The ATLANTIC study: Anti-Xa level assessment in trauma intensive care

A retrospective Cohort study on the effect of the LOw-molecular weighT heparin (LMWH) nadroparin dose on anti-XA levels in a mixed medical-surgical ICU population: CLOT-Xa

PURPOSE

Low-molecular-weight heparins (LMWHs) are widely used for prevention and treatment of venous thromboembolism (VTE) in critically ill patients. The objective of this study was to assess the dose-response relationship between nadroparin dose and anti-Xa activity in ICU patients.

MATERIALS AND METHODS

Critically ill adult patients who were admitted to the ICU, and received at least three subcutaneous injections of nadroparin were included. The dose-effect relationship between nadroparin dose and anti-Xa level was analysed through a mixed-effects logistic regression model.

RESULTS

In total, 327 ICU patients were included. Median anti-Xa levels ranged from <0.1 IU/mL after nadroparin 0-37 IU/kg/day to 0.6 IU/mL after nadroparin >85 IU/kg/day (p < 0.01). Among all 1520 anti-Xa measurements, 859 (57 %) measurements were in the desired anti-Xa range. The best adequacy of anti-Xa levels was observed in nadroparin doses of 38-85 IU/kg (73 %). No differences in the odds of bleeding events or VTE between different anti-Xa levels were found.

CONCLUSIONS

We found a clear dose-response relationship between nadroparin dose and anti-Xa levels. Increasing nadroparin doses led to more adequate anti-Xa levels without a change in the occurrence of VTE or major bleeding events, suggesting that LMWH therapy can be successfully and safely personalized using anti-Xa guided dosing.

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

PURPOSE

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Evaluation of the impact of bundled nursing strategies on the prevention of venous thromboembolism in patients with cerebral hemorrhage

To investigate the effectiveness and value of bundled nursing strategies for venous thromboembolism prevention in nonsurgical patients with cerebral hemorrhage, 200 patients who underwent treatment for cerebral hemorrhage in our hospital from January 2023 to July 2023 were chosen as the study subjects. Patients were divided into control group and experimental group according to different treatment methods. For patients in the control group, regular care was used, while for patients in the observation group, bundled care was used for intervention. This study used a venous thromboembolism risk factor assessment form to assess the probability of patients suffering from venous thromboembolism. It used the incidence of venous thromboembolism, disease cognition level, coagulation function, fibrinolysis, changes in blood routine, exercise ability, improvement in quality of life, and patient satisfaction with nursing mode as detection indicators to obtain the changes in various indicator values and patient satisfaction scores under different nursing interventions. Prior to nursing intervention, the significant statistical differences did not exist (P > .05) between the control group and the observation group in terms of general information, number of venous thromboembolism risk levels, degree of disease cognition, coagulation function, blood routine, exercise ability, quality of life, and fibrinolysis indicators. After a period of nursing intervention, the significant statistical difference existed (P < .05) between the control group and the observation group in terms of general information, number of venous thromboembolism risk levels, degree of disease cognition, coagulation function, blood routine, exercise ability, quality of life, and fibrinolysis indicators. In the patient satisfaction score, the satisfaction scores of male and female patients with general care were 0.865 and 0.878, respectively, and the satisfaction scores for bundled care were 0.942 and 0.965, respectively. In conclusion, bundled care can better improve the coagulation status and blood routine indexes of nonsurgical patients with cerebral hemorrhage compared with ordinary care, thus contributing to better prevention of venous thromboembolism in nonsurgical patients with cerebral hemorrhage.

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.

Addition of aspirin to venous thromboembolism chemoprophylaxis safely decreases venous thromboembolism rates in trauma patients

Background

Trauma patients exhibit a multifactorial hypercoagulable state and have increased risk of venous thromboembolism (VTE). Despite early and aggressive chemoprophylaxis (CP) with various heparin compounds ("standard" CP; sCP), VTE rates remain high. In high-quality studies, aspirin has been shown to decrease VTE in postoperative elective surgical and orthopedic trauma patients. We hypothesized that inhibiting platelet function with aspirin as an adjunct to sCP would reduce the risk of VTE in trauma patients.

Methods

We performed a retrospective observational study of prospectively collected data from all adult patients admitted to an American College of Surgeons Level I Trauma center from January 2012 to June 2015 to evaluate the addition of aspirin (sCP+A) to sCP regimens for VTE mitigation. Cox proportional hazard models were used to assess the potential benefit of adjunctive aspirin for symptomatic VTE incidence.

Results

10,532 patients, median age 44 (IQR 28 to 62), 68% male, 89% blunt mechanism of injury, with a median Injury Severity Score (ISS) of 12 (IQR 9 to 19), were included in the study. 8646 (82%) of patients received only sCP, whereas 1886 (18%) patients received sCP+A. The sCP+A cohort displayed a higher median ISS compared with sCP (13 vs 11; p<0.01). The overall median time of sCP initiation was hospital day 1 (IQR 0.8 to 2) and the median day for aspirin initiation was hospital day 3 (IQR 1 to 6) for the sCP+A cohort. 353 patients (3.4%) developed symptomatic VTE. Aspirin administration was independently associated with a decreased relative hazard of VTE (HR 0.57; 95% CI 0.36 to 0.88; p=0.01). There were no increased bleeding or wound complications associated with sCP+A (point estimate 1.23, 95% CI 0.68 to 2.2, p=0.50).

Conclusion

In this large trauma cohort, adjunctive aspirin was independently associated with a significant reduction in VTE and may represent a potential strategy to safely mitigate VTE risk in trauma patients. Further prospective studies evaluating the addition of aspirin to heparinoid-based VTE chemoprophylaxis regimens should be sought.

Level of evidence

Level III/therapeutic.

Surviving Sepsis After Burn Campaign

INTRODUCTION

The Surviving Sepsis Campaign was developed to improve outcomes for all patients with sepsis. Despite sepsis being the primary cause of death after thermal injury, burns have always been excluded from the Surviving Sepsis efforts. To improve sepsis outcomes in burn patients, an international group of burn experts developed the Surviving Sepsis After Burn Campaign (SSABC) as a testable guideline to improve burn sepsis outcomes.

METHODS

The International Society for Burn Injuries (ISBI) reached out to regional or national burn organizations to recommend members to participate in the program. Two members of the ISBI developed specific "patient/population, intervention, comparison and outcome" (PICO) questions that paralleled the 2021 Surviving Sepsis Campaign [1]. SSABC participants were asked to search the current literature and rate its quality for each topic. At the Congress of the ISBI, in Guadalajara, Mexico, August 28, 2022, a majority of the participants met to create "statements" based on the literature. The "summary statements" were then sent to all members for comment with the hope of developing an 80% consensus. After four reviews, a consensus statement for each topic was created or "no consensus" was reported.

RESULTS

The committee developed sixty statements within fourteen topics that provide guidance for the early treatment of sepsis in burn patients. These statements should be used to improve the care of sepsis in burn patients. The statements should not be considered as "static" comments but should rather be used as guidelines for future testing of the best treatments for sepsis in burn patients. They should be updated on a regular basis.

CONCLUSION

Members of the burn community from the around the world have developed the Surviving Sepsis After Burn Campaign guidelines with the goal of improving the outcome of sepsis in burn patients.

Anti-factor Xa Activity Is Not Associated With Venous Thromboembolism in Critically Ill Patients Receiving Enoxaparin for Thromboprophylaxis: A Retrospective Observational Study

Background

Anti-factor Xa activity has been suggested as a surrogate parameter for judging the effectiveness of pharmacological thromboprophylaxis with low molecular weight heparins in critically ill patients. However, this practice is not supported by evidence associating low anti-factor Xa activity with venous thromboembolism.

Methods

We performed a retrospective observational study including 1,352 critically ill patients admitted to 6 intensive care units of the Medical University of Vienna, Austria between 01/2015 and 12/2018. Included patients received prophylactically dosed enoxaparin (≤100 IU/kg body weight per day). We analyzed median peak, 12-h trough and 24-h trough anti-factor Xa activity per patient and compared anti-factor Xa activity between patients without vs. with venous thromboembolic events.

Results

19 patients (1.4%) developed a total of 22 venous thromboembolic events. We did not observe a difference of median (IQR) anti-factor Xa activity between patients without venous thromboembolism [peak 0.22 IU/mL (0.14–0.32); 12-h trough 0.1 IU/mL (<0.1–0.17), 24-h trough < 0.1 IU/mL (<0.1– <0.1)] vs. patients with venous thromboembolism [peak 0.33 IU/mL (0.14–0.34); 12-h trough 0.12 IU/mL (<0.1–0.26); 24-h trough < 0.1 IU/mL (<0.1–<0.1)].

Conclusion

Patients who developed venous thromboembolism had anti-factor Xa activities comparable to those who did not suffer from venous thromboembolism.

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.

Enoxaparin titrated by anti-Xa levels reduces venous thromboembolism in trauma patients

BACKGROUND

Trauma is a major risk factor for the development of a venous thromboembolism (VTE). After observing higher than expected VTE rates within our center's Trauma Quality Improvement Program data, we instituted a change in our VTE prophylaxis protocol, moving to enoxaparin dosing titrated by anti-Xa levels. We hypothesized that this intervention would lower our symptomatic VTE rates.

METHODS

Adult trauma patients at a single institution meeting National Trauma Data Standard criteria from April 2015 to September 2019 were examined with regards to VTE chemoprophylaxis regimen and VTE incidence. Two groups of patients were identified based on VTE protocol-those who received enoxaparin 30 mg twice daily without routine anti-Xa levels ("pre") versus those who received enoxaparin 40 mg twice daily with dose titrated by serial anti-Xa levels ("post"). Univariate and multivariate analyses were performed to define statistically significant differences in VTE incidence between the two cohorts.

RESULTS

There were 1698 patients within the "pre" group and 1406 patients within the "post" group. The two groups were essentially the same in terms of demographics and risk factors for bleeding or thrombosis. There was a statistically significant reduction in VTE rate (p = 0.01) and deep vein thrombosis rate (p = 0.01) but no significant reduction in pulmonary embolism rate (p = 0.21) after implementation of the anti-Xa titration protocol. Risk-adjusted Trauma Quality Improvement Program data showed an improvement in rate of symptomatic pulmonary embolism from fifth decile to first decile.

CONCLUSION

A protocol titrating prophylactic enoxaparin dose based on anti-Xa levels reduced VTE rates. Implementation of this type of protocol requires diligence from the physician and pharmacist team. Further research will investigate the impact of protocol compliance and time to appropriate anti-Xa level on incidence of VTE.

LEVEL OF EVIDENCE

Therapeutic/care management, Level IV.

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.

Chinese expert consensus on diagnosis and treatment of trauma-induced hypercoagulopathy

Trauma-induced coagulopathy (TIC) is caused by post-traumatic tissue injury and manifests as hypercoagulability that leads to thromboembolism or hypocoagulability that leads to uncontrollable massive hemorrhage. Previous studies on TIC have mainly focused on hemorrhagic coagulopathy caused by the hypocoagulable phenotype of TIC, while recent studies have found that trauma-induced hypercoagulopathy can occur in as many as 22.2-85.1% of trauma patients, in whom it can increase the risk of thrombotic events and mortality by 2- to 4-fold. Therefore, the Chinese People's Liberation Army Professional Committee of Critical Care Medicine and the Chinese Society of Thrombosis, Hemostasis and Critical Care, Chinese Medicine Education Association jointly formulated this Chinese Expert Consensus comprising 15 recommendations for the definition, pathophysiological mechanism, assessment, prevention, and treatment of trauma-induced hypercoagulopathy.

Venous thromboembolism in burns patients: Are we underestimating the risk and underdosing our prophylaxis?

BACKGROUND

Burns patients exhibit all factors of Virchow's triad and are thus at high theoretical risk of venous thromboembolism (VTE). At our tertiary referral burns unit, a standard dose of low molecular weight heparin, which acts primarily by inhibiting Factor Xa, is given for thromboprophylaxis. However, the pharmacokinetics of enoxaparin are altered following a burn injury, and thus burns patients are likely underdosed on their thromboprophylaxis. The objectives of this study were to determine the incidence and risk factors for VTE among burns patients at the Victorian Adult Burns Service (VABS) and to determine the adequacy of the current enoxaparin thromboprophylaxis regimen through measurement of anti-factor Xa (AFXa) levels and comparison with established reference ranges.

METHODS

This study consisted of two parts. In part 1, the Burns Registry of Australia and New Zealand (BRANZ) was reviewed for cases of VTE in burns patients admitted to the VABS from 2013 - 2018. Part 2 was a prospective study that determined peak and trough AFXa levels in patients admitted to the VABS with >10% total body surface area (TBSA) burns.

RESULTS

Part 1. Totally, 1,475 patients were admitted to the VABS between 2013 - 2018. There were 20 cases of VTE (1.36%). Percent TBSA of burn (OR = 1.04, 95% CI: 1.03 - 1.06), full thickness burns (OR = 2.78, 95% CI: 1.15 - 6.73), ICU admission (OR = 15.08, 95% CI: 5.01 - 45.44), mechanical ventilation (OR = 10.62, 95% CI: 4.05 - 27.91), operative procedures (OR = 1.43, 95% CI: 1.29 - 1.59), and a longer hospital stay (OR = 1.05, 95% CI: 1.04 - 1.07) were all associated with an increased VTE risk. Part 2. A total of 20 participants with >10% TBSA burns were recruited to the prospective study. Peak anti Factor Xa (AFXa) levels were measured for all 20 participants with 15% recording an initial prophylactic peak AFXa level within reference range. Upon subsequent measurements, 50% of participants reached a prophylactic peak AFXa level. Trough AFXa levels were measured for 17 participants with no participant recording an initial or subsequent trough AFXa level at or above the prophylactic threshold.

CONCLUSION

Our study demonstrates a high incidence of VTE among burns patients at the VABS, especially among the major burns patients, and a thromboprophylaxis protocol that is ineffective in achieving prophylactic levels of AFXa level. The evidence suggests a need to evaluate different dosing protocols among burns patients in order to improve AFXa levels, with the aim of decreasing incidence of VTE in high-risk patients.