Objective: Sheep are commonly used as large animal pre-clinical models for investigating cardiovascular therapies, interventions, anatomy and physiology. Further, novel small diameter vascular grafts are frequently tested via implantation into sheep carotid arteries (CAs). This is because, unlike humans, acute occlusion of one or both sheep CAs is not associated with morbidity or mortality and thus provides safer experimental testing, with reduced ethical constraints, animal numbers and costs. However, to date there has been no evidence regarding sheep tolerance of femoral artery (FA) occlusion.
Methods: In this study, seven sheep underwent CA graft surgery, with digital subtraction angiography (DSA) of the CAs performed every 2 months via femoral access, for a total of 8 months. Four months into the study, the left FA of two sheep became inaccessible due to a suspected FA occlusion. Thus, femoral angiography was performed, followed by FA dissection, FA histology and retrospective analysis of both veterinarian animal monitoring and pain scores.
Results: FA angiography and histology confirmed complete left FA occlusion in two sheep. Retrospective animal monitoring demonstrated sheep with occluded FAs did not display increased pain scores or deleterious effects on their gait or wellbeing.
Conclusion: Our data shows that sheep tolerate FA occlusion with no symptoms, similar to their cerebral circulation, making them an appropriate model for assessing small diameter femoral graft interposition studies and testing other cardiovascular interventions.
