CAN RETROGRADE PERFUSION MITIGATE CEREBRAL INJURY AFTER PARTICULATE EMBOLIZATION - A STUDY IN A CHRONIC PORCINE MODEL

Objective: We assessed the impact on histologic and behavioral outcome of an interval of retrograde cerebral perfusion after arterial emboli zation, comparing retrograde cerebral perfusion with and without infer ior vena caval occlusion with continued antegrade perfusion. Methods: Sixty Yorkshire pigs (27 to 30 kg) were randomly assigned to the follo wing groups: antegrade cerebral perfusion control; antegrade cerebral perfusion after embolization; retrograde cerebral perfusion control; r etrograde cerebral perfusion after embolization; retrograde cerebral p erfusion with inferior vena cava occlusion, retrograde cerebral perfus ion with inferior vena cava occlusion control, and retrograde cerebral perfusion with inferior vena cava occlusion after embolization, After cooling to 20 degrees C, a bolus of 200 mg of polystyrene microsphere s 250 to 750 (mu m diameter (or saline solution) was injected into the isolated aortic arch. After 5 minutes of antegrade cerebral perfusion , 25 minutes of antegrade cerebral perfusion, retrograde cerebral perf usion, or retrograde cerebral perfusion with inferior vena cava occlus ion was instituted. After the operation, all animals underwent daily a ssessment of neurologic status until the time of death on day 7. Resul ts: Aortic arch return, cerebral vascular resistance, and oxygen extra ction data during retrograde cerebral perfusion showed differences, su ggesting that more effective flow occurs during retrograde cerebral pe rfusion with inferior vena cava occlusion, which also resulted in more pronounced fluid sequestration. Microsphere recovery from the brain r evealed significantly fewer emboli after retrograde cerebral perfusion with inferior vena cava occlusion, Behavioral scores showed full reco very in all but one control animal (after retrograde cerebral perfusio n with inferior vena cave occlusion) by day 7 but were considerably lo wer after embolization, with no significant differences between groups , The extent of histopathologic injury was not significantly different among embolized groups. Although no histopathologic lesions were pres ent in either the antegrade cerebral perfusion control group or the re trograde cerebral perfusion control group, mild significant ischemic d amage occurred after retrograde cerebral perfusion with inferior vena cava occlusion even in control animals. Conclusions: Although effectiv e washout of particulate emboli from the brain can be achieved with re trograde cerebral perfusion,vith inferior vena cava occlusion, no adva ntage of retrograde cerebral perfusion with inferior vena cava occlusi on after embolization is seen from behavioral scores, electroencephalo graphic recovery, or histopathologic examination; retrograde cerebral perfusion with inferior vena cava occlusion results in greater fluid s equestration and mild histopathologic injury even in control animals. Retrograde cerebral perfusion with inferior vena cava occlusion shows clear promise in the management of embolization, but further refinemen ts must be sought to address its still worrisome potential for harm.