vs. 80% (p = 1.0); LOS, 5 days in each group (p = 0.95). There was also no association between outcomes and time to reach the therapeutic range. Our findings demonstrate the practicability of monitoring UFH based on AFXa values in this population of patients with CVT, but reaching target AFXa levels within 24 h of arrival may not necessarily be prognostic.

Anti-factor Xa level monitoring of low-molecular-weight heparin for prevention of venous thromboembolism in critically ill patients (AXaLPE): protocol of a randomised, open-label controlled clinical trial

IntroductionWhether and when to monitor the amount of anti-factor Xa (aFXa) activity in critically ill patients with complex diseases to prevent venous thromboembolism (VTE) remain unclear. This study is a...

Management of an unintentional enoxaparin overdose: A case report and literature review.

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. The aim of this article is to describe a case in which protamine was used for a low-molecular-weight heparin (LMWH) overdose and present an up-to-date review of the literature on the management of LMWH overdose in adults. An unintentional administration of enoxaparin 900mg occurred in a 73-year-old man with COVID-19-related pulmonary embolism. Management of the overdose included a protamine bolus followed by an infusion. Anti-factor Xa levels and activated partial thromboplastin time were monitored. Anti-factor Xa levels declined in a linear fashion irrespective of protamine administration. No bleeding or further thrombotic complications occurred in the patient. A review of the literature revealed that the optimal strategy to treat an LMWH overdose is unknown, with treatment of overdoses ranging from clinical observation to aggressive protamine dosing in reported cases. Although protamine effectively neutralizes unfractionated heparin, it is unable to completely reverse LMWH activity and has variable effects on laboratory measures of LMWH anticoagulant activity. The current case report provides additional data to previous literature suggesting that protamine may have a limited effect in decreasing anti-factor Xa levels in LMWH overdose. Continued reporting on the management of LMWH overdoses is warranted to clarify the optimal treatment strategy.

Clinical Impact of a Standardized Risk-Stratified Thromboprophylaxis Protocol for Multisystem Inflammatory Syndrome in Children

To evaluate the clinical impact of an institutional thromboprophylaxis protocol in patients with multisystem inflammatory syndrome in children (MIS-C), who are at increased risk for thromboembolism (TE). We conducted a single-center retrospective cohort study of children less than 18years between March 2020 and December 2021. Eligible patients were confirmed with MIS-C and were managed with a standardized multidisciplinary treatment approach that included a thromboprophylaxis protocol to guide and unify clinical practice. For high-risk patients, prophylactic dose enoxaparin (target anti-Factor Xa 0.1-0.3 U/mL) was added. In high-risk patients with TE risk factors persistent at hospital discharge, thromboprophylaxis was prescribed for an additional 30days. Of 135 patients with MIS-C, 124 (92%) required intensive care unit stay and 64 (47%) required a central venous catheter for a median duration of 5days (IQR, 4-7). Prophylactic dose enoxaparin was initiated in 116 out of 121 patients (96%) deemed high-risk per our protocol at a median of 1day after admission [IQR, 0-3] achieving target levels at a median of 1day [IQR, 1-2]. The median initial anti-Factor Xa level was 0.13 u/mL [IQR, 0.05-0.19]. One patient (0.7%) developed symptomatic noncatheter related superficial vein thrombosis requiring therapeutic anticoagulation. Thromboprophylaxis was extended for 30days after discharge in 108 out of 135 patients (80%). Bleeding events occurred in 5 patients during hospitalization (4.2%). All bleeding events were clinically relevant nonmajor bleeding. There were no deaths. Implementation of an institutional standardized thromboprophylaxis protocol in MIS-C was feasible and led to timely initiation of prophylactic anticoagulation and low rates of TEs and bleeding complications.

Anti-Xa level monitoring of low-molecular-weight heparin during intermittent venovenous hemofiltration

Low-molecular-weight heparin (LMWH) is an anticoagulant used to prevent clotting during blood purification treatments. This study aimed to evaluate the clinical use of the anti-factor Xa level (anti-Xa) for monitoring LMWH anticoagulant levels during intermittent venovenous hemofiltration (IVVHF). This prospective observational study enrolled patients who required IVVHF for renal failure in Beijing Hospital between May 2019 and February 2021. The LMWH anticoagulation was assessed by the coagulation grade of the filter and line. One hundred and ten participants were included. There were 90 patients with a filter and line coagulation grade of ≤ 1 and 20 patients with grade > 1. The anti-Xa level of 0.2 IU/mL was a critical value. The multivariable logistic regression analysis showed that anti-Xa level > 0.2 IU/mL (odd ratio [OR] = 2.263; 95% CI: 1.290–4.871, P = 0.034) and cardiovascular disease (OR = 10.028; 95% CI: 1.204–83.488; P = 0.033) were independently associated with the coagulation grade of the filter and line. Anti-Xa level could monitor LMWH anticoagulation during IVVHF.

In vitro evaluation of anticoagulant therapy management when urgent percutaneous coronary intervention is required in rivaroxaban-treated patients.

We investigated in vitro the management of intraprocedural anticoagulation in patients requiring immediate percutaneous coronary intervention (PCI) while using regular direct oral anticoagulants (DOACs). Twenty-five patients taking 20 mg of rivaroxaban once daily comprised the study group, while five healthy volunteers included the control group. In the study group, a beginning (24 h after the last rivaroxaban dose) examination was performed. Then, the effects of basal and four different anticoagulant doses (50 IU/kg unfractionated heparin (UFH), 100 IU/kg UFH, 0.5 mg/kg enoxaparin, and 1 mg/kg enoxaparin) on coagulation parameters were investigated at the 4th and 12th h following rivaroxaban intake. The effects of four different anticoagulant doses were evaluated in the control group. The anticoagulant activity was assessed mainly by anti-factor Xa (anti-Xa) levels. Beginning anti-Xa levels were significantly higher in the study group than in the control group (0.69 ± 0.77 IU/mL vs. 0.20 ± 0.14 IU/mL; p < 0.05). The study group's 4th and 12th-h anti-Xa levels were significantly higher than the beginning level (1.96 ± 1.35 IU/mL vs. 0.69 ± 0.77 IU/mL; p < 0.001 and 0.94 ± 1.21 IU/mL vs. 0.69 ± 0.77 IU/mL; p < 0.05, respectively). Anti-Xa levels increased significantly in the study group with the addition of UFH and enoxaparin doses at the 4th and 12th h than the beginning (p < 0.001 at all doses). The safest anti-Xa level (from 0.94 ± 1.21 to 2.00 ± 1.02 IU/mL) was achieved 12 h after rivaroxaban with 0.5 mg/kg enoxaparin. Anticoagulant activity was sufficient for urgent PCI at the 4th h after rivaroxaban treatment, and additional anticoagulant administration may not be required at this time. Twelve hours after taking rivaroxaban, administering 0.5 mg/kg of enoxaparin may provide adequate and safe anticoagulant activity for immediate PCI. This experimental study result should confirm with clinical trials (NCT05541757).

Anti-Factor Xa Level Monitoring for Enoxaparin Prophylaxis and Treatment in High-Risk Patient Groups.

Description Monitoring anti-factor Xa levels is a controversial topic in the inpatient setting due to resource utilization and unclear conditional guideline recommendations regarding this practice. Enoxaparin dosing in certain high-risk patient populations such as those with low body weight, obesity, renal insufficiency, and pregnancy has not been determined. The objective of this review was to assess the safety and efficacy of enoxaparin monitoring via anti-factor Xa levels in high-risk patient populations. The PubMed database was searched for articles related to low-molecular-weight heparin monitoring. Randomized controlled trials and meta-analyses that evaluated the safety and efficacy of enoxaparin prophylaxis and treatment in patients with extremes of weight, renal insufficiency, and pregnancy were selected. Fourteen studies representing four high-risk population patient groups were included. Patients with extremes of weight or who were pregnant were found to have subtherapeutic anti-factor Xa levels due to the weight-based dosing of enoxaparin. Those with renal insufficiency were found to be accumulating enoxaparin, indicating the need for a lower dose. Studies have shown that monitoring may be required in specific high-risk patient groups. Dose adjustments based on anti-factor Xa levels can prevent adverse events associated with enoxaparin. Further research involving larger patient populations would be necessary to determine the clinical efficacy of enoxaparin monitoring with anti-factor Xa levels.