“Never use only clinical assessment to estimate the progress of a laminitic horse,” began Ric Redden, DVM, moderator of the laminitis Sunrise Session on Dec. 7 and founder of the International Equine Podiatry Center in Versailles, Ky. “X rays and venograms (images of blood flow in the foot) are essential.” He went on to discuss cases where horses had little to no blood flow in the feet but weren’t very lame, and contrasted this with horses which were still very lame but for which imaging showed that their feet were recovering. The implication was that the horse’s outward presentation can often contradict what’s really going on inside the foot.

Since venograms are relatively new to many veterinarians’ diagnostic arsenals, technique for taking them was discussed. Redden described in detail his procedure for taking venograms and the radiographic views he prefers. He strongly suggested that attendees interesting in learning venogram technique “go buy a $20-100 horse at the stockyard and do about 12 venograms on him. Look at the anatomy. He probably won’t be normal, but he might be more normal than a laminitic horse. If you learn your technique on a laminitic horse, you run the risk of misinterpreting the data you receive, and of not producing the optimum results with your technique. There is a learning curve for this procedure. There are all kinds of problems you can have with the technique as well with a very lame horse that has compromised blood flow, fragile vessels, edema, etc. It’s a tough way to learn the procedure.”

He also encouraged veterinarians to learn the technique first, before worrying about interpreting the films. “Don’t jump to conclusions until you’ve polished your technique,” he advised. “You could have a loose tourniquet and perivascular leak (puncturing the vessel twice, resulting in contrast media concentrating at the injection site instead of perfusing throughout the foot) causing misinterpretation of what’s going on in that foot…Telltale signs of these problems are quite obvious on venograms.”

Describing further polishing of venographic procedure, he advised attendees to rock the horse’s foot to allow perfusion of the anterior laminae (which doesn’t occur during weight bearing). He added that this helps mechanically open the vessels, enhancing perfusion. “It’s important to get total perfusion of the laminae and the front of the foot,” he said. “And if you have therapeutic shoes on the horse, don’t take them off for the venogram,” meaning that if the horse will be wearing these shoes, you need to see what blood flow is with them on