Venous thromboembolic prophylaxis: current practice of surgeons in Australia and New Zealand for major abdominal surgery

Should intermittent pneumatic compression devices be standard therapy for the prevention of venous thromboembolic events in major surgery? Protocol for a randomised clinical trial (IMPOSTERS)

INTRODUCTION

Venous thromboembolism (VTE) is a recognised postsurgical risk. Current prevention methods involve low molecular weight heparin (LMWH), graduated compression stockings (GCS), and intermittent pneumatic compression devices (IPCDs). Australian guidelines, commonly adopted by surgeons, recommend LMWH with GCS and/or IPCDs. IPCDs pose clinical risks, increase care burden, are poorly tolerated, and are costly single-use plastic items. Utilising only LMWH and GCS, without IPCDs, could be more practical, patient-friendly, and cost-effective, with added environmental benefits.

METHODS

This is a multicentre, prospective, two-arm randomised controlled non-inferiority trial at five New South Wales (NSW) hospitals, in Australia. We propose to randomise 4130 participants in a 1:1 ratio between arm A: LMWH+GCS+IPCDs (n=2065) or arm B: LMWH+GCS (n=2065). The primary outcome of interest is symptomatic VTE (deep vein thrombosis/pulmonary embolism) identified at the day 30 phone follow-up (FU), confirmed by ultrasound or imaging. Radiologists interpreting the lower-extremity ultrasonography will be blinded to intervention allocation. Secondary outcomes are quality of life at baseline, days 30 and 90 FU using the 5-level European Quality of Life Score, compliance and adverse events with IPCDs, GCS, and LMWH, as well as healthcare costs (from the perspective of the patient and the hospital), and all-cause mortality. The trial has 90% power to detect a 2% non-inferiority margin to detect a reduction rate of VTE from 4% to 2%.

ETHICS AND DISSEMINATION

This study has been approved by the Hunter New England Human Research Ethics Committee (2022/ETH02276) protocol V.10, 13 July 2023. Study findings will be presented at local and national conferences and in scientific research journals.

TRIAL REGISTRATION NUMBER

ANZCTR12622001527752.