Evaluation of Anti-Xa Levels in Surgery Patients Receiving Weight-based Heparin

The purpose of this study is to determine if weight-based heparin infusions at a rate of 10 units/kg/hour are sufficient to maintain a target anti-Xa of 0.1-0.35 IU/mL for VTE prophylaxis in patients undergoing microvascular surgery. Additionally, a pilot protocol has been developed to titrate these heparin infusions to ensure patients have sufficient VTE prophylaxis. All patients will be enrolled in the observational arm of the study and receive anti-Xa level monitoring. Patients with out-of-range anti-Xa levels will cross over to the interventional arm of the study and receive real time heparin infusion dose adjustments per the pilot protocol. The primary outcome measured will be the percentage of patients with anti-Xa levels in the target range of 0.1-0.35 IU/mL while on a heparin infusion at 10 units/kg/hour.

Study Overview

• Status: Completed
• Conditions: Deep Vein Thrombosis; Venous Thromboembolism; Pulmonary Embolism
• Intervention / Treatment: Drug: Standard heparin dose; Drug: Real time heparin dose adjustment

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Early Phase 1

Contacts and Locations

Study Locations

• United States
  • Utah
    • Salt Lake City, Utah, United States, 84112
      • University of Utah

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients undergoing surgical procedures
• Initiation of a heparin infusion at a rate of 500 units/hour intraoperatively or postoperatively

Exclusion Criteria:

• Age <18 years old
• Pregnant
• Incarcerated
• Mentally disabled

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Standard heparin dose; The investigators will identify surgical patients placed on fixed dose heparin infusions at their attending surgeon's discretion-the proposed research will not dictate the initiation of the heparin drip intraoperatively. However, the investigators will identify patients already on heparin, evaluate steady state heparin anti-Xa levels and adjust patient's dose if necessary based on steady state anti-Xa levels. Eligible patients will be started on heparin fixed-dose intraoperatively and transitioned to a weight-based dose by their surgeons. Steady state anti-Xa levels will be drawn at least 6 hours after initiation of heparin infusion. Goal anti-Xa levels will be 0.1-0.35 IU/mL.	Drug: Standard heparin dose; Patients will be placed on heparin infusions per their surgeon's discretion.
Active Comparator: Real time heparin dose adjustment; Patients with identified out of range levels will receive pharmacist-driven real time heparin dose adjustment and will receive follow-up steady state anti-Xa levels. Anti-Xa level monitoring will be discontinued when in range peak levels are obtained, when heparin infusions are discontinued at surgeon discretion, or when the patient is discharged	Drug: Real time heparin dose adjustment; Patients will have steady state anti-Xa levels drawn at least 6 hours after initiation of heparin infusion. Patients with out of range anti-Xa levels will receive real time heparin dose adjustment followed by repeat anti-Xa levels.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Percentage of Anti-Xa Levels Within Target Range (0.1-0.35 IU/mL)	Through study completion, an average of 1 year

Secondary Outcome Measures

Outcome Measure	Time Frame
Number of Rate Adjustments	Through study completion, an average of 1 year

Collaborators and Investigators

• Sponsor: University of Utah
• Investigators: Principal Investigator: Anne Prazak, PharmD, University of Utah

Study record dates

Study Major Dates

• Study Start (Actual): March 23, 2018
• Primary Completion (Actual): June 30, 2019
• Study Completion (Actual): August 24, 2021

Study Registration Dates

• First Submitted: April 24, 2018
• First Submitted That Met QC Criteria: April 24, 2018
• First Posted (Actual): May 4, 2018

Study Record Updates

• Last Update Posted (Actual): May 17, 2023
• Last Update Submitted That Met QC Criteria: May 15, 2023
• Last Verified: November 1, 2020

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Respiratory Tract Diseases; Lung Diseases; Embolism and Thrombosis; Embolism; Thrombosis; Venous Thrombosis; Thromboembolism; Venous Thromboembolism; Pulmonary Embolism; Molecular Mechanisms of Pharmacological Action; Fibrinolytic Agents; Fibrin Modulating Agents; Anticoagulants; Heparin; Calcium heparin
• Other Study ID Numbers: IRB_00107294

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No