Postoperative bleeding in retired racing greyhounds

Background: Some retired racing Greyhounds (RRG) that undergo surgery bleed excessively. Hypothesis: Greyhounds that bleed excessively will have one or more preoperative hemostatic abnormalities that can be used to predict the risk and severity of postoperative bleeding. Animals: Eighty-eight RRG undergoing ovariohysterectomy or castration. Methods: All dogs were evaluated preoperatively with a physical exam, CBC, platelet count, OSPT, APTT, platelet function with PFA-100(a); fibrinogen, D-dimer, plasminogen (Plmg), antiplasmin (AP), antithrombin (AT), and vWF concentration (vWF: Ag); vWF collagen binding assay (vWF: CBA), and Factor XIII assay. Assays were repeated in the dogs that bled, and in an age- and sex-matched control group of RRG. Results: Twenty-six percent of the dogs had bleeding 36-48 hours after surgery. AP (P <. 0001) and AT concentration (P = .007) were significantly lower, and vWF: CBA (P = .0284) was higher preoperatively in the dogs with excessive hemorrhage. A lower platelet count (P = .001) and hematocrit (P = .002), shorter OSPT (P = .0002) and higher plasma fibrinogen (P < .0001), and AP (P = .001) concentration were detected at the time of bleeding compared with preoperative values in the dogs that bleed excessively. The same findings were observed postoperatively for the control group, except for the decrease in hematocrit. Conclusions and Clinical Importance: The results indicate that this excessive postoperative bleeding is not attributable to a primary or secondary hemostatic defect, but could result from altered fibrinolysis.