Anti-Xa-guided enoxaparin thromboprophylaxis reduces rate of deep venous thromboembolism in high-risk trauma patients

BACKGROUND

Appropriate prophylaxis against venous thromboembolism (VTE) remains undefined. This study evaluated an anti-Xa-guided enoxaparin thromboprophylaxis (TPX) protocol on the incidence of VTE in high-risk trauma patients based on Greenfield's Risk Assessment Profile (RAP) score.

METHODS

This is a retrospective observational study of patients admitted to a trauma intensive care unit over a 12-month period. Patients were included if they received anti-Xa-guided enoxaparin TPX. Dosage was adjusted to a prophylactic peak anti-Xa level of 0.2 to 0.4 IU/mL. Subgroup analysis was performed on high-risk patients (RAP score ≥10) who received lower-extremity duplex ultrasound surveillance for deep vein thrombosis (DVT). Data are expressed as mean ± SD. Significance was assessed at p < 0.05.

RESULTS

One hundred thirty-one patients received anti-Xa-guided enoxaparin TPX. Four patients were excluded for age or acute VTE on admission. Fifty-six patients with RAP score of ≥10 and surveillance duplex evaluations were included in the subgroup analysis with mean age 43 ± 20 years, Injury Severity Score of 25 ± 10, and RAP score of 16 ± 4. Prophylactic anti-Xa levels were initially achieved in 34.6% of patients. An additional 25.2% required 40 to 60 mg twice daily to reach prophylactic levels; 39.4% never reached prophylactic levels. Weight, body mass index, ISS, and RAP score were significantly higher with subprophylactic anti-Xa levels. One patient developed bleeding complications (0.8%). No patient developed intracerebral bleeding or heparin-induced thrombocytopenia.Nine VTE events occurred in the high-risk subgroup, including four DVT (7.1%), all asymptomatic, and five pulmonary emboli (8.9%). The historical rate of DVT in similar patients (ISS 31 ± 12 and RAP score 16 ± 5) was 20.5%, a significant decrease (p = 0.031). Mean chest Abbreviated Injury Scale scores were significantly higher for patients developing pulmonary emboli than DVT, 3.0 ± 1.1 vs. 0.0 (p < 0.001).

CONCLUSIONS

Mean chest Abbreviated Injury Scale score was higher in patients developing pulmonary embolism. Increased weight, body mass index, ISS, and RAP score are associated with subprophylactic anti-Xa levels. Anti-Xa-guided enoxaparin dosing reduced the rate of DVT from 20.5% to 7.1% in high-risk trauma patients.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

Venous thromboembolism prophylaxis for patients receiving regional anesthesia following injury in Iraq and Afghanistan

BACKGROUND

Soldiers with combat-related traumatic injury are at high risk for venous thromboembolism (VTE) and often require regional anesthesia (RA) for pain control. We evaluated whether the recommended reduction in chemoprophylaxis in the presence of RA increases VTE rates.

METHODS

We collected data each hospital day for all soldiers admitted to the Walter Reed Army Medical Center following injury in Iraq or Afghanistan. We analyzed thromboprophylaxis and RA rates and assessed risk factors for VTE. We separated outcomes by whether RA was central neuraxial (cNAB) or peripheral blockade.

RESULTS

Among 1,259 patients, 323 received RA for a median of 12 days (5-27 days). Those with RA were younger and more likely to have been injured in combat or by an improvised explosive device. They also received more packed red blood cell transfusions and had longer admissions. Patients with RA spent a greater percentage of days on enoxaparin 40 mg daily compared with those without RA (34.4% vs. 22.0%, p < 0.001) and more hospital days without any chemoprophylaxis (2.0 [1.0-6.0] vs. 1.0 [0.0-3.0], p < 0.001). Patients with cNAB were less likely to be placed on enoxaparin 30 mg twice daily. Patients with RA in place had mechanical prophylaxis ordered at the same rate as those without RA. Neither the presence of any RA nor cNAB specifically was associated with an increased risk for VTE. No bleeding or neurologic complications occurred in those receiving RA.

CONCLUSION

Despite changes to chemoprophylaxis, soldiers wounded in combat who receive RA are not at increased risk for VTE.

LEVEL OF EVIDENCE

Therapeutic study, level III.

Thromboprophylaxis and VTE rates in soldiers wounded in Operation Enduring Freedom and Operation Iraqi Freedom

OBJECTIVES

US soldiers suffer catastrophic injuries during combat. We sought to define risk factors and rates for VTE in this population.

METHODS

We gathered data each hospital day on all patients injured in Afghanistan or Iraq who were admitted to the Walter Reed Army Medical Center (WRAMC). We analyzed prophylaxis rates and efficacy and identified risk factors for VTE.

RESULTS

We recorded data on 506 combat casualties directly admitted to WRAMC after medical air evacuation. The average injury severity score for the group was 18.4 ± 11.7, and the most common reason for air evacuation was injury by improvised explosive device (65%). As part of the initial resuscitation, patients received 4.7 ± 9.0 and 4.00 ± 7.8 units of packed RBCs and fresh frozen plasma, respectively, and 42 patients received factor VIIa. Forty-six patients (9.1%) were given a diagnosis of VTE prior to discharge, 18 (3.6%) during air evacuation, and 28 (5.5%) during the hospital stay. In Cox regression analysis, administration of 1 unit of packed RBCs was associated with a hazard ratio (HR) of 1.04 (95% CI, 1.02-1.07; P = .002), and enoxaparin, 30 mg bid, administered subcutaneously for the majority of hospital days was associated with a HR of 0.31 (95% CI, 0.11-0.86; P = .02) for VTE during the hospitalization.

CONCLUSIONS

Patients who suffer traumatic injuries in combat overseas are at high risk for VTE during evacuation and recovery. Those with large resuscitations are at particularly high risk, and low-molecular-weight heparin is associated with a decrease in VTE.

Safety and efficacy of rivaroxaban for thromboprophylaxis following lower limb surgery: an update

INTRODUCTION

Thromboprophylaxis in orthopedic surgery remains a controversial issue despite recent changes to NICE guidelines, particularly with the addition of oral factor Xa inhibitors. The healthcare burden of venous thromboembolism is substantial and needs frequent academic and clinical appraisal.

AREAS COVERED

The authors review the available relevant literature on the use of rivaroxaban in orthopedic surgery, identified using an EMBASE (1980 - 2010) and Ovid MEDLINE (1950 - 2010) search of published articles up to August 2010. This includes clinical studies, case reports and experimental studies where applicable. Search terms include: 'rivaroxaban', 'safety', 'efficacy', 'bleeding', 'toxicity', 'tolerability' and 'complication'.

EXPERT OPINION

Rivaroxaban is a safe and effective choice of thromboprophylactic agent following lower limb arthroplasty surgery. More research is required to expand the application of this novel agent to other areas of orthopedic surgery.

Unfractionated Heparin Three Times a Day versus Enoxaparin in the Prevention of Deep Vein Thrombosis in Trauma Patients

Venous thromboembolic disease is a significant source of morbidity and mortality in hospitalized trauma patients. Multiple drugs and dosing regimens have been suggested for pharmacoprophylaxis. In this study, we compared efficacy, complications, and cost of unfractionated heparin administered subcutaneously three times a day with standard-dosed enoxaparin for prophylaxis of deep venous thrombosis (DVT) in adult trauma patients over 1 year. Patients admitted for greater than 72 hours who received pharmacoprophylaxis as part of a comprehensive DVT protocol were included. A change was made in the protocol from enoxaparin (30 mg twice a day or 40 mg per day) to heparin (5000 U three times a day) at midyear. Surveillance lower extremity venous ultrasound was performed according to established institutional guidelines. Data, including demographics, associated injuries, complications, and cost, were collected and analyzed. Four hundred seventy-six patients met inclusion criteria. Two hundred thirty-seven (49.8%) patients received enoxaparin and 239 (50.2%) received heparin. Proximal lower extremity DVTs were detected in 16 (6.75%) patients in the enoxaparin group and 17 (7.11%) in the heparin group ( P = 0.999). Risk factors for DVT in these patients included spinal cord injury ( P = 0.001) and closed head injury ( P = 0.031). There was no difference between the incidence of pulmonary emboli and bleeding. There was an estimated yearly pharmacy cost savings of $135,606. In trauma patients, subcutaneous heparin dosed three times a day may be as effective as standard-dosed enoxaparin for prophylaxis of venous thromboembolism without increased complications. Heparin three times a day for venous thromboembolism prophylaxis was associated with significant pharmaceutical cost savings.

Thromboprophylaxis after multiple trauma: what treatment and for how long?

A review of current literature discussing thromboprophylaxis in the multiple-trauma patient to provide insight on the type of treatment and its duration of use. AMEDLINE search was conducted in May 2009 using keywords associated with thromboprophylactic measures in multiple-trauma patient care, including inferior vena cava (IVC) filters, mechanical-compression devices and anticoagulants. Abstracts were evaluated for relevance to this study and full-text articles were then examined individually. Fourteen full text articles were evaluated including guidelines published by the American College of Chest Physicians (ACCP) and the Eastern Association for the Surgery of Trauma (EAST) and other studies dealing with multiple-trauma patients, including those in hip-fracture surgery, lower-leg trauma and head trauma. Limited research has been performed for the multiple-trauma patient and recommendations regarding the type of treatment and its duration of use cannot be suggested beyond what has been extrapolated from existing trauma and major surgery patients. IVC filters, mechanical compression devices and anticoagulants therefore remain the standard, but their duration of use in the multiple-trauma patient is not well described. New oral anticoagulants that inhibit factor Xa or thrombin directly show promising qualities but have not been evaluated for multiple-trauma applications. Therefore, optimal thromboprophylaxis and its duration after multiple trauma is largely based on rational, clinical decision making on a case-by-case basis.

Four years of an aggressive prophylaxis and screening protocol for venous thromboembolism in a large trauma population

BACKGROUND

This retrospective review of a prospectively collected database was conducted to analyze the efficacy of 4 years of aggressive prophylaxis and screening protocols for venous thromboembolism (VTE) in a large population of trauma patients.

METHODS

Trauma patients at a Level I Trauma Center found to be nonambulatory or otherwise high risk were placed on a protocol of lower-extremity (LE) compression devices and subcutaneous enoxaparin as soon as feasible after admission. Duplex scans of LEs were conducted weekly.

RESULTS

During 4 years, 2,939 patients were admitted to trauma with length of stay >2 days. There was a 3.2% incidence of VTE in the length of stay >2 days population, 2.5% rate of deep venous thrombosis (DVT), and 0.7% pulmonary embolism. All VTE patients had factors known to increase risk of VTE and were included in our prophylaxis and screening protocol. Twenty-one percent of these received pharmacologic prophylaxis within the first 2 days of admission; 62% received enoxaparin at some point before diagnosis of VTE. Duplex scans were conducted in 982 patients. Notably, 86% of LE DVTs were found on routine screening duplex.

CONCLUSION

To our knowledge, this is the largest population of trauma patients followed by screening duplexes. All patients with VTEs were identified as high risk, and screening revealed multiple patients with an asymptomatic DVT. We conclude our aggressive prophylaxis regimen lead to low rates of VTE and think screening duplex is a critical component for identifying unsuspected DVT.

Is Upper Extremity Deep Venous Thrombosis Underdiagnosed in Trauma Patients?

It has been suggested that upper extremity deep venous thrombosis (UEDVT) is as common and dangerous as lower extremity deep venous thrombosis. Pulmonary embolism (PE) is often found with no evidence of associated lower extremity deep venous thrombosis and could have originated from UEDVT. Routine screening is well accepted for lower extremity deep venous thrombosis but not for UEDVT. We hypothesized that UEDVT in trauma is frequent but undetected; therefore, routine screening of trauma patients at risk will increase the UEDVT rate and decrease the PE rate due to early diagnosis and treatment. We evaluated the incidence of UEDVT and PE over 6 months before (Group BEFORE) and 6 months after (Group AFTER) implementing a policy of screening patients at high risk for deep venous thrombosis with Duplex ultrasonography. Group BEFORE was evaluated retrospectively and group AFTER prospectively. There were 1110 BEFORE and 911 AFTER patients. The two groups were similar. Of the AFTER patients, 86 met predetermined screening criteria and were evaluated routinely by a total of 130 Duplex exams. One patient in each group developed UEDVT (0.09% vs 0.11%, P = 1.00). The brachial vein was involved in both patients. Six BEFORE (0.54%) and 1 AFTER (0.11%) patients developed PE ( P = 0.137). The single AFTER patient with PE was not screened for UEDVT because he had no high-risk criteria. UEDVT is an uncommon event with unclear significance in trauma. Aggressive screening did not result in a higher rate of UEDVT diagnosis, nor an opportunity to prevent PE.

Venous thromboembolism in trauma patients

Serial venous duplex scans (VDS) were done in 507 trauma patients with at least one risk factor (RF) for venous thromboembolism (VTE) during a 2-year study period. Deep vein thrombosis (DVT) was detected in 31 (6.1%) patients. This incidence was 3.1 per cent in low (1-2 RFs), 3.4 per cent in moderate (3-5 RFs), and 7.7 per cent in high (> or =6 RFs) VTE scores (P = 0.172). Incidence was statistically different (3% vs. 7.2%, P = 0.048) on reanalyzing patients in two risk categories, low-risk (1-4 RFs) and high-risk (> or =5 RFs). Only 4 of 16 RFs had statistically higher incidence of DVT in patients with or without RFs: previous VTE (27.3% vs. 5.6%, odds ratio (OR) 6.628, P = 0.024), spinal cord injury (22.6% vs. 5%, OR 5.493, P = 0.001), pelvic fractures (11.4% vs. 5.1%, OR 2.373, P = 0.042), and head injury with a greater than two Abbreviated Injury Score (10.5% vs. 4.2%, OR 2.639, P = 0.014). On reanalyzing patients with > or =5 RFs vs. <5RFs, obesity (14.3 vs. 6.1%, P = 0.007), malignancy (5.6% vs. 0.6%, P = 0.006), coagulopathy (10.8% vs. 1.8%, P = 0.000), and previous VTE (3.2% vs. 0%, P = 0.019) were significant on univariate analysis. Patients with DVT had 3.70 +/- 1.75 RFs and a 9.61 +/- 4.93 VTE score, whereas, patients without DVT had 2.66 +/- 1.50 RFs and a 6.83 +/- 3.91 VTE score (P = 0.000). DVTs had a direct positive relationship with higher VTE scores, length of stay, and number of VDS (>1 r, P < or = 0.001). Increasing age was a weak risk factor (0.03 r, P = 0.5). First two VDS diagnosed 77 per cent of DVTs. Patients with injury severity score of > or =15 and 25 had higher DVTs compared with the ones with lower injury severity score levels (P < or = 0.05). Pulmonary embolism was silent in 63 per cent and DVTs were asymptomatic in 68 per cent.

Early Placement of Optional Vena Cava Filter in High-Risk Patients with Traumatic Brain Injury

OBJECTIVES

Patients sustaining severe trauma are at high risk for the development of venous thromboembolic events (VTE). Pharmacologic VTE prophylaxis may be contraindicated early after trauma due to potential bleeding complications. The purpose of this study was to evaluate safety and feasibility of early prophylactic vena cava filter (VCF) placement and subsequent retrieval in multiple injured patients with traumatic brain injury (TBI).

METHODS

Analysis of single-institution case series of consecutive patients who received a prophylactic VCF after severe TBI (Abbreviated Injury Scale, AiS ≥ 3) between August 2003 and October 2006.

RESULTS

A total of 34 optional VCF were prophylactically placed with a median delay of 1 day after trauma (range, 0-7 days). All patients had sustained multiple injuries (median Injury Severity Score 41, range, 18-59) with severe TBI (median AiS 4, range 3-5). Median age was 41 years (range, 17-67 years). Two patients had succumbed before potential filter retrieval. Of the remaining patients, 27 (84%) had their filters uneventfully retrieved between 11 and 32 days (median, 18 days) after placement with no retrieval-related morbidity. Five VCF (16%) were left permanently. In one patient (3%) early inferior vena cava occlusion and deep venous thrombosis occurred 14 days after VCF placement. Symptomatic pulmonary embolism was observed in one patient (3%) 5 days after VCF retrieval. Overall trauma-related mortality was 9%.

CONCLUSIONS

Early VCF placement may be of benefit for multiple injured patients with TBI when pharmacologic VTE prophylaxis is contraindicated. VCF retrieval is safe and feasible. Filter placement- and retrieval-related morbidity is low.