Adequacy of brain and spinal blood supply with antegrade cerebral perfusion in a rat model

Objective: The purpose of this study was to examine whether different techniques used for antegrade cerebral perfusion could account for variation in the perfusion adequacy of the brain and spinal cord. Methods: Selected vessels were ligated in 30 rats, recreating a selection of approaches used in aortic arch surgery for patients undergoing circulatory arrest with antegrade cerebral perfusion. Filling of spinal and cerebral vessels was mapped after cannulation and perfusion with E20, gelatin/India ink, or buffered saline/India ink. Three clinical approaches were replicated: unilateral perfusion, bilateral perfusion, and bilateral perfusion with additional left subclavian artery perfusion. Filling of the spinal arteries via the common carotid arteries or the subclavian arteries alone was examined. Penetration of the marker was analyzed histologically. Results: The control experiments achieved maximal arterial filling of both brain and spinal cord at gross and microscopic levels. Unilateral and bilateral antegrade cerebral perfusion provided comprehensive arterial filling of all cerebral vessels with all vascular markers. In contrast, only bilateral antegrade cerebral perfusion provided complete spinal cord perfusion with all markers. Unilateral antegrade cerebral perfusion with a viscous marker resulted in significantly reduced spinal cord arterial filling. Examination of the relative importance of either both common carotid arteries alone or both subclavian arteries alone, in terms of their adequacy of subsequent arterial filling of the spinal cord, showed severe impairment of spinal cord perfusion with either technique. Thus perfusion of both common carotid arteries resulted in only the proximal 30% of the spinal cord arteries being filled, whereas perfusion of both subclavian arteries resulted in only the proximal 40% of the spinal cord arteries being filled. Conclusions: Approaches to antegrade cerebral perfusion using the brachiocephalic and left common carotid arteries together gave good perfusion of both the brain and the spinal cord. Brachiocephalic perfusion alone gave good cerebral perfusion but showed some significant limitation in spinal cord perfusion with one vascular marker. Complete spinal cord perfusion with all markers under conditions of antegrade cerebral perfusion required some contribution from both the carotid system and the subclavian system together. Selected perfusion of either system alone was very inadequate for spinal cord perfusion. (J Thorac Cardiovasc Surg 2011;141:1070-6)