Tierärztliche Hochschule Hannover Vergleichende Studie zur

Publikation 3
embolization has been identified as another major cause of spinal cord ischemia. In
cats and man, the formation of arterial thrombi is strongly associated with underlying
cardiovascular and thromboembolic diseases 8
or abdominal aortic operation 9 . In
calves and horses the origin of occluding thrombi is less clear 10,11 . In the few
described cases, predisposing factors associated with the formation of thrombemboli
were identified to be valvular endocarditis, bacterial endotoxins 12 , immune
complexes 13 , disruption of laminar blood flow 14 , injury to vascular endothelium and
alteration in the coagulability of the blood 15 . However, the clinical and post mortem
examination provided no informative basis for such alterations being the cause for
the ischemic myelopathy and the chronology of events appears highly indicative of a
direct causal relationship to the catheterization process. The application of a recently
published classification system for forensic histological age determination of
thromboses and embolisms in human fatal pulmonary thromboembolism 16 revealed
that both, the aortic arterial thrombus and the spinal cord thrombemboli display
changes characteristic for a 1-7 week-old process, including infiltrating endothelial
sprouts, fibroblasts, and macrophages containing hemosiderin, coalescing ribbons of
fibrin with entrapped necrotic white blood cells, and re-endothelization of the
thrombus surface (phase II; 2 nd to 8 th week) which is in accordance with the one week
period between catheterization and necropsy of the present case.
Trauma to the vascular endothelium at insertion, caused by the needle, the
catheter tip or the guide wire exposes luminal blood to collagen and tissue factors
and may have stimulated thrombus formation through the activation of the platelet
and coagulation cascade. This was further exacerbated by the alterations in normal
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