Evaluation of the use of a heparin dose-response test in dogs to determine the optimal heparin dose during intravascular procedures and assessment of the in vitro heparin response in healthy dogs.

The HDR test poorly estimated the required heparin dose in dogs. This is most likely attributed to a nonlinear heparin - ACT relationship, as observed in vitro. Anti-Xa is a promising alternative for ACT; however, unavailability as a point-of-care test and lack of in vivo target values restrict its current use.