Review of a large clinical series: once- versus twice-daily enoxaparin for venous thromboembolism prophylaxis in high-risk trauma patients

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

Introduction

Optimal venous thromboembolism (VTE) enoxaparin prophylaxis dosing remains elusive. Weight-based (WB) dosing safely increases anti-factor Xa levels without the need for routine monitoring but it is unclear if it leads to lower VTE risk. We hypothesized that WB dosing would decrease VTE risk compared with standard fixed dosing (SFD).

Methods

Patients from the prospective, observational CLOTT-1 registry receiving prophylactic enoxaparin (n=5539) were categorized as WB (0.45-0.55 mg/kg two times per day) or SFD (30 mg two times per day, 40 mg once a day). Multivariate logistic regression was used to generate a predicted probability of VTE for WB and SFD patients.

Results

Of 4360 patients analyzed, 1065 (24.4%) were WB and 3295 (75.6%) were SFD. WB patients were younger, female, more severely injured, and underwent major operation or major venous repair at a higher rate than individuals in the SFD group. Obesity was more common among the SFD group. Unadjusted VTE rates were comparable (WB 3.1% vs. SFD 3.9%; p=0.221). Early prophylaxis was associated with lower VTE rate (1.4% vs. 5.0%; p=0.001) and deep vein thrombosis (0.9% vs. 4.4%; p<0.001), but not pulmonary embolism (0.7% vs. 1.4%; p=0.259). After adjustment, VTE incidence did not differ by dosing strategy (adjusted OR (aOR) 0.75, 95% CI 0.38 to 1.48); however, early administration was associated with a significant reduction in VTE (aOR 0.47, 95% CI 0.30 to 0.74).

Conclusion

In young trauma patients, WB prophylaxis is not associated with reduced VTE rate when compared with SFD. The timing of the initiation of chemoprophylaxis may be more important than the dosing strategy. Further studies need to evaluate these findings across a wider age and comorbidity spectrum.

Level of evidence

Level IV, therapeutic/care management.

Optimizing Perioperative Venous Thromboembolism Chemoprophylaxis on a Gynecologic Oncology Service

BACKGROUND

Perioperative venous thromboembolism (VTE) is a significant cause of morbidity and mortality after gynecologic cancer surgery. Here we report a quality improvement intervention to increase perioperative VTE chemoprophylaxis compliance.

STUDY DESIGN

All operations performed by a gynecologic oncologist at a tertiary urban university medical center admitted to the hospital for at least one midnight were included. Using a pre/post design with a washout period, we sought to increase perioperative VTE chemoprophylaxis compliance from 22% in the historical control (HC) cohort to 90% in the quality improvement (QI) cohort. The perioperative VTE chemoprophylaxis process was standardized by addressing four domains: preoperative VTE chemoprophylaxis, surgical time-out, postoperative VTE chemoprophylaxis, and intervention education and compliance tracking. Pearson's chi-square test was used to compare HC vs QI cohort compliance.

RESULTS

There were 130 surgical cases in the HC cohort and 131 in the QI cohort. Forty-two percent underwent laparotomy, and 57% had cancer at the time of operation. VTE chemoprophylaxis compliance improved from 22% in the HC cohort to 82% in the QI cohort (p < 0.001). Preoperative VTE chemoprophylaxis compliance improved from 76% in the HC cohort to 94% in the QI cohort (p < 0.001), and postoperative VTE chemoprophylaxis compliance improved from 27% to 87% (p < 0.001). Thirty-day postoperative VTE occurred in three patients (2%) in the HC cohort and none in the QI cohort (p = 0.08).

CONCLUSIONS

A low-cost and low-technology QI initiative intervention improved perioperative compliance with VTE chemoprophylaxis.

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.

Impact of antithrombin III and enoxaparin dosage adjustment on prophylactic anti-Xa concentrations in trauma patients at high risk for venous thromboembolism: a randomized pilot trial

The impact of antithrombin III activity (AT-III) on prophylactic enoxaparin anti-factor Xa concentration (anti-Xa) is unknown in high-risk trauma patients. So too is the optimal anti-Xa-adjusted enoxaparin dosage. This prospective, randomized, pilot study sought to explore the association between AT-III and anti-Xa goal attainment and to preliminarily evaluate two enoxaparin dosage adjustment strategies in patients with subprophylactic anti-Xa. Adult trauma patients with Risk Assessment Profile (RAP) ≥ 5 prescribed enoxaparin 30 mg subcutaneously every 12 h were eligible. AT-III and anti-Xa were drawn 8 h after the third enoxaparin dose and compared between patients with anti-Xa ≥ 0.1 IU/mL (goal; control group) or anti-Xa < 0.1 IU/mL (subprophylactic; intervention group). The primary outcome was difference in baseline AT-III. Subsequently, intervention group patients underwent 1:1 randomization to either enoxaparin 40 mg every 12 h (up to 50 mg every 12 h if repeat anti-Xa < 0.1 IU/mL) (enox12) or enoxaparin 30 mg every 8 h (enox8) with repeat anti-Xa assessments. The proportion of patients achieving goal anti-Xa after dosage adjustment were compared. A total of 103 patients were included. Anti-Xa was subprophylactic in 50.5%. Baseline AT-III (median [IQR]) was 87% [80-98%] in control patients versus 82% [71-96%] in intervention patients (p = 0.092). Goal trough anti-Xa was achieved on first assessment in 38.1% enox12 versus 50% enox8 patients (p = 0.67), 84.6% versus 53.3% on second assessment (p = 0.11), and 100% vs. 54.5% on third trough assessment (p = 0.045). AT-III activity did not differ between high-risk trauma patients with goal and subprophylactic enoxaparin anti-Xa concentrations, although future investigation is warranted. Enoxaparin dose adjustment rather than frequency adjustment may be associated with a higher proportion of patients achieving goal anti-Xa over time.

Venous Thromboembolism in Trauma: The Role of Anticoagulation and Inferior Vena Cava Filters

Venous thromboembolism (VTE) is a significant contributor to morbidity and mortality among patients with severe trauma. Historically, prophylactic inferior vena cava filters (IVCFs) were used in high-risk trauma patients with suspected risk factors for VTE, including prolonged immobilization, and concurrent contraindication to anticoagulation. Mounting data regarding the efficacy of IVCF in this cohort, as well as concerns regarding morbidity of an in situ IVCF, have challenged this practice paradigm. In this review, we discuss the comanagement of VTE and trauma, including anticoagulation and the use of IVCF.

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.

Prevention, diagnosis, and management of venous thromboembolism in the critically ill surgical and trauma patient

PURPOSE OF REVIEW

Venous thromboembolism (VTE), which encompasses deep vein thrombosis and pulmonary embolism, is common among trauma patients and critically ill surgical patients admitted to the ICU. Critical care surgical patients are at an extremely high risk for VTE and the related morbidity and mortality associated with it. The present review aims to provide an overview of the importance of identifying risk factors, prescribing effective prohylaxis, accurate diagnosis, and timely appropriate treatment for trauma and critically ill surgical patients with VTE in the ICU.

RECENT FINDINGS

VTE is a healthcare burden among critically ill surgical patients that is mostly preventable through adherence to prophylactic protocols that aim to recognize VTE risk factors while simultaneously providing guidance to appropriate timing and administration prophylaxis regimens. Newer pharmacologic therapies for prophylaxis and treatment, diagnostic modalities, and indications for therapy of VTE have continued to evolve.

SUMMARY

Critical care surgical and trauma patients represent a population that are at a heightened risk for VTE and associated complications. Appropriate screening, prevention strategies, accurate diagnosis, and timely administration of appropriate treatment must be utilized to reduce morbidity and mortality.

Pharmacist recommendations for prophylactic enoxaparin monitoring and dose adjustment in trauma patients admitted to a surgical intensive care unit

Background:

There is limited information describing pharmacist participation in prophylactic enoxaparin monitoring in the surgical intensive care unit (SICU).

Objective:

Our study sought to: 1) characterize pharmacist recommendations for enoxaparin monitoring in trauma patients admitted to the SICU, 2) describe the frequency that medical providers accept pharmacist recommendations for enoxaparin monitoring in trauma patients admitted to the SICU, and 3) illustrate the frequency that trauma patients admitted to our SICU service achieve anti-factor Xa trough concentrations (AFXa-TRs) of 0.11 - 0.20 IU/mL following pharmacist recommendation to adjust prophylactic enoxaparin dosing.

Methods:

Adult patients who had an AFXa-TR drawn after at least three consecutive prophylactic enoxaparin doses between June 1, 2017 and March 1, 2018 were identified through chart review and included in this study. Patients were excluded based on the following criteria: 1) age less than 18 years, 2) anti-factor Xa (AFXa) level not representative of a trough concentration, 3) AFXa-TR not representative of steady state concentration, and 4) non-trauma based prophylactic enoxaparin dosing. This study was exempt from IRB review.

Results:

The final analysis consisted of 42 patients. A pharmacist provided at least one recommendation in 97.6% (41/42) of trauma patients with enoxaparin monitoring during their SICU stay. In total, a pharmacist made 170 recommendations, mean of 4.2 (SD 1.8) recommendations per patient. Recommendations were: 1) obtain an AFXa-TR, n=90; 2) adjust enoxaparin dose based on AFXa-TR, n=58; and 3) maintain enoxaparin dose based on AFXa-TR, n=22. Medical providers accepted 89.4% (152/170) of pharmacist recommendations for enoxaparin monitoring. Dose adjustments were made in 33 patients following pharmacist recommendation; of these, 27 had a repeat AFXa-TR following at least one dose adjustment. Target AFXa-TRs were achieved in 19/27 patients, indicating 70.4% had recommended AFXa concentrations.

Conclusions:

Pharmacists provided recommendations for prophylactic enoxaparin monitoring and dose adjustment in trauma patients admitted to the SICU. Medical providers regularly accepted pharmacist recommendations and trauma patients commonly achieved target AFXa-TR following pharmacist recommendation for dose adjustment. Further research is required to identify the optimal enoxaparin dose for VTE prophylaxis in trauma patients.

Is the Caprini Score Predictive of Venothromboembolism Events in Orthopaedic Fracture Patients?

OBJECTIVE

Explore the validity of the Caprini Score in orthopaedic patients with lower-extremity fractures.

DESIGN

Retrospective cohort study.

SETTING

Level I trauma academic medical center.

PATIENTS/PARTICIPANTS

Eight hundred forty-eight patients with lower-extremity fractures from 2002 to 2015 with exclusion criteria: minors, follow-up less than 30 days.

INTERVENTION

Stratify patients into 2 groups: high-risk (pelvic and acetabular fractures) and low-risk groups (isolated foot and ankle fractures).

MAIN OUTCOME

Caprini Score, fracture classification, length of follow-up, deep vein thrombosis (DVT) chemoprophylaxis, and venothromboembolism (VTE) events [DVT and/or pulmonary embolism (PE)] diagnosed with objective testing.

RESULTS

Eight hundred forty-eight patients (499 M; 349 F) 18-93 years of age (average 43.7) with average body mass index of 29. Three hundred high-risk and 548 low-risk patients with no differences in demographics with average follow-up of 288 days. There were 33 (3.9%) VTE events, which were more common in the high-risk group (8%: 9 DVT, 15 PE) than the low-risk group (1.6%: 8 DVT, 1 PE) (P < 0.0001). The cutoff that best-predicted VTE events based on receiver-operating curves was 12 (c = 0.74) in the high-risk group, 11 (c = 0.79) in the low-risk group, and 12 (c = 0.83) overall.

CONCLUSION

There was a significant lower VTE rate found in the low-risk group, but the Caprini prediction model was not significantly different between the 2 groups. This displays that patient factors play a large role in the development of VTE events independent of injury type. The Caprini score may help identify patients who may require increased protection.

LEVEL OF EVIDENCE

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

Contemporary thromboprophylaxis of trauma patients

PURPOSE OF REVIEW

The traumatically injured patient is at high risk for developing venous thromboembolism. Clinical practice guidelines developed by the American College of Chest Physicians and the Eastern Association for the Surgery of Trauma recognize the importance of initiating thromboprophylaxis, but the guidelines lack specific recommendations regarding the timing and dose of pharmacologic thromboprophylaxis. We review the literature regarding initiation of thromboprophylaxis in different injuries, the use of inferior vena cava filters, laboratory monitoring, dosing regimens, and the use of antiplatelet therapy.

RECENT FINDINGS

Use of pharmacologic thromboprophylaxis with invasive intracranial monitors is not associated with increased bleeding complications. The initiation of low-molecular-weight heparin (LMWH) prophylaxis 48 h postinjury in blunt solid organ injury is not associated with an increase in the rate of failed nonoperative management. Antiplatelet therapy in conjunction with LMWH may help to prevent venous thromboembolism.

SUMMARY

In the setting of blunt traumatic brain and solid organ injury, initiation of pharmacologic thromboprophylaxis 48 h after injury is not associated with increased bleeding complications. There is no consensus or clear data showing which dosing regimen of LMWH is most effective or whether routine laboratory measurements are beneficial for determining effective thromboprophylaxis.

Venous thromboembolism in major trauma patients: a single-center retrospective cohort study of the epidemiology and utility of D-dimer for screening

Aim

Venous thromboembolism (VTE) can be a life‐threatening complication after major trauma. The aim of this study was to investigate the epidemiology of VTE and to assess the usefulness of D‐dimer for screening for VTE in major trauma cases among the Japanese population.

Methods

We examined a single‐center retrospective cohort of severely injured trauma patients who had been admitted to the emergency intensive care unit at Okayama University Hospital (Okayama, Japan) from April 2013 through to March 2016. Venous thromboembolism was confirmed by computed tomography angiography and computed tomography venography, which was determined based on the attending physician monitoring daily D‐dimer levels. Independent risk factors for VTE were determined by multiple logistic regression analysis. D‐dimer levels were evaluated using area under the receiver operating characteristic curve (AUROC) to predict VTE.

Results

The study cohort consisted of 204 trauma patients (median Injury Severity Score, 20). Of the 204 patients, 65 (32%) developed VTE. The median time from admission to VTE diagnosis was 10 days. In multiple logistic regression analysis, higher Injury Severity Score and the presence of lower extremity fractures were revealed to be a risk factor for VTE. D‐dimer levels at day 10 showed moderate accuracy, of which the AUROC was 0.785 (95% confidence interval, 0.704–0.866; P < 0.001). The cut‐off that maximized the Youden index was 12.45 μg/mL.

Conclusions

At least one of every three major trauma patients had potential development of VTE at a median of 10 days following admission to the intensive care unit. D‐dimer levels on day 10 can be a useful predictor of VTE.

Effect of a dalteparin prophylaxis protocol using anti-factor Xa concentrations on venous thromboembolism in high-risk trauma patients

BACKGROUND

Low anti-factor Xa (anti-Xa) concentrations with twice-daily enoxaparin are associated with venous thromboembolism (VTE) in high-risk trauma patients. Concerns have been raised with once-daily dalteparin regarding effectiveness and achievable anti-Xa concentrations. The purpose of this before-and-after study was to evaluate the effectiveness of a VTE prophylaxis protocol using anti-Xa concentrations and associated dalteparin dose adjustment in high-risk trauma patients.

METHODS

Adult trauma patients receiving VTE chemoprophylaxis and hospitalized for at least 3 days were prospectively followed during two 6-month epochs before (PRE) and after (POST) implementation of anti-Xa monitoring. In both groups, high-risk patients received dalteparin 5,000 U subcutaneously once daily; low-risk patients received subcutaneous unfractionated heparin. High-risk POST patients with anti-Xa less than 0.1 IU/mL 12 hours after initial dalteparin dose received dalteparin every 12 hours. All patients underwent routine VTE ultrasound surveillance of the lower extremities. The primary outcome was incidence of VTE.

RESULTS

A total of 785 patients (PRE, n = 428; POST, n = 357) were included. Demographics, injury patterns, Injury Severity Score (ISS), red blood cell transfusions, intensive care unit and hospital stays, and mortality did not differ between groups. Overall, POST patients had lower VTE (7.0% vs. 13%, p = 0.009) including acute VTE (6.4% vs. 12%, p = 0.01) and proximal deep vein thromboembolism (2.2% vs. 5.7%, p = 0.019). Between high-risk patients, VTE occurred in 53 (16.3%) PRE compared with 24 (9.0%) POST patients (p = 0.01); there was no difference in VTE between low-risk patients (PRE, 2.0% vs. POST, 1.1%; p = 0.86). Among 190 high-risk POST patients with anti-Xa, 97 (51%) were less than 0.1 IU/mL. Patients with low anti-Xa had higher rates of VTE (14.0% vs. 5.4%, p = 0.05) and deep vein thromboembolism (14.4% vs. 3.2%, p = 0.01). Younger age (odds ratio, 0.97; 95% confidence interval, 0.95-0.99) and greater weight (odds ratio, 1.02; 95% confidence interval, 1.00-1.03) predicted low anti-Xa on multivariate regression.

CONCLUSION

A VTE prophylaxis protocol using anti-Xa-based dalteparin dosage adjustment in high-risk trauma patients was associated with decreased VTE. Once-daily dalteparin 12-hour anti-Xa concentrations are suboptimal in a majority of patients and associated with VTE.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

Evaluating the efficacy and safety of apixaban, a new oral anticoagulant, using Bayesian meta-analysis

Apixaban is a direct inhibitor of factor Xa, and is a potential alternative for the treatment of acute venous thromboembolism. This study sought to evaluate the efficacy and safety of apixaban versus enoxaparin. A systematic search of the literature for randomized controlled trials of apixaban thromboprophylaxis versus enoxaparin was conducted using three databases: PubMed, EMBASE, and the Cochrane library. Five studies that included a total of 12,938 patients were analyzed using Bayesian random-effects meta-analysis. To evaluate efficacy, a composite of venous thromboembolism and death during follow-up was measured. To evaluate safety, major and total bleeding events were considered. The odds ratio (OR) for the composite outcome of efficacy was 0.66 (95 % CI 0.33-1.29) for apixaban compared to enoxaparin, while there was a similar risk of major bleeding (OR 1.03, 95 % CI 0.36-3.73) and total bleeding (OR 0.92, 95 % CI 0.64-1.20). These results suggest a lack of clear superiority of apixaban relative to enoxaparin. Apixaban is an oral alternative with similar efficacy and safety to existing anticoagulant therapies.

The effects of location and low-molecular-weight heparin administration on deep vein thrombosis outcomes in trauma patients

BACKGROUND

Deep vein thrombosis (DVT) is common after trauma. Pulmonary embolism (PE) is a feared complication of DVT. Standard doses of low-molecular-weight heparin (LMWH) are commonly used to prevent and treat DVT and PE. There is variable bioavailability of LMWH with standard therapy. The traditional concept that below-knee DVT is associated with a lower risk of subsequent PE may result in less aggressive therapy. The purposes of this study were to assess the rates of PE in above-knee versus below-knee DVT and longitudinally evaluate outcomes of DVT treated with LMWH therapy.

METHODS

This was a retrospective review of patients at a university Level I trauma center during the years 2005 through 2010. Patients diagnosed with lower-extremity DVT were included in this study. Patients were classified by location of lower-extremity DVT and type of LMWH therapy received. All high-risk trauma patients were evaluated with weekly duplex Doppler ultrasonography. All duplex studies were reviewed for DVT resolution or improvement. Symptomatic patients were evaluated with computed tomographic angiography to rule out PE. Demographics, total length of hospital stay, length of intensive care unit stay, and Injury Severity Score (ISS) were collected.

RESULTS

Three-hundred eight trauma patients with lower-extremity DVT were included. More patients developed below-knee DVT (65.6%) compared with above-knee DVT (34.4%). Increased length of hospital stay, intensive care unit stay, and higher ISS were noted in patients with above-knee DVT. More patients had below-knee DVT in the prophylactic dosing group. With LMWH therapy, three PEs occurred in patients in the prophylactic dosing group with below-knee DVT, and no PEs occurred in the therapeutic treatment group. The incidence of PE between patients with below-knee DVT compared with above-knee DVT overall was not different (3.3% and 4.7%, p = 0.59). To assess DVT outcomes, 157 of the 308 patients had serial duplex studies following diagnosis of lower-extremity DVT. The number of patients receiving either therapeutic or prophylactic LMWH was similar (51% and 49%). There was no difference in rates of resolution or improvement between LMWH dosing groups or location of DVT.

CONCLUSION

In screened trauma patients, below-knee DVT is more common than above-knee DVT. There was no difference in the incidence of PE between groups. Standard prophylactic and therapeutic dosing of LMWH does not affect the rates of resolution or improvement of lower-extremity DVT. Rates of resolution and improvement of DVT is not dependent of location of lower-extremity DVT.

LEVEL OF EVIDENCE

Therapeutic study, level IV; epidemiologic study, level III.

Incidence of deep vein thrombosis is increased with 30 mg twice daily dosing of enoxaparin compared with 40 mg daily

BACKGROUND

The purpose of this study was to analyze whether 2 standard dosing regimens of enoxaparin (30 mg twice daily vs 40 mg once daily) would result in different deep vein thrombosis (DVT) rates and anti-factor Xa activity (anti-Xa) in surgical patients.

METHODS

Patients who required enoxaparin for prophylaxis were followed prospectively. Demographics were recorded. Patients underwent standardized duplex screening. Peak anti-Xa levels were drawn on 4 consecutive days.

RESULTS

Sixty-three patients were followed up (28 patients on 30 mg twice daily, 35 patients on 40 mg once daily). There was no significant difference in demographics between groups. Twenty-five percent of patients on 30 mg twice daily developed a DVT, whereas 2.9% of patients on 40 mg once daily developed a DVT. Patients on 30 mg twice daily had significantly lower anti-Xa levels.

CONCLUSIONS

The incidence of DVT is increased in surgical patients who receive 30 mg twice daily dosing of enoxaparin compared with 40 mg daily. Dosing of 40 mg once daily results in significantly higher peak anti-Xa levels compared with 30 mg twice daily.