Retrograde cerebral perfusion (RCP) in aortic arch surgery: efficacy and possible mechanisms of brain protection.

Retrograde cerebral perfusion (RCP) was first introduced to treat air embolism during cardiopulmonary bypass (CPB). Its use was reintroduced to extend the safety of hypothermic circulatory arrest (HCA) during operations involving an open aortic arch. RCP seems to prevent cerebral rewarming during HCA. Both clinical and animal data suggest that RCP provides between 10% and 30% of baseline cerebral blood flow when administered through the superior vena cava (SVC) at jugular pressures of 20 to 25 mm Hg. RCP flows producing jugular venous pressures higher than 30 mm Hg may cause cerebral edema. Cerebral blood flow generated by RCP is able to sustain some cerebral metabolic activity, yet is not able to fully meet cerebral energy demands even at temperatures of 12 degrees to 18 degrees C. RCP may further prevent embolic events during aortic arch surgery when administered at moderate jugular vein pressures (< 40 mm Hg). Clinical results suggest that RCP, when applied during aortic arch reconstruction, may extend the safe HCA period and improve morbidity and mortality, especially when HCA times are more than 60 minutes. RCP applied in patients and severe carotid and brachiocephalic occlusive disease may be ineffective, and caution is in order when RCP times are greater than 90 minutes.