Agonal Thrombus at Necropsy-A Third Category of Blood Coagulation in Domestic Carnivores

Agonal thrombus is infrequently discussed in veterinary forensic pathology, being misdiagnosed as postmortem coagulation. The main purpose of the present study is to confirm that agonal thrombosis is an important tool in ruling out sudden death and to characterize it by gross, histological, and immunohistochemical approaches. The investigations have been conducted on 56 domestic carnivores. Fibrin was observed as rosette-like arrangements around platelet aggregates, loose network, wave-like pattern or short fibers and the additional tendency of lines of Zahn being noted inconsistently. All agonal thrombi had positive reactions for anti-CD61 for platelets, disposed in variable-sized clumps or in a linear pattern close to endothelial cells of endocardium. The same positive reaction has been noted to anti-fibrinogen and anti-fibrin antibodies. CD45, CD68 and von Willebrand factor had a very low to absent expression. Cardiac lesions were found in 22 cases (39.29%) suggesting predisposition to agonal thrombosis in animals with cardiovascular diseases. The results prove that agonal thrombus is a third category of blood coagulation that forms strictly during agonal death. The microscopical findings describe the agonal thrombus similar to the morphology of recent thrombus vera. Given the results, the agonal thrombus is a useful tool that confirms the agonal suffering prior to death.