The presence of a hypercoagulable state in cats with cardiomyopathies with or without thromboembolic disease: A scoping review.

Despite many decades of research into the underlying pathophysiology of thromboembolic disease in cats with cardiomyopathy, findings across the literature are still limited with inconsistencies across study findings. The aim of this scoping review is to describe the literature evaluating thromboembolic disease in cats with cardiomyopathy, to identify coagulation pathways that are involved, and their respective findings and limitations. All studies except two had a healthy control cat group for comparison, and intervention groups varied with regards to severity of cardiomyopathy, and/or the presence of thromboembolic disease. Included studies were observational and randomised controlled trials investigating the difference in coagulation abnormalities between cats with cardiomyopathy and healthy cats. Studies were identified using Pubmed and Scopus, from the first paper available until December 2024. The search resulted in 244 studies. Duplicate, title and abstract screening resulted in 29 studies assessed for eligibility; 17 of which were included; of which 15 were observational and 2 were randomised controlled trials. Groups of interest included were cats with cardiomyopathy (hypertrophic, dilated and restrictive cardiomyopathies) that fulfilled the inclusion criteria and explored coagulation activity. The most consistent findings from this scoping review was the presence of increased von Willebrand Factor and platelet activation across the studies. The remaining results across studies were mixed, potentially due to small study populations, uneven spread of cardiomyopathy severity amongst cats with cardiomyopathy, varying subgroupings, and other possible confounding factors. This study has shown that our knowledge of the underlying pathophysiology of thromboembolic disease in cats with cardiomyopathy still has large knowledge gaps with great potential for further discoveries and findings.