Gastroenterology

Tests May Help Identify Clotting Problems in Horses With Gastrointestinal Ailments

By Adam Marcus

A pair of sophisticated tests for clotting can accurately identify clotting problems in horses experiencing gastrointestinal illness, researchers in Denmark found.

In a pilot study, the researchers showed that the calibrated automated thrombogram (CAT) and plasma-thromboelastography (TEG), which assess the coagulability of blood, can differentiate animals with severe versus mild or no GI problems.

The CAT and TEG are considered more accurate ways to measure clotting anomalies than conventional hemostatic markers, such as platelet count, fibrinogen, D-dimer concentration and other commonly used tests. However, CAT in particular had not previously been assessed in horses, according to the researchers.

“Critically ill horses often suffer from hemostatic changes. In equine medicine the conventional static hemostatic markers are still the most commonly used,” said Marie Louise Honoré, a doctoral student at the Department of Veterinary Clinical Sciences at the University of Copenhagen, who led the study. “Global hemostatic tests on the other hand are dynamic and show the entire hemostatic process. There has however only been moderate progression in the use of these more advanced hemostatic tests in equine medicine. Hence, there was a need for further exploring the use of these global hemostatic tests in horses.”

For the study, Ms. Honoré and her colleagues sought to determine if plasma-TEG, which has been investigated in humans, dogs and pigs, was applicable on equine citrated platelet poor plasma (PPP) as an alternative to whole blood-TEG. If so, that would make the assay more widely available, given its reduced time sensitivity, she told Modern Equine Vet.

“In addition, we wanted to demonstrate that the CAT assay, which has been applied in humans, dogs and cats, would be applicable on equine citrated PPP with a high degree of validity and reliability,” she said.

Finally, the researchers hoped to show that both the CAT and plasma-TEG could differentiate clotting anomalies in horses with GI conditions (15 severe, 9 mild) compared with 10 healthy animals. The severely ill horses were suffering from a variety of GI ailments, including peritonitis, acute colitis and ruptured intestines.

Using CAT, the researchers observed statistically significant differences in peak (P=0.04) and time to peak (P=0.01) among the 3 groups of horses. They also found that CAT revealed a significantly higher peak in horses with severe GI disease than those with mild ailments (P=0.04), as well as a significantly lower time to peak for horses with severe GI disease compared with healthy animals (P=0.008). Using plasma-TEG revealed statistically significant differences in angle (P=0.016), maximum amplitude (P=0.023) and shear elastic force (P=0.022) among the 3 groups of horses. The plasma-TEG test showed a significantly higher angle (P=0.032), maximum amplitude (P=0.017) and shear elastic force (P=0.017) in horses with severe GI disease compared with healthy animals, according to the researchers.

“The CAT assay performed well in horses with intra- and inter-assay coefficients of variation below the accepted limits and are thus reliable,” the authors reported. “Additionally, the heparin dilution curve showed that the CAT assay is valid in horses. The CAT assay and plasma-TEG were applicable for use in equine citrated PPP and both assays showed hemostatic aberrations in horses with GI disease. Except for time to peak in the CAT assay, the assays could not distinguish mild from severe GI disease.”

Ms. Honoré added that for the moment, the 2 tests generally are performed in teaching hospitals or larger veterinary clinics rather than in smaller facilities. “They require trained personnel to operate them, and they are fairly expensive. However, our hope with this study was to make both tests more accessible since the use of plasma makes it possible to store the samples for longer and transport them to facilities where the relevant machines and tests are available,” she said.

For more information:

Honoré ML, et al. A pilot study evaluating the calibrated automated thrombogram assay and application of plasma-thromboelastography for detection of hemostatic aberrations in horses with gastrointestinal disease. BMC Vet Res. 2021 Nov 8;17(1):346. doi: 10.1186/s12917-021-03058-7.

https://bmcvetres.biomedcentral.com/articles/10.1186/s12917-021-03058-7#Sec2