At the Cummings School of Veterinary Medicine at Tufts, many veterinarians who see patients also engage in research. That is, clinicians routinely double as scientific investigators. Armelle de Laforcade, DVM, is one of those Tuft veterinarians who takes care of sick dogs and animals of other species at the same time that she participates in clinical research.
Her particular interest is the coagulation of blood. That’s why she is pleased that with the help of a significant gift by a donor to the Cummings School, the Clinical Sciences Research Lab (housed in the same building as the Hospital for Small Animals) has within it a Coagulation Lab that allows the veterinarians at Tufts to “run pretty significant tests about coagulation that most clinics have to send blood away for.” This requires a few different kinds of equipment that are hard to come by.
One is a hemostasis analyzer. “It allows us to run tests for both research purposes and to help patients in the hospital,” Dr. de Laforcade says. “For instance, if you have a Doberman that comes in bleeding, you can find out right away whether she has Von Willebrand disease, and if she does, you can initiate treatment that involves a plasma transfusion to prevent bleeding. “Or if the dog needs surgery, we can assess bleeding issues quickly to avoid a bleeding incident while the animal is lying on the table. Having that machine available to us has really allowed us to provide a better service. Otherwise, you’ve got a turn-around time that’s at least 24 hours and sometimes up to three days — you have to make the decision of whether you initiate the costly therapy or not before confirming the diagnosis. This way, the test results come back in about 20 minutes, so you know right away what you’re dealing with.
“We also have two thromboelastographs. They, too, are very useful for helping us identify animals that have a bleeding or clotting tendency. In people, they use these machines in the OR, say, if you’re getting a heart or liver transplant. They will tell you whether the patient needs more blood thinners or not. They have become more widely used in veterinary medicine in the last five years or so.”
One of the things that makes a thromboelastograph so helpful in evaluating the bleeding/clotting tendencies of a dog is that it looks at the blood in its entirety. Conventional clotting tests look only at plasma — the fluid part of blood that doesn’t have cells. But there’s a growing recognition that cells play an important role in how blood clots, and this machine allows a whole blood assay, allowing a clinician or researcher to see the effects of plasma and cells together.
“If you have a dog with low platelets, you worry that she might bleed,” Dr. de Laforcade says. But if she has an infection, that can predispose her to clotting. So you worry — is she going to bleed or clot? A conventional clotting test won’t give the answer, but the thromboelastograph will tell you which direction the tendency is going to go in. It provides information on the overall clotting status of a dog who comes in sick. We’re at the point that our internal medicine specialists and cardiologists use it as well.”
A third piece of equipment in the Tufts Coagulation Lab is just for research at this point. Called a multiplate platelet analyzer, it helps determine if the platelets are functioning as they should.
“Between all these pieces of equipment we can definitely contribute to veterinary coagulation research,” says Dr. de Laforcade. “We’ve been able to publish quite a few articles looking at clotting in various diseases states.”
Indeed, on the research side, the Coagulation Lab at Tufts has helped to resolve a number of issues with serious diseases. One of them is immune-mediated hemolytic anemia. “The dog’s immune system starts attacking its own red blood cells,” explains Dr. de Laforcade. “She’ll come in very weak, and we have to suppress the immune system to prevent further breakdown of red blood cells. These animals are really sick. When I first started as a vet, back in the late 90s, only 40 to 50 percent of them survived. But then, using thromboelastography we discovered that a tendency to form clots was a main reason that these animals did not do well, and we started using blood thinners more aggressively. And today, many more of these dogs survive with therapy.”
More recently, Dr. de Laforcade says, researchers at the Coagulation Lab have been looking into dogs with a condition called glomerulonephritis. A dog with this disease loses protein through her kidney, including proteins related to clotting. Ironically, this make them more, not less, likely to clot. “Our internal medicine group is now measuring clotting routinely in these dogs and treating them with blood thinners, just like the dogs with immune-mediated hemolytic anemia.
“We’ve also collaborated with the veterinary school at Cornell for dogs who experience bleeding from a tumor in the spleen. It has always been thought that these dogs over-bleed because the tumor is vascular in nature. But in collaborating with Cornell, we found that the way clots break down is accelerated in dogs with splenic tumors, which can contribute to bleeding. Using the machines in the Coagulation Lab to understand what we see clinically, we can add therapies to help the patient.”