Differentiation between dogs with thrombosis and normal dogs using the overall hemostasis potential assay.

OBJECTIVE: To determine whether the overall hemostasis potential (OHP) and calibrated automated thrombogram (CAT) were significantly different between dogs with thrombosis and normal dogs. ANIMALS: Ten dogs with clinical evidence of thromboembolic disease had both OHP and CAT performed. Forty healthy control dogs had OHP performed, and 23 of these also had CAT performed. MEASUREMENTS AND MAIN RESULTS: Dogs with thrombosis had significantly higher OHP (P = 0.003), overall coagulation potential (P = 0.0001), and maximum optical density (Max OD, P < 0.0001) than normal dogs, and a significantly longer delay in the start of clot formation (P = 0.01). Max OD was higher than established reference intervals in 80% of the dogs with thrombosis. Using the CAT assay, dogs with thrombosis had a significantly longer lag time than normal dogs (P < 0.001). Plasma fibrinogen concentration correlated positively with overall coagulation potential, OHP, Max OD, and the slope of the OHP curve (P < 0.05), and was increased in 90% of dogs with thrombosis. CONCLUSIONS: The OHP assay findings were significantly different between normal dogs and those with thrombosis. CAT did not detect any significant differences between these populations of dogs, other than the lag time of the assay.

Evaluation and modification of the overall hemostasis potential assay for use with canine plasma.

OBJECTIVE: To optimize the overall hemostasis potential (OHP) assay for use with canine platelet-poor plasma and determine reference intervals in healthy dogs. ANIMALS: 40 healthy dogs. PROCEDURES: Blood was collected from the dogs into citrated tubes, and platlet-poor plasma was obtained. The OHP assay and standard coagulation assays (prothrombin time, activated partial thromboplastin time, and fibrinogen concentration) were performed for each sample. The OHP assay outputs were tested for correlations with results of the standard coagulation assays, age, and sex. RESULTS: Modifications to the published methodology for the OHP assay were required for use with canine plasma, with less coagulation activator (thrombin) and more fibrinolysis activator (tissue plasminogen activator) than used with human plasma. Male dogs had a higher OHP than did females. High fibrinogen concentrations were associated with increases in maximum optical density, OHP, and overall coagulation potential, and reduced prothrombin time was associated with increases in maximum optical density, overall coagulation potential, OHP, and maximum slope. CONCLUSIONS AND CLINICAL RELEVANCE: Results supported the use of the OHP assay as an accessible, cost-effective global coagulation assay. Further research is required to determine its clinical application as an alternative to thromboelastography or thrombin generation assays.

Low-grade alimentary lymphoma: clinicopathological findings and response to treatment in 17 cases.

Low-grade alimentary lymphoma (LGAL) was diagnosed by histological and immunohistochemical evaluation of full-thickness biopsies from multiple regions of the gastrointestinal tract collected during exploratory laparotomy in 17 cats. The most common clinical signs were weight loss (n=17) and vomiting and/or diarrhoea (n=15). Clinical signs were chronic in 11 cases. Abdominal palpation was abnormal in 12 cats, including diffuse intestinal thickening (n=8), an abdominal mass due to mesenteric lymph node enlargement (n=5) and a focal mural intestinal mass (n=1). The most common ultrasonographic finding was normal or increased intestinal wall thickness with preservation of layering. Ultrasound-guided fine-needle aspirates of mesenteric lymph nodes (n=9) were incorrectly identified as benign lymphoid hyperplasia in eight cats, in which the histological diagnosis from biopsies was lymphoma. There was neoplastic infiltration of more than one anatomic region of the gastrointestinal tract in 16/17 cats. The jejunum (15/15 cats) and ileum (13/14 cats), followed by the duodenum (10/12 cats), were the most frequently affected sites. Twelve cats were treated with oral prednisolone and high-dose pulse chlorambucil, two with a modified Madison-Wisconsin multiagent protocol and three with a combination of both protocols. Thirteen of the 17 cats (76%) had complete clinical remission with a median remission time of 18.9 months. Cats that achieved complete remission had significantly longer median survival times (19.3 months) than cats that did not achieve complete remission (n=4) (4.1 months; P=0.019). The prognosis for cats with LGAL treated with oral prednisolone in combination with high-dose pulse chlorambucil is good to excellent.