The Anti-Factor Xa Range For Low Molecular Weight Heparin Thromboprophylaxis

Histidine-Rich Glycoprotein Modulates the Toxic Effects of High-Dose Polyphosphate in Mice

BACKGROUND

Polyphosphate (polyP), a procoagulant released from platelets, activates coagulation via the contact system and modulates cardiomyocyte viability. High-dose intravenous polyP is lethal in mice, presumably because of thrombosis. Previously, we showed that HRG (histidine-rich glycoprotein) binds polyP and attenuates its procoagulant effects. In this study, we investigated the mechanisms responsible for the lethality of intravenous polyP in mice and the impact of HRG on this process.

METHODS

The survival of wild-type or HRG-deficient mice given intravenous synthetic or platelet-derived polyP in doses up to 50 mg/kg or saline was compared. To determine the contribution of thrombosis, the effect of FXII (factor XII) knockdown or enoxaparin on polyP-induced fibrin deposition in the lungs was examined. To assess cardiotoxicity, the ECG was continuously monitored, the levels of troponin I and the myocardial band of creatine kinase were quantified, and the viability of a cultured murine cardiomyocyte cell line exposed to polyP in the absence or presence of HRG was determined.

RESULTS

In HRG-deficient mice, polyP was lethal at 30 mg/kg, whereas it was lethal in wild-type mice at 50 mg/kg. Although FXII knockdown or enoxaparin administration attenuated polyP-induced fibrin deposition in the lungs, neither affected mortality. PolyP induced dose-dependent ECG abnormalities, including heart block and ST-segment changes, and increased the levels of troponin and myocardial band of creatine kinase, effects that were more pronounced in HRG-deficient mice than in wild-type mice and were attenuated when HRG-deficient mice were given supplemental HRG. Consistent with its cardiotoxicity, polyP reduced the viability of cultured cardiomyocytes in a dose-dependent manner, an effect attenuated with supplemental HRG.

CONCLUSIONS

High-dose intravenous polyP is cardiotoxic in mice, and HRG modulates this effect.

Calibration-free electrochemical sensor to monitor factor-Xa inhibitors at the point-of-care anticoagulation therapy

This article presents a novel proof of concept for the blood plasma quantification of clinically relevant concentrations of direct oral anticoagulants, DOACs, including rivaroxaban and edoxaban, as well as low-molecular-weight heparins, LMWHs, such as enoxaparin and dalteparin, utilising a calibration-free disposable electrochemical sensor with co-facing electrodes. A dose-response curve was generated for rivaroxaban and edoxaban to demonstrate the sensor's ability to detect ≥9.00 ng mL-1 rivaroxaban and quantify it in the 11.0-140 ng mL-1 range. Similarly, the lower detection limit for edoxaban was 12.9 ng mL-1, with a quantification range of 16.8-140 ng mL-1. The significance of this sensor lies in its ability to quantify rivaroxaban and edoxaban below 30 ng mL-1, which is crucial in emergency care centres when patients undergoing DOAC therapy require emergency surgery or reversal of DOACs due to bleeding or ischemic stroke. Furthermore, the sensor can detect ≥0.016 IU mL-1 enoxaparin and ≥0.013 IU mL-1 dalteparin and quantify them in the 0.025-0.75 and 0.019-0.75 IU mL-1 range, respectively. Additionally, a dose-response curve was presented to demonstrate the potential ability of this sensor to quantify factor-Xa inhibitors independently of which DOACs or LMWHs are used. With the assay completed in less than 30 s using a minimal volume of 7 μL sample, the possibility to work at physiological pH and under calibration-free format makes this assay an excellent candidate for point-of-care testing.

Weight-Based Dosing for Low-Molecular-Weight Heparin (Enoxaparin) Administration to Achieve Optimal VTE Prophylaxis in Trauma Patients

INTRODUCTION

Patients admitted after traumatic injuries are at high risk for developing venous thromboembolism (VTE). Low-molecular-weight heparin (LMWH) is commonly used to prevent VTE in this patient population; however, the optimal dosing strategy has yet to be determined. To address this question, a fixed-dosing strategy of LMWH was compared to a weight-based dosing strategy of LMWH for VTE prophylaxis.

METHODS

A retrospective, pre-post implementation cohort study compared a fixed vs a weight-based dosing strategy of LMWH for VTE prophylaxis. Patients admitted to our level 1 trauma center were included if they had an estimated glomerular filtration rate >30 mL/min/1.73 m2, received at least 3 doses of LMWH, and had an appropriately drawn anti-Xa level on their initial dosing regimen. Patients in the pre-cohort received 30 mg LMWH subcutaneously twice daily as the initial dosing regimen. Patients in the post-cohort received .5 mg/kg (max 60 mg) LMWH subcutaneously every 12 h as the initial dosing regimen. A goal anti-Xa of .2-.4 IU/mL was targeted for prophylaxis.

RESULTS

There were 817 patients in the fixed-dosing group (FDG) and 874 patients in the weight-based dosing group (WBDG). In the FDG, 42.8% of the patients achieved the goal initial anti-Xa level, with 54.1% and 3.1% reaching sub- and supratherapeutic doses, respectively. In the WBDG, 66.5% of patients reached goal initial anti-Xa levels, with 23.5% and 10.1% at sub- and supratherapeutic levels. The distribution of dose ranges was significantly different between the dosing strategies (P-value <.001). There was no difference in the number of patients who received blood products (39.1% vs 41.7%. P-value = .299).

CONCLUSIONS

In our study, weight-based dosing of LMWH yielded a significantly higher proportion of patients who achieved goal prophylactic anti-Xa levels than fixed-dosing of LMWH. Larger-scale studies are needed to assess the risk of VTE events and bleeding with these dosing strategies.

Monitoring anti-Xa Levels to Optimize Low-Molecular-Weight-Heparin Thromboprophylaxis in High-Risk Hospitalized Patients: A Stratified Meta-Analysis

It is uncertain whether monitoring or targeting anti-Xa levels is necessary when using low-molecular-weight-heparin (LMWH) to prevent venous thromboembolism (VTE). This stratified meta-analysis assessed whether monitoring trough or peak anti-Xa levels with LMWH dosing would reduce risk of VTE. Twelve non-randomized studies involving 3604 hospitalized patients met the inclusion criteria and were subject to meta-analysis. Eight studies assessed the association between VTE and peak anti-Xa levels (between .2 and .5 IU/ml) and four studies assessed the benefits of targeting the trough anti-Xa levels (>.1 IU/ml). Achieving an adequate peak or trough anti-Xa level was associated with a reduced risk of VTE (random-effects model odds ratio [OR] .52, 95% confidence interval [CI] .34-.77; P = .001, I2 = 30% and P-value for heterogeneity = .171) compared with using a fixed standard dose of LMWH. Targeting the trough level (OR .40, 95%CI 0.22-.75, P = .004) appeared to be more effective than targeting the peak level (OR .62, 95%CI 0.37-1.03, P = .066), although a formal interaction analysis did not confirm they were statistically different (ratio of ORs = 1.52, 95%CI 0.68-3.40; z score = 1.03, P = .306). Targeting a higher anti-Xa level did not appear to increase the risk of bleeding or transfusion (OR 1.20, 95%CI 0.46-3.17, P = .707).

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

PURPOSE

Critically 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.

METHODS

This 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.

RESULTS

A 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).

CONCLUSION

A 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 REGISTRATION

Retrospectively registered, ClinicalTrials.gov ID NTC 05926518 g, date of registration 06/01/23, unique ID 2020/1725.

Evaluating residual anti-Xa levels following discontinuation of treatment-dose enoxaparin in patients presenting for elective surgery: a prospective observational trial

INTRODUCTION

Prior studies have demonstrated that patients presenting for elective surgery may have higher-than-expected residual anti-Xa level activity at or beyond 24 hours following their last treatment dose of enoxaparin. Given that 24 hours of abstinence is currently recommended by both European and American societies before the performance of neuraxial or deep anesthetic/analgesic procedures, determining the actual timeframe at which residual anti-Xa level activity reliably falls below 0.2 IU/mL, the lower limit of the target range for thromboprophylaxis, is critical.

METHODS

This was a prospective observational trial. Consenting patients on treatment-dose enoxaparin were randomized to either a 24-hour group (last dose at 07:00 the day prior to surgery) or a 36-hour group (last dose at 19:00 2 days prior to surgery). On arrival for surgery, blood samples were obtained to assess residual anti-Xa level activity and renal function. The primary outcome was residual anti-Xa level activity following the last treatment dose of enoxaparin. Incorporating all patients, linear regression modeling was performed to predict the timepoint at which the level of anti-Xa activity reliably fell below 0.2 IU/mL.

RESULTS

103 patients were analyzed. Time from the last dose at which residual anti-Xa activity fell below 0.2 IU/mL, based on the upper bound of the 95% CI, was 31.5 hours. No correlation overall between age, renal function, or sex was found.

CONCLUSION

Residual levels of anti-Xa activity do not reliably fall below 0.2 IU/mL 24 hours following discontinuation of treatment-dose enoxaparin. Therefore, current time-based guidelines are not conservative enough. Routine anti-Xa testing should be strongly considered, or current time-based guidelines should be reassessed.

TRIAL REGISTRATION NUMBER

NCT03296033.

Enoxaparin for VTE thromboprophylaxis during inpatient rehabilitation care: assessment of the standard fixed dosing regimen

BACKGROUND

We aimed to examine the efficiency of fixed daily dose enoxaparin (40 mg) thromboprophylaxis strategy for patients undergoing inpatient rehabilitation.

METHODS

This was an observational, prospective, cohort study that included 63 hospitalized patients undergoing rehabilitative treatment following sub-acute ischemic stroke (SAIS) or spinal cord injury (SCI), with an indication for thromboprophylaxis. Anti-Xa level measured three hours post-drug administration (following three consecutive days of enoxaparin treatment or more) was utilised to assess in vivo enoxaparin activity. An anti-Xa level between 0.2-0.5 U/ml was considered evidence of effective antithrombotic activity.

RESULTS

We found sub-prophylactic levels of anti-Xa (<0.2 U/ml) in 19% (12/63). Results were within the recommended prophylactic range (0.2-0.5 U/ml) in 73% (46/63) and were supra-prophylactic (>0.5 U/ml) in 7.9% (5/63) of patients. Anti-Xa levels were found to inversely correlate with patients' weight and renal function as defined by creatinine clearance (CrCl) (p<0.05).

CONCLUSIONS

Our study confirmed that a one-size-fits-all approach for venous thromboembolism (VTE) prophylaxis may be inadequate for rehabilitation patient populations. The efficacy of fixed-dose enoxaparin prophylaxis is limited and may be influenced by renal function and weight. This study suggests that anti-Xa studies and prophylactic enoxaparin dose adjustments should be considered in certain patients, such as those who are underweight, overweight and or have suboptimal renal function.

TRIAL REGISTRATION

No. NCT103593291, registered August 2018.

Histologic changes of porcine portal vein anastomosis after electrochemotherapy with bleomycin

Electrochemotherapy (ECT1) is used for treatment of unresectable abdominal malignancies. This study aims to show that ECT of porcine portal vein anastomosis is safe and feasible in order to extend the indications for margin attenuation after resection of locally advanced pancreatic carcinoma. No marked differences were found between the control group and ECT treated groups. Electroporation thus caused irreversible damage to the vascular smooth muscle cells in tunica media that could bedue to the narrow irreversible electroporation zone that may occur near the electrodes, or due to vasa vasorum thrombosis in the tunica externa. Based on the absence of vascular complications, and similar histological changes in lienal veinanastomosis, we can conclude that ECT of portal vein anastomosis is safe and feasible.

Intermediate dose enoxaparin in hospitalized patients with moderate-severe COVID-19: a pilot phase II single-arm study, INHIXACOVID19

BACKGROUND

Randomized clinical trials in non-critically ill COVID-19 patients showed that therapeutic-dose heparin increased survival with reduced organ support as compared with usual-care thromboprophylaxis, albeit with increased bleeding risk. The purpose of the study is to assess the safety of intermediate dose enoxaparin in hospitalized patients with moderate to severe COVID-19.

METHODS

A phase II single-arm interventional prospective study including patients receiving intermediate dose enoxaparin once daily according to body weight: 60 mg for 45-60 kg, 80 mg for 61-100 kg or 100 mg for > 100 kg for 14 days, with dose adjustment according to anti-factor Xa activity (target range: 0.4-0.6 UI/ml); an observational cohort (OC) included patients receiving enoxaparin 40 mg day for comparison. Follow-up was 90 days. Primary outcome was major bleeding within 30 and 90 days after treatment onset. Secondary outcome was the composite of all-cause 30 and 90-day mortality rates, disease severity at the end of treatment, intensive care unit (ICU) admission and length of ICU stay, length of hospitalization. All outcomes were adjudicated by an independent committee and analyzed before and after propensity score matching (PSm).

RESULTS

Major bleeding was similar in IC (1/98 1.02%) and in the OC (none), with only one event observed in a patient receiving concomitantly anti-platelet therapy. The composite outcome was observed in 53/98 patients (54%) in the IC and 132/203 (65%) patients in the OC (p = 0.07) before PSm, while it was observed in 50/90 patients (55.6%) in the IC and in 56/90 patients (62.2%) in the OC after PSm (p = 0.45). Length of hospitalization was lower in the IC than in OC [median 13 (IQR 8-16) vs 14 (11-21) days, p = 0.001], however it lost statistical significance after PSm (p = 0.08). At 30 days, two patients had venous thrombosis and two pulmonary embolism in the OC. Time to first negative RT-PCR were similar in the two groups.

CONCLUSIONS

Weight adjusted intermediate dose heparin with anti-FXa monitoring is safe with potential positive impact on clinical course in COVID-19 non-critically ill patients.

TRIAL REGISTRATION

The study INHIXACOVID19 was registred on ClinicalTrials.gov with the trial registration number (TRN) NCT04427098 on 11/06/2020.

A retrospective multicenter cohort study of the association between anti-Factor Xa values and death, thromboembolism, and bleeding in patients with critical COVID-19

BACKGROUND

Patients with critical COVID-19 have a high risk of thromboembolism, but intensified thromboprophylaxis has not been proven beneficial. The activity of low-molecular-weight heparins can be monitored by measuring anti-Factor Xa. We aimed to study the association between anti-Factor Xa values and death, thromboembolism, and bleeding in patients with critical COVID-19.

METHOD

This retrospective cohort study included adult patients with critical COVID-19 admitted to an intensive care unit at three Swedish hospitals between March 2020 and May 2021 with at least one valid peak and/or trough anti-Factor Xa value. Within the peak and trough categories, patients' minimum, median, and maximum values were determined. Logistic regressions with splines were used to assess associations.

RESULTS

In total, 408 patients had at least one valid peak and/or trough anti-Factor Xa measurement, resulting in 153 patients with peak values and 300 patients with trough values. Lower peak values were associated with thromboembolism for patients' minimum (p = 0.01), median (p = 0.005) and maximum (p = 0.001) values. No association was seen between peak values and death or bleeding. Higher trough values were associated with death for median (p = 0.03) and maximum (p = 0.002) values and with both bleeding (p = 0.01) and major bleeding (p = 0.02) for maximum values, but there were no associations with thromboembolism.

CONCLUSIONS

Measuring anti-Factor Xa activity may be relevant for administrating low-molecular-weight heparin to patients with critical COVID-19. Lower peak values were associated with an increased risk of thromboembolism, and higher trough values were associated with an increased risk of death and bleeding. Prospective studies are needed to confirm the results.

TRIAL REGISTRATION

The study was retrospectively registered at Clinicaltrials.gov, NCT05256524, February 24, 2022.

Is There a Role for Anti-factor Xa Activity Assay in Venous Thromboembolism Prophylaxis Management Among Orthopaedic Trauma Patients? Systematic Review and Meta-analysis

OBJECTIVES

To determine the effect of anti-factor Xa assay dosing of low-molecular-weight heparin (LMWH) on rates of venous thromboembolism (VTE), deep vein thrombosis (DVT), pulmonary embolism (PE), bleeding, and mortality among orthopaedic trauma patients.

DATA SOURCES

PubMed/MEDLINE, Embase, Ovid, Cochrane Central Register of Controlled Trials (CENTRAL), clinicaltrials.gov , and Scopus were systematically searched from inception of the database to 2021.

STUDY SELECTION

Prospective, retrospective, and randomized controlled trial studies were included if they compared rates of VTE, DVT, PE, bleeding, and/or mortality between orthopaedic trauma patients receiving anti-factor Xa-based LMWH dosing and those receiving standard dosing.

DATA EXTRACTION

Two independent reviewers screened titles and abstracts for eligibility. Study characteristics including study design, inclusion criteria, and intervention were extracted.

DATA SYNTHESIS

Meta-analysis was performed using pooled proportion of events (effect size) with 95% confidence intervals. A random-effects model was used. Heterogeneity was quantified by Higgins I 2 . Heterogeneity and variability between subgroups indicated differences in the pooled estimate represented by a P -value.

RESULTS

Six hundred eighty-five studies were identified, and 10 studies including 2870 patients were included. In total, 30.3% and 69.7% received an adjusted and nonadjusted dose of LMWH, respectively. The rate of VTE and DVT were significantly lower in the anti-factor Xa-adjusted cohort, whereas there was no statistically significant difference in rates of PE, bleeding, or mortality between the cohorts.

CONCLUSIONS

This systematic review and meta-analysis demonstrates that anti-factor Xa activity assay dosing of LMWH among orthopaedic trauma patients leads to a reduction in overall DVT rates, although not PE rates, without an increased risk of bleeding events.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Rate of prophylactic anti-Xa achievement and impact on venous thromboembolism following oncologic hepato-pancreatico-biliary surgery: A prospective cohort study

BACKGROUND

Hepato-pancreatico-biliary (HPB) patients experience competing risk of venous thromboembolism (VTE) and bleeding. We sought to evaluate the effect of anti-Xa levels on VTE and bleeding, and to characterize factors associated with subprophylaxis.

METHODS

This prospective cohort study evaluated adult HPB surgical patients; cohorts were described by anti-Xa levels as subprophylactic (<0.2 IU/mL), prophylactic (0.2-0.5 IU/mL), and supraprophylactic (>0.5 IU/mL). Primary outcome evaluated bleeding and VTE complications. Secondary outcomes evaluated factors associated with subprophylaxis.

RESULTS

We included 157 patients: 68 (43.6%) attained prophylactic anti-Xa and 89 (56.7%) were subprophylactic. Subprophylactic patients experienced more VTE compared to prophylactic patients (6.9% vs 0%; p = 0.028) without differences in bleeding complications (14.6% vs 5.9%; p = 0.081). Factors associated with subprophylactic anti-Xa included female sex (OR 2.90, p = 0.008), and Caprini score (OR 1.30, p = 0.035). Enoxaparin was protective against subprophylaxis compared to tinzaparin (OR 0.43, p = 0.029).

CONCLUSIONS

Many HPB patients have subprophylactic anti-Xa levels, placing them at risk of VTE. Enoxaparin may be preferential, however, studies evaluating optimized prophylaxis are needed.

Population Pharmacokinetics and Probability of Target Attainment Analysis of Nadroparin in Different Stages of COVID-19

BACKGROUND AND OBJECTIVE

The risk of thrombotic complications in critical patients with COVID-19 remains extremely high, and multicenter trials failed to prove a survival benefit of escalated doses of low-molecular-weight heparins (nadroparin calcium) in this group. The aim of this study was to develop a pharmacokinetic model of nadroparin according to different stages of COVID-19 severity.

METHODS

Blood samples were obtained from 43 patients with COVID-19 who received nadroparin and were treated with conventional oxygen therapy, mechanical ventilation, and extracorporeal membrane oxygenation. We recorded clinical, biochemical, and hemodynamic variables during 72 h of treatment. The analyzed data comprised 782 serum nadroparin concentrations and 219 anti-Xa levels. We conducted population nonlinear mixed-effects modeling (NONMEM) and performed Monte Carlo simulations of the probability of target attainment for reaching 0.2-0.5 IU/mL anti-Xa levels in study groups.

RESULTS

We successfully developed a one-compartment model to describe the population pharmacokinetics of nadroparin in different stages of COVID-19. The absorption rate constant of nadroparin was 3.8 and 3.2 times lower, concentration clearance was 2.22 and 2.93 times higher, and anti-Xa clearance was 0.87 and 1.1 times higher in mechanically ventilated patients and the extracorporeal membrane oxygenation group compared with patients treated with conventional oxygen, respectively. The newly developed model indicated that 5.900 IU of nadroparin given subcutaneously twice daily in the mechanically ventilated patients led to a similar probability of target attainment of 90% as 5.900 IU of subcutaneous nadroparin given once daily in the group supplemented with conventional oxygen.

CONCLUSIONS

Different nadroparin dosing is required for patients undergoing mechanical ventilation and extracorporeal membrane oxygenation to achieve the same targets as those for non-critically ill patients.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier no. NCT05621915.

Targeting pleckstrin-2/Akt signaling reduces proliferation in myeloproliferative neoplasm models

Myeloproliferative neoplasms (MPNs) are characterized by the activated JAK2/STAT pathway. Pleckstrin-2 (Plek2) is a downstream target of the JAK2/STAT5 pathway and is overexpressed in patients with MPNs. We previously revealed that Plek2 plays critical roles in the pathogenesis of JAK2-mutated MPNs. The nonessential roles of Plek2 under physiologic conditions make it an ideal target for MPN therapy. Here, we identified first-in-class Plek2 inhibitors through an in silico high-throughput screening approach and cell-based assays, followed by the synthesis of analogs. Plek2-specific small-molecule inhibitors showed potent inhibitory effects on cell proliferation. Mechanistically, Plek2 interacts with and enhances the activity of Akt through the recruitment of downstream effector proteins. The Plek2-signaling complex also includes Hsp72, which protects Akt from degradation. These functions were blocked by Plek2 inhibitors via their direct binding to the Plek2 dishevelled, Egl-10 and pleckstrin (DEP) domain. The role of Plek2 in activating Akt signaling was further confirmed in vivo using a hematopoietic-specific Pten-knockout mouse model. We next tested Plek2 inhibitors alone or in combination with an Akt inhibitor in various MPN mouse models, which showed significant therapeutic efficacies similar to that seen with the genetic depletion of Plek2. The Plek2 inhibitor was also effective in reducing proliferation of CD34-positive cells from MPN patients. Our studies reveal a Plek2/Akt complex that drives cell proliferation and can be targeted by a class of antiproliferative compounds for MPN therapy.

Low and Highly Variable Exposure to Prophylactic LMWH Nadroparin in Critically Ill Patients: Back to the Drawing Board for Prophylactic Dosing?

BACKGROUND AND OBJECTIVE

Low-molecular-weight heparins are routinely administered to patients in the intensive care unit to prevent venous thromboembolisms. There is considerable evidence that low-molecular-weight heparin doses should be personalised based on anti-Xa levels, but pharmacokinetic data in intensive care unit patients are lacking. This study aimed to characterise the pharmacokinetics and associated variability of the low-molecular-weight heparin nadroparin in critically ill patients.

METHODS

Critically ill adult patients who were admitted to the intensive care unit and received nadroparin for prophylaxis of venous thromboembolism were included in a study. Population pharmacokinetic analysis was performed by means of parametric non-linear mixed-effects modelling (NONMEM).

RESULTS

A total of 30 patients were enrolled with 12 patients undergoing continuous veno-venous hemodialysis and 18 patients not undergoing continuous veno-venous hemodialysis. Very high variability in pharmacokinetics was observed with an inter-individual variability in the volume of distribution of 63.7% (95% confidence interval 46.5-90.6), clearance of 166% (95% confidence interval 84.7-280) and relative bioavailability of 40.2% (95% confidence interval 29.5-52.6). We found that standard doses of 2850 IE and 5700 IE of nadroparin resulted in sub-prophylactic exposure in critically ill patients.

CONCLUSIONS

Low exposure and highly variable pharmacokinetics of nadroparin were observed in intensive care unit patients treated with a prophylactic dose. It can be debated whether nadroparin is currently dosed optimally in intensive care unit patients and our findings encourage the investigation of higher and tailored dosing of nadroparin in the critically ill.

Safety and Efficacy of Prophylactic Enoxaparin Adjusted by Anti-Factor Xa Peak Levels in Pancreatic Surgery

BACKGROUND

Recommended prophylactic doses of enoxaparin (Lovenox) are associated with subprophylactic anti-Factor Xa (anti-Xa) levels. This study examines the safety and efficacy of anti-Xa-guided dosing of enoxaparin in pancreatic surgery.

METHODS

Prospectively enrolled patients undergoing pancreatic surgery received enoxaparin dosing adjusted based on peak anti-Xa levels and were compared to a historical cohort of patients.

RESULTS

Baseline characteristics were similar between the intervention and control groups. In the intervention group, 73.9% initially had subprophylactic peak anti-Xa levels. There were no differences in the venous thromboembolism (VTE) rates between the intervention and control groups (0% vs. 7.69%; P = .084), major bleeding events (4.35% vs. 2.56%; P = .627), RBC transfusion (15.2% vs. 25.6%; P = .257), or Hgb on discharge (9.82 vs. 9.44 g/dL; P = .244). Subtherapeutic anti-Xa levels were correlated with a higher BMI (P = .033), longer OR time (P = .011), and length of stay (P = .018).

CONCLUSIONS

Enoxaparin 40 mg once daily is associated with subprophylactic peak anti-Xa levels. Dose adjustment based on anti-Xa levels trended toward a lower rate of in-hospital VTE without an increase in bleeding or transfusion requirement.

Antithrombin Activity is Associated with Persistent Thromboinflammation and Mortality in Patients with Severe COVID-19 Illness

BACKGROUND

Severe COVID-19 illness can lead to thrombotic complications, organ failure, and death. Antithrombin (AT) regulates thromboinflammation and is a key component of chemical thromboprophylaxis. Our goal was to examine the link between AT activity and responsiveness to thromboprophylaxis, markers of hypercoagulability, and inflammation among severe COVID-19 patients.

METHODS

A single-center, prospective observational study enrolling SARS-CoV-2 positive patients admitted to the intensive care unit on prophylactic enoxaparin. Blood was collected daily for 7 days to assess AT activity and anti-FXa levels. Patient demographics, outcomes, and hospital laboratory results were collected. Continuous variables were compared using Mann-Whitney tests, and categorical variables were compared using Chi-square tests. Multivariable logistic regression was used to determine the association between AT activity and mortality.

RESULTS

In 36 patients, 3 thromboembolic events occurred, and 18 (50%) patients died. Patients who died had higher fibrinogen, D-dimer, and C-reactive protein (CRP) levels and lower AT activity. Reduced AT activity was independently associated with mortality and correlated with both markers of hypercoagulability (D-dimer) and inflammation (CRP).

CONCLUSIONS

Low AT activity is associated with mortality and persistent hypercoagulable and proinflammatory states in severe COVID-19 patients. The anti-thromboinflammatory properties of AT make it an appealing therapeutic target for future studies.

Efficacy and Safety of Two Different Enoxaparin Doses for Thromboprophylaxis in Non-critically Ill Patients: A Randomized Controlled Trial

Background

Recently, a few studies based on anti-factor Xa activity levels have propounded doubtful and sub-prophylactic levels by the usual dose of enoxaparin in surgical and critically ill patients. In this study, we assessed two doses of enoxaparin in adult non-critically ill patients.

Methods

Patients were randomly assigned into two groups of intervention and control. While the intervention group received enoxaparin with a daily dose of 60 mg, the control group received enoxaparin 40 mg. Anti-factor Xa activity was measured based on the peak steady-state levels. The level of 0.2 to 0.4 IU/mL was considered as a prophylactic goal. All individuals were followed for bleeding or thromboembolic events during admission.

Results

The mean levels of anti-factor Xa were 0.29 ± 0.13 IU/mL in the control group (n = 31) and 0.44 ± 0.19 IU/mL in the intervention group (n = 29). More patients in the control group had an optimal level of anti-factor Xa compared to the patients in the intervention group (62.1% vs. 29%). No adverse outcomes were detected in any of the groups.

Conclusions

Enoxaparin dose of 60 mg daily provided anti-factor Xa level higher than desired in most patients. In non-critically ill patients, the dose of 40 mg is the proper dose for thromboprophylaxis.

Operative management of acute abdomen after bariatric surgery in the emergency setting: the OBA guidelines

BACKGROUND

Patients presenting with acute abdominal pain that occurs after months or years following bariatric surgery may present for assessment and management in the local emergency units. Due to the large variety of surgical bariatric techniques, emergency surgeons have to be aware of the main functional outcomes and long-term surgical complications following the most performed bariatric surgical procedures. The purpose of these evidence-based guidelines is to present a consensus position from members of the WSES in collaboration with IFSO bariatric experienced surgeons, on the management of acute abdomen after bariatric surgery focusing on long-term complications in patients who have undergone laparoscopic sleeve gastrectomy and laparoscopic Roux-en-Y gastric bypass.

METHOD

A working group of experienced general, acute care, and bariatric surgeons was created to carry out a systematic review of the literature following the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA-P) and to answer the PICO questions formulated after the Operative management in bariatric acute abdomen survey. The literature search was limited to late/long-term complications following laparoscopic sleeve gastrectomy and laparoscopic Roux-en-Y gastric bypass.

CONCLUSIONS

The acute abdomen after bariatric surgery is a common cause of admission in emergency departments. Knowledge of the most common late/long-term complications (&gt; 4 weeks after surgical procedure) following sleeve gastrectomy and Roux-en-Y gastric bypass and their anatomy leads to a focused management in the emergency setting with good outcomes and decreased morbidity and mortality rates. A close collaboration between emergency surgeons, radiologists, endoscopists, and anesthesiologists is mandatory in the management of this group of patients in the emergency setting.

Prophylactic Dose of Dalteparin in Pregnant Women With History of Venous Thromboembolisms and/or Thrombophilia: Real-World Data

Women with a history of venous thromboembolisms (VTEs) and/or thrombophilia are at increased risk of VTE during pregnancy. We analysed our cohort of such women who were treated with a prophylactic doses of dalteparin. 152 pregnant women with 179 pregnancies were classified into 3 groups: (1) previous VTE without thrombophilia (122 pregnancies); (2) previous VTE with thrombophilia (26 pregnancies) and (3) thrombophilia only (31 pregnancies). They were treated with prophylactic dalteparin in the prepartum and postpartum periods or only in the postpartum period. Occurrences of symptomatic VTE and bleeding episodes were followed, as well as dalteparin discontinuation and anti-Xa activity. Symptomatic deep vein thrombosis occurred in 4 women (2.2%) with 2 episodes in group 1 (in the postpartum period) and 2 episodes in group 2 (one in the prepartum and another in the postpartum period). Seven episodes (3.9%) of minor bleeding occurred. Dalteparin was not stopped in any women. Anti-Xa levels were within the prophylactic range. Our real-world data show a low incidence of thrombosis and minor bleeding in pregnant women treated with prophylactic dalteparin. The incidence of recurrent VTE was lower than that reported in women with similar risk, but without prophylactic anticoagulation.

Adjusted versus fixed doses of LMWHs in trauma patients: A systematic review and meta-analysis

PURPOSE

Venous thromboembolism (VTE) causes significant morbidity and mortality in patients with traumatic injuries, despite thromboprophylaxis. To decrease both thrombotic and bleeding risks, some authors suggest adjusting the thromboprophylactic doses of low-molecular-weight heparins (LMWH), in particular according to body weight at treatment initiation or to changes in anti-factor Xa level during treatment. Our objective was to estimate in trauma patients the efficacy and safety of such adjustments, compared with the conventional strategy of fixed-dose LMWH thromboprophylaxis.

SOURCE

A systematic review and a meta-analysis were conducted to identify and assess randomised control trials and observational studies with prospective enrolment that included trauma patients and compared adjustment of LMWH thromboprophylaxis versus no adjustment. The primary and secondary endpoints were VTE and bleeding, respectively. The Odds Ratio (OR) and 95% Confidence Interval (95% CI) were calculated using the Mantel-Haenszel method.

PRINCIPAL FINDINGS

Nine studies were included in the meta-analysis. No significant reduction in the risk of VTE was observed with adjusted doses of LMWH compared with fixed doses when considering only randomised control trials (OR 1.02 [95% CI, 0.09 to 11.6]) or all trials (OR 0.70 [95% CI, 0.34 to 1.42]). Similarly, there was no significant difference in bleeding risk (OR 1.36, 95% CI 0.59 to 3.10).

CONCLUSION

This meta-analysis shows that, to date, there is no evidence to justify adjusting LMWH doses, in agreement with the recommendations of the American College of Chest Physicians.

Role of Physical Therapists in the Management of Individuals at Risk for or Diagnosed With Venous Thromboembolism: Evidence-Based Clinical Practice Guideline 2022

No matter the practice setting, physical therapists work with patients who are at risk for or who have a history of venous thromboembolism (VTE). In 2016, the first clinical practice guideline (CPG) addressing the physical therapist management of VTE was published with support by the American Physical Therapy Association's Academy of Cardiovascular and Pulmonary Physical Therapy and Academy of Acute Care, with a primary focus on lower extremity deep vein thrombosis (DVT). This CPG is an update of the 2016 CPG and contains the most current evidence available for the management of patients with lower extremity DVT and new key action statements (KAS), including guidance on upper extremity DVT, pulmonary embolism, and special populations. This document will guide physical therapist practice in the prevention of and screening for VTE and in the management of patients who are at risk for or who have been diagnosed with VTE. Through a systematic review of published studies and a structured appraisal process, KAS were written to guide the physical therapist. The evidence supporting each action was rated, and the strength of statement was determined. Clinical practice algorithms based on the KAS were developed that can assist with clinical decision-making. Physical therapists, along with other members of the health care team, should implement these KAS to decrease the incidence of VTE, improve the diagnosis and acute management of VTE, and reduce the long-term complications of VTE.

Current Antithrombotic Therapy Strategies in Children with a Focus on Off-Label Direct Oral Anticoagulants—A Narrative Review

(1) Background: The incidence of thromboembolic events is relatively low in the general population, but it increases in hospitalized children and those who underwent thrombogenic procedures. Although the evidence regarding direct oral anticoagulants (DOACs) in children with venous thromboembolism (VTE) is growing, DOACs were excluded from existing guidelines due to the lack of reliable data at that moment. Therefore, current evidence on VTE management in children needs to be critically reviewed. (2) Methods: We have conducted a literature search in the Scopus, EMBASE, and MEDLINE databases using prespecified keywords to retrieve studies published between 2010 and 2022. (3) Results: Clinical trials highlighted that rivaroxaban and dabigatran had predictable pharmacokinetic and pharmacodynamic profiles in children, similar to those observed in adults. Dabigatran and rivaroxaban had a similar safety profile to standard therapy but improved thrombotic burden and resolution during follow-up. Most studies involving apixaban and edoxaban are ongoing, and results are awaited. (4) Conclusions: Dabigatran and rivaroxaban could be valid therapeutic options for VTE management in children. In the case of apixaban and edoxaban, results from ongoing clinical studies are required before using them in pediatric VTE.

Standard Fixed Enoxaparin Dosing for Venous Thromboembolism Prophylaxis Leads to Low Peak Anti-Factor Xa Levels in Both Head and Neck and Breast Free Flap Patients

INTRODUCTION

 Venous thromboembolism (VTE) is a serious complication, particularly in cancer patients undergoing free flap reconstruction. Subcutaneous enoxaparin is the conventional prophylaxis for VTE prevention, and serum anti-factor Xa (afXa) levels are being increasingly used to monitor enoxaparin activity. In this study, free flap patients receiving standard enoxaparin prophylaxis were prospectively followed to investigate postoperative afXa levels and 90-day VTE and bleeding-related complications.

METHODS

 Patients undergoing free tissue transfer during an 8-month period were identified and prospectively followed. Patients received standard fixed enoxaparin dosing at 30 mg twice daily in head and neck (H&N) and 40 mg daily in breast reconstructions. Target peak prophylactic afXa range was 0.2 to 0.5 IU/mL. The primary outcome was the occurrence of 90-day postoperative VTE- and bleeding-related events. Independent predictors of afXa level and VTE incidence were analyzed for patients that met the inclusion criteria.

RESULTS

 Seventy-eight patients were prospectively followed. Four (5.1%) were diagnosed with VTE, and six (7.7%) experienced bleeding-related complications. The mean afXa levels in both VTE patients and bleeding patients were subprophylactic (0.13 ± 0.09 and 0.11 ± 0.07 IU/mL, respectively). Forty-six patients (21 breast, 25 H&N) had valid postoperative peak steady-state afXa levels. Among these, 15 (33%) patients achieved the target prophylactic range: 5 (33%) H&N and 10 (67%) breast patients. The mean afXa level for H&N patients was significantly lower than for breast patients (p = 0.0021). Patient total body weight was the sole negative predictor of afXa level (R ² = 0.47, p < 0.0001).

CONCLUSION

 Standard fixed enoxaparin dosing for postoperative VTE prophylaxis does not achieve target afXa levels for the majority of our free flap patients. H&N patients appear to be a particularly high-risk group that may require a more personalized and aggressive approach. Total body weight is the sole negative predictor of afXa level, supporting a role for weight-based enoxaparin dosing.

THE EFFICACY OF WEIGHT-BASED ENOXAPARIN DOSING FOR VTE-PROPHYLAXIS IN TRAUMA PATIENTS: A SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND

Trauma patients are at high risk of developing venous thromboembolism (VTE), and standard dosing enoxaparin regimens may be inadequate for prophylaxis. This meta-analysis was performed to clarify the efficacy of alternative dosing regimens for VTE prophylaxis in this high-risk group. The objective of this systematic review was to review the evidence regarding weight-based dosing of enoxaparin for VTE prophylaxis in trauma patients.

METHODS

A systematic database search was undertaken for studies comparing standard vs weight-based dosing of enoxaparin for VTE prophylaxis in adult trauma patients, aged ≥18 years. The primary outcome was the achievement of Anti-Factor Xa (AFXa) levels within the prophylactic range. Secondary outcomes included: sub-prophylactic AFXa levels, supra-prophylactic AFXa levels, VTE incidence and bleeding events. Meta-analysis was conducted using both fixed- and random-effects models, and presented as odds ratios (OR), risk ratios (RR) and risk differences (RD) with 95% confidence intervals (CI).

RESULTS

Four cohort studies were eligible for inclusion. Compared to standard dosing, weight-based enoxaparin prophylaxis dosing was associated with increased odds of prophylactic AFXa levels (OR = 5.85., 95%CI: 3.02-11.30, p < 0.00001) and reduced risk of sub-prophylactic AFXa levels (RR = 3.97, 95%CI: 3.02-5.22, p < 0.00001). Standard dosing was associated with a reduced risk of supra-therapeutic AFXa levels (RR = 0.23, 95%CI: 0.11-0.50, P = 0.0002), but this was not associated with a difference in risk of bleeding events (RD = -0.00, 95%CI: -0.02-0.01, P = 0.55). There was no statistical difference in incidence VTE between the two groups (RD = 0.01, 95%CI: -0.02-0.03, P = 0.64).

CONCLUSIONS

Compared with standard dosing, weight-based enoxaparin dosing regimens are associated with increased odds of prophylactic range AFXa levels. Further investigation is required to determine if this translates into improved VTE prophylaxis and reduced VTE incidence.

LEVEL OF EVIDENCE

Systematic Review, level III.

Chemoprophylaxis for venous thromboembolism in pelvic and/or acetabular fractures: A systematic review

BACKGROUND

It is unclear which pharmacological agents, and at what dosage and timing, are most effective for venous thromboembolism (VTE) prophylaxis in patients with pelvic/acetabular fractures.

METHODS

We searched the Cochrane Database of Systematic Reviews, Embase, Web of Science, EBSCO, and PubMed on October 3, 2020, for English-language studies of VTE prophylaxis in patients with pelvic/acetabular fractures. We applied no date limits. We included studies that compared efficacy of pharmacological agents for VTE prophylaxis, timing of administration of such agents, and/or dosage of such agents. We recorded interventions, sample sizes, and VTE incidence, including deep vein thrombosis (DVT) and pulmonary embolism.

RESULTS

Two studies (3604 patients) compared pharmacological agents, reporting that patients who received direct oral anticoagulants (DOACs) were less likely to develop DVT than those who received low molecular weight heparin (LMWH) (p < 0.01). Compared with unfractionated heparin (UH), LMWH was associated with lower odds of VTE (odds ratio [OR] = 0.37, 95% confidence interval [CI]: 0.22-0.63) and death (OR = 0.27, 95% CI: 0.10-0.72). Three studies (3107 patients) compared timing of VTE prophylaxis, reporting that late prophylaxis was associated with higher odds of VTE (OR = 1.9, 95% CI: 1.2-3.2) and death (OR = 4.0, 95% CI: 1.5-11) and higher rates of symptomatic DVT (9.2% vs. 2.5%, p = 0.03; and 22% vs. 3.1%, p = 0.01). One study (31 patients) investigated dosage of VTE prophylaxis, reporting that a higher proportion of patients with acetabular fractures were underdosed (23% of patients below range of anti-Factor Xa [aFXa] had acetabular fractures vs. 4.8% of patients within adequate range of aFXa, p<0.01).

CONCLUSIONS

Early VTE chemoprophylaxis (within 24 or 48 h after injury) was better than late administration in terms of VTE and death. Many patients with acetabular fractures are underdosed with LMWH, with inadequate aFXa levels. Compared with UH, LMWH was associated with lower odds of VTE and death. DOACs were associated with lower risk of DVT compared with LMWH.

LEVEL OF EVIDENCE

III, systematic review of retrospective cohort studies.

Anticoagulation Monitoring in the Intensive Care Unit

Patients with critical illness often display variable hypo- and hypercoagulable sequalae requiring intense monitoring and anticoagulation pharmacotherapy to prevent or treat inappropriate clot formation. It is imperative to understand the various stages of the clotting cascade and where each pharmacotherapy agent exerts its therapeutic effect. Common coagulation tests are utilized to monitor the areas of the clotting cascade and the effects that anticoagulant pharmacotherapy exhibits. Many novel coagulation tests are also in development. The purpose of this narrative review is to evaluate commonly utilized coagulation tests that monitor anticoagulation while in the intensive care unit.

Relationship Between Anti-Xa Level Achieved with Prophylactic Low-Molecular Weight Heparin and Venous Thromboembolism in Trauma Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Trauma patients have simultaneously high venous thromboembolism (VTE) and bleeding risk. Optimal chemoprophylaxis regimens remain unclear. This study aims to answer three questions for trauma patients. Is there any association between anti-Xa and VTE? Does dose adjustment improve prophylactic anti-Xa rates? Does dose adjustment improve anti-Xa adequacy and VTE compared to standard dosing?

METHODS

Systematic search of MEDLINE, Embase, Scopus, and Web of Science occurred in May 2021.Two author review included trauma studies that: evaluated low molecular weight heparin chemoprophylaxis, reported anti-Xa level, and evaluated ≥1 outcome. Data was dually extracted and estimated effects were calculated using RevMan 5.4 applying the Mantel-Haenszel method. Analysis #1 compared patients with peak anti-Xa ≥ 0.2 IU/ml or trough ≥0.1 IU/ml to those with lower anti-Xa using VTE as the primary outcome. Analysis #2 reported the effect of dose adjustment on anti-Xa. Analysis #3 compared standard dosing to dose adjustment with the primary outcome being anti-Xa adequacy; secondary outcomes were VTE, pulmonary embolism, and bleeding complications.

RESULTS

3401 studies were evaluated with 24 being included (19 retrospective studies, 5 prospective studies). In analysis #1, achieving adequate anti-Xa was associated with reduced odds of VTE (4.0% to 3.1%, OR 0.52, p = 0.03). Analysis #2 demonstrated that 768 (75.3%) patients achieved prophylactic anti-Xa with adjustment protocols.Analysis three suggested that dose adjusted chemoprophylaxis achieves prophylactic anti-Xa more frequently (OR 4.05, p = 0.007) but without VTE (OR 0.72, p = 0.15) or PE (OR 0.48, p = 0.10) differences. In subgroup analysis, anti-Xa dose adjustment also suggested no VTE reduction (OR 0.68, p = 0.08).

CONCLUSIONS

Patients with higher anti-Xa levels are less likely to experience VTE, and anti-Xa guided chemoprophylaxis increases anti-Xa adequacy. However, dose adjustment, including anti-Xa guided dosing, may not reduce VTE.

LEVEL OF EVIDENCE

Level IV; Systematic Review Meta-Analysis.

Regional anaesthesia in patients on antithrombotic drugs: Joint ESAIC/ESRA guidelines

BACKGROUND

Bleeding is a potential complication after neuraxial and peripheral nerve blocks. The risk is increased in patients on antiplatelet and anticoagulant drugs. This joint guideline from the European Society of Anaesthesiology and Intensive Care and the European Society of Regional Anaesthesia aims to provide an evidence-based set of recommendations and suggestions on how to reduce the risk of antithrombotic drug-induced haematoma formation related to the practice of regional anaesthesia and analgesia.

DESIGN

A systematic literature search was performed, examining seven drug comparators and 10 types of clinical intervention with the outcome being peripheral and neuraxial haematoma. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used for assessing the methodological quality of the included studies and for formulating recommendations. A Delphi process was used to prepare a clinical practice guideline.

RESULTS

Clinical studies were limited in number and quality and the certainty of evidence was assessed to be GRADE C throughout. Forty clinical practice statements were formulated. Using the Delphi-process, strong consensus (>90% agreement) was achieved in 57.5% of recommendations and consensus (75 to 90% agreement) in 42.5%.

DISCUSSION

Specific time intervals should be observed concerning the adminstration of antithrombotic drugs both prior to, and after, neuraxial procedures or those peripheral nerve blocks with higher bleeding risk (deep, noncompressible). These time intervals vary according to the type and dose of anticoagulant drugs, renal function and whether a traumatic puncture has occured. Drug measurements may be used to guide certain time intervals, whilst specific reversal for vitamin K antagonists and dabigatran may also influence these. Ultrasound guidance, drug combinations and bleeding risk scores do not modify the time intervals. In peripheral nerve blocks with low bleeding risk (superficial, compressible), these time intervals do not apply.

CONCLUSION

In patients taking antiplatelet or anticoagulant medications, practitioners must consider the bleeding risk both before and after nerve blockade and during insertion or removal of a catheter. Healthcare teams managing such patients must be aware of the risk and be competent in detecting and managing any possible haematomas.

Comparison of Anti-factor Xa Levels in Female and Male Patients with Obesity After Enoxaparin Application for Thromboprophylaxis

Purpose

Venous thromboembolic events (VTEs) are common complications after bariatric surgery, and enoxaparin is commonly used to prevent VTEs. The risk for VTEs is sex-specific. Whether enoxaparin application results in similar anti-factor Xa activities (aFXa) in males and females with obesity remains to be determined. We investigated whether our dosage regimen of enoxaparin resulted in similar serum aFXa levels in female and male patients undergoing bariatric surgery.

Materials and Methods

We administered enoxaparin twice daily in patients undergoing bariatric surgery. Patients with a body mass index (BMI) > 60 kg/m² (n = 11) received 60 mg enoxaparin (group 2), and patients with lower BMI (n = 86) received 40 mg per dose (group 1). Peak aFXa levels were measured 3 days after surgery. The primary outcome was the aFXa level. As a secondary outcome, we detected VTEs and major bleeding events and explored the possible influencing factors of aFXa.

Results

Women had higher aFXa than men, but after matching for anthropometric values, the two groups were similar (females: 0.17 ± 0.08 U/ml; males: 0.18 ± 0.08 U/ml). Linear regression revealed a moderate relationship between weight and aFXa levels. The 3-month follow-up was attended by 94.9%, at which one patient had pulmonary embolism.

Conclusion

Individual enoxaparin dosage regimens for men and women do not seem to be required. Weight-based dosing regimen seems to be a more reasonable choice.

Graphical abstract

Are the Placement, Maintenance, and Removal of Femoral and Sciatic Catheters Associated With Bleeding Complications in Vascular Patients on Antithrombotics? A Single-Center, Retrospective Cohort Study

BACKGROUND

Information on the safety of placement, maintenance, and removal of peripheral nerve blocks in the presence of therapeutic or prophylactic antithrombotics is limited to case reports.

METHODS

In this retrospective, descriptive study, we examined the use of femoral and gluteal or subgluteal sciatic perineural catheters in 146 patients on antithrombotics who received lower limb amputation (LLA) above or below the knee at the University of Florida Health Shands Hospital between January 2015 and December 2019. We searched patient surgical records for complications such as bleeding, nerve damage, infection, and hematoma during placement, maintenance, and removal of the perineural catheters.

RESULTS

In this cohort of 146 patients on antithrombotics, there was 1 episode of hematoma with an estimated incidence of 1 of 146 (0.68%, 95% confidence interval [CI], 0.02-3.76). This patient developed a hematoma at the location of the femoral catheter and required a blood transfusion. This patient was on aspirin daily and subcutaneous heparin 3 times per day and had a normal coagulation profile during their hospital stay.

CONCLUSIONS

This report investigates bleeding complications of femoral and sciatic perineural catheters in patients undergoing LLA on antithrombotics. We found that, except for 1 patient, most patients on varying combinations of antithrombotics did not experience bleeding complications related to the femoral and sciatic perineural catheters.

Effects of dalteparin on anti-Xa activities cannot be predicted in critically ill COVID-19 patients

Critically ill COVID‐19 patients are at high risk of thromboembolic events despite routine‐dosed low‐molecular‐weight heparin thromboprophylaxis. However, in recent randomized trials increased‐intensity thromboprophylaxis seemed futile and possibly even harmful. In this explorative pharmacokinetic (PK) study we measured anti‐Xa activities on frequent timepoints in 15 critically ill COVID‐19 patients receiving dalteparin and performed PK analysis by nonlinear mixed‐effect modelling. A linear one‐compartment model with first‐order kinetics provided a good fit. However, wide interindividual variation in dalteparin absorption (variance 78%) and clearance (variance 34%) was observed, unexplained by routine clinical covariates. Using the final PK model for Monte Carlo simulations, we predicted increased‐intensity dalteparin to result in anti‐Xa activities well over prophylactic targets (0.2‐0.4 IU/mL) in the majority of patients. Therapeutic‐intensity dalteparin results in supratherapeutic anti‐Xa levels (target 0.6‐1.0 IU/mL) in 19% of patients and subtherapeutic levels in 22%. Therefore, anti‐Xa measurements should guide high‐intensity dalteparin in critically ill COVID‐19 patients.

Anti-Xa Activity of Enoxaparin for Prevention of Venous Thromboembolism in Severe Nephrotic Syndrome-A Single Center Prospective Study

Severe nephrotic syndrome (NS) is associated with high risk of venous thromboembolic events (VTE), as well as presumably altered heparin pharmacokinetics and pharmacodynamics. Although prophylactic anticoagulation is recommended, the optimal dose is not established. The aim of the study was to test two co-primary hypotheses: of reduced enoxaparin effectiveness and of the need for dose-adjustment in NS. Forty two nephrotic patients with serum albumin ≤2.5 g/dL were alternately assigned to a standard fixed-dose of enoxaparin (NS-FD: 40 mg/day) or ideal body weight (IBW)-based adjusted-dose (NS-AD: 1 mg/kg/day). Twenty one matched non-proteinuric individuals (C-FD) also received fixed-dose. Co-primary outcomes were: the achievement of low- and high-VTE risk threshold of antifactor-Xa activity (anti-FXa) defined as 0.2 IU/mL and 0.3 IU/mL, respectively. Low-VTE-risk threshold was achieved less often in NS-FD than C-FD group (91 vs. 62%, p = 0.024), while the high-VTE-risk threshold more often in NS-AD than in NS-FD group (90 vs. 38%, p < 0.001). Two VTE were observed in NS during 12 months of follow-up (incidence: 5.88%/year). In both cases anti-FXa were 0.3 IU/mL implying the use of anti-FXa >0.3 IU/mL as a target for dose-adjustment logistic regression models. We determined the optimal dose/IBW cut-off value at 0.8 mg/kg and further developed bivariate model (termed the DoAT model) including dose/IBW and antithrombin activity that improved the diagnostic accuracy (AUC 0.85 ± 0.06 vs. AUC 0.75 ± 0.08). Enoxaparin efficacy is reduced in severe NS and the dose should be adjusted to ideal body weight to achieve target anti-FXa activity.

Standard- versus intermediate-dose enoxaparin for anti-factor Xa guided thromboprophylaxis in critically ill patients with COVID-19

The prevalence of venous thromboembolism (VTE) is high in critically ill patients with COVID-19. Dosing of Low Molecular Weight Heparin (LMWH) for thromboprophylaxis in patients with severe COVID-19 is subject to ongoing debate.

In this brief report, we describe our study where we retrospectively examined the efficacy of standard- versus intermediate-dosing of enoxaparin in attaining and maintaining accepted prophylactic levels of anti-Factor Xa (anti-FXa) in critically ill patients with COVID-19.

We collected data for all patients with confirmed COVID-19 who were treated with enoxaparin for thromboprophylaxis in a single Intensive Care Unit (ICU) in the United Kingdom between 31st March and 16th November 2020. Standard-dose of enoxaparin was 40 mg subcutaneously once daily for patients with normal renal function and body weight between 50 and 100 kg; the intermediate-dose was 40 mg subcutaneously twice daily. Anti-FXa peak concentrations between 0.2-0.4 IU/ml were considered appropriate for thromboprophylaxis.

Age, sex, weight, Body Mass Index, APACHE II score, ICU length of stay, initial P/F ratio and creatinine were not statistically significantly different between standard- and intermediate-dose thromboprophylaxis cohorts. In the standard-dose group, the median initial anti-FXa level was 0.13 (interquartile range 0.06-0.18) compared to 0.26 (0.21-0.33) in the intermediate-dose cohort (p < 0.001). On repeated measurement, in the standard dose cohort, 44 of 95 (46%) anti-FXa levels were < 0.2 IU/ml compared with 24 of 132 (18%) levels in the intermediate-dose cohort even after dose-adjustment. There was one radiologically confirmed pulmonary embolism (PE) on computed tomography pulmonary angiogram during hospital admission in each cohort.

Our study supports starting intermediate-dose thromboprophylaxis for critically ill patients with COVID-19 to achieve anti-FXa levels in the accepted thromboprophylactic range although further study is required to investigate whether anti-FXa guided thromboprophylaxis is safe and effective in reducing the incidence of VTEs in critically ill patients with COVID-19.

Factor Xa Levels in Patients Receiving Prophylactic Enoxaparin Sodium in the Intensive Care Unit of an Academic Hospital

Background: The aim of this study was to determine the anti-factor Xa levels in patients receiving enoxaparin sodium for venous thromboembolism prophylaxis in the intensive care unit (ICU).

Patients and methods: Using a cross-sectional study methodology, 73 ICU patients receiving 40 mg enoxaparin sodium daily were enrolled in this study. Anti-factor Xa levels were measured following the second dose. Prophylactic and subprophylactic groups of patients were compared for age, sex, weight, body mass index, total bilirubin, serum albumin, and APACHE II score.

Results: Anti-factor Xa levels were prophylactic (0.2–0.6 IU/mL) in 44 (60.3%) patients and subprophylactic (<0.2 IU/mL) in 29 (39.7%) patients. The mean (SD) actual delivered dose of enoxaparin per kilogram body weight was significantly higher, at 0.59 (0.11) mg/kg in the prophylactic group compared to 0.53 (0.13) mg/kg in the subprophylactic group (p = 0.043). The subprophylactic group had significantly lower serum albumin levels compared to the prophylactic group. The total bilirubin levels were not found to be significantly different between the two groups (p = 0.110).

Conclusion: A fixed prophylactic 40 mg dose of enoxaparin was associated with a high proportion of subprophylactic anti-factor Xa levels. Weight-based dose and serum albumin level were independent predictors of achieving the prophylactic target range.

How to cite this article: Baloo MM, Scribante J, Perrie H, Calleemalay D, Omar S. Factor Xa Levels in Patients Receiving Prophylactic Enoxaparin Sodium in the Intensive Care Unit of an Academic Hospital. Indian J Crit Care Med 2021;25(8):917–919.

Heparin resistance in severe thermal injury: A prospective cohort study

BACKGROUND

Low molecular-weight heparin (LMWH) is routinely administered to burn patients for thromboprophylaxis. Some studies have reported heparin resistance, yet the mechanism(s) and prevalence have not been systematically studied. We hypothesized that nucleosomes, composed of histone structures with associated DNA released from injured tissue and activated immune cells in the form of neutrophil extracellular traps (NETs or NETosis), neutralize LMWH resulting in suboptimal anticoagulation, assessed by reduction in anti-factor Xa activity.

METHODS

Blood was sampled from >15% total body surface area (TBSA) burn patients receiving LMWH on days 5, 10 and 14. Peak anti-factor Xa (AFXa) activity, anti-thrombin (ATIII) activity, cell-free DNA (cfDNA) levels and nucleosome levels were measured. Mixed effects regression was adjusted for multiple confounders, including injury severity and ATIII activity, and was used to test the association between nucleosomes and AFXa.

RESULTS

A total of 30 patients with severe burns were included. Mean TBSA 43% (SD 17). Twenty-three (77%) patients were affected by heparin resistance (defined by AFXa activity <0.2 IU/mL). Mean peak AFXa activity across samples was 0.18 IU/mL (SD 0.11). Mean ATIII was 81.9% activity (SD 20.4). Samples taken at higher LWMH doses were found to have significantly increased AFXa activity, though the effect was not observed at all doses, at 8000 IU no samples were heparin resistant. Nucleosome levels were negatively correlated with AFXa (r = -0.29, p = 0.050) consistent with the hypothesis. The final model, with peak AFXa as the response variable, was adjusted for nucleosome levels (p = 0.0453), ATIII activity (p = 0.0053), LMWH dose pre-sample (p = 0.0049), drug given (enoxaparin or tinzaparin) (p = 0.03), and other confounders including severity of injury, age, gender, time point of sample.

CONCLUSIONS

Heparin resistance is a prevalent issue in severe burns. Nucleosome levels were increased post-burn, and showed an inverse association with AFXa consistent with the hypothesis that they may interfere with the anticoagulant effect of heparin in vivo and contribute to heparin resistance. Accurate monitoring of AFXa activity with appropriate therapy escalation plans are recommended with dose adjustment following severe burn injury.

Monitoring of Enoxaparin during Hemodialysis Covered by Regional Citrate Anticoagulation in Acute Kidney Injury: A Prospective Cohort Study

Background: Current guidelines recommend the monitoring of anti-factor Xa (anti-Xa) levels to avoid an accumulation of low-molecular-weight heparins in patients with acute kidney injury, but there is no evidence on how to proceed with such monitoring during continuous renal replacement therapy. Against this background, we investigated the potential accumulation of enoxaparin administered subcutaneously for venous thromboembolism prophylaxis in critically ill patients during continuous renal replacement therapy covered by regional citrate anticoagulation. Methods: Anti-Xa levels were measured at baseline (≤12 h before renal replacement therapy) and on three consecutive days (A to C) when enoxaparin had reached trough levels. Supplementary testing included modified assays of rotational thromboelastometry known to be highly sensitive for low-molecular-weight heparins. Results: The 16 men and 13 women included were adults comparable in age, body mass index, thromboembolism risk assessment, and clinical severity of the disease. Throughout the four examinations, the median trough levels of anti-Xa remained below the detection limit of the test (<0.1 IU mL⁻¹), with interquartile ranges of <0.1 to 0.14 IU mL⁻¹ at baseline and <0.1 to 0.16 IU mL⁻¹ on days A/B/C. All rotational thromboelastometry parameters of clot initiation and clot formation dynamics did not significantly change from baseline to day C. Conclusions: Neither anti-Xa levels nor modified assays of rotational thromboelastometry revealed any accumulation of enoxaparin administered for thromboprophylaxis during continuous renal replacement therapy covered by regional citrate anticoagulation. Although generally recommended in patients with acute kidney injury, monitoring of anti-Xa levels should be questioned in this defined setting.

The antithrombin binding regions of heparin mediate fetal growth and reduced placental damage in the RUPP model of preeclampsia†

Preeclampsia is a serious hypertensive disorder of pregnancy, which is only cured with delivery of the placenta, thereby commonly necessitating preterm birth of the fetus. Low-molecular-weight heparin (LMWH) has demonstrated potential to reduce the incidence of preeclampsia in high-risk pregnant women, although the underlying mechanism by which LMWH protects against preeclampsia is unknown. Given the complex structure and biologic actions of heparin, we tested the hypothesis that heparin can mediate preeclampsia prevention via nonanticoagulant pathways. We compared the effects of a nonanticoagulant, glycol-split LMWH (gsHep)—rendered nonanticoagulant through disruption of the antithrombin binding regions—with the LMWH dalteparin in the rat reduced uterine perfusion pressure (RUPP) surgical model of preeclampsia. Although RUPP animals exhibit significantly elevated blood pressure and reduced plasma levels of placental growth factor (PGF) compared to sham, neither dalteparin nor gsHep treatment significantly impacted these parameters. However, the observed positive correlation between PGF levels and number of viable fetuses in RUPP-induced animals suggests that reduced PGF levels were predominately due to placental loss. Daily subcutaneous injections of low-dose dalteparin but not gsHep significantly restored fetal growth that was impaired by RUPP surgery. Placentas from RUPP animals exhibited an abnormal labyrinth structure, characterized by expanded sinusoidal blood spaces, relative to sham-operated animals. Morphometric analysis demonstrated that dalteparin but not gsHep treatment normalized development of the labyrinth in RUPP-exposed conceptuses. These data suggest that the antithrombin-binding regions of LMWH are required to confer its protective effects on fetal growth and placental development.

Weight-adjusted versus fixed dose heparin thromboprophylaxis in hospitalized obese patients: A systematic review and meta-analysis

BACKGROUND

Fixed dose unfractionated or low molecular weight heparin is the recommended treatment for venous thromboembolism (VTE) prevention in hospitalized patients. However, its efficacy has been questioned in obese population. Results of previous studies on weight-adjusted doses of heparin for VTE prevention are contradictory. Different anticoagulant regimens are used in clinical practice, but their role remains to be elucidated.

AIMS

To clarify the efficacy and safety of weight-adjusted dose heparin for VTE prevention in obese subjects hospitalized for medical and surgical conditions.

METHODS

Twelve studies were identified as reporting VTE occurrence, major or minor bleeding and anti-Xa levels. A random-effect meta-analysis was conducted to derive odds ratios (OR) comparing fixed vs weight adjusted-doses heparins on VTE occurrence, bleeding, anti-Xa levels. Medical and surgical patients, prospective vs retrospective and quality of studies were extracted for moderators and meta-regression analysis.

RESULTS

Weight-adjusted dose heparin administration was not associated with reduced VTE occurrence (6320/13317 patients, OR 1.03, 95% C.I. 0.79 to 1.35), nor increased bleeding (5840/10906 patients, OR 0.84, 95% C.I. 0.65 to 1.08), but it was associated with higher anti-Xa levels (284/294 patients, ES 2.04, 95% C.I. 1.16 to 2.92, p<0.0001). A significant heterogeneity was present for comparison of anti-Xa levels (I²=94%, p=0.0001) but not for VTE occurrence or bleeding (I²=7.6% and 12.8% respectivel). None of the moderators explained the heterogeneity of the results among primary studies.

CONCLUSION

Weight-adjusted dose as compared to fixed-dose of heparins in the prevention of VTE in obese patients was not associated with a lower risk of VTE nor a higher risk of bleeding.

Fixed-dose enoxaparin provides efficient DVT prophylaxis in mixed ICU patients despite low anti-Xa levels: A prospective observational cohort study

BACKGROUND

Deep vein thrombosis (DVT) is a serious but preventable complication of critical illness with a reported incidence from 4 to 17%. Anti-Xa activity in critically ill patients achieved with standard dosing of low-molecular-weight heparins (LMWH) is often below the target of 0.2-0.5 IU/mL. However, the clinical significance of this finding is unclear. The quality of thromboprophylaxis also strongly impacts the incidence of DVT. We performed a prospective observational study to evaluate the incidence of DVT in a mixed medical-surgical-trauma intensive care unit (ICU) using a thromboprophylaxis protocol with a fixed dose of enoxaparin. We also explored the relation between DVT incidence and anti-Xa activity.

METHOD

All consecutive patients with expected ICU stay ≥72 hours and without evidence of DVT upon admission were included. They underwent ultrasound screening for DVT twice a week until ICU discharge, death, DVT or pulmonary embolism. Peak anti-Xa activity was measured twice a week. Patients received 40 mg of enoxaparin subcutaneously (60 mg in obese, 20 mg in case of renal failure). Graduated compression stockings were used in case of LMWH or another anticoagulant contraindication.

RESULTS

A total of 219 patients were enrolled. We observed six cases of DVT (incidence of 2.7%). The agreement between expected and delivered DVT prophylaxis was 94%. Mean peak anti-Xa activity level was 0.24 (SD, 0.13) IU/mL. There was no significant difference in anti-Xa activity in DVT and non-DVT group.

CONCLUSION

A low incidence of DVT was achieved with meticulous adherence to the standard prophylactic protocol. The low incidence of DVT was observed despite low levels of anti-Xa activity. Our findings suggest that enoxaparin dose adjustment based on regular monitoring of anti-Xa activity is unlikely to result in further reduction of DVT incidence in a mixed ICU population.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03286985.

Utility of coagulation analyses to assess thromboprophylaxis with dalteparin in intensive care unit patients

BACKGROUND

The aim of this study was to evaluate the utility of coagulation analyses to assess thromboprophylaxis with dalteparin in intensive care unit (ICU) patients.

METHODS

Prospective observational study of ICU patients receiving dalteparin prophylaxis at Oslo University Hospital in Norway. Trough and peak antithrombin, protein C, anti-factor Xa activity (aFXa), d-dimer, thromboelastography, calibrated automated thrombogram and microparticles were analysed. Levels were compared in patients with and without venous thromboembolism (VTE), major bleeding, acute kidney injury (AKI) with use of renal replacement therapy (RRT) and variable dalteparin dose.

RESULTS

Among 50 included patients (76% male, mean age 62 years) five (10%) developed VTE and eight (16%) major bleeding. Median through aFXa level was 0.03 (0.02-0.05) IU/mL, and 48 (96%) of patients were within and two (4%) above target range. Peak aFXa level was 0.21 (0.13-0.29) IU/mL, the number of patients below, within and above prophylactic range were 21 (42%), 25 (50%) and four (8%). Peak aFXa levels were similar in patients with and without VTE (0.18 vs 0.21 IU/L, P = .72), major bleeding (0.22 vs 0.21 IU/mL, P = .38) and AKI with RRT (0.18 vs 0.24, P = .13), but lower in patients receiving dalteparin 5000 IU od compared to 7500 IU od (0.19 vs 0.30 IU/mL, P < .01).

CONCLUSIONS

Intensive care unit patients receiving dalteparin prophylaxis had half of patients within prophylactic peak aFXa target range. Peak aFXa levels was affected by administered dalteparin dose, but not presence of VTE, major bleeding or AKI with RRT.

A fixed dose approach to thrombosis chemoprophylaxis may be inadequate in heavier critically ill patients

Objectives: Overweight patients are at greater risk of venous thromboembolism. We aimed to describe prescribing patterns of thrombosis chemoprophylaxis in critically ill patients weighing ≥ 100 kg and quantify the effectiveness of these regimens using the surrogate biomarker of plasma anti-Xa level. Design, setting and patients: A prospective single-centre cohort study was conducted over a 6-month period. Patients weighing ≥ 100 kg who were prescribed enoxaparin for chemoprophylaxis and expected to remain in the intensive care unit for > 48 hours were eligible. Anti-Xa levels were measured once a patient had received at least three consecutive doses of enoxaparin. Peak levels were measured 4-6 hours after the third dose and trough levels were measured before the fourth dose. Anti-Xa levels were compared with established target ranges for peak and trough anti-Xa levels (0.2-0.5 IU/mL and > 0.1 IU/mL, respectively). Results: Eighty-eight patients met the eligibility criteria, and anti-Xa levels for 42 patients were obtained. Fixed dose chemoprophylaxis approaches varied considerably, with 40 mg once daily (54/88 [61%]) and 40 mg twice daily (20/88 [23%]) being the most frequently prescribed regimens. No patient had a peak anti-Xa level > 0.5 IU/mL. When comparing 40 mg once daily versus twice daily, the once daily regimen had lower median trough levels (0.01 IU/mL [interquartile range (IQR), 0.00-0.04] v 0.09 IU/mL [IQR, 0.05-0.13]; P < 0.001) and greater proportions of patients with levels below the established range (< 0.1 IU/mL) (15/16 [95%] v 7/14 [50%]; P = 0.002) and levels that were undetectable (0.00 IU/mL) (8/16 [50%] v 1/14 [7%]; P = 0.01). Conclusions: At a single centre, thrombosis chemoprophylaxis prescribing patterns for heavier critically ill patients varied considerably. Current fixed dose approaches may be inadequate in this cohort.

Anti-Factor Xa Levels in Low-weight Surgical Patients Receiving Enoxaparin for Venous Thromboembolism Prophylaxis: A Prospective Cohort Study

Enoxaparin is indicated for thromboprophylaxis in non-orthopedic surgical patients at a fixed dose of 40 mg daily. According to the US Food and Drug Administration’s enoxaparin prescribing information, this dose exposes low-weight patients (males < 57 kg, females < 45 kg) to a higher risk of bleeding. This study aimed to determine the rate of achieving a prophylactic peak anti-factor Xa (AFXa) level in low-weight surgical patients using enoxaparin 30 mg daily. Low-weight patients admitted for abdominopelvic or noncardiac thoracic surgery from May 2018 to May 2019 were prospectively studied. After receiving daily enoxaparin 30 mg, peak AFXa levels were assessed for achieving a prophylactic level (0.2-0.5 IU/mL). In 121 patients, the proportion of achieving a prophylactic peak AFXa level was 66.1%. More females (84.8%) achieved a prophylactic level compared to males (54.7%, P = .001). All out-of-range peak AFXa levels (33.9%) were sub-prophylactic. The median peak AFXa level was lower in males (0.24 [0.1-0.47] IU/mL) than females (0.31 [0.1-0.5] IU/mL; P < .001). On univariate analysis, female sex and weight were associated with achieving a prophylactic peak AFXa level. On multivariate analysis, only female sex was independently associated with an adequate prophylactic AFXa level (odds ratio 3.17, 95% CI: 1.32-11.94; P = .014). Four venous thromboembolism events (3.3%) were observed in patients with sub-prophylactic peak AFXa levels (9.7%). Two-thirds of low-weight surgical patients achieved a prophylactic peak AFXa level using daily enoxaparin 30 mg. This dose is likely to provide adequate thromboprophylaxis in low-weight females.

Understanding the andromeda strain - The role of cytokine release, coagulopathy and antithrombin III in SARS-CoV2 critical illness

As the current coronavirus pandemic continues and cases of COVID-19 critical illness rise, physicians and scientists across the globe are working to understand and study its pathophysiology. Part of the pathology of this illness may result from its prothrombotic potential as witnessed from derangements in coagulation and thrombotic complications reported in observational studies performed in China and Europe to findings of microthrombosis upon autopsy analysis of patients who succumbed to COVID-19. Multiple organizations, including the American Society of Hematology (ASH), recommend the routine use of prophylactic heparin to temper the thrombotic complications of this illness given its mortality benefit in severe COVID-19 infections. Reductions in circulating levels of Antithrombin III (AT), the primary mediator of heparin's action, is present in cases of coronavirus related critical illness. AT's use as a prognostic marker, an important effector of heparin resistance, and a potential therapeutic target for COVID-19 remains to be explored.

Hypercoagulopathy in Severe COVID-19: Implications for Acute Care

COVID-19 was first described in late 2019 and has since developed into a pandemic affecting more than 21 million people worldwide. Of particular relevance for acute care is the occurrence of COVID-19-associated coagulopathy (CAC), which is characterised by hypercoagulability, immunothrombosis and venous thromboembolism, and contributes to hypoxia in a significant proportion of patients. This review describes diagnosis and treatment of CAC in the emergency department and in intensive care. We summarise the pathological mechanisms and common complications of CAC such as pulmonary thrombosis and venous thromboembolic events and discuss current strategies for thromboprophylaxis and therapeutic anti-coagulation in the acute care setting.

Clinical Outcomes With the Use of Prophylactic Versus Therapeutic Anticoagulation in Coronavirus Disease 2019

Objectives:

To determine the impact of anticoagulation on inhospital mortality among coronavirus disease 2019-positive patients with the a priori hypothesis that there would be a lower risk of inhospital mortality with use of preemptive therapeutic over prophylactic dose enoxaparin or heparin.

Design Setting:

Retrospective cohort study from April 1, 2020, to April 25, 2020. The date of final follow-up was June 12, 2020 Two large, acute-care hospitals in Western Connecticut.

Patients:

Five hundred and one inpatients were identified after discharge as 18 years or older and positive for severe acute respiratory syndrome coronavirus 2. The final sample size included 374 patients after applying exclusion criteria. Demographic variables were collected via hospital billing inquiries, whereas the clinical variables were abstracted from patients’ medical records.

Exposure:

Preemptive enoxaparin or heparin at a therapeutic or prophylactic dose.

Main Results:

When comparing treatments through multivariable analysis, risk of inhospital mortality was 2.3 times greater in patients receiving preemptive therapeutic anticoagulation (95% CI = 1.0–4.9; p = 0.04). Additionally, the average treatment effects were higher (β = 0.11, p = 0.01) in the therapeutic group.

Conclusions:

An increase in inhospital mortality was observed among patients on preemptive therapeutic anticoagulation. Thus, in the management of coronavirus disease 2019 and its complications, we recommend further research and cautious use of preemptive therapeutic over prophylactic anticoagulation.