Hemostatic response to surgical neutering via ovariectomy and ovariohysterectomy in dogs.

OBJECTIVE: To investigate the hemostatic response to surgery and compare the response for ovariohysterectomy with that for ovariectomy and to evaluate the usefulness of thromboelastography on plasma samples. ANIMALS: 42 female dogs. PROCEDURES: Dogs were assigned to undergo ovariohysterectomy or ovariectomy. Blood samples were collected immediately before and 1, 6, and 24 hours after surgery and stored at -80°C for subsequent analysis. Plasma samples were subjected to thromboelastography after thawing. In addition, coagulation variables were measured, including concentrations of von Willebrand factor antigen, fibrinogen, antithrombin, and protein C; activity of factor VIII; activated partial thromboplastin time; prothrombin time; and thrombin time. The fibrinolytic response was assessed via concentrations of D-dimer, plasminogen, and α-2-antiplasmin (plasmin inhibitor). RESULTS: Substantial hemostatic and fibrinolytic activation was evident after surgery in both groups, as characterized by significantly increased global clot strength and an overall hypercoagulable state at 4 hours after surgery in addition to decreases in von Willebrand factor antigen and factor VIII concentrations and shortened prothrombin and thrombin times. The dogs also typically had activation of the fibrinolytic system, as evidenced by increased postoperative concentrations of D-dimer, plasminogen, and plasmin inhibitor. Differences between the 2 groups could not be detected for any variables. CONCLUSIONS AND CLINICAL RELEVANCE: Elective surgery with limited tissue trauma induced hemostatic activation in dogs, which led to hypercoagulability after surgery. A difference between the ovariohysterectomy and ovariectomy groups was not detected. Thromboelastography can be used on plasma samples and may be useful for evaluating patterns over time.

Comparison of surgical variables and short-term postoperative complications in healthy dogs undergoing ovariohysterectomy or ovariectomy.

OBJECTIVE: To determine whether ovariohysterectomy (OVH) required more time to complete and was associated with more short-term postoperative complications than ovariectomy (OVE) in dogs. DESIGN: Randomized prospective clinical trial. ANIMALS: 40 healthy, sexually intact female dogs. PROCEDURES: OVH (in 20 dogs) or OVE (20 dogs) was performed by use of standardized anesthetic and surgical protocols. Physical characteristics of the dogs, surgical variables, pain scores derived from behavior-based composite pain scales, and surgical wound characteristics were analyzed. RESULTS: Body weight, age, body condition score, and distance between the sternal manubrium and the pubic rim were comparable among dogs that underwent either surgical procedure. Body weight was positively correlated with the total duration of the procedure and with time required for closure of the surgical wound. No effect of body condition score was determined for any variable. Skin and fascia incision lengths relative to the distance from the sternal manubrium to pubic rim were significantly greater in dogs that underwent OVH, compared with those of dogs that underwent OVE, but total surgical time was not different for the 2 procedures. No other significant differences were detected between the 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE: Significant differences in total surgical time, pain scores, and wound scores were not observed between dogs that underwent OVH and dogs that underwent OVE via standardized protocols.

Oncocytoma in the mandibular salivary gland of a cat.

A cat was referred for investigation of a soft tissue mass caudal to the left mandible. Initial investigations suggested a malignant salivary gland tumour, and the mass was removed by extracapsular resection of the mandibular gland. Histopathology showed an oncocytoma within the salivary gland. An oncocytoma is a neoplastic transformation of oncocytes. Oncocytes are cells with a small nucleus and intense eosinophilic granular cytoplasm due to numerous mitochondria, which proliferate during ageing in exocrine and endocrine glandular tissues. Physiological proliferation occurs next to oncocytosis, oncocytoma, and oncocytic carcinoma. This is the first report of an oncocytoma in a feline mandibular salivary gland, and the first report of long-term survival after surgical removal.

Results of thyroidectomy in 101 cats with hyperthyroidism.

OBJECTIVE: To describe outcome after thyroidectomy in hyperthyroid cats, with emphasis on peri- and postsurgical complications and recurrence. STUDY DESIGN: Retrospective study. ANIMALS: One hundred and one hyperthyroid cats. METHODS: Diagnostic work-up included preoperative measurement of plasma calcium, sodium, potassium, urea, and creatinine concentrations, and thyroid scintigraphy. A modified intracapsular dissection technique was performed. Postoperatively, parathyroid gland function was evaluated by measuring plasma calcium concentration several times daily. Outcome was obtained by standard telephone questionnaire. RESULTS: Thyroid scintigraphy revealed ectopic hyperplastic thyroid tissue (EHTT) in 9 cats. Preoperatively, 29 of 91 cats had hypokalemia. Two cats died within 3 days after surgery and 5 of 86 cats developed postoperative transient hypocalcemia. On histologic examination, thyroid carcinoma was identified in 3 of 88 cats. Hyperthyroidism recurred in 5 cats between 3 and 59 months; 4 of these cats had EHTT preoperatively. The difference in recurrence rate between hyperthyroid cats with and without EHTT was significant (P<.001). CONCLUSION: Complications were uncommon after thyroidectomy performed by an experienced surgeon when combined with an anesthetic regimen associated with minimal adverse cardiovascular effects. Hyperthyroid cats with EHTT had a significantly higher chance of recurrence. CLINICAL RELEVANCE: Thyroidectomy is associated with a low incidence of surgical complications and is an effective treatment for hyperthyroid cats when radioactive iodine therapy is not available. Preoperative thyroid scintigraphy is advised. Surgery is not recommended when EHTT is present, because of a higher chance of developing recurrent disease.

Feline thyroid adenomas are in part associated with mutations in the G(s alpha) gene and not with polymorphisms found in the thyrotropin receptor.

The etiopathogenesis of feline thyrotoxicosis is unknown. The transmembrane part (gene codons 480-640) of the thyrotropin receptor (TSHR) gene of hyperthyroid cats has already been investigated for the presence of stimulating mutations. No mutations were found in this part of the TSHR gene. We have investigated the TSHR gene codons 66-530 for gene mutations in 10 hyperthyroid cats and in 1 euthyroid cat. This part of the TSHR gene encodes the transmembrane part as well as most of the extracellular part of the receptor. The G(s alpha) gene of these cats was also sequenced and subjected to mutational analysis. Although our study revealed a polymorphism in the TSHR gene, no association was found with tumor formation. In 4 of 10 cats with hyperthyroidism a G(s alpha) gene mutation was found. This work suggests that mutations in the extracellular or transmembrane part of the TSHR gene are not likely the cause of feline hyperthyroidism. Mutations in the G(s alpha) gene, however, may play a role in the etiopathogenesis of this disease.