Weight-Based Enoxaparin Dosing and Real-Time Dose Adjustment in Orthopaedic Trauma

Utah System of Higher Education (USHE)

Status and phase: Completed; Phase 2

Conditions: Venous Thromboembolism; Pulmonary Embolus; Deep Vein Thrombosis

Treatments: Drug: Enoxaparin

Study type: Interventional

Funder types: Other

Identifiers

NCT03339349

102526

Details and patient eligibility

About

The rates of Venous thromboembolism (VTE) after orthopedic surgery are as high as 40-60% without prophylactic measures. Enoxaparin, a low-molecular-weight heparin, produces an anticoagulant effect by binding antithrombin, thereby accelerating antithrombin's inactivation of coagulation factor Xa (FXa), thus decreasing the likelihood of clot formation. Despite standard dosing enoxaparin prophylaxis, VTE rates in post-operative orthopedic trauma patients remain as high as 12.2%.The investigators will examine enoxaparin pharmacokinetics and test whether a clinical protocol for real-time enoxaparin dose adjustment can favorably alter the proportion of patients with in-range anti-Factor Xa (aFXa) levels. Outcomes will include peak and trough steady-state aFXa levels in response to standard and escalated doses of enoxaparin and the incidence of venous thromboembolism and bleeding events post-surgery. In the trauma and orthopaedic populations, patients with low initial aFXa levels are significantly more likely to develop deep venous thrombosis. Thus, this study has important implications for appropriate enoxaparin dose magnitude and frequency, and may ultimately help to decrease the substantial morbidity and mortality associated with post-operative VTE.

Enrollment: 80 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Receiving orthopedic trauma surgery
• Able to have enoxaparin initiated within 36 hours after procedure

Exclusion criteria

• Intracranial bleeding/stroke
• bleeding disorder
• heparin-induced thrombocytopenia
• creatinine clearance < 30 mL/minute
• epidural catheter
• serum creatinine > 1.6 mg/dL

Trial design

Primary purpose: Other

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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80 participants in 1 patient group

Enoxaparin Metabolism

Experimental group

Description:

Eligible patients will have steady state peak and trough anti-Xa levels drawn after the third enoxaparin dose. For patients in-range (levels 0.2-0.4 IU/mL), no intervention will be undertaken. For patients out of range, enoxaparin dose will be adjusted according to an established dose adjustment algorithm. Repeat levels will be checked after the third administration of the new dose.

Treatment:

Drug: Enoxaparin