Objective: To compare viscoelastic parameters between healthy control dogs and dogs with primary immune-mediated hemolytic anemia (pIMHA) using a new, point-of-care viscoelastic coagulation monitor (VCM).a DESIGN: Retrospective study from 2017 to 2021.
Setting: Three regional private referral centers.
Animals: Eighteen client-owned dogs with pIMHA and 33 healthy control dogs. pIMHA dogs were defined based on established criteria.
Measurements and main results: Medical records of dogs with pIMHA and VCM performed at diagnosis from 2017 to 2021 and apparently healthy control dogs voluntarily enrolled in the blood donor program from 2017 to 2018 were reviewed. For the healthy control dogs, consent was obtained to perform VCM in addition to traditional screening. Compared to healthy control dogs, dogs with pIMHA had mean VCM parameters consistent with hypercoagulability, demonstrated by lower mean (SD) clot formation time (108 s  vs 233 s ; P < 0.0001), higher mean alpha angle (62 degrees  vs 52 degrees ; P < 0.0001), higher mean maximum clot formation (49 VCM units  vs 32 VCM units ; P < 0.0001), higher mean amplitude at 10 minutes (40 VCM units  vs 19 VCM units ; P < 0.0001), and higher mean amplitude at 20 minutes (47 VCM units  vs 25 VCM units ; P < 0.0001). pIMHA dogs also had significantly higher median (interquartile range) lysis index at 30 minutes (100% [100-100] vs 98% [90-100]; P < 0.0001). When compared to 3 established normal canine reference intervals, dogs with pIMHA had a significantly higher proportion of VCM variables (48%-57%) consistent with hypercoagulability, and a significant percentage of pIMHA dogs (78%-89%) had VCM tracings consistent with hypercoagulability overall, irrespective of the interval utilized for interpretation.
Conclusions: This study demonstrates hypercoagulability in dogs with pIMHA when compared to healthy control dogs using VCM. Prospective evaluation is warranted to further characterize these findings as well as to evaluate their clinical impact.
Keywords: canine; erythrocytes; hypercoagulability; thromboelastography.
© Veterinary Emergency and Critical Care Society 2022.