Coagulopathies in horses with colic

Disseminated intravascular coagulation (DIC) is a frequent complication in horses with severe gastrointestinal (GI) disorders that has been associated with poor outcome. It results in microvascular fibrin deposition and eventually organ dysfunction.Recent experimental studies have shown that rapid detection and treatment of subclinical coagulopathies reduce morbidity and mortality associated with DIC. Plasma D-dimer concentration is considered the most sensitive test to diagnose thromboembolic disease and DIC in human medicine, and it has been shown to be a good predictor of mortality as well. In horses, D-dimers have been found to be useful to detect hypercoagulation in horses with colic and septic foals and some studies advocate its use as prognostic aid in horses with acute GI problems.

The objectives of this PhD thesis were to go further into the study of coagulopathies in horses with colic to improve early detection and management of DIC as well as to evaluate the potential clinical applications of the measurement of plasma D-dimer concentration in horses with colic.

With that purpose, three studies were conducted in a hospital population of horses with different diagnoses of gastrointestinal disease, evaluating hemostatic profiles (including D-dimer, prothrombin time, activated partial thromboplastin time and antithrombin III) and the presence of laboratorial DIC at three different stages of the disease: on admission, during hospitalization and before dead. Furthermore, in the third study, this clinicopathological data was compared to histopathological data from the same horses evaluating microvascular fibrin deposition to detect any correlation.

Results of the first study suggest that measurement of plasma D-dimer concentration at the time of admission can be used to facilitate diagnosis and outcome prediction in horses with colic. Furthermore, this study brings new clinically useful information, proposing several cut-offs with prognostic and diagnostic utility. During hospitalization (second study), evaluation of plasma D-dimer concentration has shown to be a useful tool to monitor hypercoagulative states in equine colic cases. Important increases in D-dimer concentration were observed postoperatively as well, as mentioned in previous reports. Finally, the third study concluded that antemortem D-dimer concentration was not more useful than the rest of measured hemostatic parameters to predict which patients presented fibrin microthrombi consistent with DIC at necropsy.

Overall, the three studies within this thesis have contributed to a better knowledge of coagulopathies in horses with gastrointestinal disorders and have provided new information about applications of D-dimer determination at different stages of the colic disease.