Optimal Dosing of Prophylactic Enoxaparin after Surgical Procedures: Results of the Double-Blind, Randomized, Controlled FIxed or Variable Enoxaparin (FIVE) Trial.

Background: The accepted "one-size-fits-all" dose strategy for prophylactic enoxaparin may not optimize the medication's risks and benefits after surgical procedures. The authors hypothesized that weight-based administration might improve the pharmacokinetics of prophylactic enoxaparin when compared to fixed-dose administration.

Methods: The FIxed or Variable Enoxaparin (FIVE) trial was a randomized, double-blind trial that compared the pharmacokinetic and clinical outcomes of patients assigned randomly to postoperative venous thromboembolism prophylaxis using enoxaparin 40 mg twice daily or enoxaparin 0.

Low Anti-Factor Xa Level Predicts 90-Day Symptomatic Venous Thromboembolism in Surgical Patients Receiving Enoxaparin Prophylaxis: A Pooled Analysis of Eight Clinical Trials.

Objective: To examine the relationship between enoxaparin dose adequacy, quantified with anti-Factor Xa (aFXa) levels, and 90-day symptomatic venous thromboembolism (VTE) and postoperative bleeding.

Summary Background Data: Surgical patients often develop "breakthrough" VTE events-those which occur despite receiving chemical anticoagulation. We hypothesize that surgical patients with low aFXa levels will be more likely to develop 90-day VTE, and those with high aFXa will be more likely to bleed.

Fixed or Weight-Tiered Enoxaparin After Thoracic Surgery for Venous Thromboembolism Prevention.

Background: Venous thromboembolism is an important patient safety issue in thoracic surgery patients. The optimal enoxaparin dose remains unclear. This multicenter pre/post clinical trial compared the pharmacokinetics of fixed versus weight-tiered enoxaparin, and their impact on 90-day venous thromboembolism and bleeding.

Underdosing of Prophylactic Enoxaparin Is Common in Orthopaedic Trauma and Predicts 90-Day Venous Thromboembolism.

Objectives: To determine the feasibility and impact of real-time anti-factor Xa (aFXa) level monitoring and enoxaparin dose adjustment in orthopaedic trauma. To examine the adequacy of standard fixed-dose enoxaparin chemoprophylaxis and to examine whether patient-specific factors influence enoxaparin metabolism.

Design: Prospective cohort.

Double-Blind Randomized Clinical Trial to Examine the Pharmacokinetic and Clinical Impacts of Fixed Dose versus Weight-based Enoxaparin Prophylaxis: A Methodologic Description of the FIxed or Variable Enoxaparin (FIVE) Trial.

Venous thromboembolism is an important patient safety in plastic surgery, and multiple clinical trials in the past 10 years have provided increased understanding of the risks and benefits of venous thromboembolism prevention strategies. This paper provides an exhaustive discussion of the rationale behind and methodology for an in progress randomized double-blind clinical trial in plastic surgery inpatients, in which the 2 study arms are enoxaparin 40 mg twice daily and enoxaparin 0.5 mg/kg twice daily.

Assessment of Anti-Factor Xa Levels of Patients Undergoing Colorectal Surgery Given Once-Daily Enoxaparin Prophylaxis: A Clinical Study Examining Enoxaparin Pharmacokinetics.

Importance: Between 4% and 12% of patients undergoing colorectal surgery and receiving enoxaparin, 40 mg per day, have a postoperative venous thromboembolism (VTE) event. An improved understanding of why "breakthrough" VTE events occur despite guideline-compliant prophylaxis is an important patient safety question.

Objective: To determine the proportion of patients undergoing colorectal surgery who received adequate anticoagulation based on peak anti-factor Xa (aFXa) levels while receiving enoxaparin at 40 mg per day.

The Impact of Once- versus Twice-Daily Enoxaparin Prophylaxis on Risk for Venous Thromboembolism and Clinically Relevant Bleeding.

Background: Venous thromboembolism is a life- or limb-threatening complication that occurs in plastic surgery patients. At present, the optimal dose of enoxaparin that balances the risk of venous thromboembolism and the risk of medication-related adverse drug events-specifically, bleeding-remains unknown.

Methods: This study compared pharmacodynamic and clinical outcomes, including 90-day venous thromboembolism and 90-day clinically relevant bleeding, between two prospectively performed clinical trials whose sole difference was postoperative anticoagulation strategy.

Enoxaparin 40 mg per Day Is Inadequate for Venous Thromboembolism Prophylaxis After Thoracic Surgical Procedure.

Background: Many patients undergoing thoracic surgical procedures have venous thromboembolism (VTE) events despite the receipt of chemical prophylaxis. Enoxaparin's pharmacologic impact can be quantified by using anti-Factor Xa (aFXa) levels. We hypothesized that enoxaparin 40 mg once daily would be inadequate for most inpatients undergoing thoracic surgical procedures and that a real-time dose adjustment algorithm would be effective.

Twice-Daily Enoxaparin among Plastic Surgery Inpatients: An Examination of Pharmacodynamics, 90-Day Venous Thromboembolism, and 90-Day Bleeding.

Background: Low anti-factor Xa level, indicative of inadequate enoxaparin dosing, has a significant association with 90-day venous thromboembolism events. The authors examined the pharmacodynamics of enoxaparin 40 mg twice daily and its correlation with anti-factor Xa level, postoperative venous thromboembolism, and bleeding.

Methods: Adult patients were admitted after plastic and reconstructive surgery and received enoxaparin 40 mg twice daily.

Comparison of face-to-face interaction and the electronic medical record for venous thromboembolism risk stratification using the 2005 Caprini score.

Objective: Perioperative venous thromboembolism (VTE) risk can be quantified with the 2005 Caprini score. The Caprini score has previously been validated by review of the electronic medical record (EMR) in >3000 plastic surgery patients. However, the accuracy of Caprini-based risk stratification using the EMR, as opposed to face-to-face contact with the patient, remains unknown.

Weight-Based Dosing for Once-Daily Enoxaparin Cannot Provide Adequate Anticoagulation for Venous Thromboembolism Prophylaxis.

Background: Surgeons commonly provide enoxaparin prophylaxis to high-risk patients to decrease venous thromboembolism risk. The authors' prior work demonstrated that most patients receive inadequate venous thromboembolism prophylaxis, based on anti-factor Xa level, when enoxaparin 40 mg/day is provided and that peak anti-factor Xa level correlates with weight. This study models a weight-based strategy for daily enoxaparin prophylaxis and its impact on anti-factor Xa levels.

Anti-Factor Xa measurements in acute care surgery patients to examine enoxaparin dose.

Background: The purpose of this study was to determine if fixed dose enoxaparin prophylaxis provided effective anticoagulation for acute care surgery patients and to examine whether a real-time enoxaparin dose adjustment algorithm optimized anticoagulation.

Methods: Acute care surgical patients placed on enoxaparin prophylaxis 30 mg twice daily were recruited prospectively. Peak steady state aFXa levels were drawn with a goal peak aFXa range of 0.

Inadequate Enoxaparin Dosing Predicts 90-Day Venous Thromboembolism Risk among Plastic Surgery Inpatients: An Examination of Enoxaparin Pharmacodynamics.

Background: Evidence-based plastic surgery guidelines support the effectiveness of once-daily enoxaparin prophylaxis. Despite prophylaxis, one in 25 highest risk patients has a venous thromboembolism event. The authors examined the pharmacodynamics of standard enoxaparin doses in plastic surgery patients to examine whether patient-level factors predict enoxaparin metabolism, whether inadequate enoxaparin dose predicts downstream venous thromboembolism events, and whether a pharmacist-driven dose-adjustment protocol was effective.