How to perform a venogram of the equine foot.

Overview

• This research article demonstrates a detailed and reliable technique for performing a venogram of the equine foot, aimed at assessing vascular filling, particularly in laminitis cases.
• The study uses a sedated horse to illustrate the step-by-step procedure of preparing, injecting contrast, and taking diagnostic radiographic images for evaluation.

Purpose and Indications

• The main goal of the venogram is to evaluate blood vessel filling within the horse’s digit, which is critical in diagnosing and managing laminitis.
• Laminitis is a painful and potentially devastating condition that affects blood flow and tissue health in the equine foot.
• The venogram helps visualize abnormal or decreased vascular contrast filling to guide clinical treatment decisions, including therapeutic shoeing.

Preparation of the Horse

• A healthy university-owned horse was used, with all procedures approved under an institutional animal care and use committee (IACUC) protocol—assuring ethical standards.
• The horse is first sedated to minimize movement and stress during the procedure.
• Both medial and lateral abaxial nerve blocks are performed for local anesthesia and pain management around the foot.
• If the pastern area has long hair, it is clipped to facilitate aseptic preparation and catheter placement.
• The foot is carefully cleaned to remove any debris, and the pastern is scrubbed aseptically to reduce infection risks.

Venogram Procedure

• An Esmarch tourniquet is applied at the fetlock to temporarily restrict blood flow and allow better contrast filling of the veins.
• A 21-gauge butterfly catheter is inserted into the palmar digital vein, which drains blood from the digit.
• Iodinated contrast medium is injected through this catheter, enabling visualization of the vascular structures on radiographs.
• Immediately after injecting the contrast, radiographic images are taken in multiple views.
• The standard radiographic views include weight-bearing lateral-medial, weight-bearing dorsal-palmar, upright pedal (dorsoproximal-palmarodistal oblique), unloaded lateral-medial, unloaded dorsopalmar, and late weight-bearing lateral-medial and dorsopalmar views.
• These multiple views ensure comprehensive assessment of the entire vascular network in the digit under different loading conditions.
• Following imaging, the tourniquet is removed to restore normal blood flow, the catheter is withdrawn, and a light bandage is applied to the venipuncture site to prevent bleeding or infection.

Image Analysis and Clinical Use

• The obtained radiographs are reviewed by veterinary clinicians to identify areas with decreased or abnormal contrast filling.
• Abnormal vascular filling patterns can indicate compromised blood supply or vascular damage associated with laminitis or other pathological conditions.
• Clinical interpretations from the venogram support decisions regarding shoeing strategies, medical treatment, or prognostic considerations.
• The ability to visualize vascular status assists in tailoring therapeutic approaches to optimize recovery or manage chronic laminitic damage.

Significance

• This video-based demonstration provides veterinarians with a clear, reproducible technique for performing venography on the equine foot, improving diagnostic accuracy for laminitis.
• By standardizing the steps—from sedation and nerve blocks to image acquisition and interpretation—the technique enhances clinical confidence and patient care.
• The approach integrates modern imaging with practical veterinary procedures to improve outcomes in a common and challenging equine disease.